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How to record screen and take screenshots, using Android API?

Background

Android got a new API on Kitkat and Lollipop, to video capture the screen. You can do it either via the ADB tool or via code (starting from Lollipop).

Ever since the new API was out, many apps came to that use this feature, allowing to record the screen, and Microsoft even made its own Google-Now-On-tap competitor app.

Using ADB, you can use:

adb shell screenrecord /sdcard/video.mp4  

You can even do it from within Android Studio itself.

The problem

I can't find any tutorial or explanation about how to do it using the API, meaning in code.

What I've found

The only place I've found is the documentations (here, under "Screen capturing and sharing"), telling me this:

Android 5.0 lets you add screen capturing and screen sharing capabilities to your app with the new android.media.projection APIs. This functionality is useful, for example, if you want to enable screen sharing in a video conferencing app.

The new createVirtualDisplay() method allows your app to capture the contents of the main screen (the default display) into a Surface object, which your app can then send across the network. The API only allows capturing non-secure screen content, and not system audio. To begin screen capturing, your app must first request the user’s permission by launching a screen capture dialog using an Intent obtained through the createScreenCaptureIntent() method.

For an example of how to use the new APIs, see the MediaProjectionDemo class in the sample project.

Thing is, I can't find any "MediaProjectionDemo" sample. Instead, I've found "Screen Capture" sample, but I don't understand how it works, as when I've run it, all I've seen is a blinking screen and I don't think it saves the video to a file. The sample seems very buggy.

The questions

How do I perform those actions using the new API:

  1. start recording, optionally including audio (mic/speaker/both).
  2. stop recording
  3. take a screenshot instead of video.

Also, how do I customize it (resolution, requested fps, colors, time...)?

like image 675
android developer Avatar asked Sep 10 '15 23:09

android developer


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1 Answers

First step and the one which Ken White rightly suggested & which you may have already covered is the Example Code provided officially.

I have used their API earlier. I agree screenshot is pretty straight forward. But, screen recording is also under similar lines.

I will answer your questions in 3 sections and will wrap it up with a link. :)


1. Start Video Recording

private void startScreenRecord(final Intent intent) {  if (DEBUG) Log.v(TAG, "startScreenRecord:sMuxer=" + sMuxer);  synchronized(sSync) {   if (sMuxer == null) {    final int resultCode = intent.getIntExtra(EXTRA_RESULT_CODE, 0);    // get MediaProjection     final MediaProjection projection = mMediaProjectionManager.getMediaProjection(resultCode, intent);    if (projection != null) {     final DisplayMetrics metrics = getResources().getDisplayMetrics();     final int density = metrics.densityDpi;      if (DEBUG) Log.v(TAG, "startRecording:");     try {      sMuxer = new MediaMuxerWrapper(".mp4"); // if you record audio only, ".m4a" is also OK.       if (true) {       // for screen capturing        new MediaScreenEncoder(sMuxer, mMediaEncoderListener,        projection, metrics.widthPixels, metrics.heightPixels, density);      }      if (true) {       // for audio capturing        new MediaAudioEncoder(sMuxer, mMediaEncoderListener);      }      sMuxer.prepare();      sMuxer.startRecording();     } catch (final IOException e) {      Log.e(TAG, "startScreenRecord:", e);     }    }   }  } } 

2. Stop Video Recording

 private void stopScreenRecord() {   if (DEBUG) Log.v(TAG, "stopScreenRecord:sMuxer=" + sMuxer);   synchronized(sSync) {    if (sMuxer != null) {     sMuxer.stopRecording();     sMuxer = null;     // you should not wait here     }   }  } 

2.5. Pause and Resume Video Recording

 private void pauseScreenRecord() {   synchronized(sSync) {    if (sMuxer != null) {     sMuxer.pauseRecording();    }   }  }   private void resumeScreenRecord() {   synchronized(sSync) {    if (sMuxer != null) {     sMuxer.resumeRecording();    }   }  } 

Hope the code helps. Here is the original link to the code that I referred to and from which this implementation(Video recording) is also derived from.


3. Take screenshot Instead of Video

I think by default its easy to capture the image in bitmap format. You can still go ahead with MediaProjectionDemo example to capture screenshot.

[EDIT] : Code encrypt for screenshot

a. To create virtual display depending on device width / height

mImageReader = ImageReader.newInstance(mWidth, mHeight, PixelFormat.RGBA_8888, 2); mVirtualDisplay = sMediaProjection.createVirtualDisplay(SCREENCAP_NAME, mWidth, mHeight, mDensity, VIRTUAL_DISPLAY_FLAGS, mImageReader.getSurface(), null, mHandler); mImageReader.setOnImageAvailableListener(new ImageAvailableListener(), mHandler); 

b. Then start the Screen Capture based on an intent or action-

startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_CODE); 

Stop Media projection-

sMediaProjection.stop(); 

c. Then convert to image-

//Process the media capture image = mImageReader.acquireLatestImage(); Image.Plane[] planes = image.getPlanes(); ByteBuffer buffer = planes[0].getBuffer(); int pixelStride = planes[0].getPixelStride(); int rowStride = planes[0].getRowStride(); int rowPadding = rowStride - pixelStride * mWidth; //Create bitmap bitmap = Bitmap.createBitmap(mWidth + rowPadding / pixelStride, mHeight, Bitmap.Config.ARGB_8888); bitmap.copyPixelsFromBuffer(buffer); //Write Bitmap to file in some path on the phone fos = new FileOutputStream(STORE_DIRECTORY + "/myscreen_" + IMAGES_PRODUCED + ".png"); bitmap.compress(CompressFormat.PNG, 100, fos); fos.close(); 

There are several implementations (full code) of Media Projection API available. Some other links that can help you in your development-

  1. Video Recording with MediaProjectionManager - website

  2. android-ScreenCapture - github as per android developer's observations :)

  3. screenrecorder - github

  4. Capture and Record Android Screen using MediaProjection APIs - website


Hope it helps :) Happy coding and screen recording!

PS: Can you please tell me the Microsoft app you are talking about? I have not used it. Would like to try it :)

like image 158
bozzmob Avatar answered Sep 26 '22 18:09

bozzmob