小编给大家分享一下如何利用Android从0到1实现一个流布局控件，希望大家阅读完这篇文章之后都有所收获，下面让我们一起去探讨吧！
前言
流布局在在项目中还是会时不时地用到的，比如在搜索历史记录，分类，热门词语等可用标签来显示的，都可以设计成流布局的展示方式。这里我从0到1实现了一个搜索历史记录的流布局。
演示效果：
实现步骤：
创建FlowLayoutView，创建数据源，并添加各个子view。
在onMeasure方法中遍历子view，通过简单计算剩余宽度，用集合存储当前行的几个子view，再根据子view的累加高度设置自己的最终尺寸。
在onLayout方法中，遍历每一行，遍历该行的子view，依次调动layout设置子view位置。
核心点：
引入行的概念，每一行存储自己应该放置的子view。判断该行剩余空间和该子view的宽度，来决定能放入该行，还是需要新建下一行来存储。
主要代码：
public class FlowLayoutView extends ViewGroup { private List<Row> rows = new ArrayList<>(); private int usedWidth; private Row curRow; private int verticalPadding = 30; private int horizontalPadding = 40; public FlowLayoutView(Context context) { super(context); } public FlowLayoutView(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { restoreLine(); //每次重新布局，属性要初始化，避免onMeasure重复调用混乱问题 //子view设置宽高为父view大小减去padding值 int width = MeasureSpec.getSize(widthMeasureSpec); int height = MeasureSpec.getSize(heightMeasureSpec); int widthMode = MeasureSpec.getMode(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); //设置每个子view宽高，并且将每个子View归到自己的行 for (int i = 0; i < getChildCount(); i++) { View childView = getChildAt(i); //设置子view设置AT_MOST模式，即布局属性为wrap_content int childWidthSpec = MeasureSpec.makeMeasureSpec(width, widthMode == MeasureSpec.EXACTLY ? MeasureSpec.AT_MOST : widthMode); int childHeightSpec = MeasureSpec.makeMeasureSpec(height, heightMode == MeasureSpec.EXACTLY ? MeasureSpec.AT_MOST : heightMode); childView.measure(childWidthSpec, childHeightSpec); if (curRow == null) { curRow = new Row(); } //根据当前childview宽度和剩余宽度判断是否能放进当前行，放不了就要换行 if (childView.getMeasuredWidth() + horizontalPadding > width - usedWidth) { //先换行，再放入 nextLine(); } usedWidth += childView.getMeasuredWidth() + horizontalPadding; curRow.addView(childView); } //将最后一个row加入到rows中 rows.add(curRow); //根据子view组成的高度重设自己高度 int finalHeight = 0; for (Row row : rows) { finalHeight += row.height + verticalPadding; } setMeasuredDimension(width, finalHeight); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int top = 0; //遍历每一行，将每一行子view布局 for (Row row : rows) { row.layout(top); top = top + row.height + verticalPadding; } } private void nextLine() { rows.add(curRow); curRow = new Row(); usedWidth = 0; } private void restoreLine() { rows.clear(); curRow = new Row(); usedWidth = 0; } class Row { private List<View> childViews = new ArrayList<>(); private int height; public void addView(View view) { childViews.add(view); height = view.getMeasuredHeight() > height ? view.getMeasuredHeight() : height; //高度取最高子view的高度 } public int getSize() { return childViews.size(); } public void layout(int top) { int leftMargin = 0; for (int i = 0; i < childViews.size(); i++) { View view = childViews.get(i); view.layout(leftMargin, top, leftMargin + view.getMeasuredWidth(), top + view.getMeasuredHeight()); leftMargin = leftMargin + view.getMeasuredWidth() + horizontalPadding; } } }}MainActivity代码：
public class MainActivity extends AppCompatActivity { private FlowLayoutView flowLayoutView; private String[] tagTextArray = new String[]{"天猫精灵", "充电台灯", "睡衣", "手表", "创意水杯", "夏天T恤男", "灯光机械键盘", "计算机原理", "学霸笔记本", "可口可乐", "跑步机", "旅行箱", "竹浆卫生纸", "吹风机", "洗面奶", "窗帘"}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } private void init() { flowLayoutView = findViewById(R.id.flowlayout); TextView tvAddTag = findViewById(R.id.tv_addtag); tvAddTag.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { View view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.item_tagview, null); TextView tvContent = view.findViewById(R.id.tv_content); tvContent.setText(tagTextArray[(int) (Math.random()*tagTextArray.length)]); flowLayoutView.addView(view); } }); }}看完了这篇文章，相信你对“如何利用Android从0到1实现一个流布局控件”有了一定的了解，如果想了解更多相关知识，欢迎关注编程网行业资讯频道，感谢各位的阅读！
