[英]How to use EventBus in Activity and Fragment on Android
In my application i want use EventBus for call some methods in another activities . 在我的应用程序中,我想使用EventBus在另一个活动中调用某些方法。
I want when click on backButton
in activity
( DetailActivity ), call one method in fragment
( MainFragment ). 我想在activity
( DetailActivity )中单击backButton
时,在fragment
( MainFragment )中调用一个方法。
in MainFragment i have recyclerView
and open this activity
( DetailActivity ) with recyclerView adapter
. 在MainFragment中,我具有recyclerView
并使用recyclerView adapter
打开此activity
( DetailActivity )。
I write below codes in DetailActivity and MainFragment but when click on backButton
, not call method in MainFragment . 我下面写的DetailActivity和MainFragment代码,但点击时backButton
,而不是在MainFragment 调用方法 。
MainFragment codes : MainFragment代码:
public void onStart() {
EventBus.getDefault().register(this);
super.onStart();
}
@Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this);
}
@Subscribe(threadMode = ThreadMode.MAIN)
public void onRefreshAuctions(EventUpdateAuctionsState event){
Toast.makeText(context, "OK", Toast.LENGTH_SHORT).show();
}
DetailActivity codes : 详细活动代码:
@Override
public void onBackPressed() {
finishWithAnimate();
EventBus.getDefault().post(new EventUpdateAuctionsState());
}
EventUpdateAuctionsState codes : EventUpdateAuctions状态代码:
public class EventUpdateAuctionsState {
public EventUpdateAuctionsState() {
}
}
Why not call method in MainFragment? 为什么不在MainFragment中调用方法?
How can i fix it? 我该如何解决?
Perhaps your Fragment is in stopped state when event is fired. 触发事件时,您的Fragment可能处于停止状态。 Try to register, unregister in create/destroy lifecycle. 尝试注册,然后在创建/销毁生命周期中注销。
public void onCreate() {
super.onCreate();
EventBus.getDefault().register(this);
}
@Override
public void onDestroy() {
super.onDestroy();
EventBus.getDefault().unregister(this);
}
Suggestion 建议
By the way why are you using EventBus for just backpress implementation. 顺便说一句,为什么将EventBus用作backpress实施。 You can simply do this. 您可以简单地做到这一点。 If you fragment is child of DetailActivity
. 如果片段是DetailActivity
子DetailActivity
。
@Override
public void onBackPressed() {
finishWithAnimate();
// get your fragment
if(fragment!=null) fragment.onRefreshAuctions();
}
You can use getFragmentManager().findFragmentByTag("tag")
if you don't have fragment instance. 如果没有片段实例,则可以使用getFragmentManager().findFragmentByTag("tag")
。
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