功能：在Android中实现可拖动按钮，同时实现按钮的点击功能
相关问题：
问题描述：
解决方法：
源代码：
1.布局文件（activity_main.xml）
______________________________________________________________________________________________________
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:context=".MainActivity"
>
<Button
android:id="@+id/movebtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</RelativeLayout>
______________________________________________________________________________________________________
2.界面代码（MainActivity.java）
______________________________________________________________________________________________________
package com.luxl.slideandtouch;
import android.os.Bundle;
import android.app.Activity;
import
android.util.DisplayMetrics;
import android.view.Menu;
import
android.view.MotionEvent;
import android.view.View;
import
android.view.View.OnClickListener;
import
android.view.View.OnTouchListener;
import
android.view.ViewTreeObserver;
import
android.view.ViewTreeObserver.OnPreDrawListener;
import
android.view.Window;
import android.widget.Button;
import
android.widget.Toast;
public class MainActivity extends Activity {
private Button
movebtn; //可拖动按钮
private boolean clickormove =
true; //点击或拖动，点击为true，拖动为false
private int downX,
downY; //按下时的X，Y坐标
private boolean hasMeasured =
false; //ViewTree是否已被测量过，是为true，否为false
private View
content; //界面的ViewTree
private int
screenWidth,screenHeight; //ViewTree的宽和高
@Override
protected void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
content
=
getWindow().findViewById(Window.ID_ANDROID_CONTENT);//获取界面的ViewTree根节点View
DisplayMetrics
dm = getResources().getDisplayMetrics();//获取显示屏属性
screenWidth =
dm.widthPixels;
screenHeight = dm.heightPixels;
ViewTreeObserver vto =
content.getViewTreeObserver();获取ViewTree的监听器
vto.addOnPreDrawListener(new
OnPreDrawListener() {
@Override
public boolean onPreDraw()
{
// TODO Auto-generated method
stub
if(!hasMeasured)
{
screenHeight =
content.getMeasuredHeight();//获取ViewTree的高度
hasMeasured =
true;//设置为true，使其不再被测量。
}
return
true;//如果返回false，界面将为空。
}
});
movebtn = (Button)
findViewById(R.id.movebtn);
movebtn.setOnTouchListener(new
OnTouchListener() {//设置按钮被触摸的时间
int lastX, lastY; // 记录移动的最后的位置
@Override
public boolean onTouch(View v,
MotionEvent event) {
// TODO Auto-generated method stub
int
ea = event.getAction();//获取事件类型
switch (ea) {
case
MotionEvent.ACTION_DOWN: // 按下事件
lastX = (int) event.getRawX();
lastY =
(int) event.getRawY();
downX = lastX;
downY =
lastY;
break;
case MotionEvent.ACTION_MOVE: // 拖动事件
// 移动中动态设置位置
int dx = (int) event.getRawX() -
lastX;//位移量X
int dy = (int) event.getRawY() - lastY;//位移量Y
int
left = v.getLeft() + dx;
int top = v.getTop() + dy;
int right =
v.getRight() + dx;
int bottom = v.getBottom() + dy;
//++限定按钮被拖动的范围
if (left < 0) {
left = 0;
right = left +
v.getWidth();
}
if (right > screenWidth) {
right = screenWidth;
left = right
- v.getWidth();
}
if (top < 0) {
top = 0;
bottom = top +
v.getHeight();
}
if (bottom > screenHeight)
{
bottom = screenHeight;
top =
bottom - v.getHeight();
}
//--限定按钮被拖动的范围
v.layout(left, top, right, bottom);//按钮重画
// 记录当前的位置
lastX = (int)
event.getRawX();
lastY = (int) event.getRawY();
break;
case MotionEvent.ACTION_UP: // 弹起事件
//判断是单击事件或是拖动事件，位移量大于5则断定为拖动事件
if (Math.abs((int) (event.getRawX() - downX))
> 5
|| Math.abs((int) (event.getRawY() - downY)) > 5)
clickormove = false;
else
clickormove = true;
break;
}
return false;
}
});
movebtn.setOnClickListener(new
OnClickListener() {//设置按钮被点击的监听器
@Override
public void onClick(View arg0)
{
// TODO Auto-generated method stub
if (clickormove)
Toast.makeText(MainActivity.this, "single
click",
Toast.LENGTH_SHORT).show();
}
});
}
}
原文：http://www.cnblogs.com/ScorchingSun/p/3627330.html