Question

我在iPhone SDK中向NSArray添加对象时遇到问题。问题是它只添加了我的NSDictionary的最后一个对象。这是代码：

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
for (NSDictionary * dict in processes){
    runningprocesses = [[NSMutableArray alloc] init];
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

当我NSLog [dict objectForKey:@"ProcessName"]时，它向我展示了所有进程，但是如果我尝试添加它们，它只会添加最后一个进程。可能会发生什么？

Answer 1

我按照我的建议改编你的代码：

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
NSMutableArray *runningprocesses = [[NSMutableArray alloc] initWithCapacity:[processes count]];
for (NSDictionary * dict in processes){
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

当我尝试时，这对我有用：]

Answer 2

在您的代码中，每次循环迭代时，runningprocesses数组都指向一个新实例。

要修复它，请在for循环外移动数组实例：

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
NSMutableArray *runningprocesses = [[NSMutableArray alloc] init];
for (NSDictionary * dict in processes){

    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

Answer 3

您每次都在for循环中尝试分配“runningprocesses”数组。这就是为什么它在for循环结束时只有一个对象。尝试替换此代码。

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
runningprocesses = [[NSMutableArray alloc] init];
for (NSDictionary * dict in processes){
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

这应该有用。

Answer 4

您应该将alloc-init语句移到for循环之外。以下是代码

runningprocesses = [[NSMutableArray alloc] init];
NSArray * processes = [[UIDevice currentDevice] runningProcesses];

for (NSDictionary * dict in processes)
{
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

在iPhone SDK中将对象添加到阵列时出现问题

4 个答案: