## iOS 中用了autolayout遮擋鍵盤的處理 ##

iOS 中用了autolayout遮擋鍵盤的處理

先說明我的情況：1.我是用了masonry 和iOS內建的autolayout結合的 簡單的登入問題

loginView是我的一個登入背景，，設定的置中，，當我點擊輸入的時候，，我會判斷鍵盤是否會遮擋我的loginView,如果不會遮擋，，我就不需要改變loginView的frame，，，在autolayout中，如果要擷取正確的frame的一定要在viewDidAppear 方法中，，總之是要在viewDidAppear方法以後才可以。

-(void)viewDidLoad{    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShowNotification:) name:UIKeyboardWillShowNotification object:nil];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHideNotification:) name:UIKeyboardWillHideNotification object:nil];}#pragma mark - Notification center- (void)keyboardWillShowNotification:(NSNotification *)notification {    // 擷取鍵盤基本資料（動畫時間長度與鍵盤高度）    NSDictionary *userInfo = [notification userInfo];    NSLog(@"log:%@",NSStringFromCGRect(self.loginView.frame));    NSLog(@"%@",userInfo);    CGRect rect = [userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue];    CGFloat keyboardHeight = CGRectGetHeight(rect)-(CGRectGetHeight(self.view.frame)-self.loginView.frame.origin.y-CGRectGetHeight(self.loginView.frame));    CGFloat keyboardDuration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];    //判斷視圖是否被鍵盤遮擋住了    if (keyboardHeight>0) {        // 修改邊距約束        [self.loginView mas_updateConstraints:^(MASConstraintMaker *make) {            make.centerY.mas_equalTo(self.view).offset(-keyboardHeight);        }];        // 更新約束        [UIView animateWithDuration:keyboardDuration animations:^{            [self.view layoutIfNeeded];        }];    }}- (void)keyboardWillHideNotification:(NSNotification *)notification {    // 獲得鍵盤動畫時間長度    NSDictionary *userInfo = [notification userInfo];    CGFloat keyboardDuration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];    // 修改為以前的約束（距下邊距0）    [self.loginView mas_updateConstraints:^(MASConstraintMaker *make) {        make.center.mas_equalTo(self.view);    }];    // 更新約束    [UIView animateWithDuration:keyboardDuration animations:^{        [self.view layoutIfNeeded];    }];}- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {    [super touchesBegan:touches withEvent:event];    [self.view endEditing:YES];}- (void)dealloc{    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];}