今天在UITabBarController使用自定義圖片設置UITabItem時，發(fā)現一個問題：

在iOS7以上的手機中，第一個Tab的選中圖一直顯示的是系統(tǒng)默認的藍色圖，查看了一下UITabItem的頭文件，發(fā)現下面的內容：

/* The unselected image is autogenerated from the image argument. The selected image

is autogenerated from the selectedImage if provided and the image argument otherwise.

To prevent system coloring, provide images with UIImageRenderingModeAlwaysOriginal (see UIImage.h)

*/

- (instancetype)initWithTitle:(NSString *)title image:(UIImage *)image tag:(NSInteger)tag;

- (instancetype)initWithTitle:(NSString *)title image:(UIImage *)image selectedImage:(UIImage *)selectedImage NS_AVAILABLE_IOS(7_0);

- (instancetype)initWithTabBarSystemItem:(UITabBarSystemItem)systemItem tag:(NSInteger)tag;

意思是，如果不希望使用系統(tǒng)顏色，需要對圖片加上屬性UIImageRenderingModeAlwaysOriginal

所以按此方式實驗，代碼如下：

UIImage *musicImage = [UIImage imageNamed:@"music.png"];

UIImage *musicImageSel = [UIImage imageNamed:@"musicSel.png"];

musicImage = [musicImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

musicImageSel = [musicImageSel imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

self.musicViewController.tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Music" image:musicImage selectedImage:musicImageSel];