Floating view on Android screen

Question

I was trying to make a floating view which user can drag around on the screen.

The idea is to launch a service and then inflate a view on the screen.

But t

Answer 1

By default, View will take up the entire available space when laid out with WRAP_CONTENT. You need to either explicitly specify the view size in your WindowManager.LayoutParams, override View.onMeasure, or (ideally) extend ImageView rather than View.

Answer 2

from api 23+,before start service check Settings.ACTION_MANAGE_OVERLAY_PERMISSION permission:

 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (!Settings.canDrawOverlays(ConversationsActivityWithSpam.this)) {
                    Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
                            Uri.parse("package:" + getPackageName()));
                    startActivityForResult(intent, 16);
                    return false;
                }
            }

Answer 3

I tried your way of drawing the image on a canvas, but that didn't go anywhere. An example, EatHeat's github, where I learned from. Maybe this can get you rolling in the right direction, maybe not, but it worked for me.

WalkingIconService.java

package ...
//imports

public class WalkingIconService extends Service {
    private WindowManager mWindowManager;
    private ImageView image;

    public void onCreate() {
        super.onCreate();
        image = new ImageView(this);

        image.setImageResource(R.drawable.ic_launcher);

        mWindowManager = (WindowManager)getSystemService(WINDOW_SERVICE);

        final LayoutParams paramsF = new WindowManager.LayoutParams(
            LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT,
            LayoutParams.TYPE_PHONE,
            LayoutParams.FLAG_NOT_FOCUSABLE,
            PixelFormat.TRANSLUCENT);

        paramsF.gravity = Gravity.TOP | Gravity.LEFT;
        paramsF.x=0;
        paramsF.y=100;
        mWindowManager.addView(image, paramsF);

        try{

            image.setOnTouchListener(new View.OnTouchListener() {
                WindowManager.LayoutParams paramsT = paramsF;
                private int initialX;
                private int initialY;
                private float initialTouchX;
                private float initialTouchY;
                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    switch(event.getAction()){
                    case MotionEvent.ACTION_DOWN:
                        initialX = paramsF.x;
                        initialY = paramsF.y;
                        initialTouchX = event.getRawX();
                        initialTouchY = event.getRawY();
                        break;
                    case MotionEvent.ACTION_UP:
                        break;
                    case MotionEvent.ACTION_MOVE:
                        paramsF.x = initialX + (int) (event.getRawX() - initialTouchX);
                        paramsF.y = initialY + (int) (event.getRawY() - initialTouchY);
                        mWindowManager.updateViewLayout(v, paramsF);
                        break;
                    }
                    return false;
                }
            });
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    @Overrride
    public void onDestroy(){
        super.onDestory();
    }

}

MainActivity.java

package ...
//imports

public class MainActivity extends Activity {

    @Override
    public void onCreate(icicle) {
        super.onCreate(icicle);
        setcontentView(R.layout.activity_main);
        Button b = (Button)findViewById(R.id.tv);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //toast
                startService(new Intent(MainActivity.this, WalkingIconService.class));
            }
        });
        //stopService (from my original code)
        Button stop = (Button)findViewById.(R.id.btnStop);
        stop.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(new Intent(MainActivity.this, WalkingIconService.class));
            }
        });
    }
}