1.注册通知大家应该都是知道的
//使用NSNotificationCenter 鍵盤出現時[[NSNotificationCenterdefaultCenter] addObserver:selfselector:@selector(keyboardWasShown:) name:UIKeyboardWillShowNotificationobject:nil];//使用NSNotificationCenter 鍵盤隐藏時[[NSNotificationCenterdefaultCenter] addObserver:selfselector:@selector(keyboardWillBeHidden:) name:UIKeyboardWillHideNotificationobject:nil];
然后UIView动画...然而那是非常不协调的.
我们还得获取它的持续时间和动画类型
- (void)keyboardWasShown:(NSNotification*)aNotification{NSDictionary* info = [aNotification userInfo];//键盘尺寸CGSizekbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey]CGRectValue].size;//持续时间CGFloatduration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey]floatValue];//动画类型NSIntegeranType = [[info objectForKey:UIKeyboardAnimationCurveUserInfoKey]integerValue]; [UIViewanimateKeyframesWithDuration:duration delay:0options:anType animations:^{CGRectrect = weakKeyView.frame; rect.origin.y-= kSize.height; weakKeyView.frame= rect; } completion:^(BOOLfinished) { }];}
2. 用键盘出现、消失通知在退到后台进进到前台应该做的处理.
接上面，你要是添加了键盘出现和消失的通知，然后让TextField获取第一响应，这个时候你要是点Home键推到后台，然后再点App回到前台，你就会发现:
你在通知的方法中有动画处理的组件消失了...
经过不懈的监听，找到了解决办法:
在Appdelegate.m里面找到进入后台、进入前台的方法，然后发送通知
创建通知
/进入前台[[NSNotificationCenterdefaultCenter] addObserver:selfselector:@selector(enterForeground) name:@"EnterForeground"object:nil];//进入后台[[NSNotificationCenterdefaultCenter] addObserver:selfselector:@selector(enterBackground) name:@"EnterBackground"object:nil];
//进入后台- (void)applicationDidEnterBackground:(UIApplication*)application {//创建一个消息对象NSNotification* notice = [NSNotificationnotificationWithName:@"EnterBackground"object:niluserInfo:nil];//发送消息[[NSNotificationCenterdefaultCenter]postNotification:notice];}//进入前台- (void)applicationWillEnterForeground:(UIApplication*)application {//创建一个消息对象NSNotification* notice = [NSNotificationnotificationWithName:@"EnterForeground"object:niluserInfo:nil];//发送消息[[NSNotificationCenterdefaultCenter]postNotification:notice];}
在进到后台的方法中注销键盘出现和消失的通知
- (void)enterBackground{ [[NSNotificationCenterdefaultCenter]removeObserver:selfname:UIKeyboardWillShowNotificationobject:nil]; [[NSNotificationCenterdefaultCenter]removeObserver:selfname:UIKeyboardWillHideNotificationobject:nil];}
在进入前台的方法中再次添加为键盘出现和消失的通知的观察者
dispatch_after(dispatch_time(DISPATCH_TIME_NOW,(int64_t)(0.5* NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self addKeyNofi];
});
这样就解决了这个问题，要注意的是一定要延迟0.5秒左右再添加为观察者.
