一些小技巧

对应的IO流都可以用下面代码来close.

public static void closeSilently(Closeable c) {//close all the stream. if (c == null) return; try { c.close(); } catch (Throwable t) { // do nothing } } 

copy新的image时候出现新的name.

// Try file-1.jpg, file-2.jpg, ... until we find a filename which // does not exist yet. while (true) { x += 1; String candidate = directory.toString() + "/" + fileName + "-" + x + ".jpg"; boolean exists = (new File(candidate)).exists(); if (!exists) { break; } }

3.用这种形式可以实现在背后执行线程。然后handler来处理画面。

public static void startBackgroundJob(MonitoredActivity activity, String title, String message, Runnable job, Handler handler) { // Make the progress dialog uncancelable, so that we can gurantee // the thread will be done before the activity getting destroyed. ProgressDialog dialog = ProgressDialog.show( activity, title, message, true, false); new Thread(new BackgroundJob(activity, job, dialog, handler)).start(); }  

根据生命周期的不同可以来处理不同的事情。

private static class BackgroundJob extends MonitoredActivity.LifeCycleAdapter implements Runnable { private final MonitoredActivity mActivity; private final ProgressDialog mDialog; private final Runnable mJob; private final Handler mHandler; private final Runnable mCleanupRunner = new Runnable() { public void run() { mActivity.removeLifeCycleListener(BackgroundJob.this); if (mDialog.getWindow() != null) mDialog.dismiss(); } }; public BackgroundJob(MonitoredActivity activity, Runnable job, ProgressDialog dialog, Handler handler) { mActivity = activity; mDialog = dialog; mJob = job; mActivity.addLifeCycleListener(this); mHandler = handler; } public void run() { try { mJob.run(); } finally { mHandler.post(mCleanupRunner); } } @Override public void onActivityDestroyed(MonitoredActivity activity) { // We get here only when the onDestroyed being called before // the mCleanupRunner. So, run it now and remove it from the queue mCleanupRunner.run(); mHandler.removeCallbacks(mCleanupRunner); } @Override public void onActivityStopped(MonitoredActivity activity) { mDialog.hide(); } @Override public void onActivityStarted(MonitoredActivity activity) { mDialog.show(); } }  public static synchronized BitmapManager instance() { if (sManager == null) { sManager = new BitmapManager(); } return sManager; } 

4.线程的同步问题：

final CountDownLatch latch = new CountDownLatch(1); final Bitmap b = (mImage != null) ? mImage.fullSizeBitmap(IImage.UNCONSTRAINED, 1024 * 1024) : mBitmap; mHandler.post(new Runnable() { public void run() { if (b != mBitmap && b != null) { mImageView.setImageBitmapResetBase(b, true); mBitmap.recycle(); mBitmap = b; } if (mImageView.getScale() == 1F) { mImageView.center(true, true); } latch.countDown(); } }); try { latch.await();//the other thread must wait. until this thread finish. } catch (InterruptedException e) { throw new RuntimeException(e); } mRunFaceDetection.run();//end run this.

latch.await();//等待所以的线程都执行完了之后在执行后面的code.

5。获取实例的code:

弱引用的用法：

private final WeakHashMap<Thread, ThreadStatus> mThreadStatus = new WeakHashMap<Thread, ThreadStatus>(); 

public static synchronized BitmapManager instance() { if (sManager == null) { sManager = new BitmapManager(); } return sManager; }