碎片和方向改变

7 回答

• -1

  我遇到了同样的问题，我想我想出了另一个解决方案 . 此解决方案可能更好，因为您不必将片段添加到后台堆栈 .

  从 Activity.onSaveInstanceState() before 中调用 super.onSaveInstanceState() 的活动中删除右侧片段 . 这对我有用：

  public MyActivity extends Activity
  {   
      @Override
      public onCreate(Bundle state)
      {
          super.onCreate(state);
  
          // Set content view
          setContentView(R.layout.my_activity);
  
          // Store whether this is a dual pane layout
          mDualPane = findViewById(R.id.rightFragHolder) != null;
  
          // Other stuff, populate the left fragment, etc.
          .
          .
          .
          if (mDualPane)
          {
              mRightFragment = new RightFragment();
              FragmentManager fm = getFragmentManager();
              FragmentTransaction ft = fm.beginTransaction();
              ft.replace(R.id.rightFragHolder, mRightFragment);
              ft.commit()
          }
      }
  
  
      @Override
      public void onSaveInstanceState(Bundle state)
      {
          if (mDualPane)
          {
              FragmentManager fm = getFragmentManager();
              FragmentTransaction ft = fm.beginTransaction();
              ft.remove(mRightFragment);
              ft.commit()
          }
  
          super.onSaveInstanceState(state);
      }
  
  
      private boolean mDualPane;
      private Fragment mRightFragment;
  }
  

  回复于 2024-04-26T19:49:06+08:00
• -1

  如果要保留片段，请尝试不保留它 .

  setRetainInstance(false)
  

  代替

  setRetainInstance(true)
  

  回复于 2024-04-26T19:49:06+08:00
• 13

  通常，您将有两个片段（左/右），一个主要活动和一个容器活动用于正确的片段（仅在电话设备上显示时） . 此博客文章中描述了这一点：The Android 3.0 Fragments API

  public class MyActivity extends FragmentActivity
      implements MyListFragment.MyContextItemSelectedListener {
  
      @Override
      public void onCreate(final Bundle bundle) {
          super.onCreate(bundle);
  
          setContentView(R.layout.activity);
      }
  
      // Callback from ListFragment
      @Override
      public void myContextItemSelected(final int action, final long id) {
          if (action == R.id.men_show) {
              processShow(id);
          }
      }
  
      private void processShow(final long id) {
          if (Tools.isXlargeLand(getApplicationContext())) {
              Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.right);
              if (fragment == null ||
                      fragment instanceof MyEditFragment ||
                      (fragment instanceof MyShowFragment && ((MyShowFragment) fragment).getCurrentId() != id)) {
                  fragment = new MyShowFragment(id);
  
                  FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
                  transaction.replace(R.id.right, fragment);
                  transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
                  transaction.commit();
              }
          } else {
              Intent intent = new Intent();
              intent.setClass(this, MyShowActivity.class);
              intent.putExtra("ID", id);
              startActivityForResult(intent, MyConstants.DLG_TABLE1SHOW);
          }
      }
  
      private static boolean isXlargeLand(final Context context) {
          Configuration configuration = context.getResources().getConfiguration();
  
          return (((configuration.screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) == Configuration.SCREENLAYOUT_SIZE_XLARGE) &&
                          configuration.orientation == Configuration.ORIENTATION_LANDSCAPE);
      }
  }
  

  回复于 2024-04-26T19:49:06+08:00
• 1

  如果您有一个带有左窗格和右窗格的双窗格活动，并且其中一个窗格（通常是右窗格）假设在设备切换到纵向模式时不显示，请让Android执行其操作并重新创建右窗格 . 但是在右窗格的onCreateView中，您应该做的第一件事是检查窗格使用的布局元素之一是否可用 . 如果不是，请使用FragmentManager删除片段并立即返回：

  public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)
  {
      View myView = getActivity().findViewById(R.id.myView);
  
      if (myView == null)
      {
        FragmentTransaction fragTransaction = getFragmentManager().beginTransaction();
        fragTransaction.remove(this);
        fragTransaction.commit();
        return null;
      }
   }
  

  回复于 2024-04-26T19:49:06+08:00
• 0

  我想我已经解决了 .

  我将片段添加到后台堆栈中，然后在活动关闭之前再将其弹出，这有效地消除了它 . 到目前为止似乎工作 .

  回复于 2024-04-26T19:49:06+08:00
• 0

  Android会在屏幕旋转期间重新创建两个片段 . 但是如果你将下面的检查添加到onCreateView（）中，它将阻止你解决问题：

  @Nullable
      @Override
      public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
                               @Nullable Bundle savedInstanceState) {
          if (container == null) {
              // Currently in a layout without a container, so no
              // reason to create our view.
              return null;
          }
  
          // inflate view and do other stuff
      }
  

  我从Android Developers blog拿走了这个 .

  回复于 2024-04-26T19:49:06+08:00
• -4

  您不再需要此活动，因为片段将以内嵌方式显示 . 所以你可以完成这项活动

  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  
      if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
          // we are in landscape so you do not need this activity anymore
          finish();
          return;
      }
  
      if (savedInstanceState == null) {
           // plugin right pane fragment
           YourFragment frgm = new YourFragment();
           getSupportFragmentManager().beginTransaction()
                  .add(..., frgm).commit();
      }
  }
  

  回复于 2024-04-26T19:49:06+08:00