UIScrollView基本使用(二）

前一篇的改進版，加入圖片X/Y方向的聯結，並使用ScrollView提供滑動的視覺效果。

1. 從前一篇改進過來，多一個ScrollView，並以上下的方式排列。

 

2. 對這兩個ScrollView註冊到ScrollViewController.h

3. 對ScrollViewController.m修改如下

#import "ScrollViewController.h"

const CGFloat kScrollObjHeight    = 199.0;
const CGFloat kScrollObjWidth    = 280.0;
const NSUInteger kNumImages        = 3;

@interface ScrollViewController ()

@end

@implementation ScrollViewController
@synthesize myScrollView1;
@synthesize myScrollView2;


- (void)layoutScrollImages
{
   
    UIImageView *view = nil;
    NSArray *subviews = [myScrollView1 subviews];
   
    // reposition all image subviews in a horizontal serial fashion
    CGFloat curXLoc = 0;
    for (view in subviews)
    {
        if ([view isKindOfClass:[UIImageView class]] && view.tag > 0)
        {
            CGRect frame = view.frame;
            frame.origin = CGPointMake(curXLoc, 0);
            view.frame = frame;
           
            curXLoc += (kScrollObjWidth);
        }
    }
   
    NSInteger height = [myScrollView1 bounds].size.height;
   
    // set the content size so it can be scrollable
    [myScrollView1 setContentSize:CGSizeMake((kNumImages * kScrollObjWidth), height)];
   
   
   
    UIImageView *view1 = nil;
    NSArray *subviews1 = [myScrollView2 subviews];
   
    // reposition all image subviews in a horizontal serial fashion
    CGFloat curXLoc1 = 0;
    for (view1 in subviews1)
    {
        if ([view1 isKindOfClass:[UIImageView class]] && view1.tag > 0)
        {
            CGRect frame = view1.frame;
            frame.origin = CGPointMake( 0, curXLoc1);
            view1.frame = frame;
           
            curXLoc1 += (kScrollObjHeight);
        }
    }
   
    NSInteger width = [myScrollView2 bounds].size.width;
   
    // set the content size so it can be scrollable
    [myScrollView2 setContentSize:CGSizeMake(width, (kNumImages * kScrollObjHeight))];
   
}


- (void)viewDidLoad
{
    [super viewDidLoad];
      
    NSUInteger i;
    for (i = 1; i <= kNumImages; i++)
    {
        NSString *imageName = [NSString stringWithFormat:@"TaiwanMap.jpg", i];
        UIImage *image = [UIImage imageNamed:imageName];
        UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
       
        // setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
        CGRect rect = imageView.frame;
        rect.size.height = kScrollObjHeight;
        rect.size.width = kScrollObjWidth;
        imageView.frame = rect;
        imageView.tag = i;    // tag our images for later use when we place them in serial fashion
        [myScrollView1 addSubview:imageView];
        // [myScrollView2 addSubview:imageView];
        //    [imageView release];
    }
   
   
    for (i = 1; i <= kNumImages; i++)
    {
        NSString *imageName = [NSString stringWithFormat:@"TaiwanMap.jpg", i];
        UIImage *image = [UIImage imageNamed:imageName];
        UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
       
        // setup each frame to a default height and width, it will be properly placed when we call "updateScrollList"
        CGRect rect = imageView.frame;
        rect.size.height = kScrollObjHeight;
        rect.size.width = kScrollObjWidth;
        imageView.frame = rect;
        imageView.tag = i;    // tag our images for later use when we place them in serial fashion
        [myScrollView2 addSubview:imageView];
        //    [imageView release];
    }
     
    [self layoutScrollImages];

}

4. 完成後的結果如圖，