如何以编程方式删除在 XML 中定义的现有规则? [英] How do I programmatically remove an existing rule that was defined in XML?

问题描述

我有一个包含在相对布局中的线性布局.它在 XML 文件中设置为另一个线性布局的右侧(这很好用).在某些情况下，我想在活动的 onCreate 期间更改布局的相对位置，因此我需要修改右侧"参数以与另一个布局相关.我试过这个:

I have a linear layout that is contained inside a relative layout. It is set in the XML file to be to the right of another linear layout (this works fine). In some cases I want to change the relative position of the layout during the onCreate of the activity so I need to modify the "to the right of" param to relate to another layout. I tryed this:

    RelativeLayout.LayoutParams layoutParams;

    layoutParams = (RelativeLayout.LayoutParams) linearLayoutToMove
            .getLayoutParams();
    layoutParams.addRule(RelativeLayout.RIGHT_OF,
            R.id.new_ref_LinearLayout);

但它不起作用:o(

有什么线索吗?

推荐答案

您无法删除规则，因为所有规则始终存储在固定大小的 java 数组中.但是您可以将规则设置为 0.例如

You can't remove a rule because all rules are always stored in a fixed-size java array. But you can set a rule to 0. For example

layoutParams.addRule(RelativeLayout.RIGHT_OF, 0);
layoutParams.addRule(RelativeLayout.BELOW, R.id.new_ref_LinearLayout);

编辑(感谢 Roger Rapid):

从 API 级别 17 开始，RelativeLayout.LayoutParams 类具有以下方法:

As of API level 17, the class RelativeLayout.LayoutParams has the following method:

public void removeRule(int verb) 

因此您可以使用以下代码行删除规则:

So you can remove a rule using the following line of code:

layoutParams.removeRule(RelativeLayout.RIGHT_OF);

并且您将获得与添加"零规则时完全相同的结果:

And you will get exactly the same result as when 'adding' a zero-rule as:

layoutParams.addRule(RelativeLayout.RIGHT_OF, 0);

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