Android开发之PopupWindow创建弹窗、对话框的方法详解

public class MainActivity extends Activity {
  private PopupWindow popupWindow;
  private View root;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    root = this.getLayoutInflater().inflate(R.layout.cell,null);//add cell.xml above you mainActivity window
    popupWindow = new PopupWindow(root,560,700);//create a popupWindow object
    root.findViewById(R.id.button01).setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        //close the popupWindow
        popupWindow.dismiss();
      }
    });
  }
  public void send(View source){
    //set the location of PopupWindow
    popupWindow.showAtLocation(findViewById(R.id.send),Gravity.CENTER,20,20);//you can remove this effect
    //Use DropDown way to display
    popupWindow.showAsDropDown(root);
  }
}

<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/idtatabHost"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:layout_weight="1">
  <Button
    android:id="@+id/send"
    android:onClick="send"
    android:text="点我一下 有惊喜（吓） 。。。"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  android:id="@+id/cell"
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:orientation="vertical">
  <ImageView
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="9"
    android:src="@drawable/wechat"
    android:scaleType="fitXY"/>
  <Button
    android:id="@+id/button01"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:background="#ffffffff"
    android:text="Close"
    android:textSize="15dp"/>
</LinearLayout>