Android如何实现截屏功能

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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 {        @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);        }    }

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