选项1

Question

我有两个threads.One用于递增值。对于每个增量，我需要通知主线程。下面是我的主要线程，这是一项活动

public class MainActivity extends Activity {
    private ProgressBar progressBar;
    private int progressStatus = 1;
    private TextView textView;
    private Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        progressBar = (ProgressBar) findViewById(R.id.progressBar1);
        textView = (TextView) findViewById(R.id.textView1);

        ProgressUpdate b = new ProgressUpdate();
        b.start();
        Log.e("SAMEERA", "Satrting ProgressUpdate");
        synchronized (b) {
            try {

                Log.e("SAMEERA", "synchronized synchronized");
                Log.e("SAMEERA", "progressStatus is "+b.total);
                b.wait();


                Log.e("SAMEERA", "progressStatus is "+b.total);
                progressBar.setProgress(progressStatus);
                textView.setText(progressStatus + "/" + progressBar.getMax());
            } catch (InterruptedException e) {
            }
            System.out.println("Total is: " + b.total);
        }


    }
}

下面是我的增量线程。

package com.example.zwtouch;

import android.util.Log;

public class ProgressUpdate extends Thread {

    int total;

    public void run() {
        total=0;
        synchronized (this) {
            for (int i = 0; i < 100; i++) {
                total += i;
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                Log.e("SAMEERA", "run run total is "+i);
                notify();
            }

        }
    }

}

如果总数增加，我需要每次都通知。但是没有发生。在for循环结束后，它调用主线程......哪里出错？

Answer 1

选项1

使用Handler

使用ProgressUpdate和ProgressBar个对象填充Handler。
在每次进度中，使用Handler更新ProgressBar

public class ProgressUpdate extends Thread {

    int total;
    ProgressBar mProgressBar;
    Handler mHandler;

    public ProgressUpdate(Handler h, ProgressBar pb) {
        mHandler = h;
        mProgressBar = pb;
    }

    public void run() {
        total=0;
        for (int i = 0; i < 100; i++) {
           // Update the progress bar via a Handler
           mHandler.post(new Runnable() {
               public void run() {
                   mProgressBar.setProgress(i);
               }
           });
        }
    }
}

像这样设置

new ProgressUpdate(handler, progressBar).start();

选项2（推荐）

这是另一种方法，您可以使用AsyncTask来实现此目标。这种方式的优点是onProgressUpdate和onPostExecute都在UI-Thread上运行。

将此类置于MainActivity内部

private class ProgressUpdate extends AsyncTask<Void, Integer, Integer> {

     protected Integer doInBackground(Void... dummy) {
          int total = 0;
          for (int i = 0; i < 100; i++) {
                total += i;
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                Log.e("SAMEERA", "run run total is "+i);
                // Notify UI Thread
                publishProgress(i);
            }
         return total;
     }

     protected void onProgressUpdate(Integer... i) {
         // do something with 'i' on UI Thread   
         progressBar.setProgress(i);      
     }

     protected void onPostExecute(Integer total) {
         // do something with 'total' on UI Thread
         // for instance
         progressBar.setVisibility(View.GONE);
     }
  }

在onCreate上设置ProgressUpdate，如下所示

@Override
protected void onCreate(Bundle savedInstanceState) {
    // ... 
    new ProgressUpdate().execute();
    // ...
}

如何在每次增加价值时收到通知

1 个答案:

选项1

选项2（推荐）