我尝试从DialogFragment实现回调。
有一个很好的示例，但他们不会从DialogFragment打开此Fragment。
http://developer.android.com/guide/topics/ui/dialogs.html#PassingEvents
所以这是我的代码：
public class EditDateDialogFragment extends DialogFragment {
// Use this instance of the interface to deliver action events
EditDateDialogListener mListener;
/* The activity that creates an instance of this dialog fragment must
* implement this interface in order to receive event callbacks.
* Each method passes the DialogFragment in case the host needs to query it. */
public interface EditDateDialogListener {
public void onDialogPositiveClick(DialogFragment dialog);
public void onDialogNegativeClick(DialogFragment dialog);
}
public static EditDateDialogFragment newInstance( int currentCategoryId ) {
EditDateDialogFragment p = new EditDateDialogFragment();
Bundle args = new Bundle();
args.putInt("currentRecordId", currentCategoryId);
p.setArguments(args);
return p;
}
@Override
public void onCreate(Bundle savedInstanceState) {
mCurrentRecordId = getArguments().getInt("currentRecordId");
super.onCreate(savedInstanceState);
}
public void onAttach(SherlockActivity activity) {
super.onAttach(activity);
try {
// Instantiate the EditDateDialogListener so we can send events to the host
mListener = (EditDateDialogListener) activity;
} catch (ClassCastException e) {
// The activity doesn't implement the interface, throw exception
throw new ClassCastException(activity.toString() + " must implement EditDateDialogListener");
}
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
LayoutInflater inflater = LayoutInflater.from(getActivity());
final View v = inflater.inflate(R.layout.fragment_dialog_edit_date, null);
return new AlertDialog.Builder(getActivity()).setTitle("Set Date...").setView(v).setCancelable(true).setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Log.d("", "Dialog confirmed");
mListener.onDialogPositiveClick(EditDateDialogFragment.this);
}
}).setNegativeButton("Abort", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Log.d("", "Dialog abort");
dialog.cancel();
}
}).create();
}
}
在RecordDetailFragment.java中，我实现了接口并以这种方式创建了EditDateDialogFragment的新实例（只是重要的部分）：
public class RecordDetailFragment extends SherlockFragment implements EditDateDialogFragment.EditDateDialogListener {
...
DialogFragment editDateFragment = EditDateDialogFragment.newInstance( recordId );
editDateFragment.show(getActivity().getSupportFragmentManager(), "EditDateDialogFrame");
@Override
public void onDialogPositiveClick(DialogFragment dialog) {
LOGD(TAG, "Overriden Dialog confirmed");
//((EditDateDialogFragment) dialog).mDatePicker;
}
@Override
public void onDialogNegativeClick(DialogFragment dialog) {
// TODO Auto-generated method stub
}
...
}
现在永远不会调用onAttach(SherlockActivity activity)中的公开无效EditDateDialogFragment，因为我是从DialogFragment而不是Fragment创建Activity的？
如何解决这个问题？
更新： 在RecordDetailFragment中，我将其插入到onCreate（）
中if (savedInstanceState != null) {
EditDateDialogFragment dpf = (EditDateDialogFragment) getActivity().getSupportFragmentManager().findFragmentByTag("EditDateDialogFragment");
if (dpf != null) {
dpf.setListener((EditDateDialogListener) this);
}
}
我将DialogFragment的实例化更改为
EditDateDialogFragment editDateFragment = EditDateDialogFragment.newInstance( recordId );
editDateFragment.setListener((EditDateDialogListener) this);
editDateFragment.show(getActivity().getSupportFragmentManager(), "EditDateDialogFragment");
注意EditDateDialogFragment而不是DialogFragment。 我不确定如何在对话框中更新引用。
答案 0 :(得分：10)
刚刚遇到同样的问题，解决方案非常简单。而不是覆盖
public void onAttach(Context context) {}
重写：
public void onAttach(Activity activity) {}
DialogFragment现在一切正常。
答案 1 :(得分：9)
如何解决这个问题？
我猜你希望RecordDetailFragment实例的行为与EditDateDialogListener的{{1}}相同。如果是，则需要将其显式设置（并更新）为侦听器：
DialogFragment其中DialogFragment editDateFragment = EditDateDialogFragment.newInstance( recordId );
editDataFragment.setListener(RecordDetailFragment.this);
editDateFragment.show(getActivity().getSupportFragmentManager(), "EditDateDialogFrame");
是setListener()中的方法，如下所示：
EditDialogFragment例如，当用户旋转手机时，将重新创建活动及其片段，您需要重新设置监听器以指向新创建的public void setListener(EditDateDialogListener listener) {
mListener = listener;
}
实例（您可能希望使用{ {1}} RecordDetailFragment。您可以找到类似的内容in this answer（您将在WeakReference中查找两个片段）。
修改：在mListener的{{1}}方法中：
onCreate答案 2 :(得分：3)
onCreateDialog中的某处将mListener强制转换为getActivity（）：
try {
mListener = (EditDateDialogListener) getActivity();
} catch (Exception e) {
throw new ClassCastException(getActivity().toString()
+ " must implement EditDateDialogListener");
}
答案 3 :(得分：-3)
好的，我认为它现在有效。 我的解决方案：
public class EditDateDialogFragment extends DialogFragment {
// Use this instance of the interface to deliver action events
EditDateDialogListener mListener = new EditDateDialogListener() {
@Override
public void onDialogPositiveClick(DialogFragment dialog) {
//Should always overridden by interface implementing class
}
@Override
public void onDialogNegativeClick(DialogFragment dialog) {
//Should always overridden by interface implementing class
}
};
DatePicker mDatePicker;
/*
* The activity that creates an instance of this dialog fragment must
* implement this interface in order to receive event callbacks. Each method
* passes the DialogFragment in case the host needs to query it.
*/
public interface EditDateDialogListener {
public void onDialogPositiveClick(DialogFragment dialog);
public void onDialogNegativeClick(DialogFragment dialog);
}
public void setListener(EditDateDialogListener listener) {
mListener = listener;
}
public static EditDateDialogFragment newInstance(int currentCategoryId) {
EditDateDialogFragment p = new EditDateDialogFragment();
Bundle args = new Bundle();
args.putInt("currentRecordId", currentCategoryId);
p.setArguments(args);
return p;
}
@Override
public void onCreate(Bundle savedInstanceState) {
mCurrentRecordId = getArguments().getInt("currentRecordId");
super.onCreate(savedInstanceState);
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
LayoutInflater inflater = LayoutInflater.from(getActivity());
final View v = inflater.inflate(R.layout.fragment_dialog_edit_date, null);
mDatePicker = (DatePicker) v.findViewById(R.id.dialog_edit_date);
return new AlertDialog.Builder(getActivity()).setTitle("Set Date...").setView(v).setCancelable(true).setPositiveButton("Confirm", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Log.d("", "Dialog confirmed");
mListener.onDialogPositiveClick(EditDateDialogFragment.this);
}
}).setNegativeButton("Abort", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Log.d("", "Dialog abort");
mListener.onDialogNegativeClick(EditDateDialogFragment.this);
dialog.cancel();
}
}).create();
}
}
public class RecordDetailFragment extends SherlockFragment implements EditDateDialogFragment.EditDateDialogListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
// Update reference
// Update reference
EditDateDialogFragment attachedDialogFragment = (EditDateDialogFragment) getActivity().getSupportFragmentManager().findFragmentByTag("EditDateDialogFragment"); // "tag" is the string set as the tag for the dialog when you show it
if (attachedDialogFragment != null) {
// the dialog exists so update its listener
attachedDialogFragment.setListener(this);
}
}
}
// Called somewhere in the fragment
public void showDialog() {
EditDateDialogFragment editDateFragment = EditDateDialogFragment.newInstance(recordId);
editDateFragment.setListener((EditDateDialogListener) this);
editDateFragment.show(getActivity().getSupportFragmentManager(), "EditDateDialogFragment");
}
@Override
public void onDialogPositiveClick(DialogFragment dialog) {
Log.d("RecordDetailFragment", "Callback Dialog confirmed");
int year = ((EditDateDialogFragment) dialog).mDatePicker.getYear();
Log.d("RecordDetailFragment", "Year of DatePicker: " + year);
}
@Override
public void onDialogNegativeClick(DialogFragment dialog) {
Log.d("RecordDetailFragment", "Callback Dialog abort");
// TODO Auto-generated method stub
}
}
我不确定为什么在关闭对话框后DatePicker仍然可用。 @Luksprog：你怎么看？你的意思是这样吗？