安卓自定义控件之仅可以显示一行视图的view控件（类似 HorizontalScrollView但不可滑动一行排满不在排）

该控件的功能是显示一行视图，这一行可以无限添加view，以及添加Headview、footview；当本行呗view排列满之后不在排列，如果添加了footview，那么footview肯定会在最后显示。
代码如下：

import android.app.Activity;import android.content.Context;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.view.View;import android.view.ViewGroup;import java.util.ArrayList;import java.util.List;/** * Created by wangliang on 0022/2016/9/22. * 功能：显示一行view，水平的，多个view，最多显示一行 * 思路：动态添加view，如果添加了尾view的话，则在绘制onlayout的时候余留除尾view的空间， * 所有的view取最小view的高度进行压缩显示显示足一整行，显示不足就显示能显示的部分，显示超过，则就显示一行 */public class MyHorizontalView extends ViewGroup {    private Context context;    private int windowWidth = 0;    private int nowAllViewWidth = 0;    private boolean whetherAddHeadView = false;    private boolean whetherAddFootView = false;    private String TAG = "MyHorizontalView";    private List<View> allViews = new ArrayList<>();    private int maxHeight = 0;    private View footView;    public MyHorizontalView(Context context) {        super(context);        initSetting(context);    }    public MyHorizontalView(Context context, AttributeSet attrs) {        this(context, attrs,0);    }    public MyHorizontalView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        initSetting(context);    }    private void initSetting(Context context){        this.context = context;        DisplayMetrics dm = new DisplayMetrics();        //取得窗口属性        ((Activity)context).getWindowManager().getDefaultDisplay().getMetrics(dm);        windowWidth = dm.widthPixels;    }    /**     * 添加头view     * @param view     */    public void addHeadView(View view, ViewGroup.LayoutParams params){        if(!whetherAddHeadView) {            whetherAddHeadView = true;            allViews.add(0,view);            super.addView(view, -1,params);        }    }    /**     * 添加末尾view     * @param view     */    public void addFootView(View view, ViewGroup.LayoutParams params){        if(!whetherAddFootView) {            whetherAddFootView = true;            footView = view;            super.addView(view, -1,params);        }    }    @Override    public void addView(View child, int index, ViewGroup.LayoutParams params) {        super.addView(child, -1,params);        allViews.add(child);    }    @Override    public void addView(View child) {        addView(child,-1,null);    }    @Override    public void addView(View child, int index) {        addView(child, index,null);    }    @Override    public void addView(View child, LayoutParams params) {        addView(child,-1, params);    }    @Override    protected LayoutParams generateLayoutParams(            LayoutParams p)    {        return new MarginLayoutParams(p);    }    @Override    public LayoutParams generateLayoutParams(AttributeSet attrs)    {        return new MarginLayoutParams(getContext(), attrs);    }    @Override    protected LayoutParams generateDefaultLayoutParams()    {        return new MarginLayoutParams(LayoutParams.MATCH_PARENT,                LayoutParams.MATCH_PARENT);    }    /**     * 负责设置子控件的测量模式和大小 根据所有子控件设置自己的宽和高     */    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)    {        int minHeight = Integer.MAX_VALUE ;        // 遍历每个子元素        for (int i = 0; i < getChildCount(); i++)        {            View child = getChildAt(i);            // 测量每一个child的宽和高            child.measure(0,0);            // 得到child的lp            MarginLayoutParams lp = (MarginLayoutParams) child                    .getLayoutParams();            minHeight = Math.min(lp.height  + lp.topMargin                    + lp.bottomMargin,minHeight);        }        setMeasuredDimension(widthMeasureSpec, Math.max(minHeight,heightMeasureSpec));    }    private boolean whetherLayout;    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        if(whetherLayout){            whetherLayout = false;        }else {            whetherLayout = true;            return;        }        //判断是否有尾视图，如果有则需要计算尾视图，为尾视图预留显示空间        int footViewWidth = 0;        int footViewBc = 0;        int footViewLc = 0;        int footViewTc = 0;        int footViewRc = 0;        if(whetherAddFootView && footView != null){            MarginLayoutParams lp = (MarginLayoutParams) footView.getLayoutParams();            footView.measure(0,0);            double beiShu = getHeight() * 1.0 / (footView.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);            footViewLc = (int) (lp.leftMargin * beiShu);            footViewTc = (int) (lp.topMargin * beiShu);            footViewRc = (int) (footViewLc + (footView.getMeasuredWidth() * beiShu));            footViewBc = (int) (footViewTc + (footView.getMeasuredHeight() * beiShu));            footViewWidth = footViewRc - footViewLc;        }        //判断是否有尾视图，如果有则需要计算尾视图，为尾视图预留显示空间        //绘制尾视图其他部分        int left = 0;        int nowWidth = 0;        for(int i = 0 ; i < allViews.size() ; i++){            View child = allViews.get(i);            child.measure(0,0);            if (child.getVisibility() == View.GONE)            {                continue;            }            MarginLayoutParams lp = (MarginLayoutParams) child                    .getLayoutParams();            double beiShu = getMeasuredHeight() * 1.0 / (child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);            //计算childView的left,top,right,bottom            int lc = (int) (left + lp.leftMargin * beiShu);            int tc = (int) (lp.topMargin * beiShu);            int rc = (int) (lc + child.getMeasuredWidth() * beiShu);            int bc = (int) (tc + child.getMeasuredHeight() * beiShu);            nowWidth += child.getMeasuredWidth() * beiShu + lp.rightMargin * beiShu                    + lp.leftMargin * beiShu;            if(nowWidth + footViewWidth > getMeasuredWidth()){                break;            }            child.layout(lc, tc, rc, bc);            left += child.getMeasuredWidth() * beiShu + lp.rightMargin * beiShu                    + lp.leftMargin * beiShu;        }        //绘制尾视图其他部分        //绘制尾视图        if(whetherAddFootView && footView != null){            footView.layout(left + footViewLc, footViewTc, left + footViewRc, footViewBc);        }    }}

调用代码（其中RoundRectangleImageView可以更换为其他view）：

ViewGroup.MarginLayoutParams lp = null;        lp = new ViewGroup.MarginLayoutParams(                80, 80);        lp.leftMargin = 10;        lp.rightMargin = 10;        lp.topMargin = 50;        lp.bottomMargin = 50;        RoundRectangleImageView roundRectangleImageView = new RoundRectangleImageView(getContext());        Picasso.with(getContext()).load(R.drawable.people_head)                .placeholder(R.drawable.ic_launcher).error(R.drawable.ic_launcher).resize(500,500).into(roundRectangleImageView);        hv.addHeadView(roundRectangleImageView,lp);        hv.addFootView(roundRectangleImageView,lp);        for(int i = 0; i < 10 ; i++){            roundRectangleImageView = new RoundRectangleImageView(getContext());            Picasso.with(getContext()).load(R.drawable.ic_launcher)                    .placeholder(R.drawable.ic_launcher).error(R.drawable.ic_launcher).resize(500,500).into(roundRectangleImageView);            hv.addView(roundRectangleImageView,lp);        }