我有一个 ListFragment
,它带有用于我的 ListItem
的上下文菜单。菜单选项之一用于删除项目,我想向用户显示一个确认对话框以防止意外删除。
public class MyListFragment extends ListFragment implements ConfirmDeletePopupFragment.DialogListener {
(...)
@Override
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_delete:
ConfirmDeletePopupFragment fragment = new ConfirmDeletePopupFragment();
fragment.show(getSupportFragmentManager(), "tag");
return true;
case R.id.action_cancel:
return true;
default:
return super.onContextItemSelected(item);
}
}
}
对于类似情况,我创建了一个通用确认对话框作为 DialogFragment
,如下所示。我可以用它来让用户确认任何关键操作。为了在 Activity
中使用,它有一个带有 onDeleteConfirm
方法的接口(interface),该方法处理创建对话框的 Activity
中的实际删除。
public class ConfirmDeletePopupFragment extends DialogFragment {
(...)
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mDialogListener = (DialogListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(getTargetFragment().toString() + " must implement ConfirmDeletePopupFragment.DialogListener");
}
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final android.app.AlertDialog.Builder dialogBuilder = new android.app.AlertDialog.Builder(getActivity());
final LayoutInflater inflater = getActivity().getLayoutInflater();
final View dialogView = inflater.inflate(R.layout.popup_confirm_delete, null);
dialogBuilder.setView(dialogView);
dialogBuilder.setTitle("Delete?");
dialogBuilder.setNegativeButton(getString(R.string.activities_confirm_deletion_cancel_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
}
});
dialogBuilder.setPositiveButton(getString(R.string.activities_confirm_deletion_delete_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
((DialogListener) getActivity()).onDeleteConfirm();
}
});
deleteDialog = dialogBuilder.create();
deleteDialog.show();
return deleteDialog;
}
public interface DialogListener {
void onDeleteConfirm();
}
}
显然,只有在 Activity
(((DialogListener) getActivity()).onDeleteConfirm();
) 中创建对话框时,此接口(interface)才有效。对于上述问题,我需要从 Listfragment
中创建对话框,而仅在 ListFragment
中实现对话框接口(interface)是行不通的(“Activity 必须实现 ConfirmDeletePopupFragment。对话监听器")
调整我的 DialogFragment
以适应这两种情况(在 Activity
或 Fragment
中创建)的最佳方式是什么?
最佳答案
显示对话框时( fragment ):
<dialog>.setTargetFragment(<your fragment>);
<dialog>.show();
在 Activity 中跳过 setTargetFragment。
在 DialogFragment 代码中:
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (getTargetFragment() != null) {
myInterface = (YourCastInterface) getTargetFragment();
} else {
myInterface = (YourCastInterface) activity;
}
}
关于android - Activity 和 Fragment 中可以实现的 DialogFragment 接口(interface),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37300976/