FragmentTransaction完成时的事件

Question

FragmentTransaction完成后是否可以有一个事件？

FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, fragment).commit();

事实上,我为我的应用程序使用抽屉,并且我想invalidateOptionsMenu();在事务完成时触发以更改操作栏的菜单.

Answer 1

您无需等待片段事务完成,您可以调用

getSupportFragmentManager().executePendingTransactions();

在commit()函数调用之后.

这将确保交易完成.

Answer 2

喜!试试这个:

private OnBackStackChangedListener backStackListener =  new OnBackStackChangedListener() {

    @Override
    public void onBackStackChanged() {
        String name = "";
        int position = getSupportFragmentManager().getBackStackEntryCount();
        if(position!=0){
           FragmentManager.BackStackEntry backEntry=getSupportFragmentManager().getBackStackEntryAt(position-1);
           name=backEntry.getName();


        }
        if(position==0){
            mainActionBar();
        }
        else if(name=="someWord"){
            mainActionBar2();
        }
        else{
            mainActionBar3();
        }

    }
};
 getSupportFragmentManager().addOnBackStackChangedListener(backStackListener);

并在事务中向backStack添加标记,如下所示:

getSupportFragmentManager().beginTransaction()
                .replace(R.id.main, SomeFragment.newInstance(some argument))
                .addToBackStack("someWord").commit();

Answer 3

为时已晚，但这可能会有所帮助（放在这里供某人使用）：

....
fragmentTransaction.replace(R.id.contentFrame, fragment);
fragmentTransaction.runOnCommit(new Runnable() // be carefull on this call. check documentation!!
{
    @Override
    public void run()
    {
        ... do something...  // this will  run after fragment's on resume. you can check.
    }
});
fragmentTransaction.commit();

请检查 runOnCommit() 方法限制！

Answer 4

@Override
public void onResume() {
    super.onResume();
    getActivity().invalidateOptionsMenu();
}

FragmentTransaction完成后,将调用Fragment的生命周期方法,如onResume()

仅供参考,片段可以有自己的菜单,请参阅http://developer.android.com/reference/android/app/Fragment.html#setHasOptionsMenu(boolean)