限制保存在文檔文件夾中的圖像數

Question

我想拍攝3張圖像並將其作爲IMAGE_1，IMAGE_2和IMAGE_3保存在文檔文件夾中。我想將圖像數量限制爲只有三張圖像，這意味着第四張圖像將被保存爲替換第一張圖像（舊的IMAGE_1）的新「IMAGE_1」，第五張圖像將被保存爲「IMAGE_2」，依此類推。下面的代碼將圖像保存爲IMAGE_1，IMAGE_2，IMAGE_3，IMAGE_4，...我應該如何限制保存的圖像數量？

- (void) saveImage:(UIImage*)image 
{ 
    NSData *imageData = 
    [NSData dataWithData:UIImageJPEGRepresentation(image, 0.9f)]; 
    [imageData writeToFile:[self savePath] atomically:YES]; 
} 

- (NSString*) savePath 
{ 
    int i=1; 
    NSString *path; 
    do { 
    path = [NSString stringWithFormat: @"%@/Documents/IMAGE_%d.jpg", NSHomeDirectory(), i++]; 
} while ([[NSFileManager defaultManager] fileExistsAtPath:path]); 

    return path; 
} 

Answer 1

static int i=1; // Place it below your @implementation yourclassname 

- (void) saveImage:(UIImage*)image { 
    NSData *imageData = [NSData dataWithData:UIImageJPEGRepresentation(image, 0.9f)]; 
    NSFileManager *fileMgr = [NSFileManager defaultManager]; 
    NSString *path = [self savePath]; 

    if([fileMgr fileExistsAtPath:path]) 
     [fileMgr removeItemAtPath:path error:NULL]; 
    [imageData writeToFile:path atomically:YES]; 
} 
- (NSString*) savePath { 
    if(i==4) 
     i=1; 
    return [NSString stringWithFormat: @"%@/Documents/IMAGE_%d.jpg", NSHomeDirectory(), i++]; 
} 

希望它能幫助。