如何在BroadcastReceiver中使用ProgressDialog

Question

在BroadcastReceiver的extend活动中显示ProgressDialog时，我遇到了一个严重的问题。实际上，我想在每5秒内获取php文件中的数据。我使用AlarmManager来定义时间，并使用AsyncTask来获取托管的php数据。

这是我的AlarmDemo活动

public class AlarmDemo extends Activity {
Toast mToast;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_alarm_demo);

    // repeated alerm
    Intent intent = new Intent(AlarmDemo.this, RepeatingAlarm.class);
    PendingIntent sender = PendingIntent.getBroadcast(AlarmDemo.this, 0,
            intent, 0);

    // We want the alarm to go off 5 seconds from now.
    long firstTime = SystemClock.elapsedRealtime();
    firstTime += 5 * 1000;

    // Schedule the alarm!
    AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
    am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime,
            5 * 1000, sender);

    // Tell the user about what we did.
    if (mToast != null) {
        mToast.cancel();
    }
    mToast = Toast.makeText(AlarmDemo.this, "Rescheduled",
            Toast.LENGTH_LONG);
    mToast.show();
    // end repeatdalarm

}

}

这是我的RepeatingAlarm活动

public class RepeatingAlarm extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {

    Toast.makeText(context, "availble now", Toast.LENGTH_SHORT).show();
}

}

这是我的AsyncTask活动

public class AsyncronoustaskAndroidExample extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.asyncronoustask_android_example);



    String serverURL = "http://androidexample.com/media/webservice/getPage.php";

    new LongOperation().execute(serverURL);


}

// Class with extends AsyncTask class
private class LongOperation extends AsyncTask<String, Void, Void> {

    private final HttpClient Client = new DefaultHttpClient();
    private String Content;
    private String Error = null;
    private ProgressDialog Dialog = new ProgressDialog(
            AsyncronoustaskAndroidExample.this);
    TextView uiUpdate = (TextView) findViewById(R.id.output);

    protected void onPreExecute() {
        // NOTE: You can call UI Element here.

        // UI Element
        uiUpdate.setText("Output : ");
        Dialog.setMessage("Downloading source..");
        Dialog.show();
    }

    // Call after onPreExecute method
    protected Void doInBackground(String... urls) {
        try {



            // Server url call by GET method
            HttpGet httpget = new HttpGet(urls[0]);
            ResponseHandler<String> responseHandler = new BasicResponseHandler();
            Content = Client.execute(httpget, responseHandler);

        } catch (ClientProtocolException e) {
            Error = e.getMessage();
            cancel(true);
        } catch (IOException e) {
            Error = e.getMessage();
            cancel(true);
        }

        return null;
    }

    protected void onPostExecute(Void unused) {
        // NOTE: You can call UI Element here.

        // Close progress dialog
        Dialog.dismiss();

        if (Error != null) {

            uiUpdate.setText("Output : " + Error);

        } else {

            uiUpdate.setText("Output : " + Content);

        }
    }

}

}

现在，当我分别使用AsyncTask和报警管理器代码时，它是work find，但当我尝试将它们组合到onReceive方法中时，ProgressDialog中出现错误。它说“构造函数ProgressDialog(RepeatingAlarm)是未定义的”。你能帮帮我吗，因为我是Android新手

Answer 1

试一试

public void onReceive(Context context, Intent intent) {
    ProgressDialog Dialog = new ProgressDialog(context);

    Toast.makeText(context, "available now", Toast.LENGTH_SHORT).show();
}