从iPhone上的缓存加载图像的问题

Question

这是我的代码

UIImage * result = [[UIImage alloc] imageWithContentsOfFile:filePath];

这里是我的错误日志

> 2009-12-22 17:00:44.137
> DrillDownApp[2061:207] touchesBegan
> from root 2009-12-22 17:00:44.138
> DrillDownApp[2061:207] touchesBegan
> from root at X = 52.000 and Y = 87.000
> at INDEX = 0 2009-12-22 17:00:44.139
> DrillDownApp[2061:207] index = 0
> 2009-12-22 17:00:44.140
> DrillDownApp[2061:207] Begin Load
> Image 2009-12-22 17:00:44.141
> DrillDownApp[2061:207] Load Image
> complete 2009-12-22 17:00:44.142
> DrillDownApp[2061:207] get index = 0
> 2009-12-22 17:00:44.143
> DrillDownApp[2061:207]
> /Users/ragopor/Library/Application
> Support/iPhone
> Simulator/User/Applications/47C3AA6B-4C93-4A17-BF3C-D212D11951F2/Documents/URLCache/P4010143.jpg
> 2009-12-22 17:00:44.144
> DrillDownApp[2061:207] *** -[UIImage
> imageWithContentsOfFile:]:
> unrecognized selector sent to instance
> 0x3d180b0 2009-12-22 17:00:44.144
> DrillDownApp[2061:207] *** Terminating
> app due to uncaught exception
> 'NSInvalidArgumentException', reason:
> '*** -[UIImage
> imageWithContentsOfFile:]:
> unrecognized selector sent to instance
> 0x3d180b0' 2009-12-22 17:00:44.145
> DrillDownApp[2061:207] Stack: (
>     29721691,
>     2449544457,
>     30103611,
>     29673078,
>     29525698,
>     13756,
>     20415,
>     20979,
>     25843,
>     18694,
>     3160730,
>     3143896,
>     397754,
>     29506240,
>     29502536,
>     37812109,
>     37812306,
>     2887683,
>     11024,
>     10878 )

Answer 1

imageWithContentsOfFile是一个类方法。你应该使用

[UIImage imageWithContentsOfFile:filePath];

或

[[UIImage alloc] initWithContentsOfFile:filePath];

Answer 2

imageWithContentsOfFile是一个返回UIImage的静态函数。无需分配图像。

UIImage * result = [UIImage imageWithContentsOfFile:filePath];