完成服务后，UI组件未在onReceiveResult中更新

Question

您好我正在使用服务从本地教程中加载来自网址的数据（Background Service Tutorial）。

我有2项活动。第一个用于启动Activity，启动服务，第二个用于启动服务。当我从第二个活动开始服务并在那里等待服务完成时，ui组件会正确更新。

但是当我从第二个Activity启动服务时，完成它并再次启动第二个活动，UI组件在服务完成时不会更新。但是获取的数据正确地正确地进入onReceiveResult，只是UI视图没有得到更新。

为什么会这样？我怎样才能解决这个问题？

我的代码：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
     /* Allow activity to show indeterminate progressbar */
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setContentView(R.layout.activity_my);

    btnStartserv=(Button)findViewById(R.id.buttonserv);

      /* Initialize listView */
    //listView = (ListView) findViewById(R.id.listView);

    /* Starting Download Service */
    mReceiver = new DownloadResultReceiver(new Handler());
    mReceiver.setReceiver(MyActivity.this);

    btnStartserv.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            Toast.makeText(MyActivity.this,"Service Started",Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(Intent.ACTION_SYNC, null, MyActivity.this, DownloadService.class);

             /* Send optional extras to Download IntentService */
            intent.putExtra("url", url);
            intent.putExtra("receiver", mReceiver);
            intent.putExtra("requestId", 101);

            startService(intent);



        }
    });
}

onReceiveResult：

 @Override
 public void onReceiveResult(int resultCode, Bundle resultData) {
    switch (resultCode) {
        case DownloadService.STATUS_RUNNING:

            setProgressBarIndeterminateVisibility(true);
            break;
        case DownloadService.STATUS_FINISHED:

            setContentView(R.layout.activity_my);

            Toast.makeText(MyActivity.this,"Service Finished",Toast.LENGTH_SHORT).show();

            /* Hide progress & extract result from bundle */
            setProgressBarIndeterminateVisibility(false);

            String[] results = resultData.getStringArray("result");

            System.out.println("size"+results.length);

            listView = (ListView) findViewById(R.id.listView);

            if(listView == null ){
                System.out.println("listview is null");

            }else{
                System.out.println("listview is NOT NULL");

            }

            btnStartserv=(Button)findViewById(R.id.buttonserv);
            btnStartserv.setText("Service Finished!!!");

            /* Update ListView with result */
            arrayAdapter = new ArrayAdapter(MyActivity.this,       android.R.layout.simple_list_item_1, results);
            listView.setAdapter(arrayAdapter);

            break;
        case DownloadService.STATUS_ERROR:
            /* Handle the error */
            String error = resultData.getString(Intent.EXTRA_TEXT);
            Toast.makeText(this, error, Toast.LENGTH_LONG).show();
            break;
    }
} 

修改：添加了DownloadResultReceiver类

DownloadResultReceiver：

public class DownloadResultReceiver extends ResultReceiver {
private Receiver mReceiver;

public DownloadResultReceiver(Handler handler) {
    super(handler);
}

public void setReceiver(Receiver receiver) {
    mReceiver = receiver;
}

public interface Receiver {
    public void onReceiveResult(int resultCode, Bundle resultData);
}

@Override
protected void onReceiveResult(int resultCode, Bundle resultData) {
    if (mReceiver != null) {
        mReceiver.onReceiveResult(resultCode, resultData);
    }
}

}