Android 实现FlowLayout流式布局（类似热门标签）

今天跟大家分享一下FlowLayout，最近项目中有遇到热门标签这个样的布局（文章末尾可下载源码），如下图：

一，创建FlowLayout并继承ViewGroup

FlowLayout 类主要实现onMeasure，onLayout和generateLayoutParams方法，具体如下看代码注释；

public class FlowLayout extends ViewGroup {    public FlowLayout(Context context, AttributeSet attrs, int defStyle)    {        super(context, attrs, defStyle);    }    public FlowLayout(Context context, AttributeSet attrs)    {        this(context, attrs, 0);    }    public FlowLayout(Context context)    {        this(context, null);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)    {        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);        int modeWidth = MeasureSpec.getMode(widthMeasureSpec);        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);        int modeHeight = MeasureSpec.getMode(heightMeasureSpec);        // 如果是warp_content情况下，记录宽和高          int width = 0;        int height = 0;        // 记录每一行的宽度与高度        int lineWidth = 0;        int lineHeight = 0;        // 得到内部元素的个数        int cCount = getChildCount();        for (int i = 0; i < cCount; i++)        {            // 通过索引拿到每一个子view            View child = getChildAt(i);            // 测量子View的宽和高,系统提供的measureChild            measureChild(child, widthMeasureSpec, heightMeasureSpec);            // 得到LayoutParams            MarginLayoutParams lp = (MarginLayoutParams) child                                                                .getLayoutParams();            // 子View占据的宽度            int childWidth = child.getMeasuredWidth() + lp.leftMargin                                + lp.rightMargin;            // 子View占据的高度            int childHeight = child.getMeasuredHeight() + lp.topMargin                                + lp.bottomMargin;            // 换行 判断 当前的宽度大于 开辟新行            if (lineWidth + childWidth > sizeWidth - getPaddingLeft() - getPaddingRight())            {                // 对比得到最大的宽度                width = Math.max(width, lineWidth);                // 重置lineWidth                lineWidth = childWidth;                // 记录行高                height += lineHeight;                lineHeight = childHeight;            }            else            // 未换行            {                // 叠加行宽                lineWidth += childWidth;                // 得到当前行最大的高度                lineHeight = Math.max(lineHeight, childHeight);            }            // 特殊情况,最后一个控件            if (i == cCount - 1)            {                width = Math.max(lineWidth, width);                height += lineHeight;            }        }        setMeasuredDimension(                                modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width + getPaddingLeft() + getPaddingRight(),                                modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height + getPaddingTop() + getPaddingBottom()//        );    }    /**     * 存储所有的View     */    private List<List<View>>    mAllViews   = new ArrayList<List<View>>();    /**     * 每一行的高度     */    private List<Integer>       mLineHeight = new ArrayList<Integer>();    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b)    {        mAllViews.clear();        mLineHeight.clear();        // 当前ViewGroup的宽度        int width = getWidth();        int lineWidth = 0;        int lineHeight = 0;        // 存放每一行的子view        List<View> lineViews = new ArrayList<View>();        int cCount = getChildCount();        for (int i = 0; i < cCount; i++)        {            View child = getChildAt(i);            MarginLayoutParams lp = (MarginLayoutParams) child                                                                .getLayoutParams();            int childWidth = child.getMeasuredWidth();            int childHeight = child.getMeasuredHeight();            // 如果需要换行            if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width - getPaddingLeft() - getPaddingRight())            {                // 记录LineHeight                mLineHeight.add(lineHeight);                // 记录当前行的Views                mAllViews.add(lineViews);                // 重置我们的行宽和行高                lineWidth = 0;                lineHeight = childHeight + lp.topMargin + lp.bottomMargin;                // 重置我们的View集合                lineViews = new ArrayList<View>();            }            lineWidth += childWidth + lp.leftMargin + lp.rightMargin;            lineHeight = Math.max(lineHeight, childHeight + lp.topMargin                                                + lp.bottomMargin);            lineViews.add(child);        }// for end            // 处理最后一行        mLineHeight.add(lineHeight);        mAllViews.add(lineViews);        // 设置子View的位置        int left = getPaddingLeft();        int top = getPaddingTop();        // 行数        int lineNum = mAllViews.size();        for (int i = 0; i < lineNum; i++)        {            // 当前行的所有的View            lineViews = mAllViews.get(i);            lineHeight = mLineHeight.get(i);            for (int j = 0; j < lineViews.size(); j++)            {                View    child = lineViews.get(j);                // 判断child的状态                if (child.getVisibility() == View.GONE)                {                    continue;                }                MarginLayoutParams lp = (MarginLayoutParams) child                                                                    .getLayoutParams();                int lc = left + lp.leftMargin;                int tc = top + lp.topMargin;                int rc = lc + child.getMeasuredWidth();                int bc = tc + child.getMeasuredHeight();                // 为子View进行布局                child.layout(lc, tc, rc, bc);                left += child.getMeasuredWidth() + lp.leftMargin                        + lp.rightMargin;            }            left = getPaddingLeft();            top += lineHeight;        }    }    /**     * 与当前ViewGroup对应的LayoutParams     */    @Override    public LayoutParams generateLayoutParams(AttributeSet attrs)    {        return new MarginLayoutParams(getContext(), attrs);    }}
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二，在MainActivity调用实现

public class MainActivity extends ActionBarActivity {    private String[] mVals = new String[] { "苹果手机", "笔记本电脑", "电饭煲 ", "腊肉",            "特产", "剃须刀", "宝宝", "康佳" };    private LayoutInflater mInflater;    private FlowLayout mFlowLayout;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mInflater = LayoutInflater.from(this);        mFlowLayout = (FlowLayout) findViewById(R.id.id_flowlayout);        initData();    }    public void initData() {        /**         * 找到搜索标签的控件         */        for (int i = 0; i < mVals.length; i++) {            TextView tv = (TextView) mInflater.inflate(                    R.layout.search_label_tv, mFlowLayout, false);            tv.setText(mVals[i]);            final String str = tv.getText().toString();            //点击事件            tv.setOnClickListener(new OnClickListener() {                @Override                public void onClick(View v) {                }            });            mFlowLayout.addView(tv);//添加到父View        }    }}
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1，MainActivity的xml布局
注意 布局当中的com.example.com.lff.test.FlowLayout

activity_main.xml

<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"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.example.com.lff.test.MainActivity" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <com.example.com.lff.test.FlowLayout          android:id="@+id/id_flowlayout"                android:layout_width="fill_parent"                android:layout_height="wrap_content"                android:background="#FFFFFF"                android:padding="10dp" >    </com.example.com.lff.test.FlowLayout></RelativeLayout>
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2，单个标签空间的布局，也就是上述Activity中的search_label_tv.xml

search_label_tv

<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_margin="5dp"    android:textColor="#3f3e3e"    android:background="@drawable/search_label_bg"    android:textSize="14sp"    android:text="Helloworld" ></TextView>
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结束语：简单，清晰，明了。欢迎大家指正吐槽。

源码奉上！！！
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