Question

我知道这个问题已被提出，但我没有成功回答。

我有一个带有回收站视图的片段。我有一个按钮，可以显示和隐藏这个片段。这一切都很好，直到屏幕的变化。然后重新创建片段，顶部的片段显示并隐藏，但后面有一个片段留在那里。

我知道我需要使用

if (savedInstanceState == null)

在某个地方，但无法成功在哪里。非常感谢，这是我的代码。

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);

    recyclerViewFragment = new RecyclerViewFragment();

    FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
    trans.add(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);
    trans.commit();
    trans.show(recyclerViewFragment);

    Button showHideButton = (Button)findViewById(R.id.button_show_hide);
    showHideButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            showHideFragment(recyclerViewFragment);
        }
    });
    showHideButton.playSoundEffect(SoundEffectConstants.CLICK);

}

public void showHideFragment(final Fragment fragment){

    FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
    trans.setCustomAnimations(android.R.anim.slide_in_left , android.R.anim.slide_out_right);

    if (fragment.isHidden()) {
        trans.show(fragment);
        Log.d("hidden","Show");
    } else {
        trans.hide(fragment);
        Log.d("Shown","Hide");
    }

    trans.commit();
}

非常感谢大家!!!!!!!

Answer 1

而不是：

trans.add(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);

试试这个：

trans.replace(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);

该名称具有误导性。如果是第一次，Replace实际上也可以作为添加。发生的事情是，当您的活动轮换时，再次调用onCreate()，以便您在现有活动的基础上添加相同的片段

Answer 2

我建议您对代码进行一些更改我想RECYCLER_FRAGMENT是一个常量，包含用于标记片段的标记

 RecyclerViewFragment recyclerViewFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    if(savedInstanceState == null) {
        recyclerViewFragment = new RecyclerViewFragment();

        FragmentTransaction trans = getSupportFragmentManager().beginTransaction();
        trans.add(R.id.recycle_view_container, recyclerViewFragment, RECYCLER_FRAGMENT);
        trans.commit();
    }else{
        recyclerViewFragment = getSupportFragmentManager().findFragmentByTag(RECYCLER_FRAGMENT);
        if(savedInstanceState.getString("vi").equals("hid")){
            getSupportFragmentManager().beginTransaction().hide(recyclerViewFragment).commit();
        }
    }

    Button showHideButton = (Button)findViewById(R.id.button_show_hide);
    showHideButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            FragmentManager manager = getSupportFragmentManager();

            if (fragment.isVisible()) {
                manager.beginTransaction().hide(recyclerViewFragment).commit();
            } else {
                manager.beginTransaction().show(recyclerViewFragment).commit();
            }
        }
    });


}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if(recyclerViewFragment.isVisible() == true){
        outState.putString("vi","vis");
    }else{
        outState.putString("vi", "hid");
    }
}

片段在方向更改时创建两次

2 个答案: