frameworks/base/packages/SystemUI/src/com/android/systemui/screenshot/TakeScreenshotService.java

 

TakeScreenshotService.java

package com.android.systemui.screenshot;import android.app.Service;import android.content.Intent;import android.os.Handler;import android.os.IBinder;import android.os.Message;import android.os.Messenger;import android.os.RemoteException;import android.os.UserManager;import android.util.Log;import android.view.WindowManager;public class TakeScreenshotService extends Service {    private static final String TAG = "TakeScreenshotService";    private static GlobalScreenshot mScreenshot;    private Handler mHandler = new Handler() {        @Override        public void handleMessage(Message msg) {            final Messenger callback = msg.replyTo;            Runnable finisher = new Runnable() {                @Override                public void run() {                    Message reply = Message.obtain(null, 1);                    try {                        callback.send(reply);                    } catch (RemoteException e) {                    }                }            };            // If the storage for this user is locked, we have no place to store            // the screenshot, so skip taking it instead of showing a misleading            // animation and error notification.            if (!getSystemService(UserManager.class).isUserUnlocked()) {                Log.w(TAG, "Skipping screenshot because storage is locked!");                post(finisher);                return;            }            if (mScreenshot == null) {                mScreenshot = new GlobalScreenshot(TakeScreenshotService.this);            }            switch (msg.what) {                case WindowManager.TAKE_SCREENSHOT_FULLSCREEN:                    mScreenshot.takeScreenshot(finisher, msg.arg1 > 0, msg.arg2 > 0);                    break;                case WindowManager.TAKE_SCREENSHOT_SELECTED_REGION:                    mScreenshot.takeScreenshotPartial(finisher, msg.arg1 > 0, msg.arg2 > 0);                    break;            }        }    };    @Override    public IBinder onBind(Intent intent) {        return new Messenger(mHandler).getBinder();    }    @Override    public boolean onUnbind(Intent intent) {        if (mScreenshot != null) mScreenshot.stopScreenshot();        return true;    }}

 

 主要是创建一个 GlobalScreenshot 对象，通过GlobalScreenshot对象实现截屏，之所以将该类宿主在service里面是因为截屏可能产生耗时，这应该是设计时的理念。

当然完全可以由自己创建GlobalScreenshot对象，在线程里面实现截屏.