將對象添加到iPhone SDK中的數組時出現問題

Question

我在將對象添加到iPhone SDK中的NSArray時遇到問題。問題是它只添加我的NSDictionary的最後一個對象。這是代碼：

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

當我的NSLog [dict objectForKey:@"ProcessName"]它顯示我所有的進程，但如果我嘗試添加他們只增加了最後一個。會發生什麼？

Answer 1

我重新編輯你的代碼，我建議你嘗試，而不是：

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]; 
} 

這個工作對我來說，當我嘗試：]

Answer 2

在代碼中，每次循環迭代中，runningprocesses陣列正在指向一個新的實例。

要修復它移到您的陣列實例外的for循環：

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

您正在嘗試每次分配「runningprocesses」數組中的for循環。這就是爲什麼它在for循環結束時只有一個對象。嘗試替換此代碼。

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

這應該有效。

Answer 4

您應該將您的alloc-init聲明移至for循環之外。下面是代碼

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

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