Android onHandleIntent 和 onStartCommand 的区别

Question

我目前正在编写一个需要 IntentService 的 android 程序。当我将代码放入 onHandleIntent 函数时，代码不会运行，但它不会在 MainActivity 中给出错误。但是当我将我的代码复制到 onStartCommand 时，它运行完美。

问题是我想知道 onHandleIntent 和 onStartCommand 之间有什么区别。谢谢。

代码:

在onHandleIntent中:

System.out.println("SERVICE STARTED! ! !");
//System.out.println(intent.getBooleanExtra("once", Boolean.FALSE));
if (intent.getBooleanExtra("once", Boolean.FALSE)) {
    Check();
}
mHandler.postDelayed(mRunnable, 3000);

Answer 1

从 the docs 开始:

IntentService 执行以下操作:

• Creates a default worker thread that executes all intents delivered to onStartCommand() separate from your application's main thread.
• Creates a work queue that passes one intent at a time to your onHandleIntent() implementation, so you never have to worry about multi-threading.
• Stops the service after all start requests have been handled, so you never have to call stopSelf().
• Provides default implementation of onBind() that returns null.
• Provides a default implementation of onStartCommand() that sends the intent to the work queue and then to your onHandleIntent() implementation.

还有:

All this adds up to the fact that all you need to do is implement onHandleIntent() to do the work provided by the client. (Though, you also need to provide a small constructor for the service.)

所以 IntentService 是具有这些特殊属性的“自定义”服务。所以没有必要覆盖 onStartCommand()，实际上，您不应该这样做，除非您使用的是常规 Service 类。

IntentService 用法的一些示例:

Activity.java

Intent it = new Intent(getApplicationContext(), YourIntentService.class);
it.putExtra("Key", "Value");
startService(it);

YourIntentService.java

public YourIntentService() {
    super("YourIntentService");
}

@Override
protected void onHandleIntent(Intent intent) {

    if (intent != null) {
        String str = intent.getStringExtra("key");
        // Do whatever you need to do here.
    }
    //...
}

您还可以检查this tutorial或 this one有关 Service 和 IntentService 的更多信息。

另外，检查 the docs .