如何创建要在自定义布局上使用的自定义LayoutParams? [英] How to create a custom LayoutParams to be used on a custom layout?

问题描述

我非常精通基于ViewGroup的复杂自定义布局.我唯一缺少的是能够创建自定义LayoutParams的功能.我真的需要获得利润的能力，为什么不创建其他额外的参数以传递给父代.

I'm fairly proficient at creating complex custom layouts based on ViewGroup. The only thing I'm missing is the ability to create my custom LayoutParams. I really need the ability to get the margins and why not create other extra params to pass in to the parent.

如何创建自定义LayoutParam并通过xml使用它?我尝试使用LinearLayout.LayoutParam，但是由于父级不是LinearLayout，它显然崩溃了.如何在自定义布局上使用LayoutParams?

How can I go about creating a custom LayoutParam and using it via xml? I tried using a LinearLayout.LayoutParam but it's obviously crashing since the parent is not a LinearLayout. How can I work with LayoutParams on custom layouts?

更新:

到目前为止，我一直坚持使用FrameLayout并重写onMeasure和onLayout函数自己进行布局.这确实提供了FrameLayout.LayoutParams.我猜孩子们必须支持自定义LayoutParam?

As of now I'm sticking with using a FrameLayout and overriding the onMeasure and onLayout functions to do the layout myself. This does provide FrameLayout.LayoutParams. I'm guessing the childs would have to support the custom LayoutParam?

推荐答案

在您的自定义布局中，创建扩展ViewGroup.LayoutParams的嵌套类.然后覆盖一些方法(在我的示例中，所有必需的方法).这是我的一个自定义布局的精简版:

In your custom layout, create a nested class extending ViewGroup.LayoutParams. Then override some methods (all of the required ones are in my example). Here's a stripped-down version of one of my custom layouts:

public class MyLayout extends ViewGroup {

    public MyLayout(Context context) {

    }

    public MyLayout(Context context, AttributeSet attrs) {

    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    }

    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof LayoutParams;
    }

    @Override
    protected LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams();
    }

    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new LayoutParams(getContext(), attrs);
    }

    @Override
    protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
        return generateDefaultLayoutParams(); // TODO Change this?
    }

    public static class LayoutParams extends ViewGroup.LayoutParams {

        public LayoutParams() {

        }

        public LayoutParams(int width, int height) {

        }

        public LayoutParams(Context context, AttributeSet attrs) {

        }

    }

}

进一步的解释:如何创建FlowLayout (感谢您的链接 Luksprog ！)

Further explanation: How to create a FlowLayout (thanks for the link Luksprog!)

这篇关于如何创建要在自定义布局上使用的自定义LayoutParams?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！