第一步activity-main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".MainActivity"><EditTextandroid:id="@+id/editText"android:layout_width="301dp"android:layout_height="wrap_content"android:ems="10"android:inputType="textPersonName"android:text="请输入歌曲名称"tools:layout_editor_absoluteX="10dp"tools:layout_editor_absoluteY="11dp" /><Buttonandroid:id="@+id/button"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentRight="true"android:text="搜索歌曲"tools:layout_editor_absoluteX="264dp"tools:layout_editor_absoluteY="8dp" /><ProgressBarandroid:id="@+id/progress"android:layout_below="@+id/button"style="?android:attr/progressBarStyleHorizontal"android:layout_width="match_parent"android:layout_height="25dp"/><TextViewandroid:id="@+id/text"android:layout_below="@+id/progress"android:layout_width="match_parent"android:layout_height="20dp"android:text="TextView" /><ListViewandroid:id="@+id/ListName"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_below="@+id/text"android:layout_alignParentEnd="true"android:layout_alignParentRight="true"android:layout_marginTop="7dp"android:layout_marginEnd="3dp"android:layout_marginRight="3dp"android:text="Hello World!"tools:layout_editor_absoluteX="0dp"tools:layout_editor_absoluteY="98dp" ></ListView></RelativeLayout>
第二步MainActivity.java
package com.example.mymps001;import android.annotation.SuppressLint;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;import androidx.appcompat.app.AppCompatActivity;import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.Socket;
import java.net.URL;
import java.net.URLConnection;public class MainActivity extends AppCompatActivity {TextView tv;ListView ls;Button btn;EditText edt;String NeedFindWords;String[] strArr;private static final String Path="http://192.168.1.7/song/2.DJ - 侧脸 (言寺).mp3";private ProgressBar progressBar;private TextView textView;private Button button;private int FileLength;private int DownedFileLength=0;private InputStream inputStream;private URLConnection connection;private OutputStream outputStream;private final int HANDLER_MSG_TELL_RECV = 0x124;@SuppressLint("HandlerLeak")Handler handler = new Handler(){public void handleMessage(Message msg){//接受到服务器信息时执行
//            Toast.makeText(MainActivity.this,(msg.obj).toString(),Toast.LENGTH_LONG).show();
//            tv.setText((msg.obj).toString());System.out.println((msg.obj).toString());strArr = (msg.obj).toString().split("\n");ArrayAdapter<String> arrayAdapter= new ArrayAdapter<String> (MainActivity.this, android.R.layout.simple_list_item_1,strArr);ls.setAdapter(arrayAdapter);}};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button btn = findViewById(R.id.button);edt=(EditText)findViewById(R.id.editText);ls= (ListView) findViewById(R.id.ListName);//这个是文件下载控件progressBar=(ProgressBar) findViewById(R.id.progress);textView=(TextView) findViewById(R.id.text);button=(Button) findViewById(R.id.button);ls.setOnItemClickListener(new AdapterView.OnItemClickListener() {private String MusicPath="";@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position, long id) {System.out.println(id);System.out.println("********************************************");
//                Toast.makeText(MainActivity.this,"点击了："+position+"行",Toast.LENGTH_SHORT).show();Toast.makeText(MainActivity.this,strArr[position],Toast.LENGTH_SHORT).show();MusicPath=strArr[position];//开启下载线程DownedFileLength=0;// TODO Auto-generated method stubThread thread=new Thread(){public void run(){try {DownFile(MusicPath);} catch (Exception e) {// TODO: handle exception}}};thread.start();
//                System.out.println(strArr[position]);
//                System.out.println("********************************************");}});//        tv= (TextView) findViewById(R.id.ReData);btn.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// 响应事件NeedFindWords=edt.getText().toString();startNetThread();}});}private void startNetThread() {new Thread() {@Overridepublic void run() {try {Socket socket = new Socket("192.168.1.7", 666);InputStream is = socket.getInputStream();OutputStream out = socket.getOutputStream();out.write(NeedFindWords.getBytes());					//3.发送out.flush();byte[] bytes = new byte[1024];int n = is.read(bytes);Message msg = handler.obtainMessage(HANDLER_MSG_TELL_RECV, new String(bytes, 0, n));msg.sendToTarget();is.close();socket.close();} catch (Exception e) {}}}.start();}private Handler handler2=new Handler(){public void handleMessage(Message msg){if (!Thread.currentThread().isInterrupted()) {switch (msg.what) {case 0:progressBar.setMax(FileLength);Log.i("文件长度----------->", progressBar.getMax()+"");break;case 1:progressBar.setProgress(DownedFileLength);int x=DownedFileLength*100/FileLength;textView.setText(x+"%");break;case 2:String[]  strs=Path.split("/");int lastSTR=0;for(int i=0,len=strs.length;i<len;i++){lastSTR=len;System.out.println(strs[i].toString());}Toast.makeText(getApplicationContext(), "下载完成", Toast.LENGTH_LONG).show();Toast.makeText(getApplicationContext(), strs[lastSTR-1].toString(), Toast.LENGTH_LONG).show();break;default:break;}}}};private void DownFile(String urlString){String LastName="";/** 连接到服务器*/try {URL url=new URL(urlString);String[] MFileName=urlString.split("/");LastName=MFileName[MFileName.length-1];System.out.println("***********************"+LastName);connection=url.openConnection();if (connection.getReadTimeout()==5) {Log.i("---------->", "当前网络有问题");// return;}inputStream=connection.getInputStream();} catch (MalformedURLException e1) {// TODO Auto-generated catch blocke1.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}/** 文件的保存路径和和文件名其中Nobody.mp3是在手机SD卡上要保存的路径，如果不存在则新建*/String savePAth= Environment.getExternalStorageDirectory()+"/DownFile";File file1=new File(savePAth);if (!file1.exists()) {file1.mkdir();}String savePathString=Environment.getExternalStorageDirectory()+"/DownFile/"+LastName;File file =new File(savePathString);if (!file.exists()) {try {file.createNewFile();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** 向SD卡中写入文件,用Handle传递线程*/Message message=new Message();try {outputStream=new FileOutputStream(file);byte [] buffer=new byte[1024*4];FileLength=connection.getContentLength();message.what=0;handler2.sendMessage(message);while (DownedFileLength<FileLength) {outputStream.write(buffer);DownedFileLength+=inputStream.read(buffer);Log.i("-------->", DownedFileLength+"");Message message1=new Message();message1.what=1;handler2.sendMessage(message1);}Message message2=new Message();message2.what=2;handler2.sendMessage(message2);} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}
}权限添加<uses-permission android:name="android.permission.INTERNET"></uses-permission><uses-permission android:name="android.permission.INTERNET" /><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />android:usesCleartextTraffic="true"