如何在recyclerview中找到项目的宽度? [英] How to find width of item in recyclerview?

问题描述

我有一个 recyclerview ，它只是按钮的水平列表.我正在尝试创建以下行为:

I have a recyclerview which is just a horizontal list of buttons. I am trying to create the following behavior:

如果组合的所有按钮的总宽度小于屏幕的总宽度，请将每个按钮的宽度设置为(screenWidth/按钮数).

If the total width of all of the buttons combined is less than the total width of the screen, set the width of each button to (screenWidth/number of buttons).

我正在测试一些基本代码来获取/设置按钮宽度，例如在我的 adapter 类中:

I am testing some basic code to get/set button widths like so in my adapter class:

 override fun onBindViewHolder(holder: TabViewHolder, position: Int) {

        Log.d("TEST-APP","Button Width: " + holder.button.width.toString())

        holder.button.width = 1080

        Log.d("VED-APP","New Button Width: " + holder.button.width.toString())

        holder.button.text = items[position].first
        holder.button.setOnClickListener {
            (context as MainActivity).updateCurrentImageLayout(items[position].second)
        }
    }

奇怪的是，虽然此代码实际上将按钮的宽度更改为1080，但在设置按钮宽度之前/之后，两个 Log 函数的输出均为0.

The odd thing is, while this code does actually change the width of the button to 1080 the outputs of the two Log functions before/after setting the button width are both 0.

如何获取按钮的实际宽度?

How do I get the actual width of the button?

这是我的布局，在我的 recyclerview 中定义了一列:

Here is my layout which defines one column in my recyclerview:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/tabButton"
        android:layout_width="match_parent"
        android:minWidth="120dp"
        android:layout_height="match_parent"
        android:text="Unset-Button-Text"/>


</android.support.constraint.ConstraintLayout>

推荐答案

Android仅在测量后才返回小部件的宽度，并且发生时间晚于调用 onBindViewHolder 的时间.

Android returns width of the widget only after it is measured and it happens later than onBindViewHolder is called.

您可以延迟请求:

holder.button.post {
    Log.d("VED-APP","New Button Width: " + holder.button.width.toString()) 
};

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