[Android] 实验3.1 组件通信与广播消息之Intent的使用

运行图

代码

（1）activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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">

    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/listView"
        android:divider="@color/design_default_color_secondary_variant"
        android:dividerHeight="5dp"/>

</LinearLayout>

(2)MainActivity.java

package com.example.lab_3_1;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private ListView listView;
    private List<String >list=new ArrayList<>();
    private ArrayAdapter adapter;
    private String temp=null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView=findViewById(R.id.listView);

        list.add("张三");
        list.add("李四");
        list.add("王二");
        list.add("赵五");
        adapter=new ArrayAdapter<String >(this,android.R.layout.simple_list_item_1,list);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                temp=listView.getItemAtPosition(i).toString();
                Intent intent=new Intent(MainActivity.this,SecondActivity.class);
                intent.putExtra("info",temp);
                startActivityForResult(intent,1);
            }
        });
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch(requestCode){
            case 1: if(resultCode==2)
                adapter.remove(temp);
                break;

        }
    }
}

(3)SecondActivity.java

package com.example.lab_3_1;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;

public class SecondActivity extends AppCompatActivity {
    private String info=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        Intent intent=getIntent();
        info=intent.getStringExtra("info");
        Dialog alertDialog=new AlertDialog.Builder(this).setIcon(R.drawable.jihe).setTitle("信息如下：").setMessage("删除 "+info+" 的记录吗？")
                .setPositiveButton("确认", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Intent intent=new Intent();
                        setResult(2,intent);
                        finish();
                    }
                }).setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        finish();
                    }
                }).create();
        alertDialog.show();
    }
}

Icon: