Question

我想用NSOpenpPanel打开myfile.plist但是如果用户刚刚选择了plist，我也会访问myfile.png。我已经尝试访问png了

NSString* url = [[NSString stringWithFormat:@"file://localhost%@%@%@", pathWithoutFilename, @"/", imageFileName ]stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

但正在做：

NSData* imageData = [[NSData alloc] initWithContentsOfURL:nsurl];
NSImage *sourceImage = [[NSImage alloc] initWithData:imageData];

NSImage是零。

我怎么样？

Answer 1

使用NSURLBookmarkCreationWithSecurityScope为Sandbox Cocoa应用程序提供正确的保存和Retreive书签技巧：最后

-(void)saveTheNSData:(NSData *)data withFileName:(NSString *)fileName
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:fileName];

    [data writeToFile:filePath atomically:NO];
}

-(NSURL*) getNSURLFromBookmarkIfExists:(NSString*) filename forType:(NSString*) type
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:filename];

    NSData* data = [[NSData alloc] initWithContentsOfFile: filePath];
    if(data != nil)
    {
        NSURL* outUrl = [NSURL URLByResolvingBookmarkData:[[NSUserDefaults standardUserDefaults] objectForKey:type] options:NSURLBookmarkResolutionWithSecurityScope relativeToURL:nil bookmarkDataIsStale:nil error:nil];
        [outUrl startAccessingSecurityScopedResource];
        return outUrl;
    }
    else
        return nil;
}

另外请查看此示例，了解使用 [NSUserDefaults standardUserDefaults] 设置书签的正确方法：

-(void) savePlistWithPlistUrl:(NSURL*) plistUrl andImageUrl:(NSURL*) imageUrl
{
    NSData *bookmarkPlist = [self bookmarkFromURL:plistUrl];

    NSArray* pathSplitted = [pathFilePlist pathComponents];
    NSString* filenamePlist = [pathSplitted objectAtIndex:[pathSplitted count]-1];

    NSData *bookmarkImage = [self bookmarkFromURL:imageUrl];

    NSArray* pathImageSplitted = [imageUrl pathComponents];
    NSString* filenameImage = [pathImageSplitted objectAtIndex:[pathImageSplitted count]-1];

    NSUserDefaults* prefs = [NSUserDefaults standardUserDefaults];
    [prefs setObject:bookmarkPlist forKey:@"ExportPlist"];
    [prefs setObject:bookmarkImage forKey:@"ExportImage"];
    [prefs synchronize];
    // save the data bookmark
    [self saveTheNSData: bookmarkPlist withFileName:filenamePlist];
    [self saveTheNSData: bookmarkImage withFileName:filenameImage];
}

使用沙箱打开一个文件，可以访问另一个具有相同名称的文件

1 个答案: