过去一段时间一直有人和我说下载图片太多有时候会溢出内存 问我有啥办法，我说我也不知道除了把照片像素 参数缩小该一下，今天看源码的时候看见了SoftReference这个东西，我不知道干啥用的搜索了一下就是为了内存问题而应用的，而且好多地方用到了，我把他取出来弄了一下下载照片处理的方法，不过是handler处理的，如果用asn处理会更好一些吧
public DrawableManager() {
drawableMap = new HashMap<String, SoftReference<Drawable>>();
}
public Drawable fetchDrawable(String urlString) {
SoftReference<Drawable> drawableRef = drawableMap.get(urlString);
if (drawableRef != null) {
Drawable drawable = drawableRef.get();
if (drawable != null)
return drawable;
drawableMap.remove(urlString);
}
if (Constants.LOGGING) Log.d(this.getClass().getSimpleName(), "image url:" + urlString);
try {
InputStream is = fetch(urlString);
Drawable drawable = Drawable.createFromStream(is, "src");
drawableRef = new SoftReference<Drawable>(drawable);
drawableMap.put(urlString, drawableRef);
if (Constants.LOGGING) Log.d(this.getClass().getSimpleName(), "got a thumbnail drawable: " + drawable.getBounds() + ", "
+ drawable.getIntrinsicHeight() + "," + drawable.getIntrinsicWidth() + ", "
+ drawable.getMinimumHeight() + "," + drawable.getMinimumWidth());
return drawableRef.get();
} catch (MalformedURLException e) {
if (Constants.LOGGING) Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
return null;
} catch (IOException e) {
if (Constants.LOGGING) Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
return null;
}
}
public void fetchDrawableOnThread(final String urlString, final ImageView imageView) {
SoftReference<Drawable> drawableRef = drawableMap.get(urlString);
if (drawableRef != null) {
Drawable drawable = drawableRef.get();
if (drawable != null) {
imageView.setImageDrawable(drawableRef.get());
return;
}
// Reference has expired so remove the key from drawableMap
drawableMap.remove(urlString);
}
final Handler handler = new Handler() {
@Override
public void handleMessage(Message message) {
imageView.setImageDrawable((Drawable) message.obj);
}
};
Thread thread = new Thread() {
@Override
public void run() {
//TODO : set imageView to a "pending" image
Drawable drawable = fetchDrawable(urlString);
Message message = handler.obtainMessage(1, drawable);
handler.sendMessage(message);
}
};
thread.start();
}
public class CameraPreview extends Activity {
private Preview mPreview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
// Create our Preview view and set it as the content of our activity.
mPreview = new Preview(this,this);
setContentView(mPreview);
mPreview.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(!mPreview.onProgress)
mPreview.onClick();
}
});
}
}
// ----------------------------------
class Preview extends SurfaceView implements SurfaceHolder.Callback {
SurfaceHolder mHolder;
Camera mCamera;
Context CON;
Activity ACT;
public boolean onProgress=false;
Preview(Context context,Activity activity) {
super(context);
CON=context;
ACT=activity;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
mCamera = Camera.open();
try {
mCamera.setPreviewDisplay(holder);
} catch (IOException exception) {
mCamera.release();
mCamera = null;
// TODO: add more exception handling logic here
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
// Because the CameraDevice object is not a shared resource, it's very
// important to release it when the activity is paused.
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.05;
double targetRatio = (double) w / h;
if (sizes == null)
return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
for (Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
public void onPictureTaken(byte[] imageData, Camera c) {
onProgress=true;
if (imageData != null) {
Intent mIntent = new Intent();
try {
FileOutputStream out = new FileOutputStream(
"/sdcard/Deltio1.jpg");
Bitmap e = BitmapFactory.decodeByteArray(imageData, 0,
imageData.length);
e.compress(Bitmap.CompressFormat.JPEG, 65, out);
out.close();
Intent i = new Intent(ACT, MediaSend.class);
ACT.startActivity(i);
} catch (Exception e) {
Toast
.makeText(
CON,
"Πρόβλημα στην αποθήκευση.Βεβαιωθείτε ότι έχετε sdcard εγκατεστημένη",
Toast.LENGTH_LONG).show();
ACT.finish();
}
// FileUtilities.StoreByteImage(mContext, imageData,
// 50, "ImageName");
SystemClock.sleep(2000);
mCamera.startPreview();
onProgress=false;
// setResult(FOTO_MODE,mIntent);
// finish();
}
}
};
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = mCamera.getParameters();
//List<Size> sizes = parameters.getSupportedPreviewSizes();
//Size optimalSize = getOptimalPreviewSize(sizes, w, h);
//parameters.setPreviewSize(optimalSize.width, optimalSize.height);
parameters.setPreviewSize(w, h);
//mCamera.setParameters(parameters);
mCamera.startPreview();
}
public void onClick() {
if(!onProgress)
{onProgress=true;
mCamera.takePicture(null, mPictureCallback, mPictureCallback);
}
}
}
<!-- Page not cached by WP Super Cache. No closing HTML tag. Check your theme. -->
2.
public class CameraPreview extends Activity {
protected static final String TAG = "CameraPreview";
private Preview mPreview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
// Create our Preview view and set it as the content of our activity.
mPreview = new Preview(this);
mPreview.setId(100);
RelativeLayout mainLayout = new RelativeLayout(this);
RelativeLayout.LayoutParams mainLp = new RelativeLayout.LayoutParams(640, 480);
mainLp.leftMargin = 20;
mainLayout.addView(mPreview, mainLp);
Button btn = new Button(this);
btn.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
RelativeLayout.LayoutParams nLp = (LayoutParams) mPreview.getLayoutParams();
nLp.leftMargin += 10;
Log.v(TAG,"nLp.leftMargin: " + nLp.leftMargin);
mPreview.setLayoutParams(nLp);
}
});
btn.setText("Click me!");
RelativeLayout.LayoutParams btnLp = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
btnLp.addRule(RelativeLayout.BELOW, mPreview.getId());
mainLayout.addView(btn ,btnLp);
setContentView(mainLayout);
}
}
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setType("text/plain");
intent.putExtra(Intent.EXTRA_SUBJECT, subject);
intent.putExtra(Intent.EXTRA_TEXT, message);
Intent mailer = Intent.createChooser(intent, null);
startActivity(mailer);
用上面的方法发送邮件可行，但是如果你里面的程序较多 好多程序都可以供你选择
想缩小一下范围可以用
Intent intent = new Intent(Intent.ACTION_VIEW);
Uri data = Uri.parse("mailto:?subject=" + subject + "&body=" + body);
intent.setData(data);
startActivity(intent);
Uri data = Uri.parse("mailto:?subject=" + subject + "&body=" + body);