iOS應(yīng)用開發(fā)中監(jiān)聽鍵盤事件的代碼實(shí)例小結(jié)

更新時(shí)間：2016年03月04日 09:17:53 作者：心有思

這篇文章主要介紹了iOS應(yīng)用開發(fā)中監(jiān)聽鍵盤事件的代碼實(shí)例小結(jié),呼出鍵盤等操作為iOS App中的必備功能,示例代碼為傳統(tǒng)的Objective-C,需要的朋友可以參考下

1.注冊(cè)監(jiān)聽鍵盤事件的通知

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardShow:)
                                                 name:UIKeyboardDidShowNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardHide:)
                                                 name:UIKeyboardDidHideNotification
                                               object:nil];

2.在鍵盤將要出現(xiàn)和隱藏的回調(diào)中，加入動(dòng)畫

復(fù)制代碼代碼如下:

- (void)keyboardWillShow:(NSNotification *)notif {
    if (self.hidden == YES) {
        return;
    }

    CGRect rect = [[notif.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGFloat y = rect.origin.y;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.25];
    NSArray *subviews = [self subviews];
    for (UIView *sub in subviews) {

        CGFloat maxY = CGRectGetMaxY(sub.frame);
        if (maxY > y - 2) {
            sub.center = CGPointMake(CGRectGetWidth(self.frame)/2.0, sub.center.y - maxY + y - 2);
        }
    }
    [UIView commitAnimations];
}

- (void)keyboardShow:(NSNotification *)notif {
    if (self.hidden == YES) {
        return;
    }
}

- (void)keyboardWillHide:(NSNotification *)notif {
    if (self.hidden == YES) {
        return;
    }
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.25];
    NSArray *subviews = [self subviews];
    for (UIView *sub in subviews) {
        if (sub.center.y < CGRectGetHeight(self.frame)/2.0) {
            sub.center = CGPointMake(CGRectGetWidth(self.frame)/2.0, CGRectGetHeight(self.frame)/2.0);
        }
    }
    [UIView commitAnimations];
}

- (void)keyboardHide:(NSNotification *)notif {
    if (self.hidden == YES) {
        return;
    }
}

3.監(jiān)聽鍵盤刪除鍵之非代理實(shí)現(xiàn)
在UITextField 和 UITextView ，如何監(jiān)聽到刪除鍵。

我看到網(wǎng)上都是用代理監(jiān)聽的，我覺得不靠譜。

其實(shí)蘋果已經(jīng)寫的很清楚了。

就在他們實(shí)現(xiàn)的協(xié)議里面～～

復(fù)制代碼代碼如下:

NS_CLASS_AVAILABLE_IOS(2_0) @interface UITextView : UIScrollView<UITextInput>
@protocol UITextInput<UIKeyInput>
@protocol UIKeyInput <UITextInputTraits>

- (BOOL)hasText;

- (void)insertText:(NSString *)text;

- (void)deleteBackward;

@end

寫的非常清楚，一看就明白。

－deleteBackward 這個(gè)方法就是刪除按鈕監(jiān)聽。

只要自己寫個(gè)子類，重寫此方法就能監(jiān)聽。

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