我有一个包含 4 个 fragment 的 Activity 。在屏幕旋转时, Activity 崩溃并显示以下内容:
04-01 16:43:46.670: E/AndroidRuntime(2401): Caused by: java.lang.InstantiationException: can't instantiate class com.example.activity.FragmentActivity$UserFragment; no empty constructor
04-01 16:43:46.670: E/AndroidRuntime(2401): at java.lang.Class.newInstanceImpl(Native Method)
04-01 16:43:46.670: E/AndroidRuntime(2401): at java.lang.Class.newInstance(Class.java:1319)
04-01 16:43:46.670: E/AndroidRuntime(2401): at android.app.Fragment.instantiate(Fragment.java:574)
我看过这个question这表示必须将 fragment 类声明为公开的。它被宣布为 public,但并没有解决问题。
以下是我的代码:
public class FragmentActivity extends Activity
{
public class TabListener implements ActionBar.TabListener
{
private Fragment mFragment;
public TabListener(Fragment fragment)
{
mFragment = fragment;
}
public void onTabSelected(Tab tab, FragmentTransaction ft)
{
ft.add(R.id.fragmentContainer, mFragment, null);
}
public void onTabUnselected(Tab tab, FragmentTransaction ft)
{
ft.remove(mFragment);
}
public void onTabReselected(Tab tab, FragmentTransaction ft)
{
}
}
public class UserFragment extends Fragment
{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
.....
.....
}
}
@Override
public void onCreate(android.os.Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_container);
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
Tab userTab = actionBar.newTab();
userTab.setIcon(R.drawable.person).setTabListener(new TabListener(new UserFragment()));
actionBar.addTab(userTab);
}
}
最佳答案
UserFragment 必须是静态嵌套类才能重新实例化:
public static class UserFragment extends Fragment {
....
}
关于android - fragment 引起的屏幕旋转时 Activity 崩溃,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9969482/