UserDefaults - NSMutibleArray环路

Question

Mutible数组包含双倍。

它需要当前保存的array添加新的doubles，然后重新保存它。

NSUserDefaults *defaultDefects = [NSUserDefaults standardUserDefaults];

NSMutableArray *loadDefects = [defaultDefects objectForKey:@"defaultDefects"];

[loadDefects addObject:[NSNumber numberWithDouble:self.defectPositionX ]];
[loadDefects addObject:[NSNumber numberWithDouble:self.defectPositionY ]];

[defaultDefects setObject:loadDefects forKey:@"defaultDefects"];

那我就需要这个

NSUserDefaults *defaultDefects = [NSUserDefaults standardUserDefaults];
NSMutableArray *loadDefects = [defaultDefects objectForKey:@"defaultDefects"];

//in here I need a foreach loop so it would be something like

double defectX = 0;
double defectY = 0;
int keyValue;    

foreach (loadDefects as key => value) {
    double defectX = [[loadDefects objectAtIndex:keyValue] doubleValue];
    keyValue++;
    double defectY = [[loadDefects objectAtIndex:keyValue] doubleValue];
    keyValue++;
    CGContextMoveToPoint(context, defectX, defectY);
}

我写这个是为了程序上的意义，而不是用目标C写它的正确方式，因为这就是我想要弄清楚的。希望你能看到我想要实现的目标。

Answer 1

正如我所理解的，您需要使用步骤"2“进行for循环，以便在一个周期步骤中检索X和Y。试试这个：

for (int i = 0; i < loadDefects.count; i += 2) {
    double defectX = [loadDefects[i] doubleValue];
    double defectY = [loadDefects[i+1] doubleValue];
    CGContextMoveToPoint(context, defectX, defectY);
}

另外，不要忘记在第一次启动应用程序时初始化loadDefects数组，并在NSUserDefaults中保存更改：

NSMutableArray *loadDefects = [defaultDefects objectForKey:@"defaultDefects"];
if (loadDefects == nil) {
    loadDefects = [NSMutableArray array];
}
// ...
// Add elements to array and store it defaultDefects here
// ...
[defaultDefects synchronize];