iOS开发中的键盘高度变化处理

http://blog.unieagle.net/2012/06/04/ios%E5%BC%80%E5%8F%91%E4%B8%AD%E7%9A%84%E9%94%AE%E7%9B%98%E9%AB%98%E5%BA%A6%E5%8F%98%E5%8C%96%E5%A4%84%E7%90%86/

在ios开发中，键盘很常用。在sdk版本5.0以前，键盘高度是固定值216px；5.0出来以后，键盘高度会随着键盘语言变化（中文要高些），在这种情况下一般而言对于界面需要重新布局。方法是利用NSNotificationCenter。

UIKeyboardWillShowNotification;UIKeyboardDidShowNotification; UIKeyboardWillHideNotification; UIKeyboardDidHideNotification;

这几个notification是5.0sdk之前就有的，顾名思义就知道意思了。

UIKeyboardWillChangeFrameNotification  __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_5_0);UIKeyboardDidChangeFrameNotification   __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_5_0);

这两个是sdk 5.0以后出来的，用来处理键盘高度的变化。

使用方法是：首先在notification注册观察者，比如：

if([[[UIDevice currentDevice] systemVersion] floatValue] >= 5.0) {    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];}

当键盘高度将要变化时，就会收到通知，在通知的参数中可以得到键盘目前的高度和变化的目标高度，比如：

-(void)keyboardWillChangeFrame:(NSNotification*)notif{#if __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_3_2      NSValue *keyboardBoundsValue = [[notif userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey];  #else      NSValue *keyboardBoundsValue = [[notif userInfo] objectForKey:UIKeyboardBoundsUserInfoKey];  #endif    CGRect keyboardEndRect = [keyboardBoundsValue CGRectValue];    CGRect inputFrame = self.feedBackTextView.frame;    //kb 216 vs textFrame 185    float delta = keyboardEndRect.size.height - 216;    float originalHeight = inputFrame.size.height;    inputFrame.size.height = 185 - delta;    if (inputFrame.size.height != originalHeight) {        self.feedBackTextView.frame = inputFrame;        self.feedBackBackgroundView.frame = inputFrame;    }}

另外一些从notification.userInfo中可以取得的key如下：

UIKeyboardFrameBeginUserInfoKey        // NSValue of CGRectUIKeyboardFrameEndUserInfoKey          // NSValue of CGRectUIKeyboardAnimationDurationUserInfoKey // NSNumber of doubleUIKeyboardAnimationCurveUserInfoKey    // NSNumber of double

notif中userInfo的完整信息如下：

keyboardChange:{    UIKeyboardAnimationCurveUserInfoKey = 0;    UIKeyboardAnimationDurationUserInfoKey = "0.25";    UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {320, 216}}";    UIKeyboardCenterBeginUserInfoKey = "NSPoint: {160, 372}";    UIKeyboardCenterEndUserInfoKey = "NSPoint: {160, 588}";    UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 264}, {320, 216}}";    UIKeyboardFrameChangedByUserInteraction = 0;    UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 480}, {320, 216}}";}

下面是一个完整的解决方案，用户需要知道键盘高度的细致变化

#pragma mark Keyboard-(void)keyboardWillChangeFrame:(NSNotification*)notif{    NSLog(@"keyboardChange:%@",[notif userInfo]);    float keyboadHeightBegin = 0;    float keyboadHeightEnd = 0;    float animationDuration = [[[notif userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];    UIViewAnimationCurve animationCurve = [[[notif userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey] unsignedIntegerValue];#if __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_3_2    CGRect keyboardBeginFrame = [[[notif userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];    CGRect keyboardEndFrame = [[[notif userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];    keyboadHeightBegin = 480 - keyboardBeginFrame.origin.y;    keyboadHeightEnd = 480 - keyboardEndFrame.origin.y;#else    //these deprecated after iOS 3.2    CGRect keyboardBounds = [[[notif userInfo] objectForKey:UIKeyboardBoundsUserInfoKey] CGRectValue];    CGPoint keybordCenterBegin = [[[notif userInfo] objectForKey:UIKeyboardCenterBeginUserInfoKey] CGPointValue];    CGPoint keybordCenterEnd = [[[notif userInfo] objectForKey:UIKeyboardCenterEndUserInfoKey] CGPointValue];    keyboadHeightBegin = 480 - (keybordCenterBegin.y - keyboardBounds.size.height / 2);    keyboadHeightEnd = 480 - (keybordCenterEnd.y - keyboardBounds.size.height / 2);#endif    NSLog(@"keyboardHeightChangeFrom:%.2f,To:%.2f",keyboadHeightBegin,keyboadHeightEnd);    return;    if (keyboadHeightEnd > 0) {        //keyboard show or change frame        [UIView animateWithDuration:animationDuration delay:0 options:animationCurve animations:^{        } completion:^(BOOL finished) {        }];    } else {        //keyboard hide    }}-(void)keyboardDidChangeFrame:(NSNotification*)notif{    //info like willChangeFrame}-(void)keyboardWillShow:(NSNotification*)notif{    //keyboard height will be 216, on iOS version older than 5.0    [UIView animateWithDuration:0.3f animations:^{        self.contentTableView.height = 480 - 44 - 216;    }];}-(void)keyboardWillHide:(NSNotification*)notif{    [UIView animateWithDuration:0.3f animations:^{        self.contentTableView.height = 480 - 44 - 28;    }];}-(void)registerKeyboardEvent{    float systemVer = [[[UIDevice currentDevice] systemVersion] floatValue];    if(systemVer >= 5.0) {        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidChangeFrame:) name:UIKeyboardDidChangeFrameNotification object:nil];    } else {        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];    }}-(void)unregisterKeyboardEvent{    if([[[UIDevice currentDevice] systemVersion] floatValue] > 5.0) {        [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];        [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidChangeFrameNotification object:nil];    } else {        [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];        [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];            }}

下面这个解决方案就只考虑键盘出现和消失的处理

#pragma mark Keyboard-(void)keyboardWillShow:(NSNotification*)notif{    //keyboard height will be 216, on iOS version older than 5.0    CGRect boxFrame = self.loginBoxView.frame;    boxFrame.origin.y = 50;    [UIView animateWithDuration:0.3f animations:^{        self.loginBoxView.frame = boxFrame;    }];}-(void)keyboardWillHide:(NSNotification*)notif{    CGRect boxFrame = self.loginBoxView.frame;    boxFrame.origin.y = 216;    [UIView animateWithDuration:0.3f animations:^{        self.loginBoxView.frame = boxFrame;    }];}//在viewdidload中调用-(void)registerKeyboardEvent{    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];}//在viewdidunload中调用-(void)unregisterKeyboardEvent{    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];}