IOS——UITextField被键盘遮蔽解决方案



本人在做ios开发的时候碰到一个老生常谈的问题，UITextField被键盘遮蔽问题，网上搜索了一些资料，找到了两种前辈写的方案，方案一：http://blog.csdn.net/springsky_/article/details/7941858，在ios5之前适用，但是在5之后盘布局变了，尤其是中文输入时，中文汉字选择框就固定在键盘上方，于是有前辈出了第二种方案：http://www.apkbus.com/home.php?mod=space&uid=107838&do=blog&id=44715。第二种方案是直接把整个view向上移动键盘的宽度，有些场景显得不是很恰当，本人在两位的基础上做了些许改动，具体步骤如下：

 

本人定义了一个基本的ViewController——BaseViewController。

 

.h文件内容如下：

 

#import <UIKit/UIKit.h>

 

 

@interface BaseViewController :UIViewController<UITextFieldDelegate>{

   UITextField *_checkText; //用来标识哪一个UITextField被点击

 

 

@property(nonatomic) UITextField*checkText;

 

-(void)moveInputBarWithKeyboardHeight:(float)_CGRectHeightwithDuration:(NSTimeInterval)_NSTimeInterval;

 

@end

 

 

 

.m文件内容如下：

 

#import "BaseViewController.h"

 

@implementation BaseViewController

 

 

-(void)viewDidLoad{

   [super viewDidLoad];

 

   //注册通知

   [[NSNotificationCenter defaultCenter] addObserver:selfselector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotificationobject:nil];

   [[NSNotificationCenter defaultCenter] addObserver:selfselector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotificationobject:nil];

   

   //键盘高度变化通知，ios5.0新增的

#ifdef __IPHONE_5_0

   float version = [[[UIDevice currentDevice] systemVersion] floatValue];

   if (version >= 5.0) {

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

   }

#endif

   

}

 

#pragma mark开始编辑UITextField，本人试过这个方法在keyboardWillShow之前被调用

-(void)textFieldDidBeginEditing:(UITextField*)textField{

 

   _checkText = textField;//设置被点击的对象

 

}

 

#pragma mark -键盘弹出时调用的方法

#pragma mark Responding to keyboard events

- (void)keyboardWillShow:(NSNotification*)notification {

   if (nil == _checkText) {

       return;

   }

   /*

    Reduce the size of the text view so that it's not obscured by thekeyboard.

    Animate the resize so that it's in sync with the appearance of thekeyboard.

    */

   

   NSDictionary *userInfo = [notification userInfo];

   

   // Get the origin of the keyboard when it's displayed.

   NSValue* aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];

   

   // Get the top of the keyboard as the y coordinate of its origin inself's view's coordinate system. The bottom of the text view's frame shouldalign with the top of the keyboard's final position.

   CGRect keyboardRect = [aValue CGRectValue];

   

   // Get the duration of the animation.

   NSValue *animationDurationValue = [userInfoobjectForKey:UIKeyboardAnimationDurationUserInfoKey];

   NSTimeInterval animationDuration;

   [animationDurationValue getValue:&animationDuration];

   

   CGRect textFrame = _checkText.frame;//当前UITextField的位置

   float textY = textFrame.origin.y + textFrame.size.height;//得到UITextField下边框距离顶部的高度

   float bottomY = self.view.frame.size.height - textY;//得到下边框到底部的距离

   if(bottomY >=keyboardRect.size.height ){//键盘默认高度,如果大于此高度，则直接返回

         return;

   }

   float moveY = keyboardRect.size.height - bottomY;

    

   // Animate the resize of the text view's frame in sync with the keyboard'sappearance.

   [self moveInputBarWithKeyboardHeight:moveYwithDuration:animationDuration];

 

}

 

//键盘被隐藏的时候调用的方法

(void)keyboardWillHide:(NSNotification*)notification {

   

   NSDictionary* userInfo = [notification userInfo];

   

   /*

    Restore the size of the text view (fill self's view).

    Animate the resize so that it's in sync with the disappearance of thekeyboard.

    */

   NSValue *animationDurationValue = [userInfoobjectForKey:UIKeyboardAnimationDurationUserInfoKey];

   NSTimeInterval animationDuration;

   [animationDurationValue getValue:&animationDuration];

   

   [self moveInputBarWithKeyboardHeight:0.0withDuration:animationDuration];

}

 

 

 

#pragma mark移动view

-(void)moveInputBarWithKeyboardHeight:(float)_CGRectHeightwithDuration:(NSTimeInterval)_NSTimeInterval{

  

   CGRect rect = self.view.frame;

   

   [UIView beginAnimations:nil context:NULL];

   

   [UIView setAnimationDuration:_NSTimeInterval];

   

   rect.origin.y = -_CGRectHeight;//view往上移动

 

   self.view.frame = rect;

   

   [UIView commitAnimations];

 

}

 

 

-(void)dealloc{

   [[NSNotificationCenter defaultCenter] removeObserver:self];//在视图控制器消除时，移除键盘事件的通知

    

}

 

 

 

希望对大家有帮助！