android - 从服务内的线程更新 ProgressDialog

Question

我想从服务内的线程增加一个进度对话框，我真的很难做到，这是我的代码，请帮助我。

我尝试了很多不同的方法，包括 asyncTask(我遇到了上下文问题)并尝试使用静态函数但它无法正常工作，我是 android 的新手，请在这里向我解释问题。

Activity

public class MainActivity extends Activity {

ProgressDialog progressBar;

private void showProgrssBar() {

    progressBar.show();
}

private void dismissProgressBar() {

    progressBar.dismiss();
}

private void increaseProgressBar(int total) {

    progressBar.incrementProgressBy(total);
};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
     createProgressBarDialog();

Intent n = new Intent(this, myService.class);
startService(n);

}

private void createProgressBarDialog()
{
    progressBar = new ProgressDialog(this);
    progressBar.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    progressBar.setMax(200);
    progressBar.setMessage("Recieving bluetooth data");
    progressBar.setCanceledOnTouchOutside(false);
}

服务:

 public class myService extends Service
{

    private myThread myThread;

    Handler handler = new Handler()
    {
        @Override
        public void handleMessage(android.os.Message msg) 
        {
            int total = msg.getData().getInt("total");

            if (total == -1)
            {
                dismissProgressBar();
            }
            else if (total == 0)
            {
                showProgrssBar();
            }
            else
            {
                increaseProgressBar(total);
            }       
        }   
    };

            @Override
            public int onStartCommand(Intent intent, int flags, int startId)
            {
                myThread = new myThread(handler);
                myThread.start();

                return START_STICKY;
            }

线程

  class myThread extends Thread
    { 
         Handler h;
    int numOfLinesToRead = 220;
    int line = 0;


    public myThread(Handler h)
    {
        this.h = h;
    }

    private void increaseProgressBarOnActivity(int i_MsgType)
    {
         Message msg = h.obtainMessage();
         Bundle b = new Bundle();
         b.putInt("total", i_MsgType);
         msg.setData(b);
         h.sendMessage(msg);
    }

    @Override
    public void run() {
        super.run();
        int increase;
        try
        {
            Thread.sleep(1);
        }
        catch (InterruptedException e)
        {

            e.printStackTrace();
        }
          for (; line < 220; line++) 
            {
               increase = (line*100/numOfLinesToRead);
                if (increase != 0)
                {
                    increaseProgressBarOnActivity(increase);   
                    try
                    {
                        Thread.sleep(90);
                    }
                    catch (InterruptedException e)
                    {

                        e.printStackTrace();
                    }

                }
            }

    }
}

Answer 1

Despite you having already tried AsyncTask, I still would strongly recommend to use it.

只需看一下onProgressUpdate() 方法。它用于从 AsyncTask 更新 UI。

下面是它的外观示例:

private class DownloadFilesTask extends AsyncTask<String, Integer, Long> {

    private ProgressDialog progressBar;

    @Override
    protected void onPreExecute(){ 
       super.onPreExecute();
       progressBar= new ProgressDialog(getApplicationContext());
       progressBar.setMessage("Loading...");
       progressBar.show();    
    }

    protected Long doInBackground(String... params) {

       long someLong;
       // do something here with params

       // the Integer variable is used for progress
       publishProgress(i);
       // call it for example while downloading a file

       return someLong;
    }

    // this is called whenever you call puhlishProgress(Integer)
    protected void onProgressUpdate(Integer... progress) {
         progressBar.incrementProgressBy(progress[0]);
    }

    // the onPostexecute method receives the return type of doInBackGround()
    protected void onPostExecute(Long result) {
       // do something with the result
       progressBar.dismiss();
   }
}

您说您的问题是获取上下文。嗯:Service是 Context

因此您可以简单地将 AsyncTask 设为您服务的内部类，然后使用它的 Context。