解决Keyboard遮盖输入的几种办法

一般来说，键盘遮挡主要有这么几种情况，一个是遮住UITextView，还有就是遮住UITextField，一般来说，比较推荐在UIScrollView或者UITableView里加入textfield的控件。但是有时也许难免。。

在UITextView中

这个在苹果官方文档中的项目中给出了做法，首先是注册观察者监听UIKeyboardWillShow和WillHide事件

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

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

实现自定义的方法

- (void)keyboardWillShow:(NSNotification *)aNotification
{
    NSDictionary *userInfo = [aNotification userInfo];

    CGRect keyboardRect = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    NSTimeInterval animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];

    CGRect newFrame = self.view.frame;
    newFrame.size.height -= keyboardRect.size.height;

    [UIView beginAnimations:@"ResizeTextView" context:nil];
    [UIView setAnimationDuration:animationDuration];

    self.view.frame = newFrame;

    [UIView commitAnimations];
}

获取键盘显示的信息，然后根据信息对view的frame进行调整，然后WillHide方法就跟上面相同，只不过把高度新高度改成+= keyboardRect.size.height就可以了，最后，移除观察者：

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIKeyboardWillHideNotification
                                                  object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIKeyboardWillShowNotification
                                                  object:nil];
}

在UIView中遮挡UITextField

大体来说，处理方法同上面类似，主要采取动画平移的方法，而且还能适应切换输入法，我上来定义了个成员来记住一开始UIView的位置，然后在动画的处理上稍微进行了处理。_viewRect = self.view.frame

- (void)keyboardWillShow:(NSNotification *)aNotification
{
    NSDictionary *userInfo = [aNotification userInfo];

    CGRect keyboardRect = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    NSTimeInterval animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];

    CGRect oldFrame = _viewRect;

    [UIView beginAnimations:@"ResizeView" context:nil];
    [UIView setAnimationDuration:animationDuration];

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

    [UIView commitAnimations];
}

- (void)keyboardWillHide:(NSNotification *)aNotification
{
    NSDictionary *userInfo = [aNotification userInfo];
    NSTimeInterval animationDuration = [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];

    CGRect newFrame = _viewRect;
    newFrame.origin.y += 20;

    [UIView beginAnimations:@"ResizeView" context:nil];
    [UIView setAnimationDuration:animationDuration];

    self.view.frame = newFrame;

    [UIView commitAnimations];
}

UITableView

UITableView则有些尴尬，因为可以不用代码就可以实现向上平移，但是有一个问题就是点击空白处不能让键盘消失，它也不能去响应UIControl，看了很多方法，但是貌似都或多或少有点问题，这里也请教一下大神们有什么建议。我的方法是从GitHub上找到了一个TPKeyboardAvoidingTableView，让自己的UITableView子类去继承它，就可以很轻松的实现点击消失键盘事件了，具体的源码可以去下载看一看。