Android实现截屏功能

导言

目前截屏的方法很多,root不适用,要么其他方法就是有局限性,而其中官方给出的方案最好—MediaProjection

介绍

Android 5.0以后开放的录屏API,取视频中的一帧数据，这样就可以实现截屏

步骤

在activity中授权,在service中完成初始化并截图,当然可以后台定时截图,但是6.0系统会有内存溢出的bug

1:build.gradle

compileSdkVersion 21
    buildToolsVersion '27.0.3'

    defaultConfig {
        applicationId "com.aile.screenshot"
        multiDexEnabled true
        minSdkVersion 21
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }

2:在activity中授权

public void requestCapturePermission() {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
            return;
        }
        MediaProjectionManager mediaProjectionManager = (MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE);
        startActivityForResult(mediaProjectionManager.createScreenCaptureIntent(), REQUEST_MEDIA_PROJECTION);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case REQUEST_MEDIA_PROJECTION:
                if (resultCode == RESULT_OK && data != null) {
                    Service.setResultData(data);
                    startService(new Intent(this, Service.class));
                    finish();
                }
                break;
        }
    }

3:在service中初始化ImageReader,MediaProjection

private void createImageReader() {
        mImageReader = ImageReader.newInstance(mScreenWidth, mScreenHeight, PixelFormat.RGBA_8888, 1);
    }
 public void setUpMediaProjection() {
        mMediaProjection = getMediaProjectionManager().getMediaProjection(Activity.RESULT_OK, mResultData);
        }
    }

4:在service中完成截图重要步骤:

private void startScreenShot() {
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                startVirtual();
            }
        }, 0);

        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                startCapture();
            }
        }, 50);
    }
 public void startVirtual() {
        if (mMediaProjection != null) {
            virtualDisplay();
        } else {
            setUpMediaProjection();
            virtualDisplay();
        }
    }
 private void virtualDisplay() {
        mVirtualDisplay = mMediaProjection.createVirtualDisplay("screen-mirror",
                mScreenWidth, mScreenHeight, mScreenDensity, DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null, null);
    }

//异常处理的核心
private void startCapture() {
        Image image = null;
        try {
            image = mImageReader.acquireLatestImage();
        } catch (IllegalStateException e) {
            if (null != image) {
                image.close();
                image = null;
                image = mImageReader.acquireLatestImage();
            }
        }
        if (image == null) {
            startScreenShot();
        } else {
            SaveTask mSaveTask = new SaveTask();
            AsyncTaskCompat.executeParallel(mSaveTask, image);

            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    stopVirtual();
                    tearDownMediaProjection();
                }
            }, 0);
        }
    }
public class SaveTask extends AsyncTask<Image, Void, Bitmap> {
        @Override
        protected Bitmap doInBackground(Image... params) {
            if (params == null || params.length < 1 || params[0] == null) {
                return null;
            }
            Image image = params[0];
            int width = image.getWidth();
            int height = image.getHeight();
            final Image.Plane[] planes = image.getPlanes();
            final ByteBuffer buffer = planes[0].getBuffer();
            int pixelStride = planes[0].getPixelStride();
            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);
            //这就是初始截图
            bitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height);
            image.close();
            return bitmap;
        }

        @Override
        protected void onPostExecute(final Bitmap bitmap) {
            super.onPostExecute(bitmap);
            //处理bitmap的业务代码
    }

5:Bitmap转IS流,指定区域截图

// 将Bitmap转换成InputStream
   ByteArrayOutputStream bos = new ByteArrayOutputStream();
   bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
   InputStream inputStream = new ByteArrayInputStream(bos.toByteArray());
//指定区域截图
   Rect mRect = new Rect(51, 74, 58, 62);
   BitmapRegionDecoder bitmapRegionDecoder = BitmapRegionDecoder.newInstance(inputStream, true);
   Bitmap bm = bitmapRegionDecoder.decodeRegion(mRect, null);

6:定时任务的处理

private Timer timer = new Timer();
 public void shootByTime() {
        final Handler handler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                startScreenShot();
                super.handleMessage(msg);
            }
        };
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                Message message = new Message();
                message.what = 1;
                handler.sendMessage(message);
            }
        }, 0, 100);
    }

7:横竖屏的处理

@Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        if (newConfig.orientation == this.getResources().getConfiguration().ORIENTATION_PORTRAIT) {
            mRect = new Rect(51, 775, 745, 47);
        } else if (newConfig.orientation == this.getResources().getConfiguration().ORIENTATION_LANDSCAPE) {
            mRect = new Rect(54, 24, 545, 45);
        }
    }

8:还有很多，只需按照需求走就OK，没有难的东西，需要不停的学习和积累

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