iOS 处理键盘遮挡TextField、TextView问题

　　之前处理键盘遮挡问题都是在每一个控制器进行单独处理，这样做真的是非常的费事，今天在做项目的时候就想到自己封装一个，记录一下这个“跌宕起伏”的过程。

　　思路是这样的：计算文本编辑控件Frame与键盘Frame，如果遮挡则移动控制器View。

　　创建控制器类：WKAvoidKeyboardViewController

 1 #import <UIKit/UIKit.h>
 2
 3 @interface WKAvoidKeyboardViewController : UIViewController
 4
 5 @property (nonatomic, strong) UITextField *editTextField;
 6 @property (nonatomic, strong) UITextView *editTextView;
 7
 8 - (void)hideKeyboard:(NSNotification *)noti;
 9 - (void)showKeyboard:(NSNotification *)noti;
10
11
12 @end
13
14
15 #import "WKAvoidKeyboardViewController.h"
16
17 #define GetOSVersion [[UIDevice currentDevice].systemVersion floatValue]
18
19 #define GetTransformDistance(Distance) (GetOSVersion < 7.1 ? Distance / 2 : Distance)
20
21 @interface WKAvoidKeyboardViewController ()<UITextFieldDelegate, UITextViewDelegate>
22
23 @end
24
25 @implementation WKAvoidKeyboardViewController
26 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
27 {
28     [self.view endEditing:YES];
29 }
30 @end

　　步骤1：通过通知获取当前编辑的文本控件

//注册通知
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(showKeyboard:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(hideKeyboard:) name:UIKeyboardWillHideNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldBeginEditing:) name:UITextFieldTextDidBeginEditingNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldBeginEditing:) name:UITextViewTextDidBeginEditingNotification object:nil];

- (void)textFieldBeginEditing:(NSNotification *)noti
{
    self.editTextField = noti.object;
    self.editTextView = nil;
}
- (void)textViewBeginEditing:(NSNotification *)noti
{
    self.editTextView = noti.object;
    self.editTextField = nil;
}

　　步骤2：通知获取键盘高度

　　步骤3：计算是否需要移动

#pragma mark - 键盘躲避

- (void)showKeyboard:(NSNotification *)noti
{
    self.view.transform = CGAffineTransformIdentity;
    UIView *editView = _editTextView ? _editTextView : _editTextField;

    CGRect tfRect = [editView.superview convertRect:editView.frame toView:self.view];
    NSValue *value = noti.userInfo[@"UIKeyboardFrameEndUserInfoKey"];
    NSLog(@"%@", value);
    CGRect keyBoardF = [value CGRectValue];

    CGFloat animationTime = [noti.userInfo[@"UIKeyboardAnimationDurationUserInfoKey"] floatValue];
    CGFloat _editMaxY = CGRectGetMaxY(tfRect);
    CGFloat _keyBoardMinY = CGRectGetMinY(keyBoardF);
    NSLog(@"%f %f", _editMaxY, _keyBoardMinY);
    if (_keyBoardMinY < _editMaxY) {
        CGFloat moveDistance = _editMaxY - _keyBoardMinY;
        [UIView animateWithDuration:animationTime animations:^{
            self.view.transform = CGAffineTransformTranslate(self.view.transform, 0, -moveDistance);
        }];

    }
}

- (void)hideKeyboard:(NSNotification *)noti
{
    //    NSLog(@"%@", noti);
    self.view.transform = CGAffineTransformIdentity;
}

　　初步试验：UITextFiled成功，然后到了UITextView，坑爹的问题粗线了=.=， UITextViewTextDidBeginEditingNotification 发送时间是在键盘弹出通知之后的，导致第一次点击TextView没有用，点击第二次才能产生效果。于是乎，我又开始尝试用TextView的Delegate来做，想当然的使用的代理方法

- (void)textViewDidBeginEditing:(UITextView *)textView

1 - (void)textViewDidBeginEditing:(UITextView *)textView
2 {
3
4 }

　　令人失望的是textViewDidBeginEditing:方法调用依然是在键盘通知弹出后再调用，此时心中想的是：哔了狗了，让人怎么玩！还是看看其他方法吧。于是在代理方法中看到了

- (BOOL)textViewShouldBeginEditing:(UITextView *)textView

　　尝试之后，此方法的确在键盘弹出前调用，大功告成，接下来就是设置代理的问题了

　　设置代理方法如下：

 1 - (void)searchTextViewWithView:(UIView *)view
 2 {
 3     for (UIView *subview in view.subviews)
 4     {
 5         if ([subview isKindOfClass:[UITextView class]]) {
 6             ((UITextView *)subview).delegate = self;
 7         }
 8         if ([subview isKindOfClass:[UITextField class]]) {
 9             ((UITextField *)subview).delegate = self;
10         }
11         [self searchTextViewWithView:subview];
12     }
13 }

　　至此大功告成,使用方法：继承WKAvoidKeyboardViewController,如果是用故事版创建的文本控件，啥都不用做，如果是用代码创建的，则需要在ViewDidLoad中调用searchTextViewWithView方法

　　完整代码下载地址：https://github.com/WuKongCoo1/AvoidKeyboardDemo.git