android - 非法参数异常 : No view found for id 0x7f07003c for fragment

Question

我是 fragment 的新手。我尝试了简单的 fragment 示例。但它会抛出错误。我不知道出了什么问题。

public class NewActivity extends Activity {
    int mStackLevel = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (savedInstanceState == null) {
            Fragment newFragment = NewFragment
                    .newInstance(mStackLevel);
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.add(R.id.simple_fragment, newFragment).commit();
        } else {
            mStackLevel = savedInstanceState.getInt("level");
        }
    }
    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("level", mStackLevel);
    }
    public static class NewFragment extends Fragment {
        int mNum;
        Context context;

        static NewFragment newInstance(int num) {
            NewFragment f = new NewFragment();

            // Supply num input as an argument.
            Bundle args = new Bundle();
            args.putInt("num", num);
            f.setArguments(args);

            return f;
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            mNum = getArguments() != null ? getArguments().getInt("num") : 1;
            context = getActivity();
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View v = inflater.inflate(R.layout.example_fragment, container,
                    false);         
            return v;
        }
    }

}

我的 logcat 显示:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.FragmentExample/com.example.FragmentExample.NewActivity}: java.lang.IllegalArgumentException: No view found for id 0x7f07003c for fragment NewFragment{40ff0850 #0 id=0x7f07003c}

Answer 1

ft.add(R.id.simple_fragment, newFragment).commit();

您错过了 Activity 的 setContentView。如果没有 View 层次结构，则无法添加您的 fragment 。

注意:您的 fragment 由 Activity 托管。所以需要先给activity设置内容。