使用ontouch放大

Question

我已经使用了一些示例代码，我试图调整它让我允许用户触摸屏幕，并在代码运行正常，没有错误放大，但是当我触摸屏幕没有任何反应。

package com.thomas.zoom;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;

public class Zoom extends View {
        private Drawable image;

        private int zoomControler=20;

        public Zoom(Context context)
        {
                super(context);
                image=context.getResources().getDrawable(R.drawable.icon);
                setFocusable(true);

        }
        @Override
        protected void onDraw(Canvas canvas) {
                // TODO Auto-generated method stub
                super.onDraw(canvas);
        //here u can control the width and height of the images........ this line is very important
        image.setBounds((getWidth()/2)-zoomControler, (getHeight()/2)-zoomControler, (getWidth()/2)+zoomControler, (getHeight()/2)+zoomControler);
                image.draw(canvas);
        }
        public boolean onTouch(int action, MotionEvent event) {
               action= event.getAction();
               if(action == MotionEvent.ACTION_DOWN){
                   zoomControler+=10;               
                   }


                invalidate();
                return true;
        }
}

Answer 1

喜ontouch事件是不好的缩放图像

因此使用onkeylistener

public boolean onKeyDown(int keyCode, KeyEvent event) {
            if(keyCode==KeyEvent.KEYCODE_DPAD_UP)// zoom in
                    zoomControler+=10;
            if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN) // zoom out
                    zoomControler-=10;
            if(zoomControler<10)
                    zoomControler=10;

            invalidate();
            return true;
    }