直接上代码：
LineWrapRadioGroup.java - 有需求或问题可以自行完善的，有问题可以私信
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.RadioGroup;
/**
* 自动换行的RadioGroup
*/
public class LineWrapRadioGroup extends RadioGroup {
private static final String TAG = "RadioGroup";
//@hl 记录是第几行，需要做如果是第三行开始，则需要开始隐藏这些View
private static final int MAX_SHOW_COUNT = 2;
private int line_cout = 0;
private boolean onlayout_change_line = false;
private int totalShowHeight, totalFolderShowHeight = 0;
//@hl 控制是否显示所有
private boolean bShowAll = false;
public LineWrapRadioGroup(Context context) {
super(context);
}
public LineWrapRadioGroup(Context context, AttributeSet attrs) {
super(context, attrs);
}
@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);
//调用ViewGroup的方法，测量子view
measureChildren(widthMeasureSpec, heightMeasureSpec);
//最大的宽
int maxWidth = 0;
//累计的高
int totalHeight = 0;
//当前这一行的累计行宽
int lineWidth = 0;
//当前这行的最大行高
int maxLineHeight = 0;
//用于记录换行前的行宽和行高
int oldHeight;
int oldWidth;
int count = getChildCount();
//假设 widthMode和heightMode都是AT_MOST
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();
//得到这一行的最高
oldHeight = maxLineHeight;
//当前最大宽度
oldWidth = maxWidth;
int deltaX = child.getMeasuredWidth() + params.leftMargin + params.rightMargin;
if (lineWidth + deltaX + getPaddingLeft() + getPaddingRight() > widthSize) {//如果折行,height增加
//和目前最大的宽度比较,得到最宽。不能加上当前的child的宽,所以用的是oldWidth
maxWidth = Math.max(lineWidth, oldWidth);
//重置宽度
lineWidth = deltaX;
//累加高度
totalHeight += oldHeight;
//重置行高,当前这个View，属于下一行，因此当前最大行高为这个child的高度加上margin
maxLineHeight = child.getMeasuredHeight() + params.topMargin + params.bottomMargin;
//@hl 两行之后只显示两行的高度，不再增加换行高度
++line_cout;
if (line_cout <= MAX_SHOW_COUNT) {
totalFolderShowHeight = totalHeight;
}
} else {
//不换行，累加宽度
lineWidth += deltaX;
//不换行，计算行最高
int deltaY = child.getMeasuredHeight() + params.topMargin + params.bottomMargin;
maxLineHeight = Math.max(maxLineHeight, deltaY);
}
if (i == count - 1) {
//前面没有加上下一行的搞，如果是最后一行，还要再叠加上最后一行的最高的值
totalHeight += maxLineHeight;
//计算最后一行和前面的最宽的一行比较
maxWidth = Math.max(lineWidth, oldWidth);
}
}
//加上当前容器的padding值
maxWidth += getPaddingLeft() + getPaddingRight();
totalHeight += getPaddingTop() + getPaddingBottom();
//@hl 保存用于全部展开使用
totalShowHeight = totalHeight;
if (bShowAll) {
setMeasuredDimension(widthMode == MeasureSpec.EXACTLY ? widthSize : maxWidth,
heightMode == MeasureSpec.EXACTLY ? heightSize : totalHeight);
} else {
//@hl 高度如果超过两行，则只显示两行
setMeasuredDimension(widthMode == MeasureSpec.EXACTLY ? widthSize : maxWidth,
heightMode == MeasureSpec.EXACTLY ? heightSize :
(totalFolderShowHeight > 0 ? totalFolderShowHeight : totalShowHeight));
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int count = getChildCount();
//pre为前面所有的child的相加后的位置
int preLeft = getPaddingLeft();
int preTop = getPaddingTop();
//记录每一行的最高值
int maxHeight = 0;
//@hl 第一行不能加，之后需要添加margintop
int extern_margin_top = 0;
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();
int left;
//@hl int extern_margin_top = 0;
//r-l为当前容器的宽度。如果子view的累积宽度大于容器宽度，就换行。
if (preLeft + params.leftMargin + child.getMeasuredWidth() + params.rightMargin + getPaddingRight() > (r - l)) {
//重置
preLeft = getPaddingLeft();
//要选择child的height最大的作为设置
preTop = preTop + maxHeight;
maxHeight = getChildAt(i).getMeasuredHeight() + params.topMargin + params.bottomMargin;
//left坐标 - 刚换行的第一个不增加leftmargin
left = preLeft;
// 额外的margin_top间距，一旦换行，也就是从第二行开始就需要增加margin_top
extern_margin_top = params.topMargin;
onlayout_change_line = true;
} else { //不换行,计算最大高度
maxHeight = Math.max(maxHeight, child.getMeasuredHeight() + params.topMargin + params.bottomMargin);
//@hl 换行第一次的第二个控件不能再加一次preLeft
if (onlayout_change_line) {
//left坐标
left = preLeft;
} else {
//left坐标
left = preLeft + params.leftMargin;
}
}
//left坐标
//@hl int left = preLeft + params.leftMargin;
//top坐标
int top = preTop + extern_margin_top; //params.topMargin;
int right = left + child.getMeasuredWidth();
int bottom = top + child.getMeasuredHeight();
//为子view布局
child.layout(left, top, right, bottom);
//计算布局结束后，preLeft的值
preLeft += params.leftMargin + child.getMeasuredWidth() + params.rightMargin;
}
}
/**
* 点击显示其他控件
*/
public void requestShowMeasure(boolean _bShowAll) {
onlayout_change_line = false;
bShowAll = _bShowAll;
requestLayout();
}
/**
* 是否超过两行
* @return
*/
public boolean bHasMultiline(){
return line_cout >= MAX_SHOW_COUNT;
}
}
效果：
<iframe frameborder="0" allowfullscreen="" src="https://www.zhihu.com/video/1198654232385331200?autoplay=false&useMSE=" style="display: block; width: 688px; height: 387px;"></iframe>
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