从intenthandler传递到需要它的方法的上下文是什么?

一般来说,Android Service Activity 或 BroadcastReceiver

服务 活动 Android Service Broadcast 发送信息 广播接收机

定义 BROADCAST_FILTER 以便 可以确定消息意图来自服务:

public static String BROADCAST_FILTER = <Your service class>.class.getName();

以下内容:

//send a broadcast intent from your service
Intent intent = new Intent();
intent.setAction(BROADCAST_FILTER);
intent.putExtra("message", "<your message here>")
sendBroadcast(intent);

在你的

private BroadcastReceiver receiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String message = intent.getStringExtra();
        Utils.showMessage(<your activity>.this, ...);
        //do your update here
    }
};

@Override
protected void onResume() {
    super.onResume();

    IntentFilter filter = new IntentFilter();
    //make sure your onReceive receives only the messages with this action
    filter.addAction(<Your Service>.BROADCAST_FILTER);
    registerReceiver(receiver, filter);
}

@Override
protected void onPause() {
    super.onPause();
    unregisterReceiver(receiver);
}

您应该为这个错误使用活动上下文,我希望能解决这个错误。

context=this;//并使用此上下文

因为我的应用程序的性质,我已经有了 BroadcastManager BroadcastReceiver 在问我问题之前,我已经做了一个很弱的尝试,类似于@user805311的建议。

showMessage 在一个 IntentService

在 publishProgress 对于 QueryDb if progress )通过另一个 Intent 导致异常,并立即通过 onPostExecute

public class QueryDb extends IntentService
{
  ...
  private void publishProgress(String progress) 
  {
    Intent intent = new Intent(MatchesActivity.SOME_ACTION);

    if(progress.toLowerCase().startsWith("Revise"))
    {
      intent.putExtra(MatchesActivity.STRING_EXTRA_NAME, progress);
      onPostExecute();
    }
    else ...
    ...
    LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}

在执行过程中,这种做法被称为“类似的”,如果继续下去,将无济于事:

  String messageText = "Revise code!";
  publishProgress(messageText);

MatchesActivity 保养

显示消息

public class MatchesActivity extends Activity implements QueryDb.DbProcListenerForQueryDb
{
  private BroadcastReceiver mMessageReceiver  = new BroadcastReceiver()
  {
    @Override public void onReceive(Context context, Intent intent)
    {
      String s = intent.getStringExtra(STRING_EXTRA_NAME) ;
      if(s.startsWith("Revise"))
      {
         showMessage(_context, "Oh, no...", s, null);
         MatchesActivity.this.setResult(RESULT_CANCELED);
      }
      else ...
      ...
    };  // BroadcastReceiver

显示消息 Context 显示消息 onActivityResult MainActivity ,它也在那里工作 收到并处理取消的“坏消息”时:

public class MainActivity extends Activity
{ 
  ...
  @Override protected void onActivityResult(int requestCode, int resultCode, Intent intentData)
  {
    if(resultCode != RESULT_OK)
    {
      showMessage(this, "Bad news", "Only Scrabble", mDatabase);
      return;
    }
    ...

显示消息 --它不把活动扩展到 主要活动 .