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第一步activity-main.xml
   
       
        
        
        
        
        
    
   第二步MainActivity.javapackage 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
   
     arrayAdapter= new ArrayAdapter
    
      (                    MainActivity.this, android.R.layout.simple_list_item_1,strArr);            ls.setAdapter(arrayAdapter);        }    };    @Override    protected 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="";            @Override            public 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 stub                Thread 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() {
               @Override            public void onClick(View v) {
                   // 响应事件                NeedFindWords=edt.getText().toString();                startNetThread();            }        });    }    private void startNetThread() {
           new Thread() {
               @Override            public 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
     
      ", "当前网络有问题");                // return;            }            inputStream=connection.getInputStream();        } catch (MalformedURLException e1) {
               // TODO Auto-generated catch block            e1.printStackTrace();        } catch (IOException e) {
               // TODO Auto-generated catch block            e.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 block                e.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
      
       ", 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 block            e.printStackTrace();        } catch (IOException e) {
               // TODO Auto-generated catch block            e.printStackTrace();        }    }}权限添加    
           
           
           
                   android:usesCleartextTraffic="true"
      
     
    
   

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