Android入门之弹出式对话框的实现

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
 
    <Button
        android:id="@+id/btnTom"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:text="汤姆"
        android:textSize="18sp" />
 
    <Button
        android:id="@+id/btnJerry"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:text="杰瑞"
        android:textSize="18sp" />
 
 
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".MainActivity">
 
    <Button
        android:layout_centerInParent="true"
        android:id="@+id/btnPopWindow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="弹出Window"
    />
</RelativeLayout>

package org.mk.android.demopopupdialog;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.Context;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.PopupWindow;
import android.widget.Toast;
 
public class MainActivity extends AppCompatActivity {
    private Button btnPopWindow;
    private Context ctx;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ctx=MainActivity.this;
        btnPopWindow=(Button)findViewById(R.id.btnPopWindow);
        btnPopWindow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                popWindow(view);
            }
        });
    }
 
    private void popWindow(View v) {
        View subDlgView = LayoutInflater.from(ctx).inflate(R.layout.item_popup,
                null, false);
        Button btnTom = (Button) subDlgView.findViewById(R.id.btnTom);
        Button btnJerry = (Button) subDlgView.findViewById(R.id.btnJerry);
        //1.构造一个PopupWindow，参数依次是加载的View，宽高
        final PopupWindow popWindow = new PopupWindow(subDlgView, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, true);
 
        //这些为了点击非PopupWindow区域，PopupWindow会消失的，如果没有下面的
        //代码的话，你会发现，当你把PopupWindow显示出来了，无论你按多少次后退键
        //PopupWindow并不会关闭，而且退不出程序，加上下述代码可以解决这个问题
        popWindow.setTouchable(true);
        popWindow.setTouchInterceptor(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return false;
                // 这里如果返回true的话，touch事件将被拦截
                // 拦截后 PopupWindow的onTouchEvent不被调用，这样点击外部区域无法dismiss
            }
        });
        popWindow.setBackgroundDrawable(new ColorDrawable(0x00000000));    //要为popWindow设置一个背景才有效
 
 
        //设置popupWindow显示的位置，参数依次是参照View，x轴的偏移量，y轴的偏移量
        popWindow.showAsDropDown(v, 50, 0);
 
        //设置popupWindow里的按钮的事件
        btnTom.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "你点击了Tom, Tom吃Jerry", Toast.LENGTH_SHORT).show();
            }
        });
        btnJerry.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "你点击了Jerry, Jerry揍Tom", Toast.LENGTH_SHORT).show();
                popWindow.dismiss();
            }
        });
    }
}