在Android中使用wrap向左浮动

我很有兴趣获得与css

float:left

样式中相同的效果。我现在使用的是

RelativeLayout

和

android:layout\u-toRightOf

，但需要在视图不合适时转到下一行。如何在android布局中实现这一点

<RelativeLayout 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">

    <Button
        android:id="@+id/a"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:width="300dp" />

    <Button
        android:id="@+id/b"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/a"
        android:width="300dp" />

    <Button
        android:id="@+id/c"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/b"
        android:width="300dp" />

</RelativeLayout>

我需要这样的东西

在较宽的屏幕上，我需要获得例如，一行中有3个按钮，但在较小的屏幕上，一行中有2个按钮，第二行中有第三个按钮。如下图所示

小型设备

宽设备

---

对于单行，使用具有水平方向的

线性布局，而不是相对线布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

<!-- add your views here -->

</LinearLayout>



对于多行，您希望自动将元素“流动”到新行。您可以查看或尝试根据

/**扩展{@link RelativeLayout}的自定义视图
*将其子对象水平放置，
*当线条超出宽度时，流向一条新的线条*/
公共类水平流布局
扩展相对长度
{
/**从代码创建视图时要使用的构造函数*/
公共水平流布局（上下文）
{
超级（上下文）；
}
/**从XML扩展视图时调用的构造函数*/
公共水平流布局（上下文、属性集属性）
{
超级（上下文，attrs）；
}
/**从XML执行膨胀并应用特定于类的基本样式*/
公共水平流布局（上下文上下文、属性集属性、int-defStyle）
{
超级（上下文、属性、定义样式）；
}
@凌驾
测量时的保护空隙（内部宽度测量等级、内部高度测量等级）
{
//需要调用super.onMeasure（…），否则会出现一些有趣的行为
超级测量（宽度测量、高度测量）；
最终int width=MeasureSpec.getSize（widthmasurespec）；
int height=MeasureSpec.getSize（heightMeasureSpec）；
//当我们通过一条直线时，增加x位置
int xpos=getPaddingLeft（）；
//当我们通过这些线时，增加y位置
int ypos=getPaddingTop（）；
//当前行的高度
int line_高度=0；
//检查儿童
//计算此视图所需的高度的步骤
//我想不需要打电话来测量孩子的大小？！
//没有它，获取孩子的测量高度/宽度似乎可以正常工作
//测量儿童（宽度测量，高度测量）；
看孩子；
marginlayoutparms childmarginlayoutparms；
int childWidth、childHeight、childMarginLeft、childMarginRight、childMarginTop、childMarginBottom；
对于（int i=0；iwidth）
{
//这个孩子需要换一条新线路
xpos=getPaddingLeft（）；
ypos+=线路高度；
线条高度=childMarginTop+childHeight+childMarginBottom；
}
其他的
//当前行上有足够的空间容纳此子项
线条高度=数学最大值(
线条高度，
childMarginTop+childHeight+childMarginBottom）；
xpos+=childMarginLeft+childWidth+childMarginRight；
}
}
ypos+=行_高度+getPaddingBottom（）；
if（测量等级getMode（高度测量等级）=未指定的测量等级）
//设置测量的高度，因为没有高度限制
高度=ypos；
else if（MeasureSpec.getMode（heightMeasureSpec）=MeasureSpec.AT_
&&ypos<高度）
//设置测量的高度，因为它小于允许的最大值
高度=ypos；
设置测量尺寸（宽度、高度）；
}
@凌驾
仅受保护的void布局（布尔值已更改、int l、int t、int r、int b）
{
//当我们通过一条直线时，增加x位置
int xpos=getPaddingLeft（）；
//当我们通过这些线时，增加y位置
int ypos=getPaddingTop（）；
//当前行的高度
int line_高度=0；
看孩子；
marginlayoutparms childmarginlayoutparms；
int childWidth、childHeight、childMarginLeft、childMarginRight、childMarginTop、childMarginBottom；
对于（int i=0；i/** Custom view which extends {@link RelativeLayout}
 * and which places its children horizontally,
 * flowing over to a new line whenever it runs out of width.*/
public class HorizontalFlowLayout
  extends RelativeLayout
{
  /** Constructor to use when creating View from code.*/
  public HorizontalFlowLayout(Context context)
  {
    super(context);
  }

  /** Constructor that is called when inflating View from XML.*/
  public HorizontalFlowLayout(Context context, AttributeSet attrs)
  {
    super(context, attrs);
  }

  /** Perform inflation from XML and apply a class-specific base style.*/
  public HorizontalFlowLayout(Context context, AttributeSet attrs, int defStyle)
  {
    super(context, attrs, defStyle);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
  {
    // need to call super.onMeasure(...) otherwise get some funny behaviour
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    final int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = MeasureSpec.getSize(heightMeasureSpec);

    // increment the x position as we progress through a line
    int xpos = getPaddingLeft();
    // increment the y position as we progress through the lines
    int ypos = getPaddingTop();
    // the height of the current line
    int line_height = 0;

    // go through children
    // to work out the height required for this view

    // call to measure size of children not needed I think?!
    // getting child's measured height/width seems to work okay without it
    //measureChildren(widthMeasureSpec, heightMeasureSpec);

    View child;
    MarginLayoutParams childMarginLayoutParams;
    int childWidth, childHeight, childMarginLeft, childMarginRight, childMarginTop, childMarginBottom;

    for (int i = 0; i < getChildCount(); i++)
    {
      child = getChildAt(i);

      if (child.getVisibility() != GONE)
      {
        childWidth = child.getMeasuredWidth();
        childHeight = child.getMeasuredHeight();

        if (child.getLayoutParams() != null
            && child.getLayoutParams() instanceof MarginLayoutParams)
        {
          childMarginLayoutParams = (MarginLayoutParams)child.getLayoutParams();

          childMarginLeft = childMarginLayoutParams.leftMargin;
          childMarginRight = childMarginLayoutParams.rightMargin;
          childMarginTop = childMarginLayoutParams.topMargin;
          childMarginBottom = childMarginLayoutParams.bottomMargin;
        }
        else
        {
          childMarginLeft = 0;
          childMarginRight = 0;
          childMarginTop = 0;
          childMarginBottom = 0;
        }

        if (xpos + childMarginLeft + childWidth + childMarginRight + getPaddingRight() > width)
        {
          // this child will need to go on a new line

          xpos = getPaddingLeft();
          ypos += line_height;

          line_height = childMarginTop + childHeight + childMarginBottom;
        }
        else
          // enough space for this child on the current line
          line_height = Math.max(
              line_height,
              childMarginTop + childHeight + childMarginBottom);

        xpos += childMarginLeft + childWidth + childMarginRight;
      }
    }

    ypos += line_height + getPaddingBottom();

    if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.UNSPECIFIED)
      // set height as measured since there's no height restrictions
      height = ypos;
    else if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST
        && ypos < height)
      // set height as measured since it's less than the maximum allowed
      height = ypos;

    setMeasuredDimension(width, height);
  }

  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b)
  {
    // increment the x position as we progress through a line
    int xpos = getPaddingLeft();
    // increment the y position as we progress through the lines
    int ypos = getPaddingTop();
    // the height of the current line
    int line_height = 0;

    View child;
    MarginLayoutParams childMarginLayoutParams;
    int childWidth, childHeight, childMarginLeft, childMarginRight, childMarginTop, childMarginBottom;

    for (int i = 0; i < getChildCount(); i++)
    {
      child = getChildAt(i);

      if (child.getVisibility() != GONE)
      {
        childWidth = child.getMeasuredWidth();
        childHeight = child.getMeasuredHeight();

        if (child.getLayoutParams() != null
            && child.getLayoutParams() instanceof MarginLayoutParams)
        {
          childMarginLayoutParams = (MarginLayoutParams)child.getLayoutParams();

          childMarginLeft = childMarginLayoutParams.leftMargin;
          childMarginRight = childMarginLayoutParams.rightMargin;
          childMarginTop = childMarginLayoutParams.topMargin;
          childMarginBottom = childMarginLayoutParams.bottomMargin;
        }
        else
        {
          childMarginLeft = 0;
          childMarginRight = 0;
          childMarginTop = 0;
          childMarginBottom = 0;
        }

        if (xpos + childMarginLeft + childWidth + childMarginRight + getPaddingRight() > r - l)
        {
          // this child will need to go on a new line

          xpos = getPaddingLeft();
          ypos += line_height;

          line_height = childHeight + childMarginTop + childMarginBottom;
        }
        else
          // enough space for this child on the current line
          line_height = Math.max(
              line_height,
              childMarginTop + childHeight + childMarginBottom);

        child.layout(
            xpos + childMarginLeft,
            ypos + childMarginTop,
            xpos + childMarginLeft + childWidth,
            ypos + childMarginTop + childHeight);

        xpos += childMarginLeft + childWidth + childMarginRight;
      }
    }
  }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:weightSum="3" >

    <Button 
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"/>
    <Button 
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"/>
    <Button 
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"/>
</LinearLayout>