public class Sample extends Activity implements OnTouchListener {

    Context mContext;
    WebView webView;
    WebSettings setting;
    RelativeLayout mainLayout;
    Button keyDelBtn;
    private Rect rect = new Rect();
    private Animation anime;

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

        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

        mContext = this;
        mainLayout = new RelativeLayout(mContext);

        setContentView(mainLayout);
        
        Button keyAddBtn = new Button(mContext);
        RelativeLayout.LayoutParams keyAddParam = new RelativeLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        keyAddBtn.setId(1);
        keyAddBtn.setBackgroundResource(android.R.drawable.alert_dark_frame);
        keyAddBtn.setLayoutParams(keyAddParam);
        keyAddBtn.setPadding(10, 10, 10, 10);
        keyAddBtn.setText("+");
        keyAddBtn.setTextColor(Color.WHITE);
        keyAddBtn.setTextSize(18);
        keyAddBtn.setTypeface(null, Typeface.BOLD);
        keyAddBtn.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                mainLayout.addView(getNewButton("A"));
            }
        });
        mainLayout.addView(keyAddBtn);
        
    }

    private DragButton getNewButton(String key) {
        RelativeLayout.LayoutParams param = new RelativeLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        param.addRule(RelativeLayout.CENTER_IN_PARENT);
        
        DragButton btn = new DragButton(mContext);
        btn.setLayoutParams(param);
        btn.setText(key);
        btn.setBackgroundResource(android.R.drawable.alert_light_frame);
        btn.setTextColor(Color.BLACK);
        btn.setTextSize(18);
        btn.setTypeface(null, Typeface.BOLD);
        btn.setOnTouchListener(this);
        
        return btn;
    }

    @Override
    public boolean onTouch(View view, MotionEvent event) {
        if (view instanceof DragButton) {
            DragButton key = (DragButton) view;
            int x = (int) event.getRawX();
            int y = (int) event.getRawY();
    
            if (event.getAction() == MotionEvent.ACTION_MOVE) {
    
                int diffX = key.getOffsetX() - x;
                int diffY = key.getOffsetY() - y;
    
                key.setCurrentX(key.getCurrentX() - diffX);
                key.setCurrentY(key.getCurrentY() - diffY);
                key.layout(key.getCurrentX(), key.getCurrentY(), key.getCurrentX() + key.getWidth(),
                        key.getCurrentY() + key.getHeight());
    
                key.setOffsetX(x);
                key.setOffsetY(y);
    
            } else if (event.getAction() == MotionEvent.ACTION_DOWN) {
                key.setCurrentX(key.getLeft());
                key.setCurrentY(key.getTop());
                key.setOffsetX(x);
                key.setOffsetY(y);
            } else if (event.getAction() == MotionEvent.ACTION_UP) {
                keyDelBtn.getHitRect(rect);
                if (rect.contains(x, y)) {
                    key.setAnimation(anime);
                    key.startAnimation(anime);
                    key.setVisibility(View.GONE);
                    key = null;
                }
                key.layout(key.getCurrentX(), key.getCurrentY(), key.getCurrentX() + key.getWidth(),
                        key.getCurrentY() + key.getHeight());
            }
        }
        return true;
    }

}

 public class DragButton extends Button {

    private int currentX;
    private int currentY;
    private int offsetX;
    private int offsetY;

    publicDragButton(Context context) {
        super(context);
    }

    public int getCurrentX() {
        return currentX;
    }

    public void setCurrentX(int currentX) {
        this.currentX = currentX;
    }

    public int getCurrentY() {
        return currentY;
    }

    public void setCurrentY(int currentY) {
        this.currentY = currentY;
    }

    public int getOffsetX() {
        return offsetX;
    }

    public void setOffsetX(int offsetX) {
        this.offsetX = offsetX;
    }

    public int getOffsetY() {
        return offsetY;
    }

    public void setOffsetY(int offsetY) {
        this.offsetY = offsetY;
    }

}