Android实现单行标签流式布局
近期产品提了有关流式布局的新需求,要求显示字数不定的标签,如果一行显示不完,就只显示一行的内容,而且还在一两个页面采取了多种样式,无语了
自己归类了一下,需求有以下几个区别
1:可选择添加标签与否
2:是否有具体数量限制(比如最多显示3个)
3:是否要靠右对齐
有需求,先找一波现有的工具,看是不是可以直接用
FlowLayout原样式:
这个和我们的需求已经比较符合了,但是他并不能控制只显示单行内容
如果要实现这样的布局,官方也提供了Flexbox和FlexboxLayout,但查阅文档后发现他们都不支持设置单行,如果强行设置maxlines为1,所有子view都会被减少宽度来让第一行挤下所有的子view
希望的样式(第一行内能放下多少就放多少,第二行开始都不显示,也不占用高度):
实际上:
可以看到这些view的宽度都被严重压缩了,即使设置了padding也是没有用的。正好项目本身使用了FlowLayout,就在他的基础上进行修改。
import android.content.Context; import android.os.Build; import android.util.AttributeSet; import android.util.Log; import android.view.View; import android.view.ViewGroup; import androidx.annotation.RequiresApi; import java.util.ArrayList; import java.util.List; public class SingleLineFlowLayout extends ViewGroup { private static final String TAG = "FlowLayout"; public int position=-1; public boolean alignRight; public boolean countMore; private List<List<View>> mLineViews = new ArrayList<List<View>>(); private List<Integer> mLineHeight = new ArrayList<Integer>(); public SingleLineFlowLayout(Context context) { super(context); } public SingleLineFlowLayout(Context context, AttributeSet attrs) { super(context, attrs); } public SingleLineFlowLayout(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP) public SingleLineFlowLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } /** * 测量所有子View大小,确定ViewGroup的宽高 * * @param widthMeasureSpec * @param heightMeasureSpec */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); //由于onMeasure会执行多次,避免重复的计算控件个数和高度,这里需要进行清空操作 mLineViews.clear(); mLineHeight.clear(); //获取测量的模式和尺寸大小 int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight(); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec) + getPaddingTop() + getPaddingBottom(); //记录ViewGroup真实的测量宽高 int viewGroupWidth = widthSize; int viewGroupHeight = getPaddingTop() + getPaddingBottom(); if (widthMode == MeasureSpec.EXACTLY && heightMode == MeasureSpec.EXACTLY) { viewGroupWidth = widthSize; viewGroupHeight = heightSize; } else { //当前所占的宽高 int currentLineWidth = 0; int currentLineHeight = 0; int lastChildWidth=0; int doubleLastChildWidth=0; //用来存储每一行上的子View List<View> lineView = new ArrayList<View>(); for (int i = 0; i < getChildCount(); i++) { View childView = getChildAt(i); //对子View进行测量 measureChild(childView, widthMeasureSpec, heightMeasureSpec); MarginLayoutParams marginLayoutParams = (MarginLayoutParams) childView.getLayoutParams(); int childViewWidth = childView.getMeasuredWidth() + marginLayoutParams.leftMargin + marginLayoutParams.rightMargin; int childViewHeight = childView.getMeasuredHeight() + marginLayoutParams.topMargin + marginLayoutParams.bottomMargin; if (currentLineWidth + childViewWidth > widthSize) { //从当前位置开始,删除view,保留最后一个moreView String tag=(String) childView.getTag(); if (tag!=null&&tag.equals("More")){ currentLineHeight = Math.max(currentLineHeight, childViewHeight); }else { removeViews(i,getChildCount()-1-i); childView = getChildAt(i); tag=(String) childView.getTag(); if (tag==null||!tag.equals("More")){ currentLineHeight = Math.max(currentLineHeight, childViewHeight); }else { //对子View进行测量 measureChild(childView, widthMeasureSpec, heightMeasureSpec); marginLayoutParams = (MarginLayoutParams) childView.getLayoutParams(); childViewWidth = childView.getMeasuredWidth() + marginLayoutParams.leftMargin + marginLayoutParams.rightMargin; childViewHeight = childView.getMeasuredHeight() + marginLayoutParams.topMargin + marginLayoutParams.bottomMargin; if (currentLineWidth + childViewWidth > widthSize) { //lineView.remove(i-1); lineView.remove(getChildAt(i-1)); removeViewAt(i-1); currentLineWidth=currentLineWidth-lastChildWidth; } if (i-1>0&¤tLineWidth + childViewWidth > widthSize){ currentLineWidth=currentLineWidth-doubleLastChildWidth-marginLayoutParams.leftMargin - marginLayoutParams.rightMargin; lineView.remove(getChildAt(i-2)); removeViewAt(i-2); } currentLineWidth += childViewWidth; currentLineHeight = Math.max(currentLineHeight, childViewHeight); //添加行对象里的子View if (alignRight){ int rightMargin=marginLayoutParams.rightMargin; marginLayoutParams.setMargins(marginLayoutParams.leftMargin,marginLayoutParams.topMargin,0,marginLayoutParams.bottomMargin); childView.setLayoutParams(marginLayoutParams); marginLayoutParams=(MarginLayoutParams) getChildAt(0).getLayoutParams(); marginLayoutParams.setMargins(marginLayoutParams.leftMargin+widthSize-currentLineWidth+rightMargin,marginLayoutParams.topMargin,marginLayoutParams.rightMargin,marginLayoutParams.bottomMargin); getChildAt(0).setLayoutParams(marginLayoutParams); }else { marginLayoutParams.setMargins(widthSize-currentLineWidth,marginLayoutParams.topMargin,0,marginLayoutParams.bottomMargin); childView.setLayoutParams(marginLayoutParams); } lineView.add(childView); } } } else { //当前行宽+子View+左右外边距<=ViewGroup的宽度,不换行 if (i>1){ doubleLastChildWidth=lastChildWidth; } lastChildWidth=childViewWidth; currentLineWidth += childViewWidth; currentLineHeight = Math.max(currentLineHeight, childViewHeight); //添加行对象里的子View String tag=(String) childView.getTag(); if (tag!=null&&tag.equals("More")){ if (countMore){ lineView.add(childView); } }else { lineView.add(childView); } } if (i >= getChildCount() - 1) { //最后一个子View的时候 //添加行对象 if (alignRight){ int rightMargin=marginLayoutParams.rightMargin; marginLayoutParams.setMargins(marginLayoutParams.leftMargin,marginLayoutParams.topMargin,0,marginLayoutParams.bottomMargin); childView.setLayoutParams(marginLayoutParams); marginLayoutParams=(MarginLayoutParams) getChildAt(0).getLayoutParams(); marginLayoutParams.setMargins(marginLayoutParams.leftMargin+widthSize-currentLineWidth+rightMargin,marginLayoutParams.topMargin,marginLayoutParams.rightMargin,marginLayoutParams.bottomMargin); getChildAt(0).setLayoutParams(marginLayoutParams); } mLineViews.add(lineView); viewGroupWidth = Math.max(childViewWidth, widthSize); viewGroupHeight = viewGroupHeight+currentLineHeight; //添加行高 mLineHeight.add(currentLineHeight); } } } setMeasuredDimension(viewGroupWidth, viewGroupHeight); } /** * 设置ViewGroup里子View的具体位置 * * @param changed * @param l * @param t * @param r * @param b */ @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int left = getPaddingLeft(); int top = getPaddingTop(); //一共有几行 int lines = mLineViews.size(); for (int i = 0; i < lines; i++) { //每行行高 int lineHeight = mLineHeight.get(i); //行内有几个子View List<View> viewList = mLineViews.get(i); int views = viewList.size(); for (int j = 0; j < views; j++) { View view = viewList.get(j); MarginLayoutParams marginLayoutParams = (MarginLayoutParams) view.getLayoutParams(); int vl = left + (j == 0 ? 0 : marginLayoutParams.leftMargin); if (alignRight){ vl = left + marginLayoutParams.leftMargin; } int vt = top + marginLayoutParams.topMargin; int vr = vl + view.getMeasuredWidth(); int vb = vt + view.getMeasuredHeight(); view.layout(vl, vt, vr, vb); if (alignRight){ left += view.getMeasuredWidth() + marginLayoutParams.leftMargin + marginLayoutParams.rightMargin; }else { left += view.getMeasuredWidth() + (j == 0 ? 0 : marginLayoutParams.leftMargin) + marginLayoutParams.rightMargin; } } left = getPaddingLeft(); top += lineHeight; } } /** * 指定ViewGroup的LayoutParams * * @param attrs * @return */ @Override public LayoutParams generateLayoutParams(AttributeSet attrs) { return new MarginLayoutParams(getContext(), attrs); } }
使用方法:
1:使用addView()将所有的标签都添加到布局中
2:如果需要显示代表更多的标签,在添加完所有标签后,再添加对应的view,并且设置view.setTag("More")即可(该View会自动靠右对齐,并且会检测是否能放得下该标签,如果放不下的话会依次尝试两次从后往前删除子view后能否放得下,如果遇到特殊情况需要删除更多的子view的话,可以自己修改代码)
3:如果需要所有的view都右对齐,要在addView()前设置布局的alignRight=true
4:如果需要超过某个数量后,即使可以单行显示,也要添加更多标签的话,要在addView()前设置布局的countMore=true,使用addView()时自己控制添加的数量,并在超过数量的时候添加对应的view,并且设置view.setTag("More")
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持我们。