Android Drag and Drop ImageView into another ImageView

Question

I'm stuck on this problem in Android Drag and Drop. I've already read the documentation and more than one question/answer here on stackoverflow .
The problem is that:
i've 3 ImageView that can i move inside another 3 ImageView, but when i start to drag one of the 3 ImageView i can drop it inside in just one ImageView area.

Here the code! . Basically i'll see active only the dropViewArancio area even if i drag the other ImageView. What i want it's to have all the 3 area active where i can drop one of the 3 ImageView. Thanks for the support!

Answer 1

An ImageView can't contain another View inside, only classes derived from ViewGroup can. Then you can move an ImageView over or behind another (depending on Z order) but not inside.

Here a working example of how to move all the views contained in a RelativeLayout using onTouch. I think that onDrag event applies better to drag and drop data items, not to move views. Hope it will help

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {
    private RelativeLayout mRelLay;
    private float mInitialX, mInitialY;
    private int mInitialLeft, mInitialTop;
    private View mMovingView = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRelLay = (RelativeLayout) findViewById(R.id.relativeLayout);

        for (int i = 0; i < mRelLay.getChildCount(); i++)
            mRelLay.getChildAt(i).setOnTouchListener(this);
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        RelativeLayout.LayoutParams mLayoutParams;

        switch (motionEvent.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mMovingView = view;
                mLayoutParams = (RelativeLayout.LayoutParams) mMovingView.getLayoutParams();
                mInitialX = motionEvent.getRawX();
                mInitialY = motionEvent.getRawY();
                mInitialLeft = mLayoutParams.leftMargin;
                mInitialTop = mLayoutParams.topMargin;
                break;

            case MotionEvent.ACTION_MOVE:
                if (mMovingView != null) {
                    mLayoutParams = (RelativeLayout.LayoutParams) mMovingView.getLayoutParams();
                    mLayoutParams.leftMargin = (int) (mInitialLeft + motionEvent.getRawX() - mInitialX);
                    mLayoutParams.topMargin = (int) (mInitialTop + motionEvent.getRawY() - mInitialY);
                    mMovingView.setLayoutParams(mLayoutParams);
                }
                break;

            case MotionEvent.ACTION_UP:
                mMovingView = null;
                break;
        }

        return true;
    }
}

Answer 2

So, i've solved my problem following this tutorial . Anyway my desire solution it's something similar this , the perfect way it's a mixing of tutorial and a previous link. Thanks all for help.