Question

我正在创建一个程序，其中一只鸟的图像从屏幕顶部不断下降（如“下雨”的鸟类）。为了获得每只鸟的NSTimer，我创建了一个UIImageView子类（称为“BirdUIImageView”）。但是，我不确定如何正确实现代码 - 在哪里放什么等等。

以下是我在ViewController.m中的代码：

#import "ViewController.h"

#import "BirdUIImageView.h"

@interface ViewController ()

@end

@implementation ViewController {

    BirdUIImageView *_myImage;

}

- (void)viewDidLoad
{


    //IMAGE CREATOR TIMER
    createImagesTimer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(createImages) userInfo:nil repeats:YES];

}


  //CREATES AN IMAGE
-(void) createImages {  
    srand(time(NULL));
    int random_x_coordinate = rand() % 286;
    CGRect myImageRect = CGRectMake(random_x_coordinate, 0.0f, 40.0f, 40.0f);
    BirdUIImageView *myImage = [[BirdUIImageView alloc] initWithFrame:myImageRect];
    [myImage setImage:[UIImage imageNamed:@"flake.png"]];
    myImage.opaque = YES;
    [self.view addSubview:myImage];
    _myImage = myImage;

}

这是我在BirdUIImageView.m中的代码。我完全不知道该怎么做这个文件，但我做了一个尝试：

#import "BirdUIImageView.h"



@implementation BirdUIImageView  


- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
    }
    return self;
}

- (void)viewDidLoad
{
    //FALLING BIRDS TIMER
    moveObjectTimer = [NSTimer scheduledTimerWithTimeInterval:0.001 target:self selector:@selector(moveObject) userInfo:nil repeats:YES];
}

//FALLING BIRDS MOVER
-(void) moveObject {

    _myImage.center = CGPointMake(_myImage.center.x, _myImage.center.y +1);

}

Answer 1

首先，从viewDidLoad课程中删除moveObject和BirdUIImageView方法，然后在ViewController.m课程中尝试以下代码。您可以使用计时器设置，以获得所需的效果：

在ViewController.m

- (void)viewDidLoad {
    [super viewDidLoad];
    createImagesTimer = [NSTimer scheduledTimerWithTimeInterval:2.5
                                                         target:self
                                                       selector:@selector(createImages)
                                                       userInfo:nil
                                                        repeats:YES];
}


  //CREATES AN IMAGE
-(void) createImages {
    srand(time(NULL));
    int random_x_coordinate = rand() % 286;
    CGRect myImageRect = CGRectMake(random_x_coordinate, 0.0f, 40.0f, 40.0f);
    BirdUIImageView *myImage = [[BirdUIImageView alloc] initWithFrame:myImageRect];
    [myImage setImage:[UIImage imageNamed:@"flake.png"]];
    myImage.opaque = YES;
    [self.view addSubview:myImage];
    _myImage = myImage;

    [self move];
}


-(void)move {

    //FALLING BIRDS TIMER
    moveObjectTimer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(moveObject) userInfo:nil repeats:YES];


}


//FALLING BIRDS MOVER
-(void) moveObject {

    _myImage.center = CGPointMake(_myImage.center.x, _myImage.center.y +1);

}

xcode：使用带有NSTimers的UIImageView子类

1 个答案: