我有一个带有NavigationDrawer的Activity,所以我有几个碎片:
public class MainActivity extends FragmentActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
mDrawerMenu = (ListView) findViewById(R.id.drawer_menu);
mProfileFragment = new ProfileFragment();
mMainPageFragment = new MainPageFragment();
mTestPageFragment = new TestPageFragment();
mSettingsPageFragment = new SettingsPageFragment();
mOnlineNeededFragment = new OnlineNeededFragment();
mRegistrationFragment = new RegistrationFragment();
mAuthorizationPageFragment = new AuthorizationFragment();
//Adding fragments to NavigationDrawer
}
//selecting Fragment from NavigationDrawer
private void selectItem(int position) {
Fragment fragment = mDrawerMenuItems.get(position).getPage();
// Insert the fragment by replacing any existing fragment
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.content_frame, fragment)
.commit();
//...
}
//...
}
每个片段都有自己的私有变量,我保存
public class MainPageFragment extends Fragment {
private int var1;
private Date var2;
private Date var3;
@Override
public View onCreateView(final LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (savedInstanceState != null) {
var1 = savedInstanceState.getInt("var1");
var2 = (Date) savedInstanceState.getSerializable("var2");
var3 = (Date) savedInstanceState.getSerializable("var3");
}
//...
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("var1", var1);
outState.putSerializable("var2", var2);
outState.putSerializable("var3", var3);
}
}
并在“onCreateView”中恢复 . 但是所有我旋转屏幕活动重新创建所有碎片,所以我在所有碎片中丢失了我的旧状态 .
我找到了“getSupportFragmentManager() . putFragment(outState,TAG,Fragment)” . 此函数可以将Fragment的实例保存到Bundle并稍后使用“getSupportFragmentManager() . getFragment(savedInstanceState,TAG)”将其恢复,因此Activity不会重新创建此Fragment并且不会丢失私有变量 .
但是FragmentManager只能保存一个片段,这个片段在FragmentManager中 . 当我尝试将所有片段放入Bundle时,我得到例外:“片段ProfileFragment {41a27730}当前不在FragmentManager中” .
如何在Bundle中保存所有碎片以在旋转屏幕后恢复它们?
1 回答
你的问题在于onCreate方法总是创建一个新的Fragment
放一个if语句来检查它是否为null .