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我试图让我的片段使用findFragmentById,但每次我在它的地方得到空,我也尝试使用findFragmentByTag并添加一个标记到我的添加事务,但也是这样。为什么findFragmentById总是返回null
以下代码是经修饰的空白起始模板(为简单起见)
公共类MainActivity延伸活动{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(null);
setContentView(R.layout.activity_main);
FragmentManager fragmentManager = getFragmentManager();
if (savedInstanceState == null) {
fragmentManager.beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
PlaceholderFragment placeholderFragment = (PlaceholderFragment) fragmentManager
.findFragmentById(R.id.container);
if (placeholderFragment == null) {
Log.i("TAG", "placeholderFragment is null");
} else {
Log.i("TAG", "placeholderFragment is not null");
}
}
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}
}
}
我试图替换为add(R.id.container, new PlaceholderFragment(), "TAG")
的添加然后尝试与findFragmentByTag("TAG")
访问它也没有成功。
如何让我的代码按预期工作?
烨,事实上,这是这个问题,谢谢 – Kaylee