问题
I have a dialogfragment for a floating dialog which includes a special keyboard that pops up when a user presses inside an EditText field (the normal IME is stopped from being displayed).
I would like the keyboard to be dismissed (visibility = GONE) when the user presses the back button (just as with a normal IME service) but the dialog to remain visible. However, there does not appear to be a way to do this as far as I can see from my fairly extensive reading on SO and elsewhere.
If I set the dialog to be non-cancelable then I don't get notified by onCancel() or onDismiss() because the dialog isn't cancelable.
If I set the dialog to be cancelable then I get notified, but the dialog is dismissed.
I can't attach an onKeyListener to the dialog in the fragment because it is replaced by the system so that the fragment can handle the dialog's life cycle.
Is there any way to do this? Or has access to the detection of key events been entirely fenced off for the purposes of the Fragment system?
回答1:
The best way and cleanest way is to override onBackPressed() in the dialog you created in onCreateDialog().
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return new Dialog(getActivity(), getTheme()){
@Override
public void onBackPressed() {
//do your stuff
}
};
}
回答2:
I had the same problem than you and I've fixed it attaching the onKeyListener to the dialogfragment.
In the method onResume() of the class that extend of DialogFragment put these piece of code:
getDialog().setOnKeyListener(new OnKeyListener()
{
@Override
public boolean onKey(android.content.DialogInterface dialog, int keyCode,android.view.KeyEvent event) {
if ((keyCode == android.view.KeyEvent.KEYCODE_BACK))
{
//Hide your keyboard here!!!
return true; // pretend we've processed it
}
else
return false; // pass on to be processed as normal
}
});
Here one of the problems that you can find is this code is going to be executed twice: one when the user press tha back button and another one when he leave to press it. In that case, you have to filter by event:
@Override
public void onResume() {
super.onResume();
getDialog().setOnKeyListener(new OnKeyListener()
{
@Override
public boolean onKey(android.content.DialogInterface dialog, int keyCode,
android.view.KeyEvent event) {
if ((keyCode == android.view.KeyEvent.KEYCODE_BACK))
{
//This is the filter
if (event.getAction()!=KeyEvent.ACTION_DOWN)
return true;
else
{
//Hide your keyboard here!!!!!!
return true; // pretend we've processed it
}
}
else
return false; // pass on to be processed as normal
}
});
}
回答3:
As an addendum to Juan Pedro Martinez's answer I thought it would be helpful to clarify a specific question (one that I had) when looking at this thread.
If you wish to create a new DialogFragment and have it so the user can only cancel it using the back-button, which eliminates random screen touches from canceling the fragment prematurely, then this is the code that you would use.
In what ever code that you call the DialogFragment you need to set the cancelable setting to false so that NOTHING dismisses the fragment, no stray screen touches, etc.
DialogFragment mDialog= new MyDialogFragment();
mDialog.setCancelable(false);
mDialog.show(getFragmentManager(), "dialog");
Then, within your DialogFragment, in this case MyDaialogFragment.java, you add the onResume override code to have the dialog listen for the Back Button. When it's pressed it will execute the dismiss() to close the fragment.
@Override
public void onResume()
{
super.onResume();
getDialog().setOnKeyListener(new OnKeyListener()
{
@Override
public boolean onKey(android.content.DialogInterface dialog,
int keyCode,android.view.KeyEvent event)
{
if ((keyCode == android.view.KeyEvent.KEYCODE_BACK))
{
// To dismiss the fragment when the back-button is pressed.
dismiss();
return true;
}
// Otherwise, do nothing else
else return false;
}
});
Now your dialog will be called with the "setCancelable" to false, meaning nothing (no outside clicks) can cancel it and shut it down, and allowing (from within the dialog itself) only the back button to close it.
Ganbatte!
回答4:
How has no one suggested this?
public Dialog onCreateDialog(Bundle savedInstanceState) {
Dialog dialog = super.onCreateDialog(savedInstanceState);
// Add back button listener
dialog.setOnKeyListener(new Dialog.OnKeyListener() {
@Override
public boolean onKey(DialogInterface dialogInterface, int keyCode, KeyEvent keyEvent) {
// getAction to make sure this doesn't double fire
if (keyCode == KeyEvent.KEYCODE_BACK && keyEvent.getAction() == KeyEvent.ACTION_UP) {
// Your code here
return true; // Capture onKey
}
return false; // Don't capture
}
});
return dialog;
}
回答5:
Use Fragment onCancel override method. It's called when you press back. here is a sample:
@Override
public void onCancel(DialogInterface dialog) {
super.onCancel(dialog);
// Add you codition
}
回答6:
When creating the dialog, override both onBackPressed and onTouchEvent :
final Dialog dialog = new Dialog(activity) {
@Override
public boolean onTouchEvent(final MotionEvent event) {
//note: all touch events that occur here are outside the dialog, yet their type is just touching-down
boolean shouldAvoidDismissing = ... ;
if (shouldAvoidDismissing)
return true;
return super.onTouchEvent(event);
}
@Override
public void onBackPressed() {
boolean shouldAvoidDismissing = ... ;
if (!shouldSwitchToInviteMode)
dismiss();
else
...
}
};
回答7:
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
Dialog dialog = new Dialog(getActivity(), getTheme()) {
@Override
public void onBackPressed() {
//your code
}
};
return dialog;
}
回答8:
Use onDismiss() callback of DialogFragment with a closeActivity flag
private var closeActivity: Boolean = true
override fun onDismiss(dialog: DialogInterface?) {
super.onDismiss(dialog)
if (closeActivity) {
activity!!.finish()
}
}
来源：https://stackoverflow.com/questions/21307858/detect-back-button-but-dont-dismiss-dialogfragment