Android截屏去除黑边

• Google 官方 sample
• 主要是第44行 mActivity.getWindowManager().getDefaultDisplay().getRealMetrics 换成了 getRealMetrics
• 然后利用了 Fragment 来感知 Activity 的 onActivityResult ,不用去每个 Activity 调

直接上代码：

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public class ScreenshotUtil {

    public static final int REQUEST_MEDIA_PROJECTION = 1122 ;
    private FragmentActivity mActivity;
    private ImageReader mImageReader;
    private Intent mResultData = null;
    private MediaProjection mMediaProjection;
    private VirtualDisplay mVirtualDisplay;
    private ShotListener mShotListener;
    private ScreenshotFragment mScreenshotFragment;
    int width;
    int height;
    int dpi;

    public ScreenshotUtil(FragmentActivity activity) {
        this.mActivity = activity;
        getScreenParams();
    }

    public void onActivityResult(int resultCode, Intent mResultData){
        this.mResultData = mResultData;
        mActivity.getSupportFragmentManager().beginTransaction().remove(mScreenshotFragment).commitNowAllowingStateLoss();
        if (resultCode!= Activity.RESULT_OK){
            mShotListener.onFailed("canceled");
            return;
        }
        Handler handler=new Handler();//截屏必须在有looper的线程执行
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                startCapture();
            }
        },200);//延时截屏，避免截屏提示弹框还没消失就开始截屏
    }

    @TargetApi(Build.VERSION_CODES.KITKAT)
    private void createImageReader() {
        mImageReader = ImageReader.newInstance(width, height, PixelFormat.RGBA_8888, 1);
    }

    private void getScreenParams(){
        DisplayMetrics metric = new DisplayMetrics();
        mActivity.getWindowManager().getDefaultDisplay().getRealMetrics(metric);
        width = metric.widthPixels;
        height = metric.heightPixels;
        dpi = metric.densityDpi;
    }

    public void startScreenShot(final ShotListener shotListener) {

        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
            //5.0 之后才允许使用屏幕截图
            shotListener.onFailed("系统版本不支持");
            return;
        }
        if (!(this.mActivity instanceof FragmentActivity)){
            shotListener.onFailed("context error");
            return;
        }
        mShotListener=shotListener;
        createImageReader();
        mScreenshotFragment=new ScreenshotFragment(this);
        ((FragmentActivity) this.mActivity).getSupportFragmentManager().beginTransaction()
                .add(mScreenshotFragment,"screenshot").commitNowAllowingStateLoss();
        MediaProjectionManager mediaProjectionManager = (MediaProjectionManager)
                mActivity.getSystemService(Context.MEDIA_PROJECTION_SERVICE);
        mScreenshotFragment.startActivityForResult(
                mediaProjectionManager.createScreenCaptureIntent(),
                REQUEST_MEDIA_PROJECTION);
    }

    private MediaProjectionManager getMediaProjectionManager() {
        return (MediaProjectionManager) mActivity.getSystemService(Context.MEDIA_PROJECTION_SERVICE);
    }

    private void startCapture() {
        mMediaProjection = getMediaProjectionManager().getMediaProjection(Activity.RESULT_OK, mResultData);
        mVirtualDisplay = mMediaProjection.createVirtualDisplay("screen-mirror", width, height, dpi, DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null, null);

        mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader reader) {
                if (mShotListener==null){
                    return;
                }
                Image image = mImageReader.acquireLatestImage();
                if (image == null) {
                    mShotListener.onFailed("acquire Image is null");
                } else {
                    Bitmap bitmap = covetBitmap(image);
                    if(bitmap != null){
                        mShotListener.onSuccess(bitmap);
                    }
                }
                stopVirtual();
                mShotListener=null;
            }
        },null);
    }

    private Bitmap covetBitmap(Image image){
        int width = image.getWidth();
        int height = image.getHeight();
        final Image.Plane[] planes = image.getPlanes();
        final ByteBuffer buffer = planes[0].getBuffer();
        //每个像素的间距
        int pixelStride = planes[0].getPixelStride();
        //总的间距
        int rowStride = planes[0].getRowStride();
        int rowPadding = rowStride - pixelStride * width;
        Bitmap bitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888);
        bitmap.copyPixelsFromBuffer(buffer);
        Bitmap resultBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height);
        image.close();
        bitmap.recycle();
        bitmap = null;
        return resultBitmap;
    }

    public void stopVirtual() {
        if (mVirtualDisplay == null) {
            return;
        }
        mVirtualDisplay.release();
        mVirtualDisplay = null;

        tearDownMediaProjection();
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private void tearDownMediaProjection() {
        if (mMediaProjection != null) {
            mMediaProjection.stop();
            mMediaProjection = null;
        }
    }

    public interface ShotListener {
        void onFailed(String msg);
        void onSuccess(Bitmap bitmap);
    }

    public class ScreenshotFragment extends Fragment {

        private ScreenshotUtil mScreenshotUtil;

        @SuppressLint("ValidFragment")
        public ScreenshotFragment(ScreenshotUtil screenshotUtil){
            mScreenshotUtil = screenshotUtil;
        }

        @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            if (requestCode == ScreenshotUtil.REQUEST_MEDIA_PROJECTION){
                mScreenshotUtil.onActivityResult(resultCode,data);
            }
            mScreenshotUtil =null;
        }


    }

}