Question

我的应用的Documents文件夹中有.png图像，但是当我尝试加载它们时它不起作用：/

我有这个类用于保存和加载的方法：

UIImage + loadScan.h：

#import <UIKit/UIKit.h>

@interface UIImage (loadScan)

- (void)saveScan:(NSString*)name;

- (UIImage *)loadScan:(NSString*)name;

@end

.m：

#import "UIImage+loadScan.h"

@implementation UIImage (loadScan)

#pragma SAVE AND LOAD

- (void)saveScan:(NSString*)name{
    if (self != nil)
    {
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                             NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString* path = [documentsDirectory stringByAppendingPathComponent:
                          [NSString stringWithString:name] ];
        NSData* data = UIImagePNGRepresentation(self);
        [data writeToFile:path atomically:YES];
    }
}

- (UIImage *)loadScan:(NSString*)name{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                         NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString* path = [NSString stringWithFormat:@"%@/%@", documentsDirectory, name];
    NSLog(@"loading %@", path);

    NSData *imgData = [NSData dataWithContentsOfFile:path];
    UIImage *image = [[UIImage alloc] initWithData:imgData];

    //UIImage *image = [UIImage imageWithContentsOfFile:path];
    return image;
}

@end

saveScan方法运行良好：

[image saveScan:[NSString stringWithFormat:@"%@.png", imgName]];

但是loadScan不想工作：

UIImage *imageLoad = [[UIImage alloc] init];
[imageLoad loadScan:[NSString stringWithFormat:@"%@.png", imgName]];
cell.imageScan.image = imageLoad;

我不明白为什么，但文件存在。

由于

Answer 1

我找到了一个（奇怪的）方法，但它有效（我发送UIImage也是非参数并在方法中初始化）：

- (UIImage *)loadScan:(NSString*)name theImage:(UIImage*)theImg{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                         NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString* path = [NSString stringWithFormat:@"%@/%@", documentsDirectory, name];
    NSLog(@"loading %@", path);

    [theImg initWithContentsOfFile:path];
    return theImg;
}

致电：

UIImage *imageLoad = [UIImage alloc];
            [imageLoad loadScan:[NSString stringWithFormat:@"%@@2x.png", imgName] theImage:imageLoad];

现在imageLoad有图像数据，我们可以显示它！

如何从应用程序的Documents文件夹中加载.png图像

1 个答案: