java - 在android中创建类似glide和picasso的类结构

Question

我想创建这样的类结构:

Glide.with(context).load("url").into(imageView);

问题:-

public class Slider{

    private static Activity context;
    private static int Duration = 3000;

    public static void setContext(Activity context) {
        Slider.context = context;
    }

    public static void setDuration(Duration duration) {
        Slider.Duration = duration;
    }
}
// In Activity
Slider.setContext(this);

• 我将所有方法和必填字段声明为静态的，但它不起作用。

• 我尝试使用 setter 方法，但它只允许一个 setter。此类不允许我使用第二个 setter。

要求:

Slider.setContext(this).setDuration(3000);

我需要类似 glide 的类和方法结构和 picasso图书馆和一些方法是强制性的。

Answer 1

为此你需要使用 builder 模式

public class Slider
{
    private static Activity context;
    private static int Duration = 3000;

    private Slider(SliderBuilder builder) {
        this.context = builder.context;
        this.Duration = builder.Duration;
    }

    //All getter, and NO setter to provde immutability
    public String getContext() {
        return context;
    }
    public String getDuration() {
        return Duration;
    }

    public static SliderBuilder with(Activity context){
        return new SliderBuilder(context);
    }

    public static class SliderBuilder
    {
        private static Activity context;
        private static int Duration = 3000;

        public SliderBuilder(Activity context) {
            this.context = context;
        }
        public SliderBuilder duration(int Duration) {
            this.Duration = Duration;
            return this;
        }
        //Return the finally constructed Slider object
        public Slider build() {
            Slider slider =  new Slider(this);
            validateSliderObject(slider);
            return slider;
        }
        private void validateSliderObject(Slider slider) {
            //Do some basic validations to check
        }
    }
}

更好地解释 here

编辑

How to use

Slider.with(this).duration(3000).build();