Android文件列表 RecyclerView
1. app gradle
dependencies {
implementation 'androidx.recyclerview:recyclerview:1.1.0'
2. AndroidManifest配置权限
权限
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
3. 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>
4. Activity代码
MainActivity
package com.example.myfile;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import android.os.Environment;
import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
private List<MyFile> myFileList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = findViewById(R.id.recyclerview);
// 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(myFileList);
recyclerView.setAdapter(adapter);
initMyFile(Environment.getExternalStorageDirectory());
}
private void initMyFile(File externalStorageDirectory) {
myFileList.clear();
List<File> files = new ArrayList<>();
Collections.addAll(files, externalStorageDirectory.listFiles());
for (File file : files) {
String fileName = file.getName();
MyFile myFile = new MyFile(fileName);
myFileList.add(myFile);
}
adapter.notifyDataSetChanged();
}
}
MyAdapter
package com.example.myfile;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
private List<MyFile> mFileList;
public static class MyViewHolder extends RecyclerView.ViewHolder {
public TextView textView;
public MyViewHolder(View v) {
super(v);
textView = v.findViewById(R.id.textView);
}
}
public MyAdapter(List<MyFile> list) {
mFileList = list;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.my_view, parent, false);
MyViewHolder myViewHolder = new MyViewHolder(v);
return myViewHolder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
MyFile myFile = mFileList.get(position);
holder.textView.setText(myFile.getFileName());
}
@Override
public int getItemCount() {
return mFileList.size();
}
}
MyFile
package com.example.myfile;
public class MyFile {
private String fileName;
public MyFile(String fileName) {
super();
this.fileName = fileName;
}
public String getFileName() {
return fileName;
}
}
5. 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(myFileList);
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;
}
//初始化文件列表,将指定文件夹内的所有文件信息,添加到List中;
//通过List中保存的每一个信息,生成RecyclerView Adapter需要的数据,并添加进去。
private void initMyFile(File externalStorageDirectory) {
myFileList.clear();
List<File> files = new ArrayList<>();
Collections.addAll(files, externalStorageDirectory.listFiles());
//生成RecyclerView Adapter需要的数据
for (File file : files) {
String fileName = file.getName();
MyFile myFile = new MyFile(fileName);
myFileList.add(myFile);
}
adapter.notifyDataSetChanged();
}
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
文件列表
https://blog.csdn.net/qq_40019723/article/details/79369529
https://blog.csdn.net/u013372185/article/details/52415234