Android Studio中布局末尾视图如何实现换行显示？

LinearLayout本身不支持自动换行，所以要实现最后一个视图自动换行的需求，推荐以下两种可行方案：

方法1：使用Google FlexboxLayout（推荐） #

这是官方维护的第三方布局库，完美支持类似CSS的flex布局逻辑，自动换行功能稳定可靠。

• 先在项目的build.gradle中添加依赖：

implementation "com.google.android:flexbox:2.0.1"

• 替换原XML中的LinearLayout为FlexboxLayout，开启换行属性：

<com.google.android.flexbox.FlexboxLayout
    android:id="@+id/layout1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:flexWrap="wrap" <!-- 核心属性，开启自动换行 -->
    app:layout_constraintTop_toBottomOf="@id/layout0">
</com.google.android.flexbox.FlexboxLayout>

• 动态添加视图的代码无需修改，FlexboxLayout会自动判断剩余空间，当当前行无法容纳新视图时自动换行，不会出现最后一个视图挤在末尾的情况。

方法2：自定义支持换行的LinearLayout #

如果不想引入第三方库，可以自己实现一个支持自动换行的LinearLayout：

• 创建自定义布局类：

public class WrapLinearLayout extends LinearLayout {
    public WrapLinearLayout(Context context) {
        super(context);
        setOrientation(HORIZONTAL);
    }

    public WrapLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOrientation(HORIZONTAL);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        int totalWidth = 0;
        int totalHeight = 0;
        int lineWidth = 0;
        int lineHeight = 0;

        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            measureChild(child, widthMeasureSpec, heightMeasureSpec);

            MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
            int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
            int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;

            if (lineWidth + childWidth > widthSize - getPaddingLeft() - getPaddingRight()) {
                totalHeight += lineHeight;
                totalWidth = Math.max(totalWidth, lineWidth);
                lineWidth = childWidth;
                lineHeight = childHeight;
            } else {
                lineWidth += childWidth;
                lineHeight = Math.max(lineHeight, childHeight);
            }

            if (i == getChildCount() - 1) {
                totalHeight += lineHeight;
                totalWidth = Math.max(totalWidth, lineWidth);
            }
        }

        totalWidth += getPaddingLeft() + getPaddingRight();
        totalHeight += getPaddingTop() + getPaddingBottom();

        setMeasuredDimension(
                widthMode == MeasureSpec.EXACTLY ? widthSize : totalWidth,
                heightMode == MeasureSpec.EXACTLY ? heightSize : totalHeight
        );
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int paddingLeft = getPaddingLeft();
        int paddingTop = getPaddingTop();
        int currentX = paddingLeft;
        int currentY = paddingTop;
        int lineHeight = 0;

        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            if (child.getVisibility() == GONE) continue;

            MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();

            if (currentX + lp.leftMargin + childWidth + lp.rightMargin > r - l - getPaddingRight()) {
                currentY += lineHeight;
                currentX = paddingLeft;
                lineHeight = 0;
            }

            int left = currentX + lp.leftMargin;
            int top = currentY + lp.topMargin;
            int right = left + childWidth;
            int bottom = top + childHeight;

            child.layout(left, top, right, bottom);

            currentX += lp.leftMargin + childWidth + lp.rightMargin;
            lineHeight = Math.max(lineHeight, lp.topMargin + childHeight + lp.bottomMargin);
        }
    }
}

• 在XML中使用这个自定义布局：

<com.yourpackage.WrapLinearLayout
    android:id="@+id/layout1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constraintTop_toBottomOf="@id/layout0">
</com.yourpackage.WrapLinearLayout>

• 动态添加视图的代码保持不变，自定义布局会自动处理换行逻辑。

关于FlowLayout/GridLayout失效的说明 #

• 第三方FlowLayout通常需要配置特定的换行属性（如app:flow_wrap="true"），未正确配置会导致不生效；
• GridLayout是基于网格的布局，需要指定列数或设置auto_fit，动态添加视图时如果未正确计算列数，容易出现视图挤压的问题，灵活性远不如FlexboxLayout。

内容的提问来源于stack exchange，提问作者Sabino di Tria