单实例活动Android的碎片生命周期 [英] Android Fragment Lifecycle of Single Instance Activity

问题描述

我有一个singleInstance活动和片段，我实例中的onCreate（）方法，并添加到的FrameLayout容器放入活动的布局。活动什么都不做，除了打印出日志。 我现在用的是Android系统的支持-V4 lib和安卓2.3.3。

I have a singleInstance Activity and a Fragment which I instantiate in the onCreate() method and add into a FrameLayout container into the layout of the activity. The activity does nothing except printing out the logs. I am using the android-support-v4 lib and android 2.3.3.

我观察这个设置一个陌生的生命周期行为，我不知道你会帮我解释这一点。我将提供日志的生命周期：

I observed a strange lifecycle behavior with this setting and I wonder if you might help me to explain this. I will provide the logs for the lifecycles:

该活动的第一次调用：

    07-07 15:12:17.990 V/FragActivity( 2358): onCreate >> com.test.fragmentlife.FragActivity@44f98778
    07-07 15:12:21.010 V/FragActivity( 2358): onCreate <<
    07-07 15:12:21.020 V/LayoutFragment( 2358): onAttach > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:24.021 V/LayoutFragment( 2358): onAttach <
    07-07 15:12:24.021 V/LayoutFragment( 2358): onCreate > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:27.020 V/LayoutFragment( 2358): onCreate <
    07-07 15:12:27.020 V/LayoutFragment( 2358): onCreateView > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:30.022 V/LayoutFragment( 2358): onCreateView <
    07-07 15:12:30.030 V/LayoutFragment( 2358): onActivityCreated > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:33.030 V/LayoutFragment( 2358): onActivityCreated <
    07-07 15:12:33.030 V/LayoutFragment( 2358): onStart > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:36.030 V/LayoutFragment( 2358): onStart <
    07-07 15:12:36.040 V/FragActivity( 2358): onStart > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:12:39.041 V/FragActivity( 2358): onStart <
    07-07 15:12:39.041 V/LayoutFragment( 2358): onStop > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:42.040 V/LayoutFragment( 2358): onStop <
    07-07 15:12:42.040 V/FragActivity( 2358): onResume > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:12:45.041 V/FragActivity( 2358): onResume <
    07-07 15:12:45.041 V/LayoutFragment( 2358): onStart > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:48.040 V/LayoutFragment( 2358): onStart <
    07-07 15:12:48.040 V/LayoutFragment( 2358): onResume > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:12:51.042 V/LayoutFragment( 2358): onResume <

第一个问题：为什么是片段的onStop（）创建活动的过程中的方法？该片段在屏幕上显示的罚款。

First question: why is the onStop() method of the fragment during the creation of the activity? The Fragment displays fine on the screen.

之后，我重新启动该活动由烧制的意图，导致活动onNewIntent（）lidecycle方法。

After that I restart the activity by firing an intent, causing the onNewIntent() lidecycle method of the activity.

    07-07 15:13:17.220 V/LayoutFragment( 2358): onPause > LayoutFragment{44f467c8 #0 id=0x7f070000}
    07-07 15:13:20.220 V/LayoutFragment( 2358): onPause <
    07-07 15:13:20.230 V/FragActivity( 2358): onPause > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:13:23.231 V/FragActivity( 2358): onPause <
    07-07 15:13:23.231 V/FragActivity( 2358): onNewIntent > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:13:26.231 V/FragActivity( 2358): onNewIntent <
    07-07 15:13:26.231 V/FragActivity( 2358): onResume > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:13:29.230 V/FragActivity( 2358): onResume <

第二个问题：为什么是onResume片段（）方法不叫？它仍然显示在屏幕上。据我了解活动和生命周期方法应当齐头并进......

Second question: why is the onResume() method of the fragment not called? It is still visible on the screen. As far as i know activity and lifecycle methods should go hand in hand...

之后，我重新启动活动第二次：

After that i restart the activity a second time:

    07-07 15:13:42.140 V/FragActivity( 2358): onPause > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:13:45.143 V/FragActivity( 2358): onPause <
    07-07 15:13:45.143 V/FragActivity( 2358): onNewIntent > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:13:48.144 V/FragActivity( 2358): onNewIntent <
    07-07 15:13:48.150 V/FragActivity( 2358): onResume > com.test.fragmentlife.FragActivity@44f98778
    07-07 15:13:51.151 V/FragActivity( 2358): onResume <

现在的fragmen的生命周期方法，不会触发所有..怎么会这样？

Now the lifecycle methods of the fragmen are not triggered at all.. how is that?

推荐答案

我不能回答的问题1，虽然我已经注意到这种行为为好，但我很少做大量的工作在我的onStop方法（我喜欢的onPause和onResume），我可以帮助你的第二个问题。

I can't answer question 1, although I've noticed that behavior as well, but I rarely do much work in my onStop methods (I favor onPause and onResume), I can help with your 2nd question.

这里的问题（这绝对是一个谷歌的bug）要么是一个与FragmentActivity问题或活动的生命周期作为一个整体（取决于你如何看待它）。

The problem here (which is definitely a google bug) is either a problem with FragmentActivity or the Activity lifecycle as a whole (depending on how you look at it).

基本上，FragmentActivity移动它的片段到续状态，而不是在onResume方法（作为一个一般理智的人可能会认为），但在onPostResume方法。这是一切都很好，除了onPostResume方法永远不会被调用的singleIntstance / singleTask活动时，该活动回顾与onNewIntent。

Basically, the FragmentActivity moves its fragments to the resumed state, not in the onResume method (as a generally sane person might think) but in the onPostResume method. This is all well and good, except that the onPostResume method never gets called in a singleIntstance/singleTask activity when the activity is recalled with onNewIntent.

所以，我没有（有进口的，而不是仅仅的jar支持包code，）是修改FragmentActivity像这样...

So what I did (having imported the support package code, instead of just the jar) was modify FragmentActivity like so...

//this boolean is only ever set to true in onNewIntent
private boolean mResumeNeedsToDoDispatch = false; 

/**
 * Ensure any outstanding fragment transactions have been committed.
 */
@Override
protected void onResume() {
    super.onResume();
    mResumed = true;

    //Check if onNewIntent was called. If so, dispatch resumes to fragments now
    if (mResumeNeedsToDoDispatch) {
        mResumeNeedsToDoDispatch = false;
        mFragments.dispatchResume();
    }

    mFragments.execPendingActions();
}


/**
 * Google, I think you forgot this #(
 */
@Override
public void onNewIntent(Intent newIntent) {
    super.onNewIntent(newIntent);
    mResumeNeedsToDoDispatch = true;
}

请注意，我不只是调用mFragments.dispatchResume（）在onNewIntent导致这会导致片段onResume方法，在这种情况下被调用两次。我不是100％肯定这是为什么，但是这就是我发现在我的测试。

Notice that I didn't just call mFragments.dispatchResume() in onNewIntent cause this causes the fragment onResume methods to be called twice in this case. I'm not 100% sure why that is, but that is what I noticed in my tests.

希望这有助于：）

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