从消费者服务更新UI

Question

我正在android中构建一个简单的生产者 - 消费者用例，具有以下功能：

1. 主要活动有一个全屏ImageView
2. 生产者服务使用图像和时间填充队列，以便查看每个图像
3. 消费者线程读取这些图像并将imageView设置为所提及的时间。

MainActivity：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageView myImageView = (ImageView) findViewById(R.id.imageView);
    Intent consumerServiceIntent = new Intent(this, PlaylistConsumer.class);
    startService(consumerServiceIntent);

如何从PlaylistConsumer类更新imageView？

Answer 1

首先你需要send broadcast from your service

// somewhere in PlaylistConsumer, when it needs to update
Intent intent = new Intent();
intent.setAction(I_HAVE_CONSUMED_PLAYLIST); // I_HAVE_CONSUMED_PLAYLIST is public static final String
sendBroadcast(intent);

然后，在活动中，create和register广播接收器

//create
mReceiver = new BroadcastReceiver() {
 @Override
 public void onReceive(Context context, Intent intent) {
     ImageView myImageView = (ImageView) findViewById(R.id.imageView);
     //update myImageView here
   }
 };
//register
@Override
protected void onResume() {
     super.onResume();
     registerReceiver(mReceiver, new IntentFilter(PlaylistConsumer.I_HAVE_CONSUMED_PLAYLIST));
}
// unregister when paused
@Override
protected void onPause() {
    if(mReceiver != null) {
        unregisterReceiver(receiver);
        mReceiver = null;
    }
    super.onPause();
}

我还建议使用LocalBroadcastManager注册和发送广播。