Android gridview android：numColumns =" auto_fit"总是只创建两列 [英] Android gridview android:numColumns="auto_fit" always create only two columns

问题描述

你好我正在开发小型Android应用程序，我想用一些元素来显示简单的gridview。它工作正常。唯一的问题是，即使有空间，它总是只显示两列。它将屏幕平分为2列，只显示两个元素。如果我将列数设置为数字，即不是auto_fit，则显示正确。我的代码如下所示：

 < FrameLayout xmlns：android =http://schemas.android.com/apk/res / android
 xmlns：tools =http://schemas.android.com/tools
 android：layout_width =match_parent
 android：layout_height =match_parent
 > 
< GridView 
 android：id =@ + id / gridView
 android：layout_width =fill_parent
 android：layout_height =fill_parent
 android： layout_margin =5dp
 android：numColumns =auto_fit
 android：verticalSpacing =10dp
 android：horizo​​ntalSpacing =10dp> 
< / GridView> 
< / FrameLayout> 
  

并且我的网格元素看起来像：

 < RelativeLayout xmlns：android =http://schemas.android.com/apk/res/android
 xmlns：tools =http://schemas.android .com / tools
 android：layout_width =wrap_content
 android：layout_height =wrap_content
 tools：context =com.example.androidcardlayout.MainActivity> 
 
< android.support.v7.widget.CardView 
 xmlns：card_view =http://schemas.android.com/apk/res-auto
 android： id =@ + id / card_view
 android：layout_width =100dp
 android：layout_height =150dp
 card_view：cardCornerRadius =4dp> 
 
 RelativeLayout 
 android：id =@ + id / cardMianRlt
 android：layout_width =100dp
 android：layout_height =150dp
> 
< / RelativeLayout> 
  

我是做错了什么？需要一些帮助。谢谢。

解决方案

看起来像自适应设置只适用于固定列宽的情况。这是GridView源代码中唯一使用自适应设置的地方：

  private boolean determineColumns（int availableSpace）{
 final int requestedHorizo​​ntalSpacing = mRequestedHorizo​​ntalSpacing; 
 final int stretchMode = mStretchMode; 
 final int requestedColumnWidth = mRequestedColumnWidth; 
布尔值didNotInitiallyFit = false; 
 
 if（mRequestedNumColumns == AUTO_FIT）{
 if（requestedColumnWidth> 0）{
 //客户告诉我们选择列数
 mNumColumns =（ availableSpace + requestedHorizo​​ntalSpacing）/ 
（requestedColumnWidth + requestedHorizo​​ntalSpacing）; 
} else {
 //如果我们没有足够的信息，只需填写一个数字
 mNumColumns = 2; 
 
 
 
 
 
 
 
这个私有函数在度量/布局过程中被调用。请注意，在auto-fit if语句中，除非 requestedColumnWidth> 0 ，那么你只会得到2列，这就是你所看到的。 
 
 
 
如果固定宽度适用于您的应用程序，那么您需要像这样将它放入XML中： 
 
 
 < FrameLayout xmlns：android =http://schemas.android.com/apk/res/android
 xmlns：tools =http://schemas.android .com / tools
 android：layout_width =match_parent
 android：layout_height =match_parent
> 
< GridView 
 android：id =@ + id / gridView
 android：layout_width =fill_parent
 android：layout_height =fill_parent
 android： layout_margin =5dp
 android：numColumns =auto_fit
 android：columnWidth =30dp
 android：verticalSpacing =10dp
 android：horizo​​ntalSpacing =10dp> ; 
< / GridView> 
< / FrameLayout> 
  
 
Hi I am developing small android application in which I want to display simple gridview with some elements.Its working properly. Only problem is that it is always showing only two columns even though there is space. Its is equally dividing screen into 2 columns and displaying only two elements.If I set number of columns as number i.e. not auto_fit then it is showing properly. My code looks like:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
 >
<GridView
    android:id="@+id/gridView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_margin="5dp"
    android:numColumns="auto_fit"
    android:verticalSpacing="10dp"
    android:horizontalSpacing="10dp">
</GridView>
</FrameLayout>
and my grid element looks like:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
tools:context="com.example.androidcardlayout.MainActivity" >

<android.support.v7.widget.CardView
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/card_view"
    android:layout_width="100dp"
    android:layout_height="150dp"
    card_view:cardCornerRadius="4dp">

    <RelativeLayout 
        android:id="@+id/cardMianRlt"
        android:layout_width="100dp"
        android:layout_height="150dp"
        >
    </RelativeLayout>

    


Am I doing anything wrong? Need Some help. Thank you.
解决方案
It looks like the auto-fit setting only applies if you have fixed column widths. Here is the only place in GridView source code that uses the auto-fit setting:
private boolean determineColumns(int availableSpace) {
    final int requestedHorizontalSpacing = mRequestedHorizontalSpacing;
    final int stretchMode = mStretchMode;
    final int requestedColumnWidth = mRequestedColumnWidth;
    boolean didNotInitiallyFit = false;

    if (mRequestedNumColumns == AUTO_FIT) {
        if (requestedColumnWidth > 0) {
            // Client told us to pick the number of columns
            mNumColumns = (availableSpace + requestedHorizontalSpacing) /
                    (requestedColumnWidth + requestedHorizontalSpacing);
        } else {
            // Just make up a number if we don't have enough info
            mNumColumns = 2;
        }
    }
This private function is called during the measure / layout process. Notice that within the auto-fit if statement, unless requestedColumnWidth > 0, then you just get 2 columns, which is what you are seeing. 

If a fixed width works for your app, then you need to put it in your XML like this:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
     >
    <GridView
        android:id="@+id/gridView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_margin="5dp"
        android:numColumns="auto_fit"
        android:columnWidth="30dp"
        android:verticalSpacing="10dp"
        android:horizontalSpacing="10dp">
    </GridView>
</FrameLayout>


                        
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