第一行代码2版，RecyclerView，android studio3.4 日常踩坑

引用的改变，implementation'com.android.support:recyclerview-v7:28.0.0'

在学习第二行代码中，RecuclerView的使用中，遇到这样的问题：

1-1

妈耶，直接晕了。一个子项充满了一个屏幕，在我3天的度娘中，还好有一样的同学，

解决办法，问题出现在子项的布局

1-2

就是这个地方布局有问题。改成wrap_content就好了。

源码：

```

Adapter//适配器

package com.example.recycler_view_test;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ImageView;

import android.widget.TextView;

import androidx.annotation.NonNull;

import androidx.recyclerview.widget.RecyclerView;

import java.util.List;

public class Fruit_Adapterextends RecyclerView.Adapter {

private ListmfruitList;

static class ViewHolderextends RecyclerView.ViewHolder {//继承RecyclerView.ViewHolder  缓存最外层的布局数据

        private ImageViewimageView;

private TextViewtextView;

public ViewHolder(View itemView) {

super(itemView);

imageView=(ImageView)itemView.findViewById(R.id.fruit_image);

textView=(TextView)itemView.findViewById(R.id.fruit_name);

}

}

public  Fruit_Adapter (List fruitList){

mfruitList=fruitList;//获取数据源

    }

@Override

    public ViewHolder onCreateViewHolder( ViewGroup parent,int viewType) {

View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit,parent,false);

ViewHolder viewHolder=new ViewHolder(view);

return viewHolder;

}

@Override

    public void onBindViewHolder( ViewHolder holder,int position) {

Fruit fruit=mfruitList.get(position);

holder.imageView.setImageResource(fruit.getImage_id());

holder.textView.setText(fruit.getName());

}

@Override

    public int getItemCount() {

return mfruitList==null?0:mfruitList.size();

}

}

```

```

mainactivity 

package com.example.recycler_view_test;

import androidx.appcompat.app.AppCompatActivity;

import androidx.recyclerview.widget.LinearLayoutManager;

import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

import java.util.ArrayList;

import java.util.List;

public class MainActivityextends AppCompatActivity {

private ListmfruitList;

@Override

    protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mfruitList=getFruitList();

RecyclerView recyclerView=(RecyclerView)findViewById(R.id.recyclerview);

LinearLayoutManager llmanager=new LinearLayoutManager(MainActivity.this);

recyclerView.setLayoutManager(llmanager);

Fruit_Adapter fruit_adapter=new Fruit_Adapter(mfruitList);

recyclerView.setAdapter(fruit_adapter);

}

public List getFruitList() {

List fruitList=new ArrayList<>();

Fruit fruit=new Fruit("apple",R.drawable.ic_launcher_background);

fruitList.add(fruit);

Fruit fruit1=new Fruit("apple1",R.drawable.ic_launcher_background);

fruitList.add(fruit1);

Fruit fruit2=new Fruit("apple2",R.drawable.ic_launcher_background);

fruitList.add(fruit2);

Fruit fruit3=new Fruit("apple3",R.drawable.ic_launcher_background);

fruitList.add(fruit3);

Fruit fruit4=new Fruit("apple4",R.drawable.ic_launcher_background);

fruitList.add(fruit4);

Fruit fruit5=new Fruit("apple5",R.drawable.ic_launcher_background);

fruitList.add(fruit5);

Fruit fruit6=new Fruit("apple6",R.drawable.ic_launcher_background);

fruitList.add(fruit6);

Fruit fruit7=new Fruit("apple7",R.drawable.ic_launcher_background);

fruitList.add(fruit7);

Fruit fruit8=new Fruit("apple8",R.drawable.ic_launcher_background);

fruitList.add(fruit8);

Fruit fruit9=new Fruit("apple9",R.drawable.ic_launcher_background);

fruitList.add(fruit9);

Fruit fruit10=new Fruit("apple10",R.drawable.ic_launcher_background);

fruitList.add(fruit10);

Fruit fruit11=new Fruit("apple11",R.drawable.ic_launcher_background);

fruitList.add(fruit11);

return fruitList;

}

}

```