scrollview 图片放大 捏合 瓦片地图 相关注意事项

就职文博公司要为博物馆做APP 涉及到瓦片地图的编写 在这里总结一些开发中遇到的问题 (将会不断更新 也是学习阶段)

着急写项目的同学 可以直接看code4上现成的瓦片地图代码：http://www.code4app.com/ios/Tiled-Scroll-View/4fba3fd66803fa8413000000

1. 首先实现利用scrollview实现图片的缩放： 需要设置

maximumZoomScale;     // default is 1.0. must be > minimum zoom scale to enable zooming  *****只有设置了这个属性值大于1.0 才能实现缩放效果

下面上代码

//.h 文件
#import <UIKit/UIKit.h>

@interface HDMapView : UIScrollView <UIScrollViewDelegate>

-(instancetype)initWithFrame:(CGRect)frame andContentSize:(CGSize)contentSize;

-(void)setMapImage:(UIImage*)image;

@end

//.m 文件
#import "HDMapView.h"

@interface HDMapView ()

@property(strong,nonatomic)UIImageView *myImageView;
@end

@implementation HDMapView

-(instancetype)initWithFrame:(CGRect)frame andContentSize:(CGSize)contentSize
{
    self = [super initWithFrame:frame];
    if (self) {
        
        self.maximumZoomScale=17;
        
        self.frame = frame;
        self.delegate = self;
        self.contentSize = contentSize;
                
        self.myImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, contentSize.width, contentSize.height)];
        self.myImageView.userInteractionEnabled = YES;
        [self addSubview:self.myImageView];
        
        
        UITapGestureRecognizer *twiceTap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapTwice)];
        twiceTap.numberOfTapsRequired = 2;
        twiceTap.numberOfTouchesRequired = 1;
        [self.myImageView addGestureRecognizer:twiceTap];
    }
    
    return self;
}

-(void)tapTwice
{
    if (self.zoomScale > 3) {
        [self setZoomScale:1.0 animated:YES];
    }
    else
    {
        CGFloat a = self.zoomScale;
        a++;
        [self setZoomScale:a animated:YES];;
    }
}

-(void)setMapImage:(UIImage*)image
{
    self.myImageView.image = image;
}

#pragma mark - UIScrollViewDelegate
-(UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return self.myImageView;
}

-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale
{
    [self setZoomScale:scale animated:YES];
}