objective-c – CABasicAnimation和自定义类型

A single gradient layer is displayed and continuously animated using new random colors.

这可能是您已经以另一种方式处理的特定任务的答案.我在Xcode中的Documentation and API Reference中找到了它,示例代码的名称只是Gradients. (请注意,有一个原始版本1.0和更新版本1.1,今年4月重做,因此应该更容易使用当前工具.

但是,创建无法通过Core Animation本身自动化的自定义动画的更大问题是遵循Apple的Cocoa动画编程指南中的示例,在使用NSAnimation对象一节中.它在Subclassing NSAnimation主题下描述,推荐的方法显示在Smooth Animations标题下.您重写setCurrentProgress：方法,以便每次调用它时首先调用Super,以便NSAnimation更新进度值,即您的自定义动画属性,然后执行动画的下一帧所需的任何更新或绘图.以下是Apple在参考文档中提供的注释和示例代码：

As mentioned in “Setting and Handling Progress Marks,” you can attach a series of progress marks to an NSAnimation object and have the delegate implement the animation:didReachProgressMark: method to redraw an object at each progress mark. However,this is not the best way to animate an object. Unless you set a large number of progress marks (30 per second or more),the animation is probably going to appear jerky.

A better approach is to subclass NSAnimation and override the setCurrentProgress: method,as illustrated in Listing 4. The NSAnimation object invokes this method after each frame to change the progress value. By intercepting this message,you can perform any redrawing or updating you need for that frame. If you do override this method,be sure to invoke the implementation of super so that it can update the current progress.

Listing 4  Overriding the setCurrentProgress: method
- (void)setCurrentProgress:(NSAnimationProgress)progress
{
    // Call super to update the progress value.
    [super setCurrentProgress:progress];

    // Update the window position.
    NSRect theWinFrame = [[NSApp mainWindow] frame];
    NSRect theScreenFrame = [[NSScreen mainScreen] visibleFrame];
    theWinFrame.origin.x = progress *
        (theScreenFrame.size.width - theWinFrame.size.width);
    [[NSApp mainWindow] setFrame:theWinFrame display:YES animate:YES];
}

因此,基本上您定义了一个“进度值”(可能由多个值组成),它定义了自定义动画的状态,并编写了给定当前“进度值”的代码,用于绘制或更改动画处于该特定状态时绘制的内容.然后让NSAnimation使用设置动画的常规方法运行动画,它将执行代码以在适当的时间绘制动画的每个帧.

我希望能回答你想知道的事情.我怀疑我之前没有看过它就能轻松找到这个,因为我最终不得不去我认为可能的地方,并逐页浏览整个主题再次找到它！