Question

我试图从我上传到Parse的文件中检索一些文本，但我尝试的任何内容似乎都无法正常工作。我尝试使用Parse提供的示例，但我无法使其工作。有人可以帮我解释一下我怎么能这样做吗？

这是一个例子：

PFFile *applicantResume = anotherApplication[@"applicantResumeFile"]; 
NSData *resumeData = [applicantResume getData];

由于

Answer 1

您需要将数据转换回字符串，试试这个。

保存

PFObject * anotherApplication = [[PFObject alloc] initWithClassName:@"Resumes"];
NSData *data = [@"Working at Parse is great!" dataUsingEncoding:NSUTF8StringEncoding];
PFFile *file = [PFFile fileWithName:@"resume.txt" data:data];
anotherApplication[@"applicantResumeFile"] = file;
[anotherApplication save];

打开

[anotherApplication fetchIfNeeded];
PFFile *applicantResume = anotherApplication[@"applicantResumeFile"];
NSData *resumeData = [applicantResume getData];
NSString* dataStr = [[NSString alloc] initWithData:resumeData encoding:NSUTF8StringEncoding];
NSLog(@"Received string: %@", dataStr);

不要忘记在实践中，最好使用'getDataInBackgroundWithBlock：'，'saveInBackgroundWithBlock：'和'fetchIfNeededInBackgroundWithBlock：'

关于街区的说明：

NSLog(@"Will Run 1st: %@", reflex.description); // will be null
[applicantResume getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
    NSString* dataStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    reflex.description = dataStr;
    NSLog(@"Will Run 3rd: %@", reflex.description); // will contain string.
}];
NSLog(@"Will Run 2nd: %@", reflex.description); // will be null

Answer 2

PFFile *applicantResume = object[@"applicantResumeFile"];
NSData *resumeData = [applicantResume getData];
NSString* dataStr = [[NSString alloc] initWithData:resumeData encoding:NSUTF8StringEncoding];
reflex.description = dataStr;

itworkы

当我使用getData时，它不是

PFFile *applicantResume = object[@"applicantResumeFile"];
[applicantResume getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
    if (!error) {
        NSString* dataStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        reflex.description = dataStr;

    }
}];

Parse.com - 从.txt中检索文本

2 个答案: