java - 当另一个线程中调用Thread.sleep()时，UI线程被阻塞

我试图从SD卡中的Runnable称为PcmDataReader的文本文件中读取文本文件，并相应地在UI-Thread中更新TextView statusTextView。
我正在使用handler将消息从PcmDataReader传递到UI-Thread。
 为了能够观察statusTextView的变化，我在Thread.sleep(5000)中放置了PcmDataReader。
问题是UI线程被阻塞，直到文件I / O和睡眠完成并且最终更新（即“文件读取完成..”）仅显示在statusTextview上。
 我在这里想念什么？以下是我的代码：


MainActivity.java：

package com.example.pcmreader;

import android.Manifest;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import android.widget.Button;


public class MainActivity extends AppCompatActivity implements View.OnClickListener{
    private TextView statusTextView ;
    priavte Button updateButton;

    private PcmDataReader pcmData = new PcmDataReader();
    private static Handler handler;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        handler = new Handler()
        {
            @Override
            public void handleMessage (Message message)
            {
                String msg = (String) message.obj;
                if (statusTextView != null)
                    statusTextView.setText(msg);
            }

        };

        setContentView(R.layout.main);

        statusTextView= (TextView) findViewById(R.id.statusTextView);

        ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, 100);

    updateButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View view)
    {
    statusTextView.setText("Initiating Read .. ");
        pcmData.run();

    }

    public static Handler getHandler ()
    {
        return handler;
    }
}

PcmDataReader.java：

package com.example.pcmreader;


import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.util.Log;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;


public class PcmDataReader implements Runnable
{
    private int [] samples = new int[6000];
    private int i;
    private boolean completedReading;
    private File sdcard = Environment.getExternalStorageDirectory();
    private File file = new File(sdcard,"rishav_log.txt");

    @Override
    public void run()
    {

        i=0;
        completedReading = false;
        try
        {
            BufferedReader br = new BufferedReader(new FileReader(file));
            String line;
            Handler uiHandler= MainActivity.getHandler();
            Message msg = uiHandler.obtainMessage();
            msg.obj="File openned, Reading data..";
            uiHandler.sendMessage(msg);

            while ((line = br.readLine()) != null)
                 samples[i++]=Integer.parseInt(line);

            Thread.sleep(5000); //dummy sleep to observe the update of textView in UI thead
            br.close();
            completedReading = true;

            msg = uiHandler.obtainMessage();
            msg.obj="File Reading Complete..";
            uiHandler.sendMessage(msg);
        }
        catch (IOException e)
        {
            Log.i("file read",e.getMessage());
        }
    catch (InterruptedException e)
    {
            e.printStackTrace();
        }
    }

}

最佳答案

调用runnable应该在单独的线程中。

更换

pcmData.run();

至

Thread t1 =new Thread(pcmData);
t1.start();