自我mark一下赋焕。如下圖所示：界面上有2個(gè)textField夏漱，當(dāng)其成為第一響應(yīng)者時(shí)彈出鍵盤(pán)且要求textField的父視圖跟隨鍵盤(pán)上移。另外要求時(shí)間標(biāo)簽上的時(shí)間實(shí)時(shí)顯示霉囚。
實(shí)現(xiàn)原理：注冊(cè)通知監(jiān)聽(tīng)鍵盤(pán)的frame變化谭溉，從而改變textField父視圖的bottom約束值墙懂。
示意圖.gif
UIKeyboardAnimationCurveUserInfoKey = 7;//動(dòng)畫(huà)效果
UIKeyboardAnimationDurationUserInfoKey = "0.25";//鍵盤(pán)彈出動(dòng)畫(huà)時(shí)間
UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {375, 258}}";
UIKeyboardCenterBeginUserInfoKey = "NSPoint: {187.5, 796}";
UIKeyboardCenterEndUserInfoKey = "NSPoint: {187.5, 538}";
UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 667}, {375, 258}}";//鍵盤(pán)起始frame
UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 409}, {375, 258}}";//鍵盤(pán)彈出時(shí)frame
UIKeyboardIsLocalUserInfoKey = 1;
//1,注冊(cè)通知，監(jiān)聽(tīng)鍵盤(pán)frame變化
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
-(void)keyboardWillChangeFrame:(NSNotification*)notification{
// NSLog(@"notification-info:%@",notification.userInfo);
//獲取鍵盤(pán)彈起時(shí)y值
CGFloat keyboardY=[notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].origin.y;
//改變底部約束
self.bottomConstraint.constant=[UIScreen mainScreen].bounds.size.height-keyboardY;//bottomConstraint是textField的父視圖距離self.View的底部距離
//獲取鍵盤(pán)彈起時(shí)間
CGFloat duration=[notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
[UIView animateWithDuration: duration animations:^{
[self.view layoutIfNeeded];
}];
}
記得要在dealloc方法里移除通知：
//移除通知
[[NSNotificationCenter defaultCenter]removeObserver:self];
時(shí)間標(biāo)簽實(shí)時(shí)顯示
//創(chuàng)建定時(shí)器,刷新時(shí)間
__weak KeyboardViewController *weakSelf=self;
_timer=[NSTimer timerWithTimeInterval:1 repeats:YES block:^(NSTimer * _Nonnull timer) {
KeyboardViewController *strongSelf=weakSelf;
[strongSelf updateTime];//使用strong是為了保證實(shí)例持續(xù)存活
}];
-(void)updateTime{
//設(shè)置時(shí)間label
NSDate *currentDate = [NSDate date];//獲取當(dāng)前時(shí)間扮念、日期
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"YYYY-MM-dd hh:mm:ss"];
NSString *dateString = [dateFormatter stringFromDate:currentDate];
self.timeLabel.text=dateString;
}
