Ich mochte den Ansatz von Wayfarer und flexaddicted, fand aber (wie aZtral), dass er nicht funktionierte, da der backgroundTapButton das einzige Element war, das auf Benutzerinteraktion reagierte. Dies führte mich dazu, alle drei seiner Unteransichten: _picker, _pickerToolbar und backgroundTapButton in eine enthaltende Ansicht (Popup) zu setzen, die dann auf und neben dem Bildschirm animiert wurde. Ich brauchte auch eine Schaltfläche Abbrechen in der _pickerToolbar. Hier sind die relevanten Codeelemente für die Popup-Ansicht (Sie müssen Ihre eigene Picker-Datenquelle angeben und Methoden delegieren).
#define DURATION 0.4
#define PICKERHEIGHT 162.0
#define TOOLBARHEIGHT 44.0
@interface ViewController ()
@property (nonatomic, strong) UIView *popup;
@property (nonatomic, strong) UIPickerView *picker;
@property (nonatomic, strong) UIToolbar *pickerToolbar;
@property (nonatomic, strong) UIButton *backgroundTapButton;
@end
-(void)viewDidLoad {
// These are ivars for convenience
rect = self.view.bounds;
topNavHeight = self.navigationController.navigationBar.frame.size.height;
bottomNavHeight = self.navigationController.toolbar.frame.size.height;
navHeights = topNavHeight + bottomNavHeight;
}
-(void)showPickerView:(id)sender {
[self createPicker];
[self createToolbar];
// create view container
_popup = [[UIView alloc] initWithFrame:CGRectMake(0.0, topNavHeight, rect.size.width, rect.size.height - navHeights)];
// Initially put the centre off the bottom of the screen
_popup.center = CGPointMake(rect.size.width / 2.0, rect.size.height + _popup.frame.size.height / 2.0);
[_popup addSubview:_picker];
[_popup insertSubview:_pickerToolbar aboveSubview:_picker];
// Animate it moving up
// This seems to work though I am not sure why I need to take off the topNavHeight
CGFloat vertCentre = (_popup.frame.size.height - topNavHeight) / 2.0;
[UIView animateWithDuration:DURATION animations:^{
// move it to a new point in the middle of the screen
[_popup setCenter:CGPointMake(rect.size.width / 2.0, vertCentre)];
} completion:^(BOOL finished) {
// When done, place an invisible 'button' on the view behind the picker,
// so if the user "taps to dismiss" the picker, it will go away
self.backgroundTapButton = [UIButton buttonWithType:UIButtonTypeCustom];
_backgroundTapButton.frame = CGRectMake(0, 0, _popup.frame.size.width, _popup.frame.size.height);
[_backgroundTapButton addTarget:self action:@selector(doneAction:) forControlEvents:UIControlEventTouchUpInside];
[_popup insertSubview:_backgroundTapButton belowSubview:_picker];
[self.view addSubview:_popup];
}];
}
-(void)createPicker {
// To use the default UIPickerView frame of 216px set frame to CGRectZero, but we want the 162px height one
CGFloat pickerStartY = rect.size.height - navHeights - PICKERHEIGHT;
self.picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, pickerStartY, rect.size.width, PICKERHEIGHT)];
_picker.dataSource = self;
_picker.delegate = self;
_picker.showsSelectionIndicator = YES;
// Otherwise you can see the view underneath the picker
_picker.backgroundColor = [UIColor whiteColor];
_picker.alpha = 1.0f;
}
-(void)createToolbar {
CGFloat toolbarStartY = rect.size.height - navHeights - PICKERHEIGHT - TOOLBARHEIGHT;
_pickerToolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, toolbarStartY, rect.size.width, TOOLBARHEIGHT)];
[_pickerToolbar sizeToFit];
NSMutableArray *barItems = [[NSMutableArray alloc] init];
UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelAction:)];
[barItems addObject:cancelButton];
// Flexible space to make the done button go on the right
UIBarButtonItem *flexSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil];
[barItems addObject:flexSpace];
// The done button
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(doneAction:)];
[barItems addObject:doneButton];
[_pickerToolbar setItems:barItems animated:YES];
}
// The method to process the picker, if we have hit done button
- (void)doneAction:(id)sender {
[UIView animateWithDuration:DURATION animations:^{
_popup.center = CGPointMake(rect.size.width / 2.0, rect.size.height + _popup.frame.size.height / 2.0);
} completion:^(BOOL finished) { [self destroyPopup]; }];
// Do something to process the returned value from your picker
}
// The method to process the picker, if we have hit cancel button
- (void)cancelAction:(id)sender {
[UIView animateWithDuration:DURATION animations:^{
_popup.center = CGPointMake(rect.size.width / 2.0, rect.size.height + _popup.frame.size.height / 2.0);
} completion:^(BOOL finished) { [self destroyPopup]; }];
}
-(void)destroyPopup {
[_picker removeFromSuperview];
self.picker = nil;
[_pickerToolbar removeFromSuperview];
self.pickerToolbar = nil;
[self.backgroundTapButton removeFromSuperview];
self.backgroundTapButton = nil;
[_popup removeFromSuperview];
self.popup = nil;
}
