How to write a camera app on android that can be used by other apps like instagram,snapchat to click pictures

Question

So my stock camera app doesn't work due to some reasons nor does the camera inside apps like instagram and snapchat. So I wrote my own camera app and got that to work.The problem is the my front camera doesn't work and the way these other apps are written is that these apps check the status of the front camera app which makes it to crash. What I want to do is open my camera app whenever Im click on the camera button of an app like instagram for example and make it available as an option in "Complete action using". I added this:

<intent-filter android:label="@string/take_picture">
         <action android:name="android.intent.action.GET_CONTENT" />
         <data android:mimeType="image/*" />
</intent-filter>

But even this is not making my app visible under "complete action using". What could possibly be wrong?

Here is my code: MainActivity.java

public class MainActivity extends Activity{
private Camera mCamera;
private Preview mPreview;
String TAG="Camera";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Create an instance of Camera
    mCamera = getCameraInstance();

    // Create our Preview view and set it as the content of our activity.
    mPreview = new Preview(this, mCamera);
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
    preview.addView(mPreview);


 // Add a listener to the Capture button
    Button captureButton = (Button) findViewById(R.id.button_capture);
    captureButton.setOnClickListener(
        new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // get an image from the camera
                mCamera.takePicture(null, null, mPicture);
            }
        }
    );



}



private PictureCallback mPicture = new PictureCallback() {

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        File pictureFile = getOutputMediaFile();
        if (pictureFile == null){
            Log.d(TAG, "Error creating media file, check storage permissions: " 
               );
            return;
        }

        try {



            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
        } catch (FileNotFoundException e) {
            Log.d(TAG, "File not found: " + e.getMessage());
        } catch (IOException e) {
            Log.d(TAG, "Error accessing file: " + e.getMessage());
        }
    }
};


/** Create a File for saving the image */
private static File getOutputMediaFile(){

    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
              Environment.DIRECTORY_PICTURES), "MyCameraApp");

    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }

    // Create a media file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    File mediaFile;
        mediaFile = new File(mediaStorageDir.getPath() + File.separator +
        "IMG_"+ timeStamp + ".jpg");

    return mediaFile;
}



/** A safe way to get an instance of the Camera object. */
public static Camera getCameraInstance(){
    Camera c = null;
    try {
        c = Camera.open(); // attempt to get a Camera instance
        Camera.Parameters parameters = c.getParameters();

        parameters.setRotation(90); //set rotation to save the picture

        parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);

        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);

        parameters.setJpegQuality(100);

        parameters.setPictureFormat(ImageFormat.JPEG);

        List<Size> sizes = parameters.getSupportedPictureSizes();
        Camera.Size size = sizes.get(0);
        for(int i=0;i<sizes.size();i++)
        {
            if(sizes.get(i).width > size.width)
                size = sizes.get(i);
        }
        parameters.setPictureSize(size.width, size.height);



        c.setDisplayOrientation(90); //set the rotation for preview camera

        c.setParameters(parameters);
    }
    catch (Exception e){
        // Camera is not available (in use or does not exist)
    }
    return c; // returns null if camera is unavailable
}




}

Preview.java

public class Preview extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Camera mCamera;
String TAG="Camera";
List<Size> mSupportedPreviewSizes;
Camera.Size mPreviewSize;

public Preview(Context context, Camera camera) {
    super(context);
    mCamera = camera;

    // Install a SurfaceHolder.Callback so we get notified when the
    // underlying surface is created and destroyed.
    mHolder = getHolder();
    mHolder.addCallback(this);
    // deprecated setting, but required on Android versions prior to 3.0
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    mSupportedPreviewSizes=mCamera.getParameters().getSupportedPreviewSizes();
}

public void surfaceCreated(SurfaceHolder holder) {
    // The Surface has been created, now tell the camera where to draw the preview.
    try {
        mCamera.setPreviewDisplay(holder);

        mCamera.startPreview();
    } catch (IOException e) {
        Log.d(TAG, "Error setting camera preview: " + e.getMessage());
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    // empty. Take care of releasing the Camera preview in your activity.
}

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    // If your preview can change or rotate, take care of those events here.
    // Make sure to stop the preview before resizing or reformatting it.

    if (mHolder.getSurface() == null){
      // preview surface does not exist
      return;
    }

    // stop preview before making changes
    try {
        mCamera.stopPreview();
    } catch (Exception e){
      // ignore: tried to stop a non-existent preview
    }

    // set preview size and make any resize, rotate or
    // reformatting changes here

    // start preview with new settings
    try {
        mCamera.setPreviewDisplay(mHolder);
        Camera.Parameters parameters = mCamera.getParameters();
        parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
        mCamera.setParameters(parameters);
        mCamera.startPreview();


    } catch (Exception e){
        Log.d(TAG, "Error starting camera preview: " + e.getMessage());
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
    final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
    setMeasuredDimension(width, height);

    if (mSupportedPreviewSizes != null) {
       mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
    }
}

private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
    final double ASPECT_TOLERANCE = 0.1;
    double targetRatio=(double)h / w;

    if (sizes == null) return null;

    Camera.Size optimalSize = null;
    double minDiff = Double.MAX_VALUE;

    int targetHeight = h;

    for (Camera.Size size : sizes) {
        double ratio = (double) size.width / size.height;
        if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
        if (Math.abs(size.height - targetHeight) < minDiff) {
            optimalSize = size;
            minDiff = Math.abs(size.height - targetHeight);
        }
    }

    if (optimalSize == null) {
        minDiff = Double.MAX_VALUE;
        for (Camera.Size size : sizes) {
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
    }
    return optimalSize;
}

}

Answer 1

See https://android.googlesource.com/platform/packages/apps/Camera2/+/master/AndroidManifest.xml. For still image capture, the relevant filters are:

<intent-filter>
  <action android:name="android.media.action.IMAGE_CAPTURE" />
  <category android:name="android.intent.category.DEFAULT" />
</intent-filter>
<intent-filter>
  <action android:name="android.media.action.STILL_IMAGE_CAMERA" />
  <category android:name="android.intent.category.DEFAULT" />
</intent-filter>