出自UXGuide.net

滑块

Sliders

A slider allows users to make adjustments to a value or process throughout a range of allowed values. When users drag a slider, the value or process is updated continuously. Figure 9-12 shows an example of a slider with minimum and maximum images.

滑块允许用户在整个允许值的范围内调整一个数值或进程。当用户拖动一个滑块，数值或进程一会随之不断更新。图9-12显示了一个最大和最小的图像滑块的例子。

Figure 9-12  A slider
图9-12 滑块

Sliders are useful in two main situations:

滑块主要在下面这两种情况使用：

• When you want to allow users to have fine-grained control over the values they choose

你想让用户对他们选择的值进行精确的控制

• When you want to allow users to have fine-grained control over the current process

你想让用户对当前过程进行精确的控制

A slider consists of a track, a thumb, and optional right and left value images. Figure 9-13 shows these parts of a slider.

滑块由一个轨道，thumb和可选的左，右数值图像组成。图9-13显示了一个滑块这些部分。

Figure 9-13  Four parts of a slider
图9-13 滑块的四部分

You can set the width of a slider to fit in with the user interface of your application. In addition, you can display a slider either horizontally or vertically.

你可以设置滑块的宽度，以适应你的应用程序用户界面。此外，你可以设定水平或垂直显示滑块。

There are several ways to customize a slider:

有几种方法定制一个滑块：

• You can define the appearance of the thumb, so users can see at a glance whether the slider is active.

你可以定义thumb的外观，让使用者对滑块是否处于活动状态一目了然。

• You can supply images to appear at either end of the slider (typically, these correspond to minimum and maximum values), to help users understand what the slider does.

你可以在滑块的任一端提供图片（通常，这些对应的最小和最大值），以帮助用户了解滑块的作用。

A slider that controls font size, for example, could display a very small character at the minimum end and a very large character at the maximum end.

例如，一个用于控制字体大小的滑块，可以在最小值的一端显示一个非常小的字体，在最大值的一端显示比较大的字体。

• You can define a different appearance for the track, depending on which side of the thumb it is on and which state the control is in.

你可以定义一个不同外观的轨道，这取决于它在thumb的那一端以及控件所处的状态。

To learn more about using a slider in your code, see UISlider Class Reference.

要了解更多有关在代码中使用滑块的信息，请参阅 UISlider 类型参考。