Objective-C和ARC:为什么永远不会读取在初始化期间存储的值？

Question

我在ARC中使用此代码:

NSMutableDictionary *datesDict = [[NSMutableDictionary alloc]init];
NSMutableArray *datesArray = [[NSMutableArray alloc]init];

for (NSString *key in programsArray) {

    datesArray = [_onDemandDictionary objectForKey:key];
    NSMutableArray *newDates = [[NSMutableArray alloc]init];
    int count;
    for (count = 0; count <datesArray.count; count++) {
        NSMutableDictionary *programsDict = [[NSMutableDictionary alloc]init];
        programsDict = [datesArray objectAtIndex:count];
        [newDates addObject:[programsDict objectForKey:@"date"]];

    }

    [datesDict setObject:newDates forKey:key];
}

但是,当我运行分析器工具时,我在初始化期间将值存储到(datesArray和programsDict),从不在行上读取:

NSMutableArray *datesArray = [[NSMutableArray alloc]init];
programsDict = [datesArray objectAtIndex:count];

为什么会发生这种情况？如何隐藏警告？

谢谢!

Answer 1

问题是您创建一个新的NSMutableArray并datesArray在开始时将其分配给它

NSMutableArray *datesArray = [[NSMutableArray alloc]init];

然后后立即分配一个完全不同的值datesArray与

datesArray = [_onDemandDictionary objectForKey:key];

我会先说

NSMutableArray *datesArray = nil;

这是相同的概念programsDict.