private void checkNetworkInfo()
{
ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mobileInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
State mobileState = mobileInfo.getState();
boolean isMobileAvalilable = mobileInfo.isAvailable();
boolean isMobileConn = mobileInfo.isConnected();
boolean isMobile = mobileInfo.isConnectedOrConnecting();
txt3G.setText("3g state is : " + mobileState.toString());
Log.v(TAG, "mobile state is : " + mobileState.toString());
//isWifiAvalilable = true, isWifiConn = true, isWifi = true, when wifi connected but can not go on the web
NetworkInfo wifiInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
State wifiState = wifiInfo.getState();
boolean isWifiAvalilable = wifiInfo.isAvailable();
boolean isWifiConn = wifiInfo.isConnected();
boolean isWifi = wifiInfo.isConnectedOrConnecting();
txtWifi.setText("wifi state is : " + wifiState.toString());
Log.v(TAG, "wifi state is : " + wifiState.toString());
//active network info
NetworkInfo activeInfo = connMgr.getActiveNetworkInfo();
String typeName = activeInfo.getTypeName();
State activeState = activeInfo.getState();
Log.v(TAG, "active network is : " + typeName);
Log.v(TAG, "active state is " + activeState.toString());
if(mobileState==State.CONNECTED||mobileState==State.CONNECTING)
return;
if(wifiState==State.CONNECTED||wifiState==State.CONNECTING)
return;
// startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));
// startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
}
在Android应用开发中，很多时候都会遇到这样的需求，一个listView，含有N项，当点击某项时，该项展开，显示该项中隐藏的某些控件，再点击，该项收回，重新隐藏部分控件，当一项打开状态，点击另一项，另一项展开，该项关闭。（说的有点绕，看下图）
在去年的时候，自己的一篇文章（http://blog.csdn.net/aomandeshangxiao/article/details/6643831），里面有Item的选择问题，用的方法比较笨，要遍历一遍，把所有的item全部都设置一下，应该是很浪费资源的。还有一个问题就是，当listview的item多于一个屏幕的时候，会出现重复选择问题，就是当你选中一项滑动的时候，可能会发现滑动后出现的某项也是在选中状态，这个问题令人十分抓狂。见网上有个方法是：在adapter的getView里面不使用convertview。每一个view都是重新创建一个。能够解决问题，但是还是有点浪费资源。
先看下效果图：第二项被选中
第四项被选中：
这个方法也是在他人的帮助下，努力得来，分享一下!
[java]
public class ListViewTestActivity extends Activity implements OnItemClickListener{
private ListView mListView;
private ListAdapter mAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mListView = (ListView)findViewById(R.id.list);
mAdapter = new ListAdapter(this);
mListView.setAdapter(mAdapter);
mListView.setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
mAdapter.changeImageVisable(view, position);
}
}
这里应该注意到与平常的不同，onItemClick方法里面调用了自定义ListAdapter里面的自定义changeImageViewVisable方法。
看ListAdapter：
[html]
public class ListAdapter extends BaseAdapter {
private Context mContext;
private View mLastView;
private int mLastPosition;
public ListAdapter(Context context) {
this.mContext = context;
}
@Override
public int getCount() {
return 8;
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder;
if(convertView == null ) {
LayoutInflater inflater = LayoutInflater.from(mContext);
convertView = inflater.inflate(R.layout.list_item, null);
holder =new Holder();
holder.textView = (TextView)convertView.findViewById(R.id.textView);
holder.UEFAView = (ImageView)convertView.findViewById(R.id.image_uefa);
holder.mascotView = (ImageView)convertView.findViewById(R.id.image_mascot);
holder.hint = convertView.findViewById(R.id.hint_image);
convertView.setTag(holder);
} else {
holder = (Holder) convertView.getTag();
}
holder.textView.setText("Hello,It is " + position);
return convertView;
}
class Holder {
TextView textView;
ImageView UEFAView;
ImageView mascotView;
View hint;
}
public void changeImageVisable(View view,int position) {
if(mLastView != null && mLastPosition != position ) {
Holder holder = (Holder) mLastView.getTag();
switch(holder.hint.getVisibility()) {
case View.VISIBLE:
holder.hint.setVisibility(View.GONE);
break;
default :
break;
}
}
mLastPosition = position;
mLastView = view;
Holder holder = (Holder) view.getTag();
switch(holder.hint.getVisibility()) {
case View.GONE:
holder.hint.setVisibility(View.VISIBLE);
break;
case View.VISIBLE:
holder.hint.setVisibility(View.GONE);
break;
}
}
}
代码的最下端是changeImageVisable方法。（注意：在这个方法中，博客代码版本和提供下载代码版本中有细微差异，博客代码较下载代码性能更优，这也体现了Holder类的优越性，一定要好好用好Holder，应好好思考下，为什么这样写性能就更好些呢？欢迎留言讨论）。
布局文件：
main.xml：
[html]
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="ListView Test" />
<ListView
android:id="@+id/list"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
></ListView>
</LinearLayout>
list_item.xml：
[html]
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
>
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Test"
android:textSize="20sp"
/>
<LinearLayout
android:id="@+id/hint_image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:visibility="gone">
<ImageView
android:id="@+id/image_uefa"
android:layout_width="0dp"
android:layout_height="60dp"
android:layout_weight="1"
android:src="/blog_article/@drawable/uefa/index.html"
/>
<ImageView
android:id="@+id/image_mascot"
android:layout_width="0dp"
android:layout_height="60dp"
android:layout_weight="1"
android:src="/blog_article/@drawable/mascot/index.html"
/>
</LinearLayout>
</LinearLayout>
作者：aomandeshangxiao