<?xml version="1.0" encoding="utf-8"?>

 
 
 
 
 

package com.example.boombuttons;
import java.util.ArrayList;
public class MainActivity extends Activity implements OnClickListener{
 // 中心按钮
 private ImageButton button;
 // 四个子按钮
 private ImageButton button1;
 private ImageButton button2; 
 private ImageButton button3; 
 private ImageButton button4;
 // 子按钮列表
 private List buttonItems = new ArrayList(3);
 // 标识当前按钮弹出与否，1代表已经未弹出，-1代表已弹出
 private int flag = 1;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  // 实例化按钮并设立监听
  button = (ImageButton)findViewById(R.id.button);
  button.setOnClickListener(this);
  button1 = (ImageButton)findViewById(R.id.button1);
  button2 = (ImageButton)findViewById(R.id.button2);
  button3 = (ImageButton)findViewById(R.id.button3);
  button4 = (ImageButton)findViewById(R.id.button4);
  // 将子按钮们加入列表中
  buttonItems.add(button1);
  buttonItems.add(button2);
  buttonItems.add(button3);
  buttonItems.add(button4); 
 }
 /**
  * 按钮移动动画
  * @params 子按钮列表
  * @params 弹出时圆形半径radius
  */
 public void buttonAnimation(List buttonList,int radius){
  for(int i=0;i

public class Util {
 /**
  * 返回每个按钮应该出现的角度(弧度单位)
  * @param index
  * @return double 角度(弧度单位)
  */
 public static double getAngle(int total,int index){
  return Math.toRadians(90/(total-1)*index+90);
 }
}