024 Android 对话框(AlertDialog)的应用(与Android黑马培训班的024相对照学习)

1.介绍

2.作用

(1)消息提示对话框

(2)简单列表对话框

(3)单选列表对话框

(4)多选对话框

(5)自定义对话框

3.java后台代码

package com.lucky.test28dialog;

import android.content.DialogInterface;
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.SimpleAdapter;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {

    Button button1;
    Button button2;
    Button button3;
    Button button4;
    Button button5;
    String[] strings={"大数据","物联网","云计算","无人机","机器人"};
    boolean[] flags={false,false,false,false,false};
    String userchoice;
    String temp="";
    SimpleAdapter simpleAdapter;
    int[] images={R.mipmap.img01,R.mipmap.img02,R.mipmap.img03,R.mipmap.img04,R.mipmap.img05};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button1=findViewById(R.id.button);
        button2=findViewById(R.id.button2);
        button3=findViewById(R.id.button3);
        button4=findViewById(R.id.button4);
        button5=findViewById(R.id.button5);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //实例化消息提示对话框
                AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
                builder.setIcon(R.mipmap.ic_launcher); //设置图标
                builder.setTitle("提示框");  //设置标题
                builder.setMessage("我是消息提示对话框"); //设置提示内容
                builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"您点击了确定",Toast.LENGTH_SHORT).show();
                    }
                });
                builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"您点击了取消",Toast.LENGTH_SHORT).show();
                    }
                });
                builder.show(); //显示对话框

            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //实例化简单列表对话框
                AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
                builder.setIcon(R.mipmap.ic_launcher); //设置图标
                builder.setTitle("提示框");  //设置标题
                //设置简单列表对话框里显示的内容
                builder.setItems(strings, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,strings[which],Toast.LENGTH_SHORT).show();
                    }
                });
                builder.show();//显示对话框
            }
        });

        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //实例化单选列表对话框
                AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
                builder.setIcon(R.mipmap.ic_launcher); //设置图标
                builder.setTitle("提示框");  //设置标题
                //设置对话框的内容和监听器
                builder.setSingleChoiceItems(strings, 1, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        userchoice=strings[which];
                    }
                });

                //设置对话框的确定和取消按钮
                builder.setPositiveButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"您点击了取消",Toast.LENGTH_SHORT).show();
                    }
                });
                builder.setNegativeButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,userchoice,Toast.LENGTH_SHORT).show();
                    }
                });
                builder.show();//显示对话框(天坑！这句一定不能忘)
            }
        });

        button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //实例化多选列表对话框
                AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
                builder.setIcon(R.mipmap.ic_launcher); //设置图标
                builder.setTitle("提示框");  //设置标题
                //设置多选列表对话框的显示内容(strings)，flags表示哪几项被选中
                builder.setMultiChoiceItems(strings, flags, new DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        flags[which]=isChecked; //修改flags列表里的值
                    }
                });

                builder.setPositiveButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(MainActivity.this,"您点击了取消",Toast.LENGTH_SHORT).show();
                    }
                });
                builder.setNegativeButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        for (int i = 0; i <flags.length ; i++) {
                            if(flags[i]){
                                temp+=strings[i]+";";
                            }
                        }
                        if(temp.equals("")){
                            Toast.makeText(MainActivity.this,"您未选择任何内容",Toast.LENGTH_SHORT).show();
                            return;  //天秀：return可以提前结束方法的执行，若没有return，temp=temp.substring(0,temp.length()-1)会出错
                        }
                        temp=temp.substring(0,temp.length()-1);
                        Toast.makeText(MainActivity.this,temp,Toast.LENGTH_SHORT).show();
                        temp="";
                    }
                });
                builder.show();
            }
        });

        button5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //实例化自定义对话框
                AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
                builder.setIcon(R.mipmap.ic_launcher); //设置图标
                builder.setTitle("提示框");  //设置标题

                List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
                for (int i = 0; i < strings.length; i++) {
                    Map<String, Object> map = new HashMap<String, Object>();
                    map.put("name", strings[i]);
                    map.put("picture", images[i]);
                    list.add(map);
                }

                simpleAdapter = new SimpleAdapter(MainActivity.this, list,
                        R.layout.item, new String[] { "name", "picture" }, new int[] {
                        R.id.textView1, R.id.imageView1 });
                builder.setAdapter(simpleAdapter, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface arg0, int arg1) {
                        // TODO Auto-generated method stub
                        Toast.makeText(MainActivity.this, "您选择的是"+strings[arg1], Toast.LENGTH_SHORT).show();

                    }
                });
                builder.show();
            }
        });
    }
}

4.效果图