问题
I'm trying to get the following code work:
UIMenuController * menu = [UIMenuController sharedMenuController];
[menu setTargetRect: CGRectMake(100, 100, 100, 100) inView: self.view];
[menu setMenuVisible: YES animated: YES];
The menu instance is ready but it doesn't show - the width is always zero.
Or is there some sample code on this UIPasteboard/UIMenuController topic?
回答1:
I was not able to get it working even when I read all of your answers. I'm presenting ready code that will work for everyone.
Let's say we have a controller class named Controller. You can simply paste the following code to this controller to have the menu working on its view:
- (void)loadView {
[super loadView];
UILongPressGestureRecognizer *gr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
[self.view addGestureRecognizer:gr];
}
- (void) longPress:(UILongPressGestureRecognizer *) gestureRecognizer {
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan) {
CGPoint location = [gestureRecognizer locationInView:[gestureRecognizer view]];
UIMenuController *menuController = [UIMenuController sharedMenuController];
UIMenuItem *resetMenuItem = [[UIMenuItem alloc] initWithTitle:@"Item" action:@selector(menuItemClicked:)];
NSAssert([self becomeFirstResponder], @"Sorry, UIMenuController will not work with %@ since it cannot become first responder", self);
[menuController setMenuItems:[NSArray arrayWithObject:resetMenuItem]];
[menuController setTargetRect:CGRectMake(location.x, location.y, 0.0f, 0.0f) inView:[gestureRecognizer view]];
[menuController setMenuVisible:YES animated:YES];
}
}
- (void) copy:(id) sender {
// called when copy clicked in menu
}
- (void) menuItemClicked:(id) sender {
// called when Item clicked in menu
}
- (BOOL) canPerformAction:(SEL)selector withSender:(id) sender {
if (selector == @selector(menuItemClicked:) || selector == @selector(copy:)) {
return YES;
}
return NO;
}
- (BOOL) canBecomeFirstResponder {
return YES;
}
What has to be done in order for menu to work is that the firstResponder(in our case our controller - see line with [self becomeFirstResponder]) has to be able to become first responder (override method canBecomeFirstResponder cause default implementation returns NO) as well as - (BOOL) canPerformAction:(SEL)selector withSender:(id) sender which should return YES to any action that can be performed by firstResponder
回答2:
If you're implementing a custom view and that view is supposed to be the responder (as opposed to some other view, like a UITextField), you need to override the canBecomeFirstResponder function in your view and return YES:
- (BOOL)canBecomeFirstResponder {
return YES;
}
then, when you're displaying the menu, you should do something like the following:
- (void)myMenuFunc {
if (![self becomeFirstResponder]) {
NSLog(@"couldn't become first responder");
return;
}
UIMenuController *theMenu = [UIMenuController sharedMenuController];
CGRect selectionRect = CGRectMake(0, 0, 0, 0);
[theMenu setTargetRect:selectionRect inView:self];
[theMenu setMenuVisible:YES animated:YES];
}
回答3:
In case somebody still has problems: My menu used to work and some day stopped working miraculously. Everything else in my app still worked. Now I had removed the [window makeKeyAndVisible] method from application:didFinishLaunchingWithOptions: method, and while everything else still worked, this breaks UIMenuController!
Stupid error on my side, difficult to find the culprit...
回答4:
to display UIMenuController one has to add following
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
if (action == @selector(cut:))
return NO;
else if (action == @selector(copy:))
return YES;
else if (action == @selector(paste:))
return NO;
else if (action == @selector(select:) || action == @selector(selectAll:))
return NO;
else
return [super canPerformAction:action withSender:sender];
}
回答5:
I think Cam is right, need override both canPerformAction and canBecomeFirstResponder
- (BOOL) canPerformAction:(SEL)action withSender:(id)sender
{
if (action == @selector(doSomething:)) {
return YES;
}
return NO;
}
- (BOOL)canBecomeFirstResponder {
return YES;
}
回答6:
// MyView.h
@interface MyView : UIView {
IBOutlet UITextField * textField_;
}
@end
// MyView.m
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
NSLog(@"show menu");
[textField_ becomeFirstResponder];
// [self.window becomeFirstResponder];
UIMenuController * menu = [UIMenuController sharedMenuController];
[menu setTargetRect: CGRectMake(0, 0, 100, 10) inView: self];
[menu setMenuVisible: YES animated: YES];
NSLog(@"menu width %f, visible %d", menu.menuFrame.size.width, menu.menuVisible);
}
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender{
return YES;
}
You need to add more code in canPerformAction:withSender: - it should check the pasteboard and your selection state. Apple's iPhone Application Programming Guide provide several code snippets.
回答7:
Don't you have to add the UIMenuController* menu to the main or subview, E.G. self.view?
I think it's something like [self.view addSubView:menu.view]; Or am I missing the point of your question. You might also want to set the frame of the menu's view.
回答8:
UIMenuController doesn't have a view. I just searched some code from apple's iPhone Application Programming Guide: Event Handling:
Listing 3-4 Displaying the editing menu
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *theTouch = [touches anyObject]; if ([theTouch tapCount] == 2 && [self becomeFirstResponder]) { // selection management code goes here... // bring up editing menu. UIMenuController *theMenu = [UIMenuController sharedMenuController]; CGRect selectionRect = CGRectMake(currentSelection.x, currentSelection.y, SIDE, SIDE); [theMenu setTargetRect:selectionRect inView:self]; [theMenu setMenuVisible:YES animated:YES]; } }
回答9:
I did it in the following way below. Just call the method that shows the menu after very short delay in init. I didn't want to call it from View Controller and also didn't find an event that indicates that my custom view appeared and i'm ready to show menu. So this way OK from my perspective. Delay can be less, but its up to you.
@implementation DTSignatureImageView
- (id)initWithImage:(UIImage *)image
{
self = [super initWithImage:image];
if(self){
self.contentMode = UIViewContentModeScaleAspectFit;
self.frame = CGRectMake(0, 0, image.size.width / 2.5, image.size.height / 2.5);
self.userInteractionEnabled = YES;
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(signatureDidPan:)];
[self addGestureRecognizer:pan];
[self becomeFirstResponder];
[self performSelector:@selector(showMenu) withObject:nil afterDelay:0.5];
}
return self;
}
- (BOOL)canBecomeFirstResponder
{
return YES;
}
- (void)showMenu
{
UIMenuController *menu = [UIMenuController sharedMenuController];
menu.menuItems = @[
[[UIMenuItem alloc] initWithTitle:@"Apply" action:@selector(applySignature)],
[[UIMenuItem alloc] initWithTitle:@"Update" action:@selector(updateSignature)],
[[UIMenuItem alloc] initWithTitle:@"Clear" action:@selector(delegateSignature)]];
[menu setTargetRect:self.bounds inView:self];
[menu setMenuVisible:YES animated:YES];
}
- (NSArray *)menuActions
{
static NSArray *actions = nil;
if (actions == nil){
actions = @[
NSStringFromSelector(@selector(applySignature)),
NSStringFromSelector(@selector(updateSignature)),
NSStringFromSelector(@selector(delegateSignature))];
}
return actions;
}
- (void) signatureDidPan: (UIPanGestureRecognizer *)gesture
{
switch (gesture.state) {
case UIGestureRecognizerStateBegan: {
[[UIMenuController sharedMenuController] setMenuVisible:NO animated:YES];
break;
}
case UIGestureRecognizerStateEnded: {
[self becomeFirstResponder];
[self showMenu];
}
default:
break;
}
CGPoint point = [gesture locationInView:gesture.view.superview];
gesture.view.center = point;
}
来源：https://stackoverflow.com/questions/1146587/how-to-get-uimenucontroller-work-for-a-custom-view