Question

我是iphone的新手，请帮助我，我想使用iphone从textfile中读取文本现在能够从txtfile中读取文本，但我的问题是（在txtfile中保存了一些数据，如“欢迎使用webapps”这些文字）我想只读webapp字符串）通过使用此代码，我读取来自txtfile.please的所有数据，只提供读取指定文本的任何想法。

-(NSString *)readFile:(NSString *)fileName {
    NSString *filePath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"txt"];  
    NSData *myData = [NSData dataWithContentsOfFile:filePath];  
    NSString *str,*docStr;

    if (myData) {  
        str = [[NSString alloc] initWithData:myData encoding:NSASCIIStringEncoding];

        } 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    // the path to write file
    NSString *appFile = [documentsDirectory stringByAppendingPathComponent:fileName];
    NSError *error = nil;
    BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:appFile];
    if(fileExists)
    {
        NSLog(@"file exist in document");
        NSData *myData1 = [NSData dataWithContentsOfFile:appFile];
        if (myData1) {  
            docStr = [[NSString alloc] initWithData:myData1 encoding:NSASCIIStringEncoding];

        } 
    }
    else {
        NSLog(@"file does not exist");

        BOOL success = [str writeToFile:appFile  atomically:YES encoding:NSUTF8StringEncoding error:&error];
        if (!success) {
            NSLog(@"Error: %@", [error userInfo]);
        }
        else {
            NSLog(@"File write is successful");

        }
        NSData *myData1 = [NSData dataWithContentsOfFile:appFile];
        if (myData1) {  
            docStr = [[NSString alloc] initWithData:myData1 encoding:NSASCIIStringEncoding];

        } 
    }


    return docStr;
}

Answer 1

NSString *mystring=[docstr substringFromIndex:11];

在mystring中你将拥有“webapps”

如何使用iphone从文本文件中的特定位置读取文本？

1 个答案: