基于popupWindow实现悬浮半透明效果

//清空数据 
  private void ShowPopup() { 
    LayoutInflater mLayoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE); 
    ViewGroup mView = (ViewGroup) mLayoutInflater.inflate( 
        R.layout.soft_calendar_popup, null, true); 
    final PopupWindow popupWindow = new PopupWindow(mView, 
        LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, true); 
    final RadioButton radio1 = (RadioButton) mView 
        .findViewById(R.id.radio0); 
    final RadioButton radio2 = (RadioButton) mView 
        .findViewById(R.id.radio1); 
    final RadioButton radio3 = (RadioButton) mView 
        .findViewById(R.id.radio2); 
 
    Button btn1 = (Button) mView.findViewById(R.id.button1); 
    btn1.setOnClickListener(new OnClickListener() { 
 
      @Override 
      public void onClick(View v) { 
        //确定按钮实现的操作  
        popupWindow.dismiss(); 
      } 
    }); 
    Button btn2 = (Button) mView.findViewById(R.id.button2); 
    btn2.setOnClickListener(new OnClickListener() { 
 
      @Override 
      public void onClick(View v) { 
        // 取消按钮实现的操作 
        popupWindow.dismiss(); 
      } 
    }); 
 
    popupWindow.setBackgroundDrawable(new BitmapDrawable()); 
    popupWindow.showAtLocation(findViewById(R.id.RelativeLayout1), 
        Gravity.CENTER | Gravity.CENTER, 0, 0);//在屏幕的中间位置显示 
    popupWindow.update(); 
  } 

<?xml version="1.0" encoding="utf-8"?  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="460px" 
  android:layout_height="423px" 
  android:background="@drawable/soft_calendar_popup_bg" 
  android:orientation="vertical"   
 
  <TextView 
    android:id="@+id/textView1" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginTop="30px" 
    android:gravity="center" 
    android:text="提示" 
    android:textColor="@android:color/white" 
    android:textSize="25dip" /  
 
  <RadioGroup 
    android:id="@+id/radioGroup1" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginLeft="100px" 
    android:layout_marginRight="100px" 
    android:layout_marginTop="30px"   
 
    <RadioButton 
      android:id="@+id/radio0" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:checked="true" 
      android:text="清除当日缓存" 
      android:textSize="20dip" 
      android:textColor="@android:color/white" /  
 
    <RadioButton 
      android:id="@+id/radio1" 
      android:textSize="20dip" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="清除当月缓存" 
      android:textColor="@android:color/white" /  
 
    <RadioButton 
      android:id="@+id/radio2" 
      android:textSize="20dip" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="清除全部缓存" 
      android:textColor="@android:color/white" /  
  </RadioGroup  
 
  <LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginTop="15dip" 
    android:gravity="center_horizontal"   
 
    <Button 
      android:id="@+id/button1" 
      android:layout_width="158px" 
      android:layout_height="wrap_content" 
      android:layout_marginRight="30dip" 
      android:background="@drawable/btn2" 
      android:gravity="center" 
      android:text="确定" 
      android:textColor="@android:color/white" /  
 
    <Button 
      android:id="@+id/button2" 
      android:layout_width="158px" 
      android:layout_height="wrap_content" 
      android:background="@drawable/btn1" 
      android:gravity="center" 
      android:text="返回" 
      android:textColor="#0072D7" /  
  </LinearLayout  
 
</LinearLayout