iphone - 点击按钮浏览动画的每一帧

Question

我正在尝试创建一个应用程序，当您点击按钮时，它将转到动画中的下一帧。

我有 8 个图像文件，当我按下按钮时，我希望显示第一张图像，当我再次按下按钮时，我希望第二张图像替换第一张图像，依此类推。

我在想这样的事情:

-(IBAction)buttonPressDoStuff:(id)sender {
    imageThing.image = [UIImage imageNamed:@"image1.png"];
    imageThing.image = [UIImage imageNamed:@"image2.png"];
    imageThing.image = [UIImage imageNamed:@"image3.png"];
    imageThing.image = [UIImage imageNamed:@"image4.png"];

}

并以某种方式使这一切在每次按下时连续工作。

我对 objective-c 相当陌生，因此我们将不胜感激。

任何人都可以提供一些示例代码来执行此操作吗？

Answer 1

让我们考虑一下这个问题。如果你想按顺序做某事，这听起来像是数组的工作。那么您对此有何看法:

在您的 .h 文件中，添加以下实例变量:

NSMutableArray* picturesArray;
NSInteger counter;

现在在您的 .m 文件中，在您的类的 init 方法中:

//this loop will fill your array with the pictures
for(int idx = 0; idx < NUMBER_OF_PICTURES; idx++) {
    //IMPORTANT: this assumes that your pictures' names start with 
    //'image0.png` for the first image, then 'image1.png`, and so on

    //if your images' names start with 'image1.png' and then go up, then you
    //should change the 'int idx = 0' declaration in the for loop to 'int idx = 1'
    //so the loop will start at 0. You will then need to change the condition
    //to 'idx < (NUMBER_OF_PICTURES + 1)' to accomodate the last image
    NSString* temp = [NSString stringWithFormat:@"image%i.png", idx];
    UIImage* tempImage = [UIImage imageNamed:temp];
    [picturesArray addObject:tempImage];
}

并在您的 buttonPressDoStuff: 方法中:

//this method will move to the next picture in the array each time it is pressed
-(IBAction)buttonPressDoStuff:(id)sender {
    if(counter < [pictureArray count]) {
        imageThing.image = [picturesArray objectAtIndex:counter];
        counter++;
    }
}

您的 init 方法应如下所示:

- (id)initWithNibName:(NSString*)nibNameOrNil bundle:(NSBundle*)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if(self) {
        //do setup here
        for(int idx = 0; idx < NUMBER_OF_PICTURES; idx++) {
            NSString* temp = [NSString stringWithFormat:@"image%i.png", idx];
            UIImage* tempImage = [UIImage imageNamed:temp];
            [picturesArray addObject:tempImage];
        }
    }
    //it is important that you return 'self' no matter what- if you don't,
    //you will get the 'control reached end of non-void method' warning
    return self;
}