OnCancelListener不叫在DialogFragment [英] OnCancelListener is not called in DialogFragment
问题描述
我有一个简单的 AlertDialog 显示了一些项目，并在点击其中的一个，点击的项目被传递回封闭列表活动。我也想进行一些默认的处理，当用户取消对话框（使用的后退按钮的） - 更确切地说，我想传递一个空字符串在这种情况下，活性
不过，如果我把对话在 DialogFragment （从兼容包），在 OnCancelListener 是不是当我关闭对话框的后退按钮调用。我究竟做错了什么？
公共类SelectItemDialog扩展DialogFragment {
公共接口回调{
无效onItemSelected（字符串字符串）;
}
私有静态最后弦乐ARG_ITEMS =项目;
私人回调回调;
公共静态SelectItemDialog fromItems（集＆LT;字符串＆GT;项目）{
SelectItemDialog片段=新SelectItemDialog（）;
fragment.setArguments（newArguments（项目））;
返回片段;
}
私有静态捆绑newArguments（集＆LT;字符串＆GT;项目）{
捆绑参数=新包（）;
arguments.putStringArray（ARG_ITEMS，items.toArray（新的String [items.size（）））;
返回的参数;
}
@覆盖
公共无效onAttach（活动活动）{
super.onAttach（活动）;
回调=（回调）的活动;
}
@覆盖
公共对话onCreateDialog（包savedInstanceState）{
。最终的String []项目= getArguments（）getStringArray（ARG_ITEMS）;
返回新AlertDialog.Builder（getActivity（））
.setTitle（R.string.dialog_select_email_title）
.setItems（项目，新OnClickListener（）{
@覆盖
公共无效的onClick（DialogInterface对话，诠释它）{
callback.onItemSelected（项目[它]）;
}
}）
.setOnCancelListener（新OnCancelListener（）{
@覆盖
公共无效OnCancel的（DialogInterface对话）{
//不执行此code为
callback.onItemSelected（）;
抛出新的RuntimeException（对话框中取消）;
}
}）
。创建（）;
}
}
它可能有做的事实，那就是从没有显式调用取消（）您code。
该<一href="http://developer.android.com/reference/android/content/DialogInterface.OnCancelListener.html">OnCancelListener文件说：
这将只能被称为对话框被取消时，
这可能需要一个明确的取消（）通话。
无论是做出了积极/消极的按钮带有 OnClickListener 调用<一href="http://developer.android.com/reference/android/content/DialogInterface.html#cancel%28%29"><$c$c>DialogInterface#cancel()或者使用<一个href="http://developer.android.com/reference/android/content/DialogInterface.OnDismissListener.html"><$c$c>OnDismissListener()一个额外的检查，看是否有列表项被点击了。
另外，监听一个返回键preSS并取消该对话框，您可以建立一个<一个href="http://developer.android.com/reference/android/content/DialogInterface.OnKeyListener.html"><$c$c>OnKeyListener,像<一个概述href="http://stackoverflow.com/questions/7801971/android-how-to-override-onback$p$pssed-in-alertdialog/7815342#7815342">this SO回答
此外，一旦你的对话框中设置时，它也将使用<一个好主意href="http://developer.android.com/reference/android/app/Dialog.html#setCanceledOnTouchOutside%28boolean%29"><$c$c>Dialog#setCanceledOnTouchOutside()万一对话外的用户点击。
编辑：以下部分是最简单的方法来处理在DialogFragment取消事件
由于您使用的是 DialogFragment ，这个类有一个非常方便的方法，<一个href="http://developer.android.com/reference/android/app/DialogFragment.html#onCancel%28android.content.DialogInterface%29"><$c$c>DialogFragment#onCancel()它被调用时， DialogFragment 将被取消。难道你的逻辑在那里。
DialogFragments比较复杂，略有不同的生命周期比正常的对话。因此，首先要检查的文件，如果你有，你正试图移植到一个特定对话框为基础的方法 DialogFragment ，有些方法可能存在，让你的新的实现正常！
I have a simple AlertDialog that displays a list of some items and upon clicking one of them, the clicked item is passed back to the enclosing Activity. I also want to perform some default handling when the user cancels the dialog (using the back button) - more specifically, I want to pass an empty string to the activity in such case.
However, if I put the dialog in a DialogFragment (from the compatibility package), the OnCancelListener is not called when I close the dialog with the back button. What am I doing wrong?
public class SelectItemDialog extends DialogFragment {
public interface Callback {
void onItemSelected(String string);
}
private static final String ARG_ITEMS = "items";
private Callback callback;
public static SelectItemDialog fromItems(Collection<String> items) {
SelectItemDialog fragment = new SelectItemDialog();
fragment.setArguments(newArguments(items));
return fragment;
}
private static Bundle newArguments(Collection<String> items) {
Bundle arguments = new Bundle();
arguments.putStringArray(ARG_ITEMS, items.toArray(new String[items.size()]));
return arguments;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
callback = (Callback) activity;
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final String[] items = getArguments().getStringArray(ARG_ITEMS);
return new AlertDialog.Builder(getActivity())
.setTitle(R.string.dialog_select_email_title)
.setItems(items, new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
callback.onItemSelected(items[which]);
}
})
.setOnCancelListener(new OnCancelListener() {
@Override
public void onCancel(DialogInterface dialog) {
// this code is not executed
callback.onItemSelected("");
throw new RuntimeException("dialog cancelled");
}
})
.create();
}
}
It might have to do with the fact that there is no explicit call to cancel() from your code.
The OnCancelListener documentation says:
This will only be called when the dialog is canceled
Which probably needs an explicit cancel() call.
Either make a positive/negative button with a OnClickListener that calls DialogInterface#cancel() or use a OnDismissListener() with an extra check to see if a list item was clicked.
Also, to listen for a back keypress and cancel the dialog, you can set up an OnKeyListener, like outlined in this SO answer
Also, once you have the Dialog set up, it would also be a good idea to use Dialog#setCanceledOnTouchOutside() in case the the user taps outside the Dialog.
Edit: The below part is the easy way to handle cancel events in a DialogFragment.
Since you are using a DialogFragment, this class has a very handy method, DialogFragment#onCancel() which gets called when the DialogFragment is cancelled. Do your logic in there.
DialogFragments are more complex, with a slightly different lifecycle than normal dialogs. Therefore, first check the documentation if you have a certain Dialog-based approach that you are trying to port to a DialogFragment, some methods may exist that allow your new implementation to function properly!
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