Question

我想在imageview上标记一些东西并且必须存储在数据库中，当我将从数据库中检索它时，我必须在imageview上显示相同的坐标。

Answer 1

您在故事板（或代码中）中创建了UIImageView，并在viewController中创建了fowling属性：

@property (strong, nonatomic) UITapGestureRecognizer *tapGesture;

接下来，在viewDidLoad初始化tapGesture：

self.tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTapGesture:)];

self.tapGesture.delegate = self;

[self.view addGestureRecognizer:self.tapGesture];

接下来，为tap：

创建处理程序

- (void)handleSingleTapGesture:(UITapGestureRecognizer *)tapGestureRecognizer {

    CGPoint point = [tapGestureRecognizer locationInView:self.imageView];
    float squareSize = 10;

    UIGraphicsBeginImageContextWithOptions(self.imageView.frame.size, YES, 0);

    [self.imageView.image drawInRect:CGRectMake(0, 0, self.imageView.frame.size.width, self.imageView.frame.size.height)];

    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), point.x-squareSize, point.y - squareSize);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), point.x+squareSize, point.y-squareSize);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), point.x+squareSize, point.y+squareSize);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), point.x-squareSize, point.y+squareSize);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), point.x-squareSize, point.y-squareSize);
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1);
    CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0,0,0,1);
    CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal);

    CGContextStrokePath(UIGraphicsGetCurrentContext());
    self.imageView.image = UIGraphicsGetImageFromCurrentImageContext();
    [self.imageView setAlpha:1.0];
    UIGraphicsEndImageContext();

}

此代码在imageView上绘制一个正方形。现在，您可以将point保存在数据库中，并在需要时显示图像绘制方形标记。

我希望这对你有所帮助。

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