How do I scale a view in android using a handle?

I am trying to implement a handle for scaling a view in android. Instead of using something like multitouch, I want to be able to resize an image with just one finger.

Here is my activity code. I think I am very close, there are five things that are not working properly.

• Scaling off. It is growing much faster than it should. Solved Thanks @Salauyou
• The species will only grow, not shrink. Solved Thanks @Salauyou
• The pen view does not move with the image. Solved Thanks @Salauyou
• Scaling starts very little Solved Thanks @Salauyou
• The pen doesn't follow your finger exactly.

I am looking for any help that could implement such a feature. Whether it's a library or someone can help with my code that I already have. I found a library that helps with multiple scaling of images ( https://github.com/brk3/android-multitouch-controller ), but the only guide I could get was how to go about implementing the zoom. And this needs to be done using two points and find the distance between them.

My activity in java:

public class MainActivity extends Activity {
    ImageView imageView;
    ImageView dragHandle;
    RelativeLayout layout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = (ImageView) findViewById(R.id.imageView1);
        imageView.setBackgroundColor(Color.MAGENTA);
        dragHandle = (ImageView) findViewById(R.id.imageView2);
        dragHandle.setBackgroundColor(Color.CYAN);
        layout = (RelativeLayout) findViewById(R.id.relativeLayout2);
        layout.setBackgroundColor(Color.YELLOW);
        setUpResize();

    }

    public void setUpResize() {
        dragHandle.setOnTouchListener(new View.OnTouchListener() {

            int[] touchPoint = new int[2];
            int[] centerOfImage = new int[2];

            double originalDistance = 0;
            double modifiedDistance = 0;

            float originalScale = 0;
            float modifiedScale = 0;

            public boolean onTouch(View v, MotionEvent motionEvent) {

                if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {

                    centerOfImage[0] = (int) (imageView.getX() + imageView.getWidth() / 2);
                    centerOfImage[1] = (int) (imageView.getY() + imageView.getHeight() / 2);

                    touchPoint[0] = (int) motionEvent.getRawX();
                    touchPoint[1] = (int) motionEvent.getRawY();

                    int[] p = new int[2];
                    p[0] = touchPoint[0] - centerOfImage[0];
                    p[1] = touchPoint[1] - centerOfImage[1];

                    originalDistance = (float) Math.sqrt(p[0] * p[0] + p[1] * p[1]);
                    originalScale = imageView.getScaleX();

                } else if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
                    touchPoint[0] = (int) motionEvent.getRawX();
                    touchPoint[1] = (int) motionEvent.getRawY();

                    int[] p = new int[2];
                    p[0] = (touchPoint[0] + p[0] - centerOfImage[0]);
                    p[1] = (touchPoint[1] + p[1] - centerOfImage[1]);
                    modifiedDistance = Math.hypot(touchPoint[0] - centerOfImage[0], touchPoint[1] - centerOfImage[1]);

                    Log.e("resize", "original " + imageView.getWidth() + " modified: " + imageView.getHeight());
                    modifiedScale = (float) (modifiedDistance / originalDistance * originalScale);

                    imageView.setScaleX(modifiedScale);
                    imageView.setScaleY(modifiedScale);

                    dragHandle.setX(centerOfImage[0] + imageView.getWidth()/2 * modifiedScale);
                    dragHandle.setY(centerOfImage[1] + imageView.getHeight()/2 * modifiedScale);

                } else if (motionEvent.getAction() == MotionEvent.ACTION_UP) {

                }
                return true;
            }
        });
    }
}

      

        
        
        
      

    

My xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <RelativeLayout
        android:id="@+id/relativeLayout2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true" >

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:src="@drawable/ic_launcher" />

        <ImageView
            android:id="@+id/imageView2"
            android:layout_width="20dp"
            android:layout_height="20dp"
            android:layout_below="@+id/imageView1"
            android:layout_toRightOf="@+id/imageView1"
            android:src="@drawable/dragArrow" />

    </RelativeLayout>

</RelativeLayout>