popupWindow的使用

public class PopupWindowActivity extends Activity {
private Button mPopWinBtn;
private PopupWindow mPopWin;
private boolean hasMeasured;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.popwindow_view);

mPopWinBtn = (Button) findViewById(R.id.pop_window_btn);
mPopWin = new PopupWindow(setPopWindowData());
mPopWinBtn.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {

//加上是否显示，若已显示则清除掉存在的，不存在则显示
if (mPopWin.isShowing()) {
mPopWin.dismiss();
} else {
mPopWin.showAsDropDown(v);      
}


}
});


/*
* 让下拉框显示出来，无这部分则不会显示
*/
ViewTreeObserver vto = mPopWinBtn.getViewTreeObserver();
vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
public boolean onPreDraw() {
if (hasMeasured == false) {
int btWidth = mPopWinBtn.getMeasuredWidth(); // 得到按钮宽度
int btHeight = mPopWinBtn.getMeasuredHeight(); // 得到按钮高度


mPopWin.setWidth(btWidth); // 设置宽高属性，两属性缺一不可
mPopWin.setHeight(500);
hasMeasured = true;
}
return true;
}
});


}

//加载数据，适配器可自定，方法同自定义适配器相同
public View setPopWindowData() {


// 此处直接使用适配器控件布局,若加入外部布局则会报错
View v = LayoutInflater.from(this).inflate(
R.layout.pop_window_listview, null);
ListView content = (ListView) v;


String[] popData = { "添加", "删除", "修改", "插入" };
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, popData);
content.setAdapter(adapter);


return content;
}

}

xml 文件

<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pop_window_list"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
</ListView>