Question

我在这个数组中得到了CGPoint值

@interface CanvasView : UIView{
 NSMutableArray *_array;
}
@property (nonatomic, retain) NSMutableArray *_array;

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    CGPoint currentPoint = [touch locationInView:self];
    [_array addObject:[NSValue valueWithCGPoint: currentPoint]];
}

我已经在touchesEnded中调用了这个数组，它的工作正常我会得到nspoint的值

    - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {  
        NSLog(@"roomAtX:%@ ",_array);
    PieClass *myPieClass=[[PieClass alloc]initWithFrame:CGRectMake(8, 297, 200, 300)];
    [self addSubview:myPieClass];
}

这是我的控制台输出

"NSPoint: {595, 158}",
"NSPoint: {558, 154}",
"NSPoint: {535, 152}",
"NSPoint: {518, 152}",
"NSPoint: {500, 160}",
"NSPoint: {482, 175}",

现在我想将这个数组用于另一个类，以便我为另一个类调用它像这样

- (void)drawRect:(CGRect)rect
{
      CanvasView *cnava =[[CanvasView alloc]init];
        NSLog(@"nextview:%@ ",cnava._array);

}

但是我得到nextview:(null) 请指导如何在其他类中访问该数组。

Answer 1

拥有PieClass

的属性

@interface PieClass : UIView{
    // ... other things.
}
@property (nonatomic, retain)NSMutableArray *pointsArray;

并且不要忘记合成它。现在，当您初始化PieClass时，也将该数组传递给此

PieClass *myPieClass=[[PieClass alloc]initWithFrame:CGRectMake(8, 297, 200, 300)];
myPieClass.pointsArray = _array;
[self addSubview:myPieClass];

现在在你的drawRect

中

- (void)drawRect:(CGRect)rect
{
      //CanvasView *cnava =[[CanvasView alloc]init]; you don't need to do this
      NSLog(@"nextview:%@ ",self.pointsArray);  //passed from previous class

}

Answer 2

您必须使用旧对象CanvasView。因此，如果您分配并初始化一个新对象CanvasView，则_array将为null。您必须为_array分配内存并初始化它，或者您必须先将其设置为属性。

因此，对于要绘制的当前对象，您需要传递CanvasView对象的引用，以检测触摸并保存点。

我希望我足够清楚。

Answer 3

将对象（此时，数组）保存到第一个类中的NSUserDefaults

  - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
        CGPoint currentPoint = [touch locationInView:self];
        [_array addObject:[NSValue valueWithCGPoint: currentPoint]];

        NSUserDefaults *myArray=[NSUserDefaults standartuserdefaults];
        [myArray setObject:_array forKey:@"keyToArray"];

    }



    - (void)drawRect:(CGRect)rect
    {  
           NSArray *yourArray=[[NSUserDefaults standartuserdefaults] objectForKey:@"keyToArray"];
          //CanvasView *cnava =[[CanvasView alloc]init];
            NSLog(@"nextview:%@ ",yourArray);

    }

试试这个

Answer 4

如果我理解正确，你需要这个班级成为一个单身人士

首先在.h文件中创建一个类方法：

@interface CanvasView : UIView{
 NSMutableArray *_array;
}
...
+ (CanvasView *)sharedInstance;
...

然后在.m文件中：

@implementation CanvasView
...
static CanvasView *sharedHelper = nil;
...
+ (CanvasView *)sharedInstance
{
    @synchronized(self) 
    {
        if (!sharedHelper) 
        {
            sharedHelper = [CanvasView new;
        }
    }
    return sharedHelper;
}

并称之为：

CanvasView *view = [CanvasView sharedInstance];

从iPhone xcode中的另一个类访问数组

4 个答案: