java - 在 Android Fragments 中按下

Question

我有一个 Activity

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Activities.Dashboard.MainActivity">
        <FrameLayout
            android:id="@+id/main_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
        </FrameLayout>
</RelativeLayout>

我有 10 个 fragment ，我在 main_container 框架布局中展示它们我如何编写代码以返回到上一个 fragment 这是我的 Activity 代码:

public class MainActivity extends AppCompatActivity{
@Override
    protected void onCreate(Bundle savedInstanceState) {
        fragmentManager = getSupportFragmentManager();
        fragment = new HomeFragment(); 
        final FragmentTransaction transaction = 
        fragmentManager.beginTransaction();
        transaction.replace(R.id.main_container, fragment).commit();
  }
}

在主页 fragment 中:

public class HomeFragment extends Fragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.bottom_bar_home, container, false);
        fragmentManager = getActivity().getSupportFragmentManager();
         // ...... etc

        return view;
    }

}

并且所有 fragment 都包含另一个数据的相同代码。

Answer 1

这段代码对我有用:我输入基本 Activity :

 @Override
    public void onBackPressed() {
        int count = getFragmentManager().getBackStackEntryCount();
        if (count == 0) {
            super.onBackPressed();
        } else {
            getFragmentManager().popBackStack();
        }
    } 

每次调用 fragment 我都会放入 AddtoBackStack(null) :

  fragment = new yourFragment();
  final FragmentTransaction transaction = fragmentManager.beginTransaction();
  transaction.replace(R.id.main_container, 
  fragment).addToBackStack(null).commit();