在 Fragment 中以编程方式创建复选框

Question

我正在尝试在我的 Fragment 中创建一个复选框。我没有让它正常工作。这是我的片段代码：

 public class DriverFragment extends Fragment {

    public DriverFragment(){

    }
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        CheckBox check = new CheckBox(getActivity());
        check.setText("ff");
        check.setPadding(10,10,10,10);
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        params.setMargins(5,5,5,5);
        params.gravity = Gravity.NO_GRAVITY;
        check.setLayoutParams(params);
        check.setGravity(Gravity.CENTER);
        LinearLayout lin = (LinearLayout)getView().findViewById(R.id.driverLayout);
        lin.addView(check);
    }

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

我收到这个错误：

Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference

我得到这个是因为带有 LinearLayout 的视图尚未加载吗？

Answer 1

参见 片段生命周期 你无法在 OnCreate() 中获取视图小部件，因为它在 OnCreateView();

中膨胀

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_driver, container, false);

        CheckBox check = new CheckBox(getActivity());
        check.setText("ff");
        check.setPadding(10, 10, 10, 10);
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        params.setMargins(5, 5, 5, 5);
        params.gravity = Gravity.NO_GRAVITY;
        check.setLayoutParams(params);
        check.setGravity(Gravity.CENTER);

        LinearLayout lin = (LinearLayout) view.findViewById(R.id.driverLayout);
        lin.addView(check);

        return view;
    }

在 Fragment 中以编程方式创建复选框

Create checkbox programmatically in Fragment

android

android-checkbox

programmatically-created