Question

这是UIAlertView的委托方法。在运行应用程序时，我不知道为什么myWordsDictionary为null。（注意：_dailyWords是一个NSDictionary对象，书签是一个NSString对象。）

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex 
{
    if (buttonIndex != [alertView cancelButtonIndex]) {
        NSLog(@"Clicked button index !=0");
        // Add the action here
        NSString *documentPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)  lastObject];
        NSString *myWordsPath = [documentPath stringByAppendingPathComponent:@"MyWords.plist"];
        NSMutableDictionary *myWordsDictionary = [[NSMutableDictionary alloc] initWithContentsOfFile:myWordsPath];
        [myWordsDictionary setValue:[_dailyWords objectForKey:bookmarked] forKey:bookmarked];
        [myWordsDictionary writeToFile:myWordsPath atomically:YES];
        NSLog(@"%@", [myWordsDictionary description]);
        [myWordsDictionary release];

    } else {
        NSLog(@"Clicked button index = 0");
        // Add another action here
    }
}

提前致谢。

Answer 1

myWordsPath可能不包含任何有效文件，并且您正在从该路径中存在的文件的内容初始化NSMutableDictionary。这就是你得到一个空字典的原因。

Answer 2

首先，尝试检查myWordsPath，如果它返回null，您应该查找并找到正确的路径。

其次，你如何生成你的plist？ MyWords.plist必须包含有效格式。如果你不确定，你应该在XCode中创建，有plist对象。

Answer 3

NSBundle *bundle = [NSBundle mainBundle];
NSString *plistPath = [bundle pathForResource:
                       @"MyWords" ofType:@"plist"];
NSDictionary *dictionary = [[NSDictionary alloc]
                            initWithContentsOfFile:plistPath];

Answer 4

请尝试此代码..

NSString *documentPath =    [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,    NSUserDomainMask, YES)  objectAtIndex:0];
documentPath =    [documentPath stringByAppendingPathComponent:@"MyWords.plist"]; 
NSMutableDictionary *myWordsDictionary = [[NSMutableDictionary alloc]    initWithContentsOfFile:documentPath];

为什么我的NSMutableDictionary为null？

4 个答案: