java - 在android中浏览Fragment而不将其添加到backstack中

Question

我正在使用 Android 应用程序。我面临着像在后堆栈历史记录中添加 fragment 这样的问题。让我清楚地解释一下，我想从 fragment A 导航到 fragment B，然后使用 fragment B 中的按钮单击返回 fragment A。以上场景运行良好，在导航到 fragment A 后，当我单击设备中的后退箭头时，导航到 fragment B。我不希望这种情况发生。给我一个解决方案。我的代码结构如下:

fragment A:

.......
FragmentB fragmentB = new FragmentB();
showFragmentOmitStack(fragmentB);
....


public void showFragmentOmitStack(Fragment fragment) {
 FragmentTransaction transaction = getFragmentManager().beginTransaction();
 transaction.add(R.id.container,fragment);//add // replace
 transaction.addToBackStack(null);
 transaction.commit();
}

fragment B:

FragmentA fragmentA = new FragmentA();
showFragment(fragmentA, "FragmentA");


public void showFragment(Fragment fragment, String back_stack_name) {
 FragmentManager fragmentManager = thisActivity.getFragmentManager();
 FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
 fragmentTransaction.add(R.id.container, fragment);
 fragmentTransaction.addToBackStack(back_stack_name);
 fragmentTransaction.commit();
}

在我的 Activity java 文件中:

@Override
public void onBackPressed() {
 DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
 if (drawer.isDrawerOpen(GravityCompat.START)) {
     drawer.closeDrawer(GravityCompat.START);
   } else {
    if (getFragmentManager().getBackStackEntryCount() == 0) {
      showAlertDialog(Constants.EXIT_APP, Constants.APP_NAME);
     } else {
        getFragmentManager().popBackStackImmediate();
            }
        }
    }

Answer 1

试试这个:

@Override
public void onBackPressed() {
    if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
        getSupportFragmentManager().popBackStack();
    }else {
       if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
           drawerLayout.closeDrawer(GravityCompat.START);
         } else {
            super.onBackPressed();
        }  
    }
}