iphone - UIScrollView 触摸和监听事件

Question

我在 UIScrollView 中有一个图像，我有代码在用户拖动手指时绘制文本。我希望能够控制，当用户触摸屏幕时，如果

a) 用户应该用他们的手指画画或者

b) 用户应该用手指移动 ScrollView

我有一个 bool 值，它跟踪用户正在做什么。我有触摸方法:

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{

    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
    if(draw == false) {
        printf("calling super");
        [scrollView touchesBegan:touches withEvent:event];
    }
    else
        [myPath moveToPoint:[mytouch locationInView:self]];

}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{

    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
    if(draw == false)
        [scrollView touchesMoved:touches withEvent:event];
    else {
        [myPath addLineToPoint:[mytouch locationInView:self]];
        [self setNeedsDisplay];
    }

为什么这行不通？基本上，如果我不绘图，我会调用 ScrollView 的 touchesBegan 和 touchesMoved。如果我正在绘图，我会使用 myPath 进行绘图。

但是，当 draw 为 false 时， ScrollView 不会四处移动或放大等。

Answer 1

我以前遇到过这个问题。我这样解决:

你应该制作一个 mainView 。它有2个属性。一个是 yourScrollView ，一个是 yourDrawImageView。 [yourScrollView addSubviews:yourDrawImageView];[mainView addSubviews:yourScrollView];

然后像这样在 mainView.m 中编写你的 touches 方法(忽略 scrollView 语句)

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{

    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
   if ([[touches allObjects] isKindOfClass:[yourDrawImageView class]]) 
   {

        [myPath moveToPoint:[mytouch locationInView:self]];
   }

}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{

    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
   if ([[touches allObjects] isKindOfClass:[yourDrawImageView class]]) 
   {

        [myPath addLineToPoint:[mytouch locationInView:self]];
        [self setNeedsDisplay];
   }


}

最后一步，你忽略的是编写 scrollView touches 事件，它写在你的 SceollView.m 中，像这样:

#import "yourScrollView.h"


@implementation yourScrollView


- (id)initWithFrame:(CGRect)frame {

    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code.
    }
    return self;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesBegan:touches withEvent:event];
    if(!self.dragging)
        [[self nextResponder] touchesBegan:touches withEvent:event];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesMoved:touches withEvent:event];
    if(!self.dragging)
        [[self nextResponder] touchesMoved:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    [super touchesEnded:touches withEvent:event];
    if(!self.dragging)
        [[self nextResponder] touchesEnded:touches withEvent:event];
}

- (void)dealloc {
    [super dealloc];
}


@end 

希望对您有所帮助:-)