二 类微信界面

一、设计要求
上次仅完成微信界面的初始化和微信界面的切换功能，这次在上次作业的基础上增加列表项的单项点击功能，实现最新的activityforresult功能。
二、设计步骤
1.新建一个新的activity1，recycleview的某一项点击后跳转到这个新的activity1
activity_1.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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=".Activity1">

    <TextView
        android:id="@+id/textView10"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="344dp"
        android:gravity="center"
        android:text="具体内容"
        android:textSize="30dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView11"
        android:layout_width="0dp"
        android:layout_height="95dp"
        android:layout_marginTop="96dp"
        android:gravity="center"
        android:text="聊天记录"
        android:textSize="45dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="查看聊天记录"
        android:textSize="30dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.845" />


</androidx.constraintlayout.widget.ConstraintLayout>

activity1.java

package com.example.myapplication;

import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.TextView;

public class Activity1 extends AppCompatActivity {
    ///private Intent intent1;
    private Button button;
    private TextView textView;

    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_1);

        textView=findViewById(R.id.textView10);

        button=findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(Activity1.this,resultActivity.class);
                test.launch(intent);
            }
        });

        //Intent intent=getIntent();

    }

    public ActivityResultLauncher test= registerForActivityResult(
            new ActivityResultContracts.StartActivityForResult(),
            new ActivityResultCallback<ActivityResult>() {

                @Override
                public void onActivityResult(ActivityResult result) {
                    if(result.getResultCode()== Activity.RESULT_OK){
                        Log.d("lyr","onActivityResult 有返回值。。。");
                        //TextView textView=findViewById(R.id.textView10);
                        textView.setText(result.getData().getStringExtra("data"));
                        //textView2.setText(result.getData().getStringExtra("data"));
                    };
                }
            });


    @Override
    protected void onStart() {
        super.onStart();
        Log.d("lyr","activity2 is onStart...");
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Log.d("lyr","activity2 is onRestart...");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.d("lyr" ,"activity2 is onStop...");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("lyr","activity2 is onDestroy...");
    }

    @Override
    public void finish(){
        super.finish();
        Log.d("lyr","activity2 is finish...");
    }

    @Override
    public void finishActivity(int requestCode){
        super.finishActivity(requestCode);
        Log.d("lyr","finishActivity2...");
    }
}

 2.新建一个新的resultActivity，button点击后跳转到resultActivity

resultActivity.java

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

import java.util.Calendar;

public class resultActivity extends AppCompatActivity {
    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_result);


        Intent intent =getIntent();
        intent.putExtra("data","今天是肖蓉老师的安卓课。\n"+
                Calendar.getInstance().getTime());
        setResult(Activity.RESULT_OK,intent);
        finish();

        //String str1 = intent.getStringExtra("data");
        //textView=findViewById(R.id.textView12);
        //textView.setText(str1);
    }
}

代码仓库：app/src/main · li/android - 码云 - 开源中国 (gitee.com)