Android 自定义加载程序(整数数组列表)不会刷新用户界面

Question

我正在尝试使用整数数组的自定义加载程序 在后台有一个服务来向数组添加值。当服务将条目添加到数组列表时。我正在尝试刷新刷新 UI 列表视图。使用广播接收器作为内容观察器。

问题是正在调用 deliverResult，但它不会使用新值刷新 UI。

Listview 的主活动实现加载器回调。 非常感谢大家..

package loaders.com.myapplication;
import android.content.AsyncTaskLoader;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.Loader;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.support.v4.content.LocalBroadcastManager;
import android.widget.Toast;
import java.util.List;
import java.util.ArrayList;
import java.util.Random;
/**
 * Created by k.sekar on 1/7/2015.
 */
class testLoader extends AsyncTaskLoader<List<Integer>>{
    public static List<Integer> intlist = new ArrayList<Integer>();
    private testService mService;
    public  final String BROADCAST_ADDED = "ADDED";

    private Context mContext;
    private Receiver mReceiver;
   public testLoader(Context context)
    {
       super(context);
      
        Intent serviceMedia = new Intent(getContext(), testService.class);
        getContext().startService(serviceMedia);
        if(intlist == null)
        {
            intlist = new ArrayList<Integer>();
        }
        intlist.add(10);
        intlist.add(20);
        intlist.add(30);
        intlist.add(40);
        if(mReceiver == null)
        {
            mReceiver = new Receiver(this);
        }
    }
 
    public  class Receiver extends BroadcastReceiver{
         final testLoader mLoader;
        public Receiver(testLoader loader)
        {
            mLoader = loader;
        }
        @Override
        public void onReceive(Context context, Intent intent) {
            String message = intent.getAction();
            if(message.compareTo("ADDED") == 0)
            {            
                  mLoader.onContentChanged();
            }
        }
    }
    @Override
    public List<Integer> loadInBackground() {
      //    ArrayList<Integer> list = new ArrayList<Integer>();
        IntentFilter filter = new IntentFilter(BROADCAST_ADDED);
        LocalBroadcastManager.getInstance(getContext()).registerReceiver(mReceiver,filter);
      //  LocalBroadcastManager.getInstance(mLoader.getContext()).registerReceiver(this, filter);
        return intlist;
    }
    @Override
    protected void onStartLoading() {
        if(intlist != null)
        {
            deliverResult(intlist);
        }
        if(mRefreshData == true)
        {
            mRefreshData = false;
            forceLoad();
        }
    }
    @Override
    protected void onStopLoading()
    {
        cancelLoad();
    }
    @Override
    protected void onReset()
    {
        super.onReset();
        onStopLoading();
        intlist = null;
        if(intlist != null)
        {
            intlist = null;
        }
        if(mReceiver != null)
        {
            LocalBroadcastManager.getInstance(getContext()).unregisterReceiver(mReceiver);
            mReceiver = null;
        }
    }
    @Override
    public void cancelLoadInBackground(){
        super.cancelLoadInBackground();
    }
    @Override
    public void onCanceled(List<Integer> data)
    {
        //  mContext.unregisterReceiver(mReceiver);
         super.onCanceled(data);
         data = null;
    }
    @Override
    public void deliverResult(List<Integer> data)
    {
        if(isReset())
        {
            data = null;
            return;
        }
        List<Integer> oldData = intlist;
        intlist = data;
        if (isStarted()) {
            
            super.deliverResult(data);
        }
        if(oldData != null && oldData != intlist)
        {
            oldData = null;
        }
    }
   

}

活动的代码片段

import android.app.LoaderManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.Loader;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends ActionBarActivity implements LoaderManager.LoaderCallbacks<List<Integer>> {
     ListView mListView;
     ArrayAdapter<Integer> mAdapter;
    public static final String BROADCAST_REFRESH = "REFRESH";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView = (ListView)this.findViewById(R.id.listnumbers);
        mListView.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
        mListView.setAdapter(mAdapter);
        getLoaderManager().initLoader(1, null, this);
    }
    protected void onStop()
    {
          super.onStop();       
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    @Override
    public Loader<List<Integer>> onCreateLoader(int id, Bundle args) {
        if(id == 1)
        {
            return new IntLoader(getApplicationContext());
        }
        return null;
    }
    @Override
    public void onLoadFinished(Loader<List<Integer>> loader, List<Integer> data) {
      
        if (mAdapter == null)
        {
            mAdapter = new ArrayAdapter<Integer>(this,R.layout.list_element, data);
            mListView.setAdapter(mAdapter);
         
        }
    }
    @Override
    public void onLoaderReset(Loader<List<Integer>> loader) {
        mListView.setAdapter(null);
     
    }


}

Answer 1

在活动类中，试试这个。

@Override
public void onLoaderReset(Loader<List<Integer>> loader) {
    mListView.notifyDataSetChanged();
}

Answer 2

getLoaderManager().restartLoader(CATEGORY_LOADER, null, yourActivity.this);

这对我有用。 这里CATEGORY_LOADER有一个整数值1 null用于额外的参数。