点击button拖动效果

这个简单的代码段可以熟悉getX(),getRawX()等方法,实现按钮的拖动效果:

package com.example;

import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

public class ButtonDrag extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		final Button btn = (Button) findViewById(R.id.btn_hello);

		btn.setOnTouchListener(new OnTouchListener() {
			int[] temp = new int[] { 0, 0 };

			public boolean onTouch(View v, MotionEvent event) {

				int eventaction = event.getAction();

				int x = (int) event.getRawX();
				int y = (int) event.getRawY();

				switch (eventaction) {

				case MotionEvent.ACTION_DOWN:
					temp[0] = (int) event.getX();
					temp[1] = (int) event.getY();
					break;
				case MotionEvent.ACTION_MOVE:
					v.layout(x - temp[0], y - temp[1], x + v.getWidth()
							- temp[0], y + v.getHeight() - temp[1]);
					// run in non_UI thread
					v.postInvalidate();
					break;

				case MotionEvent.ACTION_UP:
					break;
				}
				return false;
			}

		});

	}

}