【Android 学习笔记】 Dialog 对话框使用

效果图

步骤

1. 新建一个 project

2. 编辑activity_main.xml问文件 (代码见后面)

        android:onClick="onClickShowAlert"  //按钮设置为 点击响应 
        红色提示，选择 alt+enter常见方法，下面重写

3.重写onClickShowAlert响应方法

Builder 设计模式 ，是为了

维基百科

The Builder is a design pattern designed to provide a flexible
solution to various object creation problems in object-oriented
programming. The intent of the Builder design pattern is to separate
the construction of a complex object from its representation. It is
one of the Gang of Four design patterns.

    public void onClickShowAlert(View view) {
    // 使用Builder模式构建
        AlertDialog.Builder myAlertBuilder = new
                AlertDialog.Builder(MainActivity.this);
                
        myAlertBuilder.setTitle(R.string.alert_title); //设置Title
        myAlertBuilder.setMessage(R.string.alert_message); //设置显示信息
        
        //设置正向反馈后的操作
        myAlertBuilder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(getApplicationContext(),"Pressed OK",Toast.LENGTH_SHORT).show();

            }
        });
        
 //设置负向反馈后的操作
        myAlertBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Toast.makeText(getApplicationContext(),"Pressed Cancel",Toast.LENGTH_SHORT).show();

            }
        });

        myAlertBuilder.show();
    }

---

ps：xml中的代码：

---

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/HelloWorld"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:onClick="onClickShowAlert"
        android:text="@string/alert_button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

</android.support.constraint.ConstraintLayout>