Question

我有一个在后台运行的更新程序服务，并在发现更新时保持广播意图。我有一个活动（时间轴活动），它根据Updater Service提供的更新显示一些数据。我有另一个与时间线活动相关联的广播接收器，它监听更新器服务广播的意图。现在，只要Updater Service获取新更新，它就会正确地广播意图，并且也会被与时间轴活动关联的Receiver接收。问题是在收到广播后，UI上的数据没有刷新。负责更新的SimpleCursorAdapter在接收方的notifyDataSetChanged()中调用onReceive()后没有做任何事情。

以下是TimelineActivity.java的代码

public class TimelineActivity extends BaseActivity {

public static final String TAG = "TimelineActivity";
private Cursor cursor;
private ListView listTimeline;
//Adapter for connecting ListView and the cursor containing info from database
private SimpleCursorAdapter timelineAdapter;  
static final String[] FROM = { DBHelper.C_CREATED_AT, DBHelper.C_USER,
    DBHelper.C_TEXT }; 
static final int[] TO = { R.id.textCreatedAt, R.id.textUser, R.id.textText };  

YambaApplication yamba;
private TimelineReceiver timelineReceiver = null; 
private IntentFilter intentFilter = new IntentFilter("com.pack.android.yamba.NEW_STATUS"); 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.timeline);

    //Fetch the views
    listTimeline = (ListView) findViewById(R.id.listTimeline);

    yamba = (YambaApplication) getApplication();
    if(yamba.getSharedPreferences().getString("username", null) == null)
    {
        startActivity(new Intent(this, PrefsActivity.class)); // 
        Toast.makeText(this, R.string.msgSetupPrefs, Toast.LENGTH_LONG).show();
    }

    // Check if preferences have been set
    if (yamba.getSharedPreferences().getString("username", null) == null) { // 
      startActivity(new Intent(this, PrefsActivity.class));
      Toast.makeText(this, R.string.msgSetupPrefs, Toast.LENGTH_LONG).show();
    }

    timelineReceiver = new TimelineReceiver();
}

@Override
protected void onDestroy() {
    super.onDestroy();
    Log.d(TAG, "On Destroy of Timeline Activity called !");
    //close the database
    yamba.getStatusData().close();
}

//TODO : check for onWindowFocusChanged(boolean hasFocus) method for detailed test
@Override
protected void onResume() {
    super.onResume();
    Log.d(TAG, "On Resume of Timeline Activity called !");
    setUpList();
    Log.d(TAG, "Setting up list completed !");
    registerReceiver(timelineReceiver, intentFilter);
}

@Override
protected void onPause() {
    super.onPause();
    Log.d(TAG, "On Pause of Timeline Activity called !");
    Log.d(TAG, "In onPause timelineAdapter.getCursor().close() "+timelineAdapter.getCursor());
    timelineAdapter.getCursor().close();
    Log.d(TAG, "Closed timelineAdapter.getCursor");
    Log.d(TAG, "In onPause cursor = "+cursor);
    cursor.close();
    Log.d(TAG, "Closed cursor");
    unregisterReceiver(timelineReceiver);
}

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    Log.d(TAG, "Does Timeline Activity has focus ? "+ hasFocus);
}

@Override
protected void onStop() {
    super.onStop();
    Log.d(TAG, "OnStop of Timeline Activity called !");
    Log.d(TAG, "In onStop timelineAdapter.getCursor().close() "+timelineAdapter.getCursor());
    timelineAdapter.getCursor().close();
    Log.d(TAG, "Closed timelineAdapter.getCursor");
    Log.d(TAG, "In onStop cursor = "+cursor);
    cursor.close();
    Log.d(TAG, "Closed cursor");
}

private void setUpList() {

    // Get the data from the database
    // TODO : verify for honeycomb which will use loaderManagers for managing lifecycle of a cursor
    Log.d(TAG, "Setting up the list");
    cursor = yamba.getStatusData().getStatusUpdates();
    Log.d(TAG, "cursor is "+ cursor);
    startManagingCursor(cursor);

    // Setup Adapter
    timelineAdapter = new SimpleCursorAdapter(this, R.layout.row, cursor, FROM, TO);
    Log.d(TAG, "Timeline adapter is "+ timelineAdapter);
    Log.d(TAG, "Count of data = " + timelineAdapter.getCount());
    Log.d(TAG, "Is cursor empty ? " + timelineAdapter.isEmpty());
    timelineAdapter.setViewBinder(VIEW_BINDER); // 
    listTimeline.setAdapter(timelineAdapter);
}

static final ViewBinder VIEW_BINDER = new ViewBinder() {

    @Override
    public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
        if(view.getId() != R.id.textCreatedAt)
            return false;

        // Update the created at text to relative time
        long timeStamp = cursor.getLong(columnIndex);
        CharSequence relativetime = DateUtils.getRelativeTimeSpanString(timeStamp);
        ((TextView)view).setText(relativetime);
        return true;
    }
};

class TimelineReceiver extends BroadcastReceiver 
{
    private static final String TAG = "TimelineReceiver";
    @Override
    public void onReceive(Context context, Intent intent) 
    { 
        Log.d(TAG, "Just before requery, cursor is " + cursor);
        yamba.getStatusData().getCursor().requery(); //
        Log.d(TAG, "Just after requery");
        timelineAdapter.notifyDataSetChanged(); //
        onResume();
        Log.d(TAG, "on Receive of "+TAG);
    }
}

}

UpdaterService中的以下代码是广播意图：

Intent intent = new Intent("com.pack.android.yamba.NEW_STATUS");
                  String NEW_STATUS_EXTRA_COUNT = "com.pack.android.yamba.EXTRA_COUNT";
                  intent.putExtra(NEW_STATUS_EXTRA_COUNT, newUpdates);
                  updaterService.sendBroadcast(intent);

有人可以提出建议吗？

谢谢， Adithya。

Answer 1

timelineReceiver = new TimelineReceiver();  
registerReciever(timelineReciever,new IntentFilter("EXTRA_COUNT"));

请注册接收者。

在调用关联的广播接收器的onReceive后，活动不会刷新。

1 个答案: