未调用Android DialogFragment onViewCreated

Question

我正在使用android兼容库(v4修订版8).在自定义DialogFragment中,没有调用onViewCreated的覆盖方法.例如.

public class MyDialogFragment extends DialogFragment{
    private String mMessage;
    public MyDialogFragment(String message) {
        mMessage = message;
    }

    @Override
    public Dialog onCreateDialog( Bundle savedInstanceState){
        super.onCreateDialog(savedInstanceState);
        Log.d("TAG", "onCreateDialog");
        setRetainInstance(true); 
        //....do something
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        Log.d("TAG", "onViewCreated");
        //...do something
    }
}

onViewCreated未被记录.

Answer 1

好吧,onViewCreated状态的文档"在onCreateView(LayoutInflater,ViewGroup,Bundle)之后立即调用"已经返回".

DialogFragment使用onCreateDialog而不是onCreateView,因此不会触发onViewCreated.(将是我的工作理论,我没有潜入android源来确认).

Answer 2

这就是我确保在 kotlin 中调用 onViewCreated 的方式：

class MyDialog: DialogFragment() {

    private lateinit var dialogView: View

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        dialogView = LayoutInflater.from(context).inflate(R.layout.dialog, null)
        val dialog = MaterialAlertDialogBuilder(context!!)
                .setView(dialogView)
                .create()

        return dialog
    }

    // Need to return the view here or onViewCreated won't be called by DialogFragment, sigh
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return dialogView
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        // Yay it's now called!
    }

    override fun onDestroyView() {
        dialogView = null
        super.onDestroyView()
    }
}

Answer 3

从我的测试,onViewCreated不叫,如果onCreateView返回null,这是默认行为,所以如果你不使用onCreateView但手动调用setContentView中onCreateDialog,你可以手动调用onViewCreated来自onCreateDialog:

@Override public Dialog onCreateDialog(Bundle savedInstanceState) {
    final Dialog d = super.onCreateDialog(savedInstanceState);
    d.setContentView(R.layout.my_dialog);
    // ... do stuff....
    onViewCreated(d.findViewById(R.id.dialog_content), savedInstanceState);
    return d;
}

在这种情况下,请确保in元素中my_dialog.xml有android:id="@+id/dialog_content"

Answer 4

您可以从源代码中看到发生了什么:

首先,由于您不覆盖onCreateView()您的片段,因此视图将为null.这可以从源代码中Fragment看出- 默认返回null:

// android.support.v4.app.Fragment.java
@Nullable
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
        @Nullable Bundle savedInstanceState) {
    return null;
}

其次,因为你的视图是null,所以FragmentManager不会调用onViewCreated().从源代码FragmentManager:

// android.support.v4.app.FragmentManager.java
if (f.mView != null) {
    f.mInnerView = f.mView;
    // ... 

    // only called if the fragments view is not null!
    f.onViewCreated(f.mView, f.mSavedFragmentState);
} else {
    f.mInnerView = null;
}