# recycleview的item跳转界面实现

**Repository Path**: aparece/recycleview_item

## Basic Information

- **Project Name**: recycleview的item跳转界面实现
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2023-11-13
- **Last Updated**: 2023-11-13

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# 实验目标
将第一次实验里recyclerView的每个item增加点击功能，点击后跳转到一个新的view界面。
# 技术说明
1. 使用工具 Android studio
2.  API 33 Android 13
3. 主要技术内容：recyclerview、adapter、activity、fragment，service
# 设计思路
1. 将原本作业1中的fagment1改成播放器，播放音乐
2. fragment2作为列表展示音乐文件名
3. 创建一个musicactivity播放器
4. 创建myservice1来播放音乐
5. fragment2将歌名读取出来显示在recycleview中
6. myadapter将每个选项中的歌名在歌曲名单中的下标传递给musicactivity
7. musicactivity在歌名列表中查找到原本的歌名需要，将其写入到textview中
8. musicactivity根据歌曲的序号，传给myservice1
9. myservice接收参数，播放对应序号所放的歌
# 核心代码
## 播放器
### myservice1.java
- 将歌曲对象按顺序写入列表，方便播放时调用
- 因为oncreat不接受intent参数，所以在onstartcommand中通过intent接收参数，并播放
```java
public class MyService1 extends Service {

    MediaPlayer player;
    int [] musics={
            R.raw.music1,
            R.raw.music2,
            R.raw.music3,
            R.raw.music4
    };
    public MyService1() {

    }
    @Override
    public void onCreate(){
        super.onCreate();
        Log.d("xr","MyService1:onCreate...");
        //player=MediaPlayer.create(this,musics[0]);
        //player=MediaPlayer.create(this,R.raw.music1);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d("xr","MyService1:onStart...");
        int musicIndex = intent.getIntExtra("musicIndex", 0); // 获取传递的参数，默认为0
        player = MediaPlayer.create(this, musics[musicIndex]);
        player.start();
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        player.stop();
        player.release();
        super.onDestroy();
        Log.d("xr","MyService1:onDestroy...");
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }
}
```
### musicactivity.java
- 接收intent传递过来的参数，歌曲序号
- getRawSongList获取歌名列表
- 在歌名列表中根据歌曲序号将歌名显示在textview中
- 启动myservice1服务时，将歌名序号作为参数传递
- 按钮1播放，按钮2停止，按钮3返回歌单
```java
public class MusicActivity extends AppCompatActivity {
    int index;
    TextView textView;
    Button button1,button2,button3;
    List<String> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d("test","music creat1");
        super.onCreate(savedInstanceState);
        list=getRawSongList();
        setContentView(R.layout.activity_music);
        textView=findViewById(R.id.textView1234);
		//接收传递的参数
        Intent intent1=getIntent();
        index=intent1.getIntExtra("index",0);
        Log.d("test","getintent");
        
        button1=findViewById(R.id.buttonM11);
        button2=findViewById(R.id.buttonM22);
        button3=findViewById(R.id.button66);

        Log.d("test",String.valueOf(index));
        textView.setText(list.get(index));

        Intent intent=new Intent(MusicActivity.this,MyService1.class);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                intent.putExtra("musicIndex", index); // 设置参数
                startService(intent);
            }
        });
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(intent);
            }
        });
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent3 =new Intent();
                finish();
            }
        });
    }
    public List<String> getRawSongList() {//获取歌曲列表的名字
        List<String> list = new ArrayList<>();

        Field[] fields = R.raw.class.getFields();
        for (Field field : fields) {
            String songName = field.getName();
            list.add(songName);
        }

        return list;
    }
}
```
### fragment1.java
- 将musicactivity的代码复制到fagment1里改一下。
```java
public class Fragment1 extends Fragment {
    Button button1, button2;
    int index=1;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.layout1, container, false);

        button1 = view.findViewById(R.id.buttonM11);
        button2 = view.findViewById(R.id.buttonM22);

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), MyService1.class);
                Log.d("test",String.valueOf(index));
                intent.putExtra("musicIndex", index); // 设置参数
                getActivity().startService(intent);
            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getActivity(), MyService1.class);
                getActivity().stopService(intent);
            }
        });
        return view;
    }
}
```
## recycleview跳转
### fragment2.java
- 读取歌名信息列表，初始化myadapter
- 将fragment2与adapter关联，绑定recycler view与item
```java
public class Fragment2 extends Fragment {
    RecyclerView recycleview;
    Myadapter adapter;
    Context context;
    List<String> list;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.activity_recycle_view,container,false);
        recycleview=view.findViewById(R.id.RecyclerView1);
        context=view.getContext();
        list=new ArrayList<>();
        list=getRawSongList();

        adapter =new Myadapter(context,list);
        recycleview.setAdapter(adapter);
        
        LinearLayoutManager manager=new LinearLayoutManager(context);
        manager.setOrientation(RecyclerView.VERTICAL);
        recycleview.setLayoutManager(manager);
        return view;
    }

    public List<String> getRawSongList() {//获取歌曲列表的名字
        List<String> list = new ArrayList<>();

        Field[] fields = R.raw.class.getFields();
        for (Field field : fields) {
            String songName = field.getName();
            list.add(songName);
        }

        return list;
    }

}

```
### recycleview.java
- 将当前activity和list 作为参数传递给myadapter。
```java
public class RecycleViewActivity extends AppCompatActivity {
    RecyclerView recycleview;
    Myadapter adapter;
    Context context;
    List<String> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recycle_view);

        recycleview=findViewById(R.id.RecyclerView1);
        context=this;
        adapter =new Myadapter(this,list);
        recycleview.setAdapter(adapter);
        LinearLayoutManager manager=new LinearLayoutManager(this);
        manager.setOrientation(RecyclerView.VERTICAL);
        recycleview.setLayoutManager(manager);
    }
}
```
### myadapter.java
- 使用holder.getAdapterPosition获取当前绑定的 ViewHolder 在适配器中的位置，这个跟歌名序号是对应关系，可以直接作为当前item对应的歌名序号进行调用
- 使用intent.putExtra将参数传给musicactivity
- startActivity启动musicactivity
```java
public class Myadapter  extends RecyclerView.Adapter<Myadapter.Myholder>{
    Context context1;
    List<String> list1;
    public Myadapter(Context context,List<String> list){
        context1=context;
        list1=list;
    }
    @NonNull
    @Override
    public Myholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(context1).inflate(R.layout.item,parent,false);
        Myholder holder=new Myholder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull Myholder holder, int position) {
        holder.textview.setText(list1.get(position));
        //holder.textview.setText(Integer.toString(holder.getAdapterPosition()));
		//监听器
        holder.textview.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Bundle args = new Bundle();
                //args.putInt("index", holder.getAdapterPosition());
                Log.d("test","onClick");
				//holder.getAdapterPosition()获取当前item的序号，跟歌名序号对应，作为参数调用musicactivity
                Intent intent=new Intent(context1,MusicActivity.class);
                intent.putExtra("index",holder.getAdapterPosition());
                context1.startActivity(intent);

                Log.d("test","start suc");
            }
        });
    }

    @Override
    public int getItemCount() {
        return list1.size();
    }
    public class Myholder extends RecyclerView.ViewHolder {
        TextView textview;
        public Myholder(@NonNull View itemView) {
            super(itemView);
            textview=itemView.findViewById(R.id.textView8);
        }
    }
}

```
## layout1.xml
```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=".MusicActivity">

    <Button
        android:id="@+id/buttonM11"
        android:layout_width="250dp"
        android:layout_height="48dp"
        android:layout_marginTop="59dp"
        android:text="播放"
        app:layout_constraintBottom_toTopOf="@+id/buttonM22"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView1234" />

    <Button
        android:id="@+id/buttonM22"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:text="暂停"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/buttonM11" />

    <TextView
        android:id="@+id/textView1234"
        android:layout_width="260dp"
        android:layout_height="153dp"
        android:layout_marginStart="75dp"
        android:layout_marginTop="136dp"
        android:layout_marginEnd="76dp"
        android:layout_marginBottom="59dp"
        android:text="TextView"
        app:layout_constraintBottom_toTopOf="@+id/buttonM11"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
```
## activity_music.xml
```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=".MusicActivity">

    <Button
        android:id="@+id/buttonM11"
        android:layout_width="250dp"
        android:layout_height="48dp"
        android:layout_marginTop="59dp"
        android:text="播放"
        app:layout_constraintBottom_toTopOf="@+id/buttonM22"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView1234" />

    <Button
        android:id="@+id/buttonM22"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:text="暂停"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/buttonM11" />

    <TextView
        android:id="@+id/textView1234"
        android:layout_width="260dp"
        android:layout_height="153dp"
        android:layout_marginStart="75dp"
        android:layout_marginTop="136dp"
        android:layout_marginEnd="76dp"
        android:layout_marginBottom="59dp"
        android:text="TextView"
        app:layout_constraintBottom_toTopOf="@+id/buttonM11"
        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/button66"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="返回"
        tools:layout_editor_absoluteX="-2dp"
        tools:layout_editor_absoluteY="-1dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
```
# 中间出现的问题
1. 因为原本将播放器的activity代码改到了fragment1里，开始时是想实现fragment2中的recycleview点击跳转到fragment1中，在fragment1的textview显示出歌名，并点击播放的，但是不知道怎么实现fragment跳转
1.1. 传参问题，myadapt如果要想传完参数后调用原本的fragment1对象就必须要mainactivity的环境。不能使用全局变量，就只能用this指针得传好几遍。
1.2.  静态问题，还写了一个函数，想用一个公用方法来返回fragment对象，结果因为myadapt中写入的函数是静态的，没办法调用非静态的fragment
2. 最后放弃了原本的想法，直接将播放器做成一个单独的activity，直接传参调用。

# 结果
1. 歌单界面

![歌单界面](./pic/1.png)

2. 播放界面activity

![播放界面](./pic/2.png)

3. 播放界面fragment

![fragment](./pic/3.png)

4. 返回

![返回](./pic/4.png)
# 总结
- 在这次实验中为recycleview的每一个选项添加了一个跳转到播放器的功能，并播放对应的歌曲。不知道如何跳转fragment，如何跨多个构建传递参数，传参只能每次都传，也无法使用全局变量，直接启用了一个新的activity，myadapter中每次点击会将该选项的序号作为歌名序号传递。
# 库
- gitee: [recycleview的item点击跳转实现](https://gitee.com/aparece/recycleview_item)