项目中有很多输入框，有输入框就会唤出键盘，唤出键盘就很经常键盘挡住输入框。如何解决这个问题？

这个问题并不难，相信大家都会写。但是写多了大家就会发现，项目中这么多页面有输入框的，那就意味着很多地方都要写，而且写的代码都差不多。那有没有方便点的，全局控制控制器的view跟随键盘起伏，或者调用一句代码就可以搞定的？

针对这个问题，为此我实现了一句话设置当前控制器的view跟随键盘起伏。

代码不多只有轻量级的两个类：

屏幕快照 2017-09-15 下午7.02.33.png

看看效果：

Untitled2.gif

实现思路 主要代码实现：

1、监听输入框开始编辑，键盘改变的通知

// TextField开始编辑
        [[NSNotificationCenter defaultCenter] addObserver:instance selector:@selector(textFieldTextDidBeginEditingNotification:) name:UITextFieldTextDidBeginEditingNotification
                                                   object:nil];
        // TextView开始编辑
        [[NSNotificationCenter defaultCenter] addObserver:instance selector:@selector(textViewTextDidBeginEditingNotification:) name:UITextViewTextDidBeginEditingNotification
                                                   object:nil];
        // 键盘将要改变
        [[NSNotificationCenter defaultCenter] addObserver:instance selector:@selector(keyboardWillChangeFrameNotification:) name:UIKeyboardWillChangeFrameNotification object:nil];

2、获取当前的控制器，判断键盘是否挡住输入框，然后计算偏移view

/// 偏移View
-(void)transformView:(NSNotification *)notification {
    //获取键盘弹出后的Rect
    NSValue *keyBoardEndBounds=[[notification userInfo]objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGRect  endRect=[keyBoardEndBounds CGRectValue];
    
    UIView *targetView;
    if ([self.inputObject isKindOfClass:[UIView class]]) {
        targetView = self.inputObject;
    }
    if (!targetView) {
        return;
    }
    
    UIViewController *vc = [self getCurrentVC];
    
    // targetView 在 toView 的 convertRect位置上的位置
    CGRect targetRect = [targetView convertRect:CGRectMake(0, 0, targetView.frame.size.width, targetView.frame.size.height) toView:vc.view];
    CGFloat height = [UIScreen mainScreen].bounds.size.height;
    CGFloat maxY = CGRectGetMaxY(targetRect);
    CGFloat cha = endRect.origin.y - maxY;
    
    if (maxY > endRect.origin.y) { // 键盘会挡住输入框
        
        if ([vc.view.subviews.firstObject isKindOfClass:[UIScrollView class]]) {// 如果self.view是UIScrollView，则滚动contentOffset
            UIScrollView *scrollView= vc.view.subviews.firstObject;
            //NSLog(@"%@",NSStringFromCGPoint(scrollView.contentOffset));
            scrollView.contentOffset = CGPointMake(0, scrollView.contentOffset.y + (-cha) + 10);
        }else {
            CGFloat interval = 0;
            if (cha < -10) {
                interval = 10;
            }
            [UIView animateWithDuration:0.25f animations:^{
                [vc.view setFrame:CGRectMake(vc.view.frame.origin.x, cha - interval, vc.view.frame.size.width, vc.view.frame.size.height)];
            }];
        }
    }
    if (endRect.origin.y == height) { //键盘回收 deltaY>100
        //NSLog(@"键盘回收");
        if ([vc.view.subviews.firstObject isKindOfClass:[UIScrollView class]]) {
            //UIScrollView *scrollView= self.view.subviews.firstObject;
            //NSLog(@"%@",NSStringFromCGPoint(scrollView.contentOffset));
        }else {
            [UIView animateWithDuration:0.25f animations:^{
                [vc.view setFrame:CGRectMake(0, 0, vc.view.frame.size.width, vc.view.frame.size.height)];
            }];
            self.inputObject = nil;
            self.keyboardNotifivation = nil;
        }
    }
}

使用方式有两种：

第一种：只导入JHKeyBoardManager.h这个类到项目中，在AppDelegate写一句代码即可

#import "JHKeyBoardManager.h"
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [JHKeyBoardManager sharedManager];
    return YES;
}

第二种：只导入UIViewController+KeyBoardManager.h这个类到项目中，要用的控制器只需掉用一个方法即可

#import "UIViewController+KeyBoardManager.h"
- (void)viewDidLoad {
    [super viewDidLoad];
    [self transformViewForKeyboard];
}

demo地址：https://github.com/iOSHJH/JHKeyBoardManager

有问题欢迎issues，若项目对你有用还望不吝给个star让我动力十足😀