移动开发技术作业2

1.使用log展示生命周期的状态变化；

2.新建一个新的activity，recycleview的某一项点击后跳转到这个新的activity；

3.新建一个新的activity2，在activity1上添加按钮可显示收到activity1的回传值；

本次recycle界面相比于上次作业进行了修改，结果如下

（图片内容为LOL中国战队的图标和名字，因为恰逢世界赛的举办，所以设计此内容，后续可进行修改为联系人）

首先创建四个activity文件，并设计对应的xml文件，activity-1.xml的内容如下

其余三个界面按照上述代码进行修改即可。

接下来进行设置对应 的适配器MyAdapter，具体代码如下

package com.example.mywork;

import android.app.Fragment;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

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

public class weixinFragment extends Fragment {

    private RecyclerView recyclerView;
    private MyAdapter myAdapter;
    private List> data;
    private Context context;

    public weixinFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.weixin, container, false);
        context=this.getActivity();
        recyclerView=view.findViewById(R.id.RecycleView);

        data=new ArrayList>();
        String[] name = {"LPL战队", "LPL战队", "LPL战队", "LPL战队"};
        String[] num={"EDG", "TES" , "JDG", "RNG"};
        int[] picture = {R.drawable.e,R.drawable.tes,R.drawable.jdg,R.drawable.rng};

        for (int i=0;i< name.length;i++) {
            Map map=new HashMap();
            map.put("照片", picture[i]);
            map.put("lpl",name[i]);
            map.put("战队名",num[i]);
            data.add(map);
        }

        myAdapter=new MyAdapter(data,context);
        LinearLayoutManager manager=new LinearLayoutManager(context);
        manager.setOrientation(RecyclerView.VERTICAL);
        recyclerView.setLayoutManager(manager);
        recyclerView.setAdapter(myAdapter);

        return view;
    }

}

然后设置每个item的点击监听事件在onBindViewHolder方法中设置绑定每个item的点击监听和使用log展示activity生命周期的变化。

activity1.java的代码如下（其余activity照着当前文件进行修改）：

package com.example.mywork;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class Activity1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_1);
        Log.i("Activity02","onCreate()");
    }
    @Override
    protected void onStart() {
        super.onStart();
        Log.i("Activity02","onStart()");
    }
    @Override
    protected void onRestart() {
        super.onRestart();
        Log.i("Activity02","onRestart()");
    }
    @Override
    protected void onResume() {
        super.onResume();
        Log.i("Activity02","onResume()");
    }
    @Override
    protected void onPause() {
        super.onPause();
        Log.i("Activity02","onPause()");
    }
    @Override
    protected void onStop() {
        super.onStop();
        Log.i("Activity02","onStop()");
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i("Activity02","onDestroy()");
    }

    public void click(View view){
        //创建一个Intent对象，通过该对象开启第2个Activity
        Intent intent=new Intent(this, MainActivity.class);
        startActivity(intent);
    }

}

使用log展示生命周期的状态变化结果如下（这是点击一个activity后所展现的）：

 最后设计点击收藏按钮的设置

在这里使用的是registerForActivityResult()方法,调用registerForActivityResult()方法来注册一个对Activity结果的监听。

public class Activity1 extends AppCompatActivity {
    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_1);
        button = findViewById(R.id.button2);
        Log.i("Activity02", "onCreate()");
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(Activity1.this, activity_5.class);
                activityResultLauncher.launch(intent);
            }
        });
    }

    ActivityResultLauncher activityResultLauncher = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), new ActivityResultCallback() {
        @Override
        public void onActivityResult(ActivityResult result) {
            if (result.getResultCode() == 1) {
                String s = result.getData().getStringExtra("returnNum");
                Toast.makeText(getApplicationContext(), "已被收藏" + s + "次", Toast.LENGTH_SHORT).show();
            }
        }
    });

结果如下：

https://gitee.com/fragrance-floating-rio/MyWeChat.git