iphone - 我应该如何使用 UIPinchGestureRecognizer 缩放这张 map 图片？

Question

我真的很接近能够使用 UIPinchGestureRecognizer 和缩放方法以编程方式缩放 map 图片。我试过像这样的 ScrollView :[mapScrollView addGestureRecognizer:pinchRecognizer];，但是这当然行不通，因为这会缩放整个 View 和边界。如果我执行 [mapImageView addGestureRecognizer:pinchRecognizer] 什么都不会发生。

如何在 ScrollView 中缩放图像？更重要的是，我如何设置最大和最小缩放比例的界限？谢谢

代码:

- (id)initWithFrame:(CGRect)frame {

    self = [super initWithFrame:frame];
    if (self) {

        mainMenuAppDelegate *del = (mainMenuAppDelegate *)[[UIApplication sharedApplication] delegate];

        map_List = [[NSMutableArray alloc] init];
        [map_List addObject:@"Pacific_Map_8bit.png"];
        [map_List addObject:@"Atlantic_Map_8bit.png"];

        CGRect mapScrollViewFrame = CGRectMake(0, 0, 1024, 768);

        mapScrollView = [[UIScrollView alloc]   initWithFrame:mapScrollViewFrame];

        mapScrollView.contentSize = CGSizeMake(2437, 1536);

        UIImage *mapImage = [UIImage imageNamed:[map_List objectAtIndex:mapNum]];

        mapImageView = [[UIImageView alloc] initWithImage: mapImage];

        mapScrollView.bounces = NO;

        [mapImage release];

        [mapScrollView addSubview:mapImageView];
        [self addSubview:mapScrollView];

        UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)];
        [mapImageView addGestureRecognizer:pinchRecognizer];

        [pinchRecognizer release];

        UIImage *footerMapIMG = [UIImage imageNamed:@"footer_map_alternate.png"];
        UIImageView *footerMapView = [[UIImageView alloc] initWithImage:(UIImage *)footerMapIMG];
        CGRect footerMapFrame = CGRectMake(0, 686, 213, 82);
        footerMapView.frame = footerMapFrame;
        [self addSubview:footerMapView]; 
        footerMapView.image = footerMapIMG; 

        [footerMapView release];

        CGRect backBTNFrame = CGRectMake(20, 714, 140, 52); 
        UIButton *MAP_backButton = [[UIButton alloc] init];
        MAP_backButton.frame = backBTNFrame;
        UIImage *MAP_backButtonIMG = [UIImage imageNamed:@"button_back.png"];
        [MAP_backButton setImage:MAP_backButtonIMG forState:UIControlStateNormal];
        MAP_backButton.backgroundColor = [UIColor clearColor];
        [self addSubview:MAP_backButton];

        [MAP_backButton release];

        [MAP_backButton addTarget:del.switchVC 
                           action:@selector(gotoMapAndListChooser)
                 forControlEvents:UIControlEventTouchUpInside];
    }
    return self;
}

-(void)scale:(id)sender {
    if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {

        lastScale = 1.0;
        return;
    }

    CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);

    /*
    if(scale > 1){
        scale = 1;
    }
    if(scale < .5){
        scale = .5;
    }
    */

    CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
    CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);

    [[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];

    lastScale = [(UIPinchGestureRecognizer*)sender scale];
}

Answer 1

我不确定，我不想测试但尝试添加

mapImageView.userInteractionEnabled = YES;

如果没有此设置，手势将无法在 ImageView 上工作。
编辑:也许我错误地解释了你的问题，你的缩放方法被调用但不起作用。

---

顺便说一句，你读过CATiledLayer吗？ ？WWDC10 session 视频( session 104 - 使用 ScrollView 设计应用程序)中也有很好的介绍。您应该通过 developer.apple.com 访问该视频
你应该观看它，因为 2437x1536 的图像对于 iphone 来说是相当大的。您迟早会遇到性能和/或内存问题。