Android - 何时从Fragment调用Activity的方法

Question

I have an Activity which has Toolbars . When I move to Fragment A, the Toolbar needs to be changed specifically for Fragment A.

Fragment A contains 4 other Fragments as A is a FragmentPager .

I called the method of the Activity like :

((NewsfeedActivity)getActivity()).changeTitleBesideIcon("Purchases");
        ((NewsfeedActivity)getActivity()).changeIcon(getResources().getDrawable(R.drawable.purchase));
        ((NewsfeedActivity)getActivity()).changeBackground(getResources().getColor(R.color.purpleC));
        ((NewsfeedActivity)getActivity()).hideToolbarBottomMarketplace();

Somehow, the icon doesn't get changed, BUT the title does, along with the color.. I even set the method to setVisibility(View.VISIBLE); on the icon..

Is there a specific state where that kind of method needs to be called? Or am I just doing it wrong?

Update

This is my changeIcon method

public void changeIcon(Drawable imageDrawable){
    toolbarImage.setVisibility(View.GONE);
    toolbarIcon.setVisibility(View.VISIBLE);
    toolbarIcon.setImageDrawable(imageDrawable);
}

toolbarImage is an ImageView located in the Toolbar

This is how it is :

<Toolbar>
    <RelativeLayout>
        <ImageView> //Toolbar Image
        <ImageView>// Toolbar Icon
    </RelativeLayout>
</Toolbar>

And I'm calling the methods in the onCreateView() ..

Answer 1

try it.

public void changeIconToolbar(int resId){
    getSupportActionBar().setHomeAsUpIndicator(resId);
}

it work for me

Answer 2

Well, now I can see that you possibly use Toolbar (rather than ActionBar ) and once again I assume that the Toolbar is the toolbar added in API level 21 rather than AppCompat Toolbar .

In order to use this toolbar , I assume that you have called setActionBar (toolbar) to replace the ActionBar with the toolbar from your layout.

NOTE: Without calling this setActionBar (toolbar) , your activity will continue using the default ActionBar (in onCreate() ) and nothing will be shown.

Now, when the toolbar is in its place. I think your code will work.

PS: I recommend to use AppCompat Toolbar