[英]can't get correct value of keyboard height in iOS8
我使用此代碼來確定鍵盤的大小:
- (void)keyboardWillChange:(NSNotification *)notification {
NSDictionary* keyboardInfo = [notification userInfo];
NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameBeginUserInfoKey];
CGRect keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue];
}
我在模擬器中運行它。
問題是因為iOS 8這將不會給出正確的值,如果鍵盤建議已啟動或者如果我將它們向下推,則會得到不同的(不正確的)值。
如何獲得鍵盤的確切大小,包括鍵盤建議?
隨着iOS中自定義鍵盤的引入,這個問題變得更加復雜。
簡而言之, UIKeyboardWillShowNotification可以通過自定義鍵盤實現多次調用:
為了在一個代碼行中正確處理這些場景,您需要:
注冊針對UIKeyboardWillShowNotification和UIKeyboardWillHideNotification通知的觀察者:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
創建一個全局變量來跟蹤當前鍵盤高度:
CGFloat _currentKeyboardHeight = 0.0f;
實現keyboardWillShow以響應鍵盤高度的當前變化:
- (void)keyboardWillShow:(NSNotification*)notification {
NSDictionary *info = [notification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
CGFloat deltaHeight = kbSize.height - _currentKeyboardHeight;
// Write code to adjust views accordingly using deltaHeight
_currentKeyboardHeight = kbSize.height;
}
注意:您可能希望為視圖的偏移設置動畫。 信息字典包含由UIKeyboardAnimationDurationUserInfoKey鍵入的值。 此值可用於以與顯示的鍵盤相同的速度為更改設置動畫。
將keyboardWillHide實現為reset _currentKeyboardHeight並對被解除的鍵盤作出反應:
- (void)keyboardWillHide:(NSNotification*)notification {
NSDictionary *info = [notification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
// Write code to adjust views accordingly using kbSize.height
_currentKeyboardHeight = 0.0f;
}
使用
NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameEndUserInfoKey];
我也有這個問題,直到我遇到這篇StackOverflow文章:
轉換UIKeyboardFrameEndUserInfoKey
這將向您展示如何使用convertRect
函數,將鍵盤的大小轉換為可用的,但在屏幕方向上。
NSDictionary* d = [notification userInfo];
CGRect r = [d[UIKeyboardFrameEndUserInfoKey] CGRectValue];
r = [myView convertRect:r fromView:nil];
以前,我有一個iPad應用程序使用UIKeyboardFrameEndUserInfoKey
但沒有使用convertRect
,它工作正常。
但是對於iOS 8,它已經不再適用了。 突然間,它會報告我在橫向模式下在iPad上運行的鍵盤高度為1024像素 。
現在,對於iOS 8,您必須使用此convertRect
功能。
類似於用Swift 2.0編寫的dgangsta解決方案:
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)
}
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func keyboardWillShow(notification: NSNotification) {
guard let kbSizeValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue else { return }
guard let kbDurationNumber = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber else { return }
animateToKeyboardHeight(kbSizeValue.CGRectValue().height, duration: kbDurationNumber.doubleValue)
}
func keyboardWillHide(notification: NSNotification) {
guard let kbDurationNumber = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber else { return }
animateToKeyboardHeight(0, duration: kbDurationNumber.doubleValue)
}
func animateToKeyboardHeight(kbHeight: CGFloat, duration: Double) {
// your custom code here
}
我為UIViewController
做了extension
extension UIViewController {
func keyboardWillChangeFrameNotification(notification: NSNotification, scrollBottomConstant: NSLayoutConstraint) {
let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber
let keyboardBeginFrame = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as! NSValue).CGRectValue()
let keyboardEndFrame = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()
let screenHeight = UIScreen.mainScreen().bounds.height
let isBeginOrEnd = keyboardBeginFrame.origin.y == screenHeight || keyboardEndFrame.origin.y == screenHeight
let heightOffset = keyboardBeginFrame.origin.y - keyboardEndFrame.origin.y - (isBeginOrEnd ? bottomLayoutGuide.length : 0)
UIView.animateWithDuration(duration.doubleValue,
delay: 0,
options: UIViewAnimationOptions(rawValue: UInt(curve.integerValue << 16)),
animations: { () in
scrollBottomConstant.constant = scrollBottomConstant.constant + heightOffset
self.view.layoutIfNeeded()
},
completion: nil
)
}
}
你可以像這樣使用:
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillChangeFrameNotification:", name: UIKeyboardWillChangeFrameNotification, object: nil)
}
...
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
func keyboardWillChangeFrameNotification(notification: NSNotification) {
self.keyboardWillChangeFrameNotification(notification, scrollBottomConstant: inputContainerBottom)
// Write more to here if you want.
}
有些時候開發人員在實際顯示之前需要知道鍵盤高度,允許他們適當地預先布局界面。
如果是這種情況,這里是一個包容性規范:
這包括頂部的快速類型欄,因為在所有當前版本的iOS中默認啟用它。
以下是我用來測試這個的swift 3通知設置,如果有人需要它:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
}
func keyboardWillShow(notification: NSNotification) {
guard let keyboardSize = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue else { return }
print("\(keyboardSize)")
}
我注意到在默認鍵盤和自定義( UIPickerView
)鍵盤之間切換時出現問題 - 從默認鍵盤切換后,自定義鍵盤將顯示253高度而不是162。
在這種情況下有效的是設置autocorrectionType = UITextAutocorrectionTypeNo;
用於具有自定義鍵盤的輸入字段。
該問題僅發生在iOS 8中(僅在模擬器上測試)。 它不會出現在iOS 9(模擬器或設備)中。
swift只有一個字符串:
let keyboardSize = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue().size
UIKeyboardFrameEndUserInfoKey
始終存儲NSValue
,因此無需檢查它。
在Swift中,不是一行......
self.keyboardDidShowObserver = NSNotificationCenter.defaultCenter().addObserverForName(UIKeyboardDidShowNotification, object: nil, queue: NSOperationQueue.mainQueue(), usingBlock: { (notification) in
if let userInfo = notification.userInfo, let keyboardFrameValue = userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRect = keyboardFrameValue.CGRectValue()
// keyboardRect.height gives the height of the keyboard
// your additional code here...
}
})
[notificationCenter addObserverForName:UIKeyboardWillChangeFrameNotification object:nil queue:[NSOperationQueue currentQueue] usingBlock:^(NSNotification * _Nonnull note) {
float keyboardHeight = [[note.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
}];
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