ios - 上下滚动的新闻

#import <UIKit/UIKit.h>

@interface ScrollUpDownView : UIView

//设置 要现实的文字
@property(nonatomic, strong)NSArray *array;

// 开启定时器
- (void)onOpenTimer;

// 关闭定时器
- (void)onOffTimer;

@end

#import "ScrollUpDownView.h"

@interface ScrollUpDownView ()

@property(nonatomic, weak)UILabel *label1;

@property(nonatomic, weak)UILabel *label2;

@property(nonatomic, assign)NSInteger count;

@property(nonatomic, strong)NSTimer *timer;

@property(nonatomic, assign) CGFloat mainH;
@property(nonatomic, assign) CGFloat mainW;
@property(nonatomic, assign) CGFloat mainX;
@property(nonatomic, assign) CGFloat mainY;

@end

@implementation ScrollUpDownView

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        [self initUIFrame:frame];
    }
    return self;
}

- (void)setArray:(NSArray *)array
{
    _array = array;

}

- (void)initUIFrame:(CGRect)rect
{
    self.backgroundColor = [UIColor whiteColor];
    _mainH = rect.size.height;
    _mainW = rect.size.width;
    _mainX = ;
    _mainY = ;

    // bgView
    UIView *bgView = [[UIView alloc]initWithFrame:CGRectMake(_mainX, _mainY, _mainW, _mainH)];
    bgView.layer.masksToBounds = YES;
    bgView.backgroundColor = [UIColor yellowColor];
    bgView.layer.masksToBounds = YES;
    bgView.layer.cornerRadius = CGRectGetHeight(bgView.frame) / ;
    [self addSubview:bgView];

    //
    UILabel *label1 = [[UILabel alloc]initWithFrame:CGRectMake(_mainX, _mainY, _mainW, _mainH)];
    self.label1 = label1;
    self.label1.textAlignment = NSTextAlignmentCenter;
    self.label1.textColor = [UIColor whiteColor];
    self.label1.font = [UIFont systemFontOfSize:];
    label1.backgroundColor = [UIColor redColor];
    [bgView addSubview:label1];

    //
    UILabel *label2 = [[UILabel alloc]initWithFrame:CGRectMake(_mainX, _mainH, _mainW, _mainH)];
    self.label2 = label2;
    self.label2.textAlignment = NSTextAlignmentCenter;
    self.label2.textColor = [UIColor whiteColor];
    self.label2.font = [UIFont systemFontOfSize:];
    label2.backgroundColor = [UIColor blueColor];
    [bgView addSubview:label2];

    self.count = ;
}

// 开启定时器
- (void)onOpenTimer
{

    if (self.array.count == ) return;

    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval: repeats: block:^(NSTimer * _Nonnull timer) {

        [UIView animateWithDuration: animations:^{

            self.label1.frame = CGRectMake(_mainX, -_mainH, _mainW, _mainH);
            self.label2.frame = CGRectMake(_mainX, _mainY, _mainW, _mainH);

        } completion:^(BOOL finished) {
            self.label1.frame = CGRectMake(_mainX, _mainH, _mainW, _mainH);
            if (self.count < self.array.count - ) {
                self.count ++;
                self.label1.text = self.array[self.count];
            }else{
                self.count = ;
                //数据随机重组
                [self OndataRandomReorganization];
                self.label1.text = self.array[self.count];
            }

            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)( * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                [UIView animateWithDuration: animations:^{
                    self.label2.frame = CGRectMake(_mainX, -_mainH, _mainW, _mainH);
                    self.label1.frame = CGRectMake(_mainX, _mainY, _mainW, _mainH);
                } completion:^(BOOL finished) {
                    self.label2.frame = CGRectMake(_mainX, _mainH, _mainW, _mainH);
                    if (self.count < self.array.count - ) {
                        self.count ++;
                        self.label2.text = self.array[self.count];
                    }else{
                        self.count = ;
                        //数据随机重组
                        [self OndataRandomReorganization];
                        self.label2.text = self.array[self.count];

                    }
                }];
            });
        }];
    }];

    self.timer = timer;

    // 开启定时器
    [timer setFireDate:[NSDate distantPast]];
    [[NSRunLoop currentRunLoop]addTimer:timer forMode:NSRunLoopCommonModes];
}
// 关闭定时器
- (void)onOffTimer
{
    [self.timer invalidate];
}

//数据随机重组
- (void)OndataRandomReorganization
{
    self.array = [self.array sortedArrayUsingComparator:^NSComparisonResult(NSString *str1, NSString *str2) {
        int seed = arc4random_uniform();
        if (seed) {
            return [str1 compare:str2];
        } else {
            return [str2 compare:str1];
        }
    }];
}

@end

引入

#import "ViewController.h"
#import "ScrollUpDownView.h"
@interface ViewController ()
@property(nonatomic, strong)ScrollUpDownView *dowmviewl;

@property(nonatomic, strong)NSArray *array;

@end

@implementation ViewController

- (NSArray *)array{

    if (_array == nil) {
        _array = @[@"我就想说:还有谁?",@"我可以一直杀",@"国服第一JS",@"我一贱,你就笑"];
    }
    return _array;
}

- (void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [self.dowmviewl onOpenTimer];

}

-(void)viewDidDisappear:(BOOL)animated{
    [super viewDidDisappear:animated];
    [self.dowmviewl onOffTimer];

}

- (void)viewDidLoad {
    [super viewDidLoad];
    self.dowmviewl = [[ScrollUpDownView alloc]initWithFrame:CGRectMake(, , , )];
    self.dowmviewl.backgroundColor = [UIColor yellowColor];
    self.dowmviewl.array = self.array;
    [self.view addSubview:self.dowmviewl];
}

@end