Android中的AlertDialog和ProgressDialog用法

手机APP对话框是很多APP都有的下面来看下怎么实现的吧，

打开Android studio 然他自动创建好布局和类;

下面我们修改activity_main.xml中的代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
 
    <Button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:layout_gravity="center"
        android:layout_marginTop="60pt"
        android:textAllCaps="false"
        />
 
    <Button
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="Button"
        android:layout_marginTop="3pt"
        android:textAllCaps="false"
        />
 
</LinearLayout>

　　再activity_main.xml添加了两个按钮分别是用于 AlertDialog 和 ProgressDialog的

　　下面我们再看ActivityMain中的代码

package com.example.administrator.myappalertdialog;
 
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.preference.DialogPreference;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
 
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button mBtn1;
    private Button mBtn2;  //声明控件
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ActionBar actionbar = getSupportActionBar();  // 去除标题栏
        if(actionbar!= null)
        {
            actionbar.hide();
        }
        mBtn1 = (Button) findViewById(R.id.btn1);  //查找控件
        mBtn1.setOnClickListener(this);   //创建点击事件
        mBtn2 = (Button) findViewById(R.id.btn2);
        mBtn2.setOnClickListener(this);
    }
 
    public void onClick(View view)  //点击事件
    {
        switch(view.getId())
        {
            case R.id.btn1:AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
                dialog.setTitle("This is AlertDialog");  //对话框标题
                dialog.setMessage("Hello world!");　　//内容
                dialog.setCancelable(true);　　　　//可撤销性
                dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"OK",Toast.LENGTH_SHORT).show();  //提示内容
                    }   //确定按钮的点击事件
                });
                dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"Cancel",Toast.LENGTH_SHORT).show();  //提示内容
                    }//取消按钮的点击事件
                });
                dialog.show();  //全部显示出来
                break;
//下面的原理一样。
            case R.id.btn2:
                ProgressDialog progressdialog = new ProgressDialog(MainActivity.this);
                progressdialog.setTitle("This is ProgressDialog");
                progressdialog .setMessage("Mr.Jiang");
                progressdialog.setCancelable(false);
                progressdialog.show();
                break;
 
            default: Toast.makeText(MainActivity.this,"ERROR",Toast.LENGTH_SHORT).show();break;
        }
    }
}