Android_PopupWindow提示框

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    
    android:orientation="vertical" >

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="showpopup"
        android:text="显示popupwindow" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="showpopup_two"
        android:text="显示popupwindow(三个参数)" />

    
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="showpopup_three"
        android:text="显示popupwindow(showAtLocation)" />
    
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="200dp"
    android:layout_height="200dp"
   
    android:orientation="vertical" >

    <Button
        android:id="@+id/toast"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="弹出吐司" />

    <Button
        android:id="@+id/close"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="关闭" />

</LinearLayout>

package com.bwei.day_11_popupwindow;

import android.app.Activity;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.PopupWindow;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

    private PopupWindow popupWindow;

    // private View view;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       //加载popupwindow
        View view = View.inflate(MainActivity.this, R.layout.popupwindow, null);

        popupWindow = new PopupWindow(view,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);
        // 设置popupwindow点击窗体外可以消失;但必须要给popupwindow设置背景
        popupWindow.setOutsideTouchable(true);
        // 给popupwindow设置背景颜色
        popupWindow.setBackgroundDrawable(new ColorDrawable(Color.YELLOW));
       //监听
        Button toast = (Button) view.findViewById(R.id.toast);
        Button close = (Button) view.findViewById(R.id.close);
        toast.setOnClickListener(this);
        close.setOnClickListener(this);
    }
    //3种显示
    public void showpopup(View v) {

        System.out.println(popupWindow.isShowing());
        // 判断popupwindow是否在显示
        if (!popupWindow.isShowing()) {
            popupWindow.showAsDropDown(v);

        }

    }

    public void showpopup_two(View v) {
        // 判断popupwindow是否在显示
        if (!popupWindow.isShowing()) {
            // 参数一:popupwindow显示时的参照控件,参数二:X轴的偏移量,参数三:Y轴的偏移量
            popupWindow.showAsDropDown(v, 100, 200);
        }

    }

    public void showpopup_three(View v) {
        // 参数一:popupwindow的父窗体.参数二:popupwindow显示时的相对位置,参数三:X轴的偏移量,参数四:Y轴的偏移量
        popupWindow.showAtLocation(v, Gravity.LEFT, 0, 0);

    }
    //popupWindow内部
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        // 弹出吐司
        case R.id.toast:
            Toast.makeText(MainActivity.this, "点击popupwindow内部按钮弹出的", 1).show();
            break;
        // 关闭popupwindow
        case R.id.close:
            // 关闭popupwindows
            popupWindow.dismiss();
            break;

        }
    }

}