iOS5 切换中文键盘时覆盖输入框的解决方案

在iOS3.2以后的系统中，苹果就提供了键盘使用的API以及Demo程序——“KeyboardAccessory”。

　　处理键盘事件的正确方法是这样的：（包括获取键盘的位置以及键盘弹出和消失动画的时间）

　　1）在要使用键盘的视图控制器中（既viewDidLoad中），接收键盘事件的通知：

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

2）然后添加键盘事件的处理代码：

　　　　获取到当前keyboard的高度以及动画时间，然后对视图进行对应的操作即可。

#pragma mark -
#pragma mark Responding to keyboard events
- (void)keyboardWillShow:(NSNotification *)notification {

/*

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

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

     */

    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 in self's view's coordinate system. The bottom of the text view's frame should align with the top of the keyboard's final position.

    CGRect keyboardRect = [aValue CGRectValue];

    // Get the duration of the animation.

    NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];

    NSTimeInterval animationDuration;

    [animationDurationValue getValue:&animationDuration];

    

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

    [UIView animateWithDuration:animationDuration animations:^{

//此处的viewFooter即是你的输入框View

  //20为状态栏的高度

  self.viewFooter.frame = CGRectMake(viewFooter.frame.origin.x, keyboardRect.origin.y-20-viewFooter.frame.size.height,viewFooter.frame.size.width, viewFooter.frame.size.height);

    } completion:^(BOOL finished){

        

    }];

}


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

NSDictionary* userInfo = [notification userInfo];

    NSValue* aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGRect keyboardRect = [aValue CGRectValue];

    

    /*

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

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

     */

    [UIView animateWithDuration:0 animations:^{

        self.viewFooter.frame = CGRectMake(viewFooter.frame.origin.x, keyboardRect.origin.y-20-viewFooter.frame.size.height, viewFooter.frame.size.width, viewFooter.frame.size.height);

    } completion:^(BOOL finished){

        

    }];

}

　　3）在视图控制器消除时（即viewDidUnload中），移除键盘事件的通知：

[[NSNotificationCenter defaultCenter] removeObserver:self];