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▪转载 ADROID 2.1 架构解析 十 声音 转载 ADROID 2.1 架构解析 10 声音
10 声音 10.1 音频管理 文件： frameworks/base/media/java/android/media/AudioManager.java 10.1.1 音量控制
/** @hide Default volume index values for audio streams */
public static final in.........
▪ listView中item一部分可用 listView中item部分可用
事实再一次证明有时候 自己还真的好浮躁，以前只是简单的看过这个程序 只是没有细研，今天用到item 部分可用部分不可用 当返回去查阅时 真汗颜 ，好多东西要不归于.........
▪ ADROID 2.1 架构解析 五 电池 ADROID 2.1 架构解析 5 电池
5 电池电池涉及的功能有：BatteryStatus、BatteryHealth、BatteryPresent、BatteryLevel、PlugType、BatteryVoltage、BatteryTemperature、BatteryTechnology等，它是种从下而上的表现方式，即.........
[1]转载 ADROID 2.1 架构解析 十 声音
来源: 互联网 发布时间: 2014-02-18
转载 ADROID 2.1 架构解析 10 声音
10 声音
10.1 音频管理
文件： frameworks/base/media/java/android/media/AudioManager.java
10.1.1 音量控制
以上结构定义了默认音量。
将音量控制参数转给音频服务去处理。
10.1.2 播放控制
cupcake 的播放控制采用的是 setrouting() 方式进行， eclaire 的播放控制改用 setParameter 方式，用参数设置的方式进行。
以上代码的功能是：将参数传给音频系统去进行处理。
10.2 音频服务
文件： frameworks/base/media/java/android/media/AudioService.java
10.2.1 音效
音效文件放在： /system/media/audio/ui/ 目录下。
10.2.2 音量
音量设置通过消息发给消息处理，然后再转向音频系统进行处理：
AudioSystem.setStreamVolumeIndex
10.3 音频系统
文件： frameworks/base/media/java/android/media/AudioSystem.java
10.3.1 音频类型
10.3.2 输入输出设备
10.3.3 转向底层处理
对于参数设置和音量设置都转向 C/C++ 文件进行处理。
10.4 音频系统底层处理
文件： frameworks/base/media/libmedia/AudioSystem.cpp
10.4.1 音量设置
将参数传给音频策略进行处理。
10.4.1 参数设置
将参数传给音频投掷进行处理。
主参数：
10.5 音频策略
文件： frameworks/base/libs/audioflinger/AudioPolicyService.cpp
注册名为 media.audio_policy 的服务。
调用音频策略管理器。
将音量控制参数传给音频策略管理器。
10.6 音频投掷
文件： frameworks/base/libs/audioflinger/AudioFlinger.cpp
注册名为 media.audio_flinger 的服务
将参数转向硬件接口去进行处理。
10.6.1 硬件接口
文件： frameworks/base/libs/audioflinger/AudioHardwareInterface.cpp
调用音频设备。
10.7 音频策略管理器
文件： hardware/msm7k/libaudio/AudioPolicyManager.cpp
设置音量。
10.8 音频设备
文件： hardware/msm7k/libaudio/AudioHardware.cpp
处理 setParameters 参数。
10 声音
10.1 音频管理
文件： frameworks/base/media/java/android/media/AudioManager.java
10.1.1 音量控制
/** @hide Default volume index values for audio streams */
public static final int[] DEFAULT_STREAM_VOLUME = new int[] {
4, // STREAM_VOICE_CALL
7, // STREAM_SYSTEM
5, // STREAM_RING
11, // STREAM_MUSIC
6, // STREAM_ALARM
5, // STREAM_NOTIFICATION
7, // STREAM_BLUETOOTH_SCO
7, // STREAM_SYSTEM_ENFORCED
11, // STREAM_DTMF
11 // STREAM_TTS
};
以上结构定义了默认音量。
public void adjustStreamVolume(int streamType, int direction, int flags) {
IAudioService service = getService();
try {
service.adjustStreamVolume(streamType, direction, flags);
} catch (RemoteException e) {
Log.e(TAG, "Dead object in adjustStreamVolume", e);
}
}
public void setStreamVolume(int streamType, int index, int flags) {
IAudioService service = getService();
try {
service.setStreamVolume(streamType, index, flags);
} catch (RemoteException e) {
Log.e(TAG, "Dead object in setStreamVolume", e);
}
}
将音量控制参数转给音频服务去处理。
10.1.2 播放控制
@Deprecated public void setParameter(String key, String value) {
setParameters(key+"="+value);
}
/**
* Sets a variable number of parameter values to audio hardware.
*
* @param keyValuePairs list of parameters key value pairs in the form:
* key1=value1;key2=value2;...
*
*/
public void setParameters(String keyValuePairs) {
AudioSystem.setParameters(keyValuePairs);
}
cupcake 的播放控制采用的是 setrouting() 方式进行， eclaire 的播放控制改用 setParameter 方式，用参数设置的方式进行。
以上代码的功能是：将参数传给音频系统去进行处理。
10.2 音频服务
文件： frameworks/base/media/java/android/media/AudioService.java
10.2.1 音效
private static final String SOUND_EFFECTS_PATH = "/media/audio/ui/";
private static final String[] SOUND_EFFECT_FILES = new String[] {
"Effect_Tick.ogg",
"KeypressStandard.ogg",
"KeypressSpacebar.ogg",
"KeypressDelete.ogg",
"KeypressReturn.ogg"
};
public boolean loadSoundEffects() {
...
String filePath = Environment.getRootDirectory() + SOUND_EFFECTS_PATH + SOUND_EFFECT_FILES[SOUND_EFFECT_FILES_MAP[effect][0]];
...
return true;
}
音效文件放在： /system/media/audio/ui/ 目录下。
10.2.2 音量
public void setStreamVolume(int streamType, int index, int flags) {
ensureValidStreamType(streamType);
index = rescaleIndex(index * 10, streamType, STREAM_VOLUME_ALIAS[streamType]);
setStreamVolumeInt(STREAM_VOLUME_ALIAS[streamType], index, false, true);
// UI, etc.
mVolumePanel.postVolumeChanged(streamType, flags);
// Broadcast Intent
sendVolumeUpdate(streamType);
}
private void setStreamVolumeInt(int streamType, int index, boolean force, boolean lastAudible) {
VolumeStreamState streamState = mStreamStates[streamType];
if (streamState.setIndex(index, lastAudible) || force) {
// Post message to set system volume (it in turn will post a message
// to persist). Do not change volume if stream is muted.
if (streamState.muteCount() == 0) {
sendMsg(mAudioHandler, MSG_SET_SYSTEM_VOLUME, streamType, SENDMSG_NOOP, 0, 0,
streamState, 0);
}
}
}
private class AudioHandler extends Handler {
private void setStreamVolumeIndex(int stream, int index) {
AudioSystem.setStreamVolumeIndex(s tream, (index + 5)/10);
}
private void setSystemVolume(VolumeStreamState streamState) {
// Adjust volume
setStreamVolumeIndex (streamState.mStreamType, streamState.mIndex);
...
}
public void handleMessage(Message msg) {
int baseMsgWhat = getMsgBase(msg.what);
switch (baseMsgWhat) {
case MSG_SET_SYSTEM_VOLUME:
setSystemVolume((VolumeStreamState) msg.obj);
break;
...
音量设置通过消息发给消息处理，然后再转向音频系统进行处理：
AudioSystem.setStreamVolumeIndex
10.3 音频系统
文件： frameworks/base/media/java/android/media/AudioSystem.java
10.3.1 音频类型
/* The audio stream for phone calls */
public static final int STREAM_VOICE_CALL = 0;
/* The audio stream for system sounds */
public static final int STREAM_SYSTEM = 1;
/* The audio stream for the phone ring and message alerts */
public static final int STREAM_RING = 2;
/* The audio stream for music playback */
public static final int STREAM_MUSIC = 3;
/* The audio stream for alarms */
public static final int STREAM_ALARM = 4;
/* The audio stream for notifications */
public static final int STREAM_NOTIFICATION = 5;
/* @hide The audio stream for phone calls when connected on bluetooth */
public static final int STREAM_BLUETOOTH_SCO = 6;
/* @hide The audio stream for enforced system sounds in certain countries (e.g camera in Japan) */
public static final int STREAM_SYSTEM_ENFORCED = 7;
/* @hide The audio stream for DTMF tones */
public static final int STREAM_DTMF = 8;
/* @hide The audio stream for text to speech (TTS) */
public static final int STREAM_TTS = 9;
10.3.2 输入输出设备
// output devices
public static final int DEVICE_OUT_EARPIECE = 0x1;
public static final int DEVICE_OUT_SPEAKER = 0x2;
public static final int DEVICE_OUT_WIRED_HEADSET = 0x4;
public static final int DEVICE_OUT_WIRED_HEADPHONE = 0x8;
public static final int DEVICE_OUT_BLUETOOTH_SCO = 0x10;
public static final int DEVICE_OUT_BLUETOOTH_SCO_HEADSET = 0x20;
public static final int DEVICE_OUT_BLUETOOTH_SCO_CARKIT = 0x40;
public static final int DEVICE_OUT_BLUETOOTH_A2DP = 0x80;
public static final int DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES = 0x100;
public static final int DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER = 0x200;
public static final int DEVICE_OUT_AUX_DIGITAL = 0x400;
public static final int DEVICE_OUT_DEFAULT = 0x8000;
// input devices
public static final int DEVICE_IN_COMMUNICATION = 0x10000;
public static final int DEVICE_IN_AMBIENT = 0x20000;
public static final int DEVICE_IN_BUILTIN_MIC1 = 0x40000;
public static final int DEVICE_IN_BUILTIN_MIC2 = 0x80000;
public static final int DEVICE_IN_MIC_ARRAY = 0x100000;
public static final int DEVICE_IN_BLUETOOTH_SCO_HEADSET = 0x200000;
public static final int DEVICE_IN_WIRED_HEADSET = 0x400000;
public static final int DEVICE_IN_AUX_DIGITAL = 0x800000;
public static final int DEVICE_IN_DEFAULT = 0x80000000;
10.3.3 转向底层处理
public static native int setParameters(String keyValuePairs); public static native int setStreamVolumeIndex(int stream, int index);
对于参数设置和音量设置都转向 C/C++ 文件进行处理。
10.4 音频系统底层处理
文件： frameworks/base/media/libmedia/AudioSystem.cpp
10.4.1 音量设置
const sp<IAudioPolicyService>& AudioSystem::get_audio_policy_service()
{
...
sp<IServiceManager> sm = defaultServiceManager();
...
binder = sm->getService(String16("media.audio_policy"));
...
}
status_t AudioSystem::setStreamVolumeIndex(stream_type stream, int index)
{
const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
if (aps == 0) return PERMISSION_DENIED;
return aps->setStreamVolumeIndex(stream, index);
}
将参数传给音频策略进行处理。
10.4.1 参数设置
const sp<IAudioFlinger>& AudioSystem::get_audio_flinger()
{
...
sp<IServiceManager> sm = defaultServiceManager();
..
binder = sm->getService(String16("media.audio_flinger"));
...
}
status_t AudioSystem::setParameters(audio_io_handle_t ioHandle, const String8& keyValuePairs) {
const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
if (af == 0) return PERMISSION_DENIED;
return af->setParameters(ioHandle, keyValuePairs);
}
将参数传给音频投掷进行处理。
主参数：
const char *AudioParameter::keyRouting = "routing"; const char *AudioParameter::keySamplingRate = "sampling_rate"; const char *AudioParameter::keyFormat = "format"; const char *AudioParameter::keyChannels = "channels"; const char *AudioParameter::keyFrameCount = "frame_count";
10.5 音频策略
文件： frameworks/base/libs/audioflinger/AudioPolicyService.cpp
void AudioPolicyService::instantiate() {
defaultServiceManager()->addService(
String16("media.audio_policy"), new AudioPolicyService());
}
注册名为 media.audio_policy 的服务。
AudioPolicyService::AudioPolicyService()
: BnAudioPolicyService() , mpPolicyManager(NULL)
{
...
mpPolicyManager = createAudioPolicyManager(this);
...
}
调用音频策略管理器。
status_t AudioPolicyService::setStreamVolumeIndex(AudioSystem::stream_type stream, int index)
{
...
return mpPolicyManager->setStreamVolumeIndex(stream, index);
}
将音量控制参数传给音频策略管理器。
10.6 音频投掷
文件： frameworks/base/libs/audioflinger/AudioFlinger.cpp
void AudioFlinger::instantiate() {
defaultServiceManager()->addService(
String16("media.audio_flinger"), new AudioFlinger());
}
注册名为 media.audio_flinger 的服务
AudioFlinger::AudioFlinger()
: BnAudioFlinger(),
mAudioHardware(0), mMasterVolume(1.0f), mMasterMute(false), mNextThreadId(0)
{
...
mAudioHardware = AudioHardwareInterface::create();
...
}
status_t AudioFlinger::setParameters(int ioHandle, const String8& keyValuePairs)
{
...
result = mAudioHardware->setParameters(keyValuePairs);
...
}
将参数转向硬件接口去进行处理。
10.6.1 硬件接口
文件： frameworks/base/libs/audioflinger/AudioHardwareInterface.cpp
AudioHardwareInterface* AudioHardwareInterface::create()
{
...
hw = createAudioHardware();
...
}
调用音频设备。
10.7 音频策略管理器
文件： hardware/msm7k/libaudio/AudioPolicyManager.cpp
extern "C" AudioPolicyInterface* createAudioPolicyManager(AudioPolicyClientInterface *clientInterface)
{
return new AudioPolicyManager(clientInterface);
}
status_t AudioPolicyManager::setStreamVolumeIndex(AudioSystem::stream_type stream, int index)
{
...
for (size_t i = 0; i < mOutputs.size(); i++) {
status_t volStatus = checkAndSetVolume(stream, index, mOutputs.keyAt(i), mOutputs.valueAt(i)->device());
if (volStatus != NO_ERROR) {
status = volStatus;
}
}
return status;
}
设置音量。
10.8 音频设备
文件： hardware/msm7k/libaudio/AudioHardware.cpp
extern "C" AudioHardwareInterface* createAudioHardware (void) {
return new AudioHardware();
}
status_t AudioHardware::setParameters(const String8& keyValuePairs)
{
AudioParameter param = AudioParameter(keyValuePairs);
String8 value;
String8 key;
...
key = String8(BT_NAME_KEY);
if (param.get(key, value) == NO_ERROR) {
...
}
return NO_ERROR;
}
处理 setParameters 参数。
[2] listView中item一部分可用
来源: 互联网 发布时间: 2014-02-18
listView中item部分可用
事实再一次证明有时候 自己还真的好浮躁，以前只是简单的看过这个程序 只是没有细研，今天用到item 部分可用部分不可用 当返回去查阅时 真汗颜 ，好多东西要不归于遗忘 要不归于不重视 什么时候能看过用过 全部记住就好了 那就不用写这个了
public class List5 extends ListActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setListAdapter(new MyListAdapter(this));
}
private class MyListAdapter extends BaseAdapter {
public MyListAdapter(Context context) {
mContext = context;
}
public int getCount() {
return mStrings.length;
}
@Override
public boolean areAllItemsEnabled() {
return true;
}
@Override
public boolean isEnabled(int position) {
return !mStrings[position].startsWith("-");
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
TextView tv;
if (convertView == null) {
tv = (TextView) LayoutInflater.from(mContext).inflate(
android.R.layout.simple_expandable_list_item_1, parent, false);
} else {
tv = (TextView) convertView;
}
tv.setText(mStrings[position]);
return tv;
}
private Context mContext;
}
private String[] mStrings = {
"----------",
"----------",
"Abbaye de Belloc",
"Abbaye du Mont des Cats",
"Abertam",
"----------",
"Abondance",
"----------",
"Ackawi",
"Acorn",
"Adelost",
"Affidelice au Chablis",
"Afuega'l Pitu",
"Airag",
"----------",
"Airedale",
"Aisy Cendre",
"----------",
"Allgauer Emmentaler",
"Alverca",
"Ambert",
"American Cheese",
"Ami du Chambertin",
"----------",
"----------",
"Anejo Enchilado",
"Anneau du Vic-Bilh",
"Anthoriro",
"----------",
"----------"
};
}
1 楼
zjforandroid
2011-01-13
为了给你留言，做了半天的论坛测试，其实我注册很久了
[3] ADROID 2.1 架构解析 五 电池
来源: 互联网 发布时间: 2014-02-18
ADROID 2.1 架构解析 5 电池
5 电池
电池涉及的功能有：BatteryStatus、BatteryHealth、BatteryPresent、BatteryLevel、PlugType、BatteryVoltage、BatteryTemperature、BatteryTechnology等，它是种从下而上的表现方式，即底层电池变化后通过uevent事件向上传递电池的当前状态。
5.1 硬件调用
文件：frameworks/base/services/jni/com_android_server_BatteryService.cpp
#define POWER_SUPPLY_PATH "/sys/class/power_supply"
int register_android_server_BatteryService(JNIEnv* env)
{
...
DIR* dir = opendir(POWER_SUPPLY_PATH);
if (dir == NULL) {
LOGE("Could not open %s\n", POWER_SUPPLY_PATH);
return -1;
}
while ((entry = readdir(dir))) {
const char* name = entry->d_name;
// ignore "." and ".."
if (name[0] == '.' && (name[1] == 0 || (name[1] == '.' && name[2] == 0))) {
continue;
}
char buf[20];
// Look for "type" file in each subdirectory
snprintf(path, sizeof(path), "%s/%s/type", POWER_SUPPLY_PATH, name);
int length = readFromFile(path, buf, sizeof(buf));
if (length > 0) {
if (buf[length - 1] == '\n')
buf[length - 1] = 0;
if (strcmp(buf, "Mains") == 0) {
snprintf(path, sizeof(path), "%s/%s/online", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.acOnlinePath = strdup(path);
}
else if (strcmp(buf, "USB") == 0) {
snprintf(path, sizeof(path), "%s/%s/online", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.usbOnlinePath = strdup(path);
}
else if (strcmp(buf, "Battery") == 0) {
snprintf(path, sizeof(path), "%s/%s/status", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryStatusPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/health", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryHealthPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/present", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryPresentPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/capacity", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryCapacityPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/voltage_now", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0) {
gPaths.batteryVoltagePath = strdup(path);
// voltage_now is in microvolts, not millivolts
gVoltageDivisor = 1000;
} else {
snprintf(path, sizeof(path), "%s/%s/batt_vol", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryVoltagePath = strdup(path);
}
snprintf(path, sizeof(path), "%s/%s/temp", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0) {
gPaths.batteryTemperaturePath = strdup(path);
} else {
snprintf(path, sizeof(path), "%s/%s/batt_temp", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryTemperaturePath = strdup(path);
}
snprintf(path, sizeof(path), "%s/%s/technology", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryTechnologyPath = strdup(path);
}
}
}
closedir(dir);
扫描/sys/class/power_supply目录下的文件夹，根据其type文件里的字符串来判断是哪一种类型：Mains、USB还是Battery，然后不同的参数对应着不同的文件
jclass clazz = env->FindClass("com/android/server/BatteryService");
if (clazz == NULL) {
LOGE("Can't find com/android/server/BatteryService");
return -1;
}
gFieldIds.mAcOnline = env->GetFieldID(clazz, "mAcOnline", "Z");
gFieldIds.mUsbOnline = env->GetFieldID(clazz, "mUsbOnline", "Z");
gFieldIds.mBatteryStatus = env->GetFieldID(clazz, "mBatteryStatus", "I");
gFieldIds.mBatteryHealth = env->GetFieldID(clazz, "mBatteryHealth", "I");
gFieldIds.mBatteryPresent = env->GetFieldID(clazz, "mBatteryPresent", "Z");
gFieldIds.mBatteryLevel = env->GetFieldID(clazz, "mBatteryLevel", "I");
gFieldIds.mBatteryTechnology = env->GetFieldID(clazz, "mBatteryTechnology", "Ljava/lang/String;");
gFieldIds.mBatteryVoltage = env->GetFieldID(clazz, "mBatteryVoltage", "I");
gFieldIds.mBatteryTemperature = env->GetFieldID(clazz, "mBatteryTemperature", "I");
接口说明：
env->FindClass("com/android/server/BatteryService"); 获取指定文件的类。
env->GetFieldID(clazz, "mAcOnline", "Z"); 获取指定类的mAcOnline变量值。
以上代码的功能是：将frameworks/base/services/java/com/android/server/BatteryService.java里的各变量值存到全局变量里。
clazz = env->FindClass("android/os/BatteryManager");
if (clazz == NULL) {
LOGE("Can't find android/os/BatteryManager");
return -1;
}
gConstants.statusUnknown = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_UNKNOWN", "I"));
gConstants.statusCharging = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_CHARGING", "I"));
gConstants.statusDischarging = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_DISCHARGING", "I"));
gConstants.statusNotCharging = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_NOT_CHARGING", "I"));
gConstants.statusFull = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_FULL", "I"));
gConstants.healthUnknown = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_UNKNOWN", "I"));
gConstants.healthGood = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_GOOD", "I"));
gConstants.healthOverheat = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_OVERHEAT", "I"));
gConstants.healthDead = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_DEAD", "I"));
gConstants.healthOverVoltage = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_OVER_VOLTAGE", "I"));
gConstants.healthUnspecifiedFailure = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_UNSPECIFIED_FAILURE", "I"));
以上代码的功能是：将frameworks/base/core/java/android/os/BatteryManager.java里类的变量值存到全局变量里。
...
}
static void setBooleanField(JNIEnv* env, jobject obj, const char* path, jfieldID fieldID)
{
const int SIZE = 16;
char buf[SIZE];
jboolean value = false;
if (readFromFile(path, buf, SIZE) > 0) {
if (buf[0] == '1') {
value = true;
}
}
env->SetBooleanField(obj, fieldID, value);
}
static void setIntField(JNIEnv* env, jobject obj, const char* path, jfieldID fieldID)
{
const int SIZE = 128;
char buf[SIZE];
jint value = 0;
if (readFromFile(path, buf, SIZE) > 0) {
value = atoi(buf);
}
env->SetIntField(obj, fieldID, value);
}
static void setVoltageField(JNIEnv* env, jobject obj, const char* path, jfieldID fieldID)
{
const int SIZE = 128;
char buf[SIZE];
jint value = 0;
if (readFromFile(path, buf, SIZE) > 0) {
value = atoi(buf);
value /= gVoltageDivisor;
}
env->SetIntField(obj, fieldID, value);
}
static void android_server_BatteryService_update(JNIEnv* env, jobject obj)
{
setBooleanField(env, obj, gPaths.acOnlinePath, gFieldIds.mAcOnline);
setBooleanField(env, obj, gPaths.usbOnlinePath, gFieldIds.mUsbOnline);
setBooleanField(env, obj, gPaths.batteryPresentPath, gFieldIds.mBatteryPresent);
setIntField(env, obj, gPaths.batteryCapacityPath, gFieldIds.mBatteryLevel);
setVoltageField(env, obj, gPaths.batteryVoltagePath, gFieldIds.mBatteryVoltage);
setIntField(env, obj, gPaths.batteryTemperaturePath, gFieldIds.mBatteryTemperature);
const int SIZE = 128;
char buf[SIZE];
if (readFromFile(gPaths.batteryStatusPath, buf, SIZE) > 0)
env->SetIntField(obj, gFieldIds.mBatteryStatus, getBatteryStatus(buf));
else
env->SetIntField(obj, gFieldIds.mBatteryStatus,
gConstants.statusUnknown);
if (readFromFile(gPaths.batteryHealthPath, buf, SIZE) > 0)
env->SetIntField(obj, gFieldIds.mBatteryHealth, getBatteryHealth(buf));
if (readFromFile(gPaths.batteryTechnologyPath, buf, SIZE) > 0)
env->SetObjectField(obj, gFieldIds.mBatteryTechnology, env->NewStringUTF(buf));
}
static JNINativeMethod sMethods[] = {
/* name, signature, funcPtr */
{"native_update", "()V", (void*)android_server_BatteryService_update},
};
接口说明：
env->SetIntField(obj, fieldID, value); 将指定类的变量以整型付值。
env->SetBooleanField(obj, fieldID, value); 将指定类的变量以布尔付值。
以上代码的功能是：
将全局变量的值付给frameworks/base/core/java/android/os/BatteryManager.java里类的变量；并且将ative_update与android_server_BatteryService_update绑定。
5.2 电池服务
文件：frameworks/base/services/java/com/android/server/BatteryService.java
mUEventObserver.startObserving("SUBSYSTEM=power_supply");
private UEventObserver mUEventObserver = new UEventObserver() {
@Override
public void onUEvent(UEventObserver.UEvent event) {
update();
}
};
监控uevent事件，响应SUBSYSTEM=power_supply的事件。
private synchronized final void update() {
native_update();
...
if (mAcOnline) {
mPlugType = BatteryManager.BATTERY_PLUGGED_AC;
} else if (mUsbOnline) {
mPlugType = BatteryManager.BATTERY_PLUGGED_USB;
} else {
mPlugType = BATTERY_PLUGGED_NONE;
}
...
sendIntent();
...
}
private final void sendIntent() {
// Pack up the values and broadcast them to everyone
Intent intent = new Intent(Intent.ACTION_BATTERY_CHANGED);
intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
try {
mBatteryStats.setOnBattery(mPlugType == BATTERY_PLUGGED_NONE, mBatteryLevel);
} catch (RemoteException e) {
// Should never happen.
}
int icon = getIcon(mBatteryLevel);
intent.putExtra(BatteryManager.EXTRA_STATUS, mBatteryStatus);
intent.putExtra(BatteryManager.EXTRA_HEALTH, mBatteryHealth);
intent.putExtra(BatteryManager.EXTRA_PRESENT, mBatteryPresent);
intent.putExtra(BatteryManager.EXTRA_LEVEL, mBatteryLevel);
intent.putExtra(BatteryManager.EXTRA_SCALE, BATTERY_SCALE);
intent.putExtra(BatteryManager.EXTRA_ICON_SMALL, icon);
intent.putExtra(BatteryManager.EXTRA_PLUGGED, mPlugType);
intent.putExtra(BatteryManager.EXTRA_VOLTAGE, mBatteryVoltage);
intent.putExtra(BatteryManager.EXTRA_TEMPERATURE, mBatteryTemperature);
intent.putExtra(BatteryManager.EXTRA_TECHNOLOGY, mBatteryTechnology);
if (false) {
Log.d(TAG, "updateBattery level:" + mBatteryLevel +
" scale:" + BATTERY_SCALE + " status:" + mBatteryStatus +
" health:" + mBatteryHealth + " present:" + mBatteryPresent +
" voltage: " + mBatteryVoltage +
" temperature: " + mBatteryTemperature +
" technology: " + mBatteryTechnology +
" AC powered:" + mAcOnline + " USB powered:" + mUsbOnline +
" icon:" + icon );
}
ActivityManagerNative.broadcastStickyIntent(intent, null);
}
以上代码的功能是：
通过native_update();更新各状态变量的值，如：
private boolean mAcOnline;
private boolean mUsbOnline;
private int mBatteryStatus;
private int mBatteryHealth;
private boolean mBatteryPresent;
private int mBatteryLevel;
private int mBatteryVoltage;
private int mBatteryTemperature;
private String mBatteryTechnology;
private boolean mBatteryLevelCritical;
然后通过：
intent.putExtra(BatteryManager.EXTRA_STATUS, mBatteryStatus);
intent.putExtra(BatteryManager.EXTRA_HEALTH, mBatteryHealth);
intent.putExtra(BatteryManager.EXTRA_PRESENT, mBatteryPresent);
intent.putExtra(BatteryManager.EXTRA_LEVEL, mBatteryLevel);
intent.putExtra(BatteryManager.EXTRA_SCALE, BATTERY_SCALE);
intent.putExtra(BatteryManager.EXTRA_ICON_SMALL, icon);
intent.putExtra(BatteryManager.EXTRA_PLUGGED, mPlugType);
intent.putExtra(BatteryManager.EXTRA_VOLTAGE, mBatteryVoltage);
intent.putExtra(BatteryManager.EXTRA_TEMPERATURE, mBatteryTemperature);
intent.putExtra(BatteryManager.EXTRA_TECHNOLOGY, mBatteryTechnology);
ActivityManagerNative.broadcastStickyIntent(intent, null);
发布给各实体窗口取用，EXTRA_STATUS等对应的字符是：
文件：frameworks/base/core/java/android/os/BatteryManager.java
public static final String EXTRA_STATUS = "status";
public static final String EXTRA_HEALTH = "health";
public static final String EXTRA_PRESENT = "present";
public static final String EXTRA_LEVEL = "level";
public static final String EXTRA_SCALE = "scale";
public static final String EXTRA_ICON_SMALL = "icon-small";
public static final String EXTRA_PLUGGED = "plugged";
public static final String EXTRA_VOLTAGE = "voltage";
public static final String EXTRA_TEMPERATURE = "temperature";
public static final String EXTRA_TECHNOLOGY = "technology";
5.3 显示电池状态
文件：packages/apps/DeskClock/src/com/android/deskclock/DeskClock.java
private final BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (Intent.ACTION_DATE_CHANGED.equals(action)) {
refreshDate();
} else if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {
handleBatteryUpdate(
intent.getIntExtra("status", BATTERY_STATUS_UNKNOWN),
intent.getIntExtra("level", 0));
} else if (Intent.ACTION_DOCK_EVENT.equals(action)) {
int state = intent.getIntExtra(Intent.EXTRA_DOCK_STATE, -1);
if (DEBUG) Log.d(LOG_TAG, "ACTION_DOCK_EVENT, state=" + state);
if (state == Intent.EXTRA_DOCK_STATE_UNDOCKED) {
if (mLaunchedFromDock) {
// moveTaskToBack(false);
finish();
}
mLaunchedFromDock = false;
}
}
}
};
// Adapted from KeyguardUpdateMonitor.java
private void handleBatteryUpdate(int plugStatus, int batteryLevel) {
final boolean pluggedIn = (plugStatus == BATTERY_STATUS_CHARGING || plugStatus == BATTERY_STATUS_FULL);
if (pluggedIn != mPluggedIn) {
setWakeLock(pluggedIn);
if (pluggedIn) {
// policy: update weather info when attaching to power
requestWeatherDataFetch();
}
}
if (pluggedIn != mPluggedIn || batteryLevel != mBatteryLevel) {
mBatteryLevel = batteryLevel;
mPluggedIn = pluggedIn;
refreshBattery();
}
}
private void refreshBattery() {
if (mBatteryDisplay == null) return;
if (mPluggedIn /* || mBatteryLevel < LOW_BATTERY_THRESHOLD */) {
mBatteryDisplay.setCompoundDrawablesWithIntrinsicBounds(
0, 0, android.R.drawable.ic_lock_idle_charging, 0);
mBatteryDisplay.setText(
getString(R.string.battery_charging_level, mBatteryLevel));
mBatteryDisplay.setVisibility(View.VISIBLE);
} else {
mBatteryDisplay.setVisibility(View.INVISIBLE);
}
}
由以上代码可知，程序通过接收广播信息，获取电池的当前节数：intent.getIntExtra("level", 0));，然后再将其显示。
5 电池
电池涉及的功能有：BatteryStatus、BatteryHealth、BatteryPresent、BatteryLevel、PlugType、BatteryVoltage、BatteryTemperature、BatteryTechnology等，它是种从下而上的表现方式，即底层电池变化后通过uevent事件向上传递电池的当前状态。
5.1 硬件调用
文件：frameworks/base/services/jni/com_android_server_BatteryService.cpp
#define POWER_SUPPLY_PATH "/sys/class/power_supply"
int register_android_server_BatteryService(JNIEnv* env)
{
...
DIR* dir = opendir(POWER_SUPPLY_PATH);
if (dir == NULL) {
LOGE("Could not open %s\n", POWER_SUPPLY_PATH);
return -1;
}
while ((entry = readdir(dir))) {
const char* name = entry->d_name;
// ignore "." and ".."
if (name[0] == '.' && (name[1] == 0 || (name[1] == '.' && name[2] == 0))) {
continue;
}
char buf[20];
// Look for "type" file in each subdirectory
snprintf(path, sizeof(path), "%s/%s/type", POWER_SUPPLY_PATH, name);
int length = readFromFile(path, buf, sizeof(buf));
if (length > 0) {
if (buf[length - 1] == '\n')
buf[length - 1] = 0;
if (strcmp(buf, "Mains") == 0) {
snprintf(path, sizeof(path), "%s/%s/online", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.acOnlinePath = strdup(path);
}
else if (strcmp(buf, "USB") == 0) {
snprintf(path, sizeof(path), "%s/%s/online", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.usbOnlinePath = strdup(path);
}
else if (strcmp(buf, "Battery") == 0) {
snprintf(path, sizeof(path), "%s/%s/status", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryStatusPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/health", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryHealthPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/present", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryPresentPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/capacity", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryCapacityPath = strdup(path);
snprintf(path, sizeof(path), "%s/%s/voltage_now", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0) {
gPaths.batteryVoltagePath = strdup(path);
// voltage_now is in microvolts, not millivolts
gVoltageDivisor = 1000;
} else {
snprintf(path, sizeof(path), "%s/%s/batt_vol", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryVoltagePath = strdup(path);
}
snprintf(path, sizeof(path), "%s/%s/temp", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0) {
gPaths.batteryTemperaturePath = strdup(path);
} else {
snprintf(path, sizeof(path), "%s/%s/batt_temp", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryTemperaturePath = strdup(path);
}
snprintf(path, sizeof(path), "%s/%s/technology", POWER_SUPPLY_PATH, name);
if (access(path, R_OK) == 0)
gPaths.batteryTechnologyPath = strdup(path);
}
}
}
closedir(dir);
扫描/sys/class/power_supply目录下的文件夹，根据其type文件里的字符串来判断是哪一种类型：Mains、USB还是Battery，然后不同的参数对应着不同的文件
jclass clazz = env->FindClass("com/android/server/BatteryService");
if (clazz == NULL) {
LOGE("Can't find com/android/server/BatteryService");
return -1;
}
gFieldIds.mAcOnline = env->GetFieldID(clazz, "mAcOnline", "Z");
gFieldIds.mUsbOnline = env->GetFieldID(clazz, "mUsbOnline", "Z");
gFieldIds.mBatteryStatus = env->GetFieldID(clazz, "mBatteryStatus", "I");
gFieldIds.mBatteryHealth = env->GetFieldID(clazz, "mBatteryHealth", "I");
gFieldIds.mBatteryPresent = env->GetFieldID(clazz, "mBatteryPresent", "Z");
gFieldIds.mBatteryLevel = env->GetFieldID(clazz, "mBatteryLevel", "I");
gFieldIds.mBatteryTechnology = env->GetFieldID(clazz, "mBatteryTechnology", "Ljava/lang/String;");
gFieldIds.mBatteryVoltage = env->GetFieldID(clazz, "mBatteryVoltage", "I");
gFieldIds.mBatteryTemperature = env->GetFieldID(clazz, "mBatteryTemperature", "I");
接口说明：
env->FindClass("com/android/server/BatteryService"); 获取指定文件的类。
env->GetFieldID(clazz, "mAcOnline", "Z"); 获取指定类的mAcOnline变量值。
以上代码的功能是：将frameworks/base/services/java/com/android/server/BatteryService.java里的各变量值存到全局变量里。
clazz = env->FindClass("android/os/BatteryManager");
if (clazz == NULL) {
LOGE("Can't find android/os/BatteryManager");
return -1;
}
gConstants.statusUnknown = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_UNKNOWN", "I"));
gConstants.statusCharging = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_CHARGING", "I"));
gConstants.statusDischarging = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_DISCHARGING", "I"));
gConstants.statusNotCharging = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_NOT_CHARGING", "I"));
gConstants.statusFull = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_STATUS_FULL", "I"));
gConstants.healthUnknown = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_UNKNOWN", "I"));
gConstants.healthGood = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_GOOD", "I"));
gConstants.healthOverheat = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_OVERHEAT", "I"));
gConstants.healthDead = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_DEAD", "I"));
gConstants.healthOverVoltage = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_OVER_VOLTAGE", "I"));
gConstants.healthUnspecifiedFailure = env->GetStaticIntField(clazz,
env->GetStaticFieldID(clazz, "BATTERY_HEALTH_UNSPECIFIED_FAILURE", "I"));
以上代码的功能是：将frameworks/base/core/java/android/os/BatteryManager.java里类的变量值存到全局变量里。
...
}
static void setBooleanField(JNIEnv* env, jobject obj, const char* path, jfieldID fieldID)
{
const int SIZE = 16;
char buf[SIZE];
jboolean value = false;
if (readFromFile(path, buf, SIZE) > 0) {
if (buf[0] == '1') {
value = true;
}
}
env->SetBooleanField(obj, fieldID, value);
}
static void setIntField(JNIEnv* env, jobject obj, const char* path, jfieldID fieldID)
{
const int SIZE = 128;
char buf[SIZE];
jint value = 0;
if (readFromFile(path, buf, SIZE) > 0) {
value = atoi(buf);
}
env->SetIntField(obj, fieldID, value);
}
static void setVoltageField(JNIEnv* env, jobject obj, const char* path, jfieldID fieldID)
{
const int SIZE = 128;
char buf[SIZE];
jint value = 0;
if (readFromFile(path, buf, SIZE) > 0) {
value = atoi(buf);
value /= gVoltageDivisor;
}
env->SetIntField(obj, fieldID, value);
}
static void android_server_BatteryService_update(JNIEnv* env, jobject obj)
{
setBooleanField(env, obj, gPaths.acOnlinePath, gFieldIds.mAcOnline);
setBooleanField(env, obj, gPaths.usbOnlinePath, gFieldIds.mUsbOnline);
setBooleanField(env, obj, gPaths.batteryPresentPath, gFieldIds.mBatteryPresent);
setIntField(env, obj, gPaths.batteryCapacityPath, gFieldIds.mBatteryLevel);
setVoltageField(env, obj, gPaths.batteryVoltagePath, gFieldIds.mBatteryVoltage);
setIntField(env, obj, gPaths.batteryTemperaturePath, gFieldIds.mBatteryTemperature);
const int SIZE = 128;
char buf[SIZE];
if (readFromFile(gPaths.batteryStatusPath, buf, SIZE) > 0)
env->SetIntField(obj, gFieldIds.mBatteryStatus, getBatteryStatus(buf));
else
env->SetIntField(obj, gFieldIds.mBatteryStatus,
gConstants.statusUnknown);
if (readFromFile(gPaths.batteryHealthPath, buf, SIZE) > 0)
env->SetIntField(obj, gFieldIds.mBatteryHealth, getBatteryHealth(buf));
if (readFromFile(gPaths.batteryTechnologyPath, buf, SIZE) > 0)
env->SetObjectField(obj, gFieldIds.mBatteryTechnology, env->NewStringUTF(buf));
}
static JNINativeMethod sMethods[] = {
/* name, signature, funcPtr */
{"native_update", "()V", (void*)android_server_BatteryService_update},
};
接口说明：
env->SetIntField(obj, fieldID, value); 将指定类的变量以整型付值。
env->SetBooleanField(obj, fieldID, value); 将指定类的变量以布尔付值。
以上代码的功能是：
将全局变量的值付给frameworks/base/core/java/android/os/BatteryManager.java里类的变量；并且将ative_update与android_server_BatteryService_update绑定。
5.2 电池服务
文件：frameworks/base/services/java/com/android/server/BatteryService.java
mUEventObserver.startObserving("SUBSYSTEM=power_supply");
private UEventObserver mUEventObserver = new UEventObserver() {
@Override
public void onUEvent(UEventObserver.UEvent event) {
update();
}
};
监控uevent事件，响应SUBSYSTEM=power_supply的事件。
private synchronized final void update() {
native_update();
...
if (mAcOnline) {
mPlugType = BatteryManager.BATTERY_PLUGGED_AC;
} else if (mUsbOnline) {
mPlugType = BatteryManager.BATTERY_PLUGGED_USB;
} else {
mPlugType = BATTERY_PLUGGED_NONE;
}
...
sendIntent();
...
}
private final void sendIntent() {
// Pack up the values and broadcast them to everyone
Intent intent = new Intent(Intent.ACTION_BATTERY_CHANGED);
intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
try {
mBatteryStats.setOnBattery(mPlugType == BATTERY_PLUGGED_NONE, mBatteryLevel);
} catch (RemoteException e) {
// Should never happen.
}
int icon = getIcon(mBatteryLevel);
intent.putExtra(BatteryManager.EXTRA_STATUS, mBatteryStatus);
intent.putExtra(BatteryManager.EXTRA_HEALTH, mBatteryHealth);
intent.putExtra(BatteryManager.EXTRA_PRESENT, mBatteryPresent);
intent.putExtra(BatteryManager.EXTRA_LEVEL, mBatteryLevel);
intent.putExtra(BatteryManager.EXTRA_SCALE, BATTERY_SCALE);
intent.putExtra(BatteryManager.EXTRA_ICON_SMALL, icon);
intent.putExtra(BatteryManager.EXTRA_PLUGGED, mPlugType);
intent.putExtra(BatteryManager.EXTRA_VOLTAGE, mBatteryVoltage);
intent.putExtra(BatteryManager.EXTRA_TEMPERATURE, mBatteryTemperature);
intent.putExtra(BatteryManager.EXTRA_TECHNOLOGY, mBatteryTechnology);
if (false) {
Log.d(TAG, "updateBattery level:" + mBatteryLevel +
" scale:" + BATTERY_SCALE + " status:" + mBatteryStatus +
" health:" + mBatteryHealth + " present:" + mBatteryPresent +
" voltage: " + mBatteryVoltage +
" temperature: " + mBatteryTemperature +
" technology: " + mBatteryTechnology +
" AC powered:" + mAcOnline + " USB powered:" + mUsbOnline +
" icon:" + icon );
}
ActivityManagerNative.broadcastStickyIntent(intent, null);
}
以上代码的功能是：
通过native_update();更新各状态变量的值，如：
private boolean mAcOnline;
private boolean mUsbOnline;
private int mBatteryStatus;
private int mBatteryHealth;
private boolean mBatteryPresent;
private int mBatteryLevel;
private int mBatteryVoltage;
private int mBatteryTemperature;
private String mBatteryTechnology;
private boolean mBatteryLevelCritical;
然后通过：
intent.putExtra(BatteryManager.EXTRA_STATUS, mBatteryStatus);
intent.putExtra(BatteryManager.EXTRA_HEALTH, mBatteryHealth);
intent.putExtra(BatteryManager.EXTRA_PRESENT, mBatteryPresent);
intent.putExtra(BatteryManager.EXTRA_LEVEL, mBatteryLevel);
intent.putExtra(BatteryManager.EXTRA_SCALE, BATTERY_SCALE);
intent.putExtra(BatteryManager.EXTRA_ICON_SMALL, icon);
intent.putExtra(BatteryManager.EXTRA_PLUGGED, mPlugType);
intent.putExtra(BatteryManager.EXTRA_VOLTAGE, mBatteryVoltage);
intent.putExtra(BatteryManager.EXTRA_TEMPERATURE, mBatteryTemperature);
intent.putExtra(BatteryManager.EXTRA_TECHNOLOGY, mBatteryTechnology);
ActivityManagerNative.broadcastStickyIntent(intent, null);
发布给各实体窗口取用，EXTRA_STATUS等对应的字符是：
文件：frameworks/base/core/java/android/os/BatteryManager.java
public static final String EXTRA_STATUS = "status";
public static final String EXTRA_HEALTH = "health";
public static final String EXTRA_PRESENT = "present";
public static final String EXTRA_LEVEL = "level";
public static final String EXTRA_SCALE = "scale";
public static final String EXTRA_ICON_SMALL = "icon-small";
public static final String EXTRA_PLUGGED = "plugged";
public static final String EXTRA_VOLTAGE = "voltage";
public static final String EXTRA_TEMPERATURE = "temperature";
public static final String EXTRA_TECHNOLOGY = "technology";
5.3 显示电池状态
文件：packages/apps/DeskClock/src/com/android/deskclock/DeskClock.java
private final BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (Intent.ACTION_DATE_CHANGED.equals(action)) {
refreshDate();
} else if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {
handleBatteryUpdate(
intent.getIntExtra("status", BATTERY_STATUS_UNKNOWN),
intent.getIntExtra("level", 0));
} else if (Intent.ACTION_DOCK_EVENT.equals(action)) {
int state = intent.getIntExtra(Intent.EXTRA_DOCK_STATE, -1);
if (DEBUG) Log.d(LOG_TAG, "ACTION_DOCK_EVENT, state=" + state);
if (state == Intent.EXTRA_DOCK_STATE_UNDOCKED) {
if (mLaunchedFromDock) {
// moveTaskToBack(false);
finish();
}
mLaunchedFromDock = false;
}
}
}
};
// Adapted from KeyguardUpdateMonitor.java
private void handleBatteryUpdate(int plugStatus, int batteryLevel) {
final boolean pluggedIn = (plugStatus == BATTERY_STATUS_CHARGING || plugStatus == BATTERY_STATUS_FULL);
if (pluggedIn != mPluggedIn) {
setWakeLock(pluggedIn);
if (pluggedIn) {
// policy: update weather info when attaching to power
requestWeatherDataFetch();
}
}
if (pluggedIn != mPluggedIn || batteryLevel != mBatteryLevel) {
mBatteryLevel = batteryLevel;
mPluggedIn = pluggedIn;
refreshBattery();
}
}
private void refreshBattery() {
if (mBatteryDisplay == null) return;
if (mPluggedIn /* || mBatteryLevel < LOW_BATTERY_THRESHOLD */) {
mBatteryDisplay.setCompoundDrawablesWithIntrinsicBounds(
0, 0, android.R.drawable.ic_lock_idle_charging, 0);
mBatteryDisplay.setText(
getString(R.string.battery_charging_level, mBatteryLevel));
mBatteryDisplay.setVisibility(View.VISIBLE);
} else {
mBatteryDisplay.setVisibility(View.INVISIBLE);
}
}
由以上代码可知，程序通过接收广播信息，获取电池的当前节数：intent.getIntExtra("level", 0));，然后再将其显示。
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