How to use handler to capture images at regular intervals?

Question

After one click on capture button, I need to take images at regular intervals. I have written the code using Handler. But what happens now is that, I need to click button at each capture of images. What I want is to click on the button only once and then process to be automated. That is to capture images at regular intervals without any further clickings. How can I achieve this. Thank You.

 public class MyCamera extends Activity {
        private Camera mCamera;
        private CameraPreview mCameraPreview;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            setContentView(R.layout.activity_main);
            mCamera = getCameraInstance();
            mCameraPreview = new CameraPreview(this, mCamera);
            FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
            preview.addView(mCameraPreview);



            Button captureButton = (Button) findViewById(R.id.button_capture);
            captureButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mCamera.takePicture(null, null, mPicture);
                }
            });

            final Handler handler = new Handler();
            final Runnable r = new Runnable()
            {
                public void run()
                {
                    mCamera.takePicture(null,null,mPicture);
                }
            };
            handler.postDelayed(r, 15000);

        }


        private Camera getCameraInstance() {
            Camera camera = null;
            try {
                camera = Camera.open();
            } catch (Exception e) {
                // cannot get camera or does not exist
            }
            return camera;
        }



        PictureCallback mPicture = new PictureCallback() {

            @Override
            public void onPictureTaken(byte[] data, Camera camera) {
                File pictureFile = getOutputMediaFile();
                if (pictureFile == null) {
                    return;
                }
                try {
                    FileOutputStream fos = new FileOutputStream(pictureFile);
                    fos.write(data);
                    fos.close();
                } catch (FileNotFoundException e) {
                    Log.d(TAG, e.getMessage());
                } catch (IOException e) {
                    Log.d(TAG, e.getMessage());
                }

            }
        };



    }

https://stackoverflow.com/questions/6242268/repeat-a-task-with-a-time-delay Possible duplicate. — karandeep singh, Feb 16 '18 at 20:48
Do you mean you want to trigger the interval when the button clicked? if so you just need to move the the handler code along with `handler.postDelayed` to be called inside `onClick` — MoGa, Feb 16 '18 at 20:49
@karandeepsingh I checked the link. But the problem is although the task is happening continuously, I need to click the button whenever I want to capture image. .What I want is to capture images at regular intervals after only one click on capture button. I tried this in multiple ways. Still couldn't find an answer. This is what I want. **One click- capturing of images start. Then it happens continuously at regular intervals without any user interaction.** — HMD, Feb 17 '18 at 10:47

score 0 · Answer 1 · answered Feb 16 '18 at 21:04

0

Try to make your handler and runnable global and then inside setOnclickListener() set handler.postDelayed(r, 15000);

answered Feb 16 '18 at 21:04

AIK

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score 0 · Accepted Answer · answered Feb 17 '18 at 11:18

In your onclick listener,

    handler.removeCallbacks(runnable);
    handler.postDelayed(runnable,15000);

And declare your handler and runnable like this, outside the onclick listener,

 Handler handler=new Handler();
 Runnable runnable=new Runnable() {
      @Override
      public void run() {
          mCamera.takePicture(null, null, mPicture);
          handler.postDelayed(this, 15000);
      }
  };

EXPLANATION

When you click on your camera button,a handler will be attached, which will take a picture after 15 minutes and we attach the same runnable to the handler to repeat it task. I have user handler.removeCallbacks(runnable); to avoid multiple handlers if user clicks on the camera button again. Probably you can remove the onCickListener it self. Also, you should call handler.removeCallbacks(runnable); when your activity/camera is not available.

How to use handler to capture images at regular intervals?

2 Answers2