像Messages app一样在滚动的时候可以让键盘消失是一种非常好的体验。然而，将这种行为整合到你的app很难。幸运的是，苹果给UIScrollView添加了一个很好用的属性keyboardDismissMode，这样可以方便很多。
现在仅仅只需要在Storyboard中改变一个简单的属性，或者增加一行代码，你的app可以和办到和Messages app一样的事情了。
这个属性使用了新的UIScrollViewKeyboardDismissMode enum枚举类型。这个enum枚举类型可能的值如下：
Crayon Syntax Highlighter v2.7.1
UIScrollViewKeyboardDismissModeNone // the keyboard is not dismissed automatically when scrolling
UIScrollViewKeyboardDismissModeOnDrag // dismisses the keyboard when a drag begins
UIScrollViewKeyboardDismissModeInteractive // the keyboard follows the dragging touch off screen, and may be
pulled upward again to cancel the dismiss
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UIScrollViewKeyboardDismissModeNone // the keyboard is not dismissed automatically when scrolling
UIScrollViewKeyboardDismissModeOnDrag // dismisses the keyboard when a drag begins
UIScrollViewKeyboardDismissModeInteractive // the keyboard follows the dragging touch off screen, and may be
pulled upward again to cancel the dismiss
[Format Time: 0.0007 seconds]
以下是让键盘可以在滚动的时候消失需要设置的属性：
二十、使用Core Image来检测眨眼以及微笑
iOS给Core Image增加了两种人脸检测功能：CIDetectorEyeBlink以及CIDetectorSmile。这也就是说你现在可以在照片中检测微笑以及眨眼。
以下是在app中使用它的方法：
Crayon Syntax Highlighter v2.7.1
UIImage *image = [UIImage imageNamed:@"myImage"];
CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil
options:@{CIDetectorAccuracy: CIDetectorAccuracyHigh}];
NSDictionary *options = @{ CIDetectorSmile: @YES, CIDetectorEyeBlink: @YES };
NSArray *features = [detector featuresInImage:image.CIImage options:options];
for (CIFaceFeature *feature in features) {
NSLog(@"Bounds: %@", NSStringFromCGRect(feature.bounds));
if (feature.hasSmile) {
NSLog(@"Nice smile!");
} else {
NSLog(@"Why so serious?");
}
if (feature.leftEyeClosed || feature.rightEyeClosed) {
NSLog(@"Open your eyes!");
}
}
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UIImage *image = [UIImage imageNamed:@"myImage"];