Android片段回压没有任何数据丢失

Question

当我单击每个导航列表时，我正在创建一个带有导航抽屉的应用程序，新片段将加载。其中一个片段有listView。当我单击此列表时，加载另一个片段。现在我使用导航抽屉移动到不同的片段。每次我想移动到上一个片段而不更改任何数据时，我都按后退按钮。我该怎么做？

我正在使用以下代码加载片段：

FragmentManager fm = getFragmentManager();
        for (int i = 0; i < fm.getBackStackEntryCount(); i++) {
            fm.popBackStack();
        }
    FragmentTransaction fragmentTransaction = fm.beginTransaction();
            fragmentTransaction.replace(R.id.fragmentHome, fr);
            fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
            fragmentTransaction.commit();

简而言之:: 每次后按我都想加载前一个片段而不重新创建它

Answer 1

我认为这可能会有所帮助

从Fragmentmanager做PopBackStack

FragmentManager fm = getFragmentManager();
        for (int i = 0; i < fm.getBackStackEntryCount(); i++) {
            fm.popBackStack();
        }

在那个片段中

View mView ; //this will be global

@Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        try {
            if (mView == null) {
                // view will be initialize for the first time .. you can out condition for that if data is not null then do not initialize view again. 
                mView = inflater.inflate(R.layout.xml,container, false);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return mView;
    }

Answer 2

public  void addFragment( final Fragment newFragment, final Fragment hideFragment) {
    final FragmentManager fragmentManager = getFragmentManager();
    final FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.hide(hideFragment);
    fragmentTransaction.add(R.id.container, newFragment, newFragment.getClass().getSimpleName());
    fragmentTransaction.addToBackStack(hideFragment.getClass().getSimpleName());
    fragmentTransaction.commitAllowingStateLoss();
}

使用它而不是替换片段。将解决您的问题。