Android滚动列表RecyclerView

Android滚动列表RecyclerView

1. app gradle

dependencies {

implementation 'androidx.recyclerview:recyclerview:1.1.0'

2. activity布局

MainActivity

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    </androidx.recyclerview.widget.RecyclerView>

</LinearLayout>

my_text_view

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />
</LinearLayout>

3. Activity代码

MainActivity

package com.example.listview;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;


public class MainActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private RecyclerView.Adapter adapter;
    private RecyclerView.LayoutManager layoutManager;
    private String[] myDataset;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        recyclerView = findViewById(R.id.recyclerview);
        int number = 1000;
        myDataset = new String[number];
        for(int i = 0; i < number; i++) {
            myDataset[i] = "hello" + i;
        }
        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
        recyclerView.setHasFixedSize(true);

        // use a linear layout manager
        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        // specify an adapter (see also next example)
        adapter = new MyAdapter(myDataset);
        recyclerView.setAdapter(adapter);
    }

}

MyAdapter

package com.example.listview;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.recyclerview.widget.RecyclerView;

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    private String[] mDataset;
    public static class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView textView;
        public MyViewHolder(View v) {
            super(v);
            textView = v.findViewById(R.id.textView);
        }
    }

    public MyAdapter(String[] myDataset) {
        mDataset = myDataset;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.my_text_view, parent, false);
        MyViewHolder vh = new MyViewHolder(v);
        return vh;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        holder.textView.setText(mDataset[position]);
    }

    @Override
    public int getItemCount() {
        return mDataset.length;
    }


}

4. 关键代码

//在布局中添加了 RecyclerView 微件之后，获取对象句柄，将其连接到布局管理器，并为要显示的数据附加适配器

// use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
        recyclerView.setHasFixedSize(true);

        // use a linear layout manager
        layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        // specify an adapter (see also next example)
        adapter = new MyAdapter(myDataset);
        recyclerView.setAdapter(adapter);

//要将所有数据输入列表中，您必须扩展 RecyclerView.Adapter 类。此对象会创建项的视图，并在原始项不再可见时用新数据项替换部分视图的内容。

//MyViewHolder参数需要是View,否则报错(TextView与String[]类型不匹配)

public MyViewHolder(View v) {
            super(v);
            textView = v.findViewById(R.id.textView);
        }

@Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.my_text_view, parent, false);
        MyViewHolder vh = new MyViewHolder(v);
        return vh;
    }

参考链接：
https://developer.android.google.cn/guide/topics/ui/layout/recyclerview?hl=zh_cn#java

MyViewHolder参数需要是View,否则报错(TextView与String[]类型不匹配)
https://www.jianshu.com/p/4fc6164e4709

RecyclerView 的item显示的间距过大(item占满父布局)
https://www.jianshu.com/p/3047c050b556