How to create doubled custom view for android?

I decided to try to created custom view. It is necessary to create editor with some capabilities(rotate, zoom, transform, adding overlays) on both layers(top, bottom) and make it possible to move devider to increase one layout for convenient image editing. Are there any similar works or may be someone have imagine how to start right?

I've made a custom layout that does what you asked for.
Use it programmatically, like in the example

git repository here

public class BicontLayout extends LinearLayout {

    private View divider;
    private View vTop, vBottom;
    private LinearLayout.LayoutParams vTopParams, vBottomParams;
    private int dividerClickableHeight;

    public BicontLayout(Context ctx, View viewTop, View viewBottom) {
        super(ctx);

        this.vTop = viewTop;
        this.vBottom = viewBottom;

        setOrientation(LinearLayout.VERTICAL);
        setWeightSum(1f);

        vTopParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, 0, 0.5f);
        vBottomParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, 0, 0.5f);
        addView(vTop, vTopParams);

        divider = new View(ctx);
        divider.setBackgroundColor(Color.RED);

        dividerClickableHeight = (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50f, getResources().getDisplayMetrics());
        addView(divider, LinearLayout.LayoutParams.MATCH_PARENT, 3);
        addView(vBottom, vBottomParams);

    }

    private float yStartTouch;
    private float yStartWeight;
    private boolean isDragging;
    private int[] dividerLocation = new int[2];

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if(onTouchEvent(ev)) return true;
        return super.onInterceptTouchEvent(ev);
    }

    @Override
    public boolean onTouchEvent(MotionEvent me) {
        switch(me.getAction()) {
            case MotionEvent.ACTION_DOWN:
                yStartTouch = me.getRawY();
                yStartWeight = vTopParams.weight;
                divider.getLocationOnScreen(dividerLocation);
                isDragging = Math.abs(dividerLocation[1]-yStartTouch) < dividerClickableHeight/2;
                break;
            case MotionEvent.ACTION_MOVE:
                if(!isDragging) break;

                float yDelta = me.getRawY() - yStartTouch;
                float yDeltaProg = yDelta/BicontLayout.this.getHeight();
                float yNewProg = yStartWeight + yDeltaProg;
                if(yNewProg<0.1f) yNewProg=0.1f;
                if(yNewProg>0.9f) yNewProg=0.9f;

                vTopParams.weight = yNewProg;
                vTop.setLayoutParams(vTopParams);

                vBottomParams.weight = 1f - yNewProg;
                vBottom.setLayoutParams(vBottomParams);

                break;
            case MotionEvent.ACTION_UP:
                isDragging=false;
                break;
        }

        if(isDragging) return true;
        return super.onTouchEvent(me);
    }

} // author Tiziano Munegato

Usage example

// vTop : top view
// vBottom : bottom view
BicontLayout doubleLayout = new BicontLayout(getContext(), vTop, vBottom);
setContentView(doubleLayout);

Happy coding!