源码-0103-scrollview

//
//  ViewController.m
//  03-contentOffset的使用
#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
//    UIImageView *imageView = [[UIImageView alloc] init];
//    imageView.image = [UIImage imageNamed:@"minion"];
//    imageView.frame = CGRectMake(0, 0, imageView.image.size.width, imageView.image.size.height);
    
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"minion"]];
    [self.scrollView addSubview:imageView];
    
    // 设置内容大小
    self.scrollView.contentSize = imageView.image.size;
}

- (IBAction)left:(id)sender {
    // self.scrollView.contentOffset ： 偏移量
    // 记录UIScrollView滚动的位置，滚到哪
    // 总结：内容的左上角 和 scrollView自身左上角 的 X\Y差值
    
　　//    [UIView animateWithDuration:2.0 animations:^{
　　//        self.scrollView.contentOffset = CGPointMake(0, self.scrollView.contentOffset.y);
　　//    }];
    //实现动画的方法1
    [UIView animateWithDuration:2.0 animations:^{
        self.scrollView.contentOffset = CGPointMake(0, self.scrollView.contentOffset.y);
    } completion:^(BOOL finished) {
        NSLog(@"执行完毕");
    }];
}

- (IBAction)top:(id)sender {
　　//    self.scrollView.contentOffset = CGPointMake(self.scrollView.contentOffset.x, 0);
    

　　//实现动画的方法2
    CGPoint offset = CGPointMake(self.scrollView.contentOffset.x, 0);
    [self.scrollView setContentOffset:offset animated:YES];
}

- (IBAction)bottom:(id)sender {
　　//实现动画的方法3
    [UIView animateWithDuration:2.0 animations:^{
        CGFloat offsetY = self.scrollView.contentSize.height - self.scrollView.frame.size.height;
        CGPoint offset = self.scrollView.contentOffset;
        offset.y = offsetY;
        self.scrollView.contentOffset = offset;
    }];
    
//    self.scrollView.contentOffset = CGPointMake(self.scrollView.contentOffset.x, offsetY);
    
    
//    self.scrollView.contentOffset.y = offsetY;
    // OC语法细节：不允许直接修改OC对象的结构体属性的成员
}

- (IBAction)right:(id)sender {
　　//实现动画的方法4
    [UIView beginAnimations:nil context: nil];
    [UIView setAnimationDuration:2.0];
    [UIView setAnimationDelegate:self]; // 代理
    [UIView setAnimationDidStopSelector:@selector(stop)];
    [UIView setAnimationWillStartSelector:@selector(start)];
    
    CGFloat offsetX = self.scrollView.contentSize.width - self.scrollView.frame.size.width;
    self.scrollView.contentOffset = CGPointMake(offsetX, self.scrollView.contentOffset.y);
    
    [UIView commitAnimations];
}

- (void)start
{
    NSLog(@"start");
}

- (void)stop
{
    NSLog(@"stop");
}
@end

//
//  ViewController.m
//  03-contentOffset的使用
#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"minion"]];
//    [self.scrollView addSubview:imageView];
    [self.scrollView insertSubview:imageView atIndex:0];
    
    // 设置内容大小
    self.scrollView.contentSize = imageView.image.size;
    
    // 设置contentInset
    self.scrollView.contentOffset = CGPointMake(0, -64);
    self.scrollView.contentInset = UIEdgeInsetsMake(64, 0, 0, 0);
}

- (IBAction)left:(id)sender {
    self.scrollView.contentOffset = CGPointMake(0, self.scrollView.contentOffset.y);
}

- (IBAction)top:(id)sender {
    self.scrollView.contentOffset = CGPointMake(self.scrollView.contentOffset.x, 0);
}

- (IBAction)bottom:(id)sender {
    CGFloat offsetY = self.scrollView.contentSize.height - self.scrollView.frame.size.height;
    CGPoint offset = self.scrollView.contentOffset;
    offset.y = offsetY;
    self.scrollView.contentOffset = offset;
}

- (IBAction)right:(id)sender {
    CGFloat offsetX = self.scrollView.contentSize.width - self.scrollView.frame.size.width;
    self.scrollView.contentOffset = CGPointMake(offsetX, self.scrollView.contentOffset.y);
}
@end