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Android实现热门标签的流式布局

一、概述：

在日常的app使用中，我们会在android 的app中看见 热门标签等自动换行的流式布局，今天，我们就来看看如何
自定义一个类似热门标签那样的流式布局吧（源码下载在下面最后给出）
类似的自定义布局。下面我们就来详细介绍流式布局的应用特点以及用的的技术点：

1.流式布局的特点以及应用场景

特点：当上面一行的空间不够容纳新的TextView时候，
才开辟下一行的空间
原理图：

场景：主要用于关键词搜索或者热门标签等场景

2.自定义ViewGroup,重点重写下面两个方法

1）、onMeasure:测量子view的宽高，设置自己的宽和高
2）、onLayout:设置子view的位置
    onMeasure:根据子view的布局文件中属性，来为子view设置测量模式和测量值
    测量=测量模式+测量值；

测量模式有3种：

    EXACTLY：表示设置了精确的值，一般当childView设置其宽、高为精确值、match_parent时，ViewGroup会将其设置为EXACTLY；
    AT_MOST：表示子布局被限制在一个最大值内，一般当childView设置其宽、高为wrap_content时，ViewGroup会将其设置为AT_MOST；
    UNSPECIFIED：表示子布局想要多大就多大，一般出现在AadapterView的item的heightMode中、ScrollView的childView的heightMode中；此种模式比较少见。

3.LayoutParams

ViewGroup LayoutParams :每个 ViewGroup 对应一个 LayoutParams; 即 ViewGroup -> LayoutParams
getLayoutParams 不知道转为哪个对应的LayoutParams ,其实很简单，就是如下：
子View.getLayoutParams 得到的LayoutParams对应的就是 子View所在的父控件的LayoutParams;

例如，LinearLayout 里面的子view.getLayoutParams ->LinearLayout.LayoutParams

所以 咱们的FlowLayout 也需要一个LayoutParams，由于上面的效果图是子View的 margin，

所以应该使用MarginLayoutParams。即FlowLayout->MarginLayoutParams

4.最后来看看实现的最终效果图：

二、热门标签的流式布局的实现：

1. 自定义热门标签的ViewGroup实现

根据上面的技术分析，自定义类继承于ViewGroup，并重写 onMeasure和onLayout等方法。具体实现代码如下：

<font color="#362e2b"><font style="background-color:rgb(255, 255, 255)"><font face="Arial"><font style="font-size:14px">package com.czm.flowlayout;
 
import java.util.ArrayList;
import java.util.List;
 
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
/**
 * 
 * @author caizhiming
 * @created on 2015-4-13
 */
public class XCFlowLayout extends ViewGroup{
 
 //存储所有子View
 private List<List<View>> mAllChildViews = new ArrayList<>();
 //每一行的高度
 private List<Integer> mLineHeight = new ArrayList<>();
 
 public XCFlowLayout(Context context) {
 this(context, null);
 // TODO Auto-generated constructor stub
 }
 public XCFlowLayout(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
 // TODO Auto-generated constructor stub
 }
 public XCFlowLayout(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 // TODO Auto-generated constructor stub
 }
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 // TODO Auto-generated method stub
  
 //父控件传进来的宽度和高度以及对应的测量模式
 int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
 int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
 int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
 int modeHeight = MeasureSpec.getMode(heightMeasureSpec);
  
 //如果当前ViewGroup的宽高为wrap_content的情况
 int width = 0;//自己测量的 宽度
 int height = 0;//自己测量的高度
 //记录每一行的宽度和高度
 int lineWidth = 0;
 int lineHeight = 0;
  
 //获取子view的个数
 int childCount = getChildCount();
 for(int i = 0;i < childCount; i ++){
  View child = getChildAt(i);
  //测量子View的宽和高
  measureChild(child, widthMeasureSpec, heightMeasureSpec);
  //得到LayoutParams
  MarginLayoutParams lp = (MarginLayoutParams) 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;
  //换行时候
  if(lineWidth + childWidth > sizeWidth){
  //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{//不换行情况
  //叠加行宽
  lineWidth += childWidth;
  //得到最大行高
  lineHeight = Math.max(lineHeight, childHeight);
  }
  //处理最后一个子View的情况
  if(i == childCount -1){
  width = Math.max(width, lineWidth);
  height += lineHeight;
  }
 }
 //wrap_content
 setMeasuredDimension(modeWidth == MeasureSpec.EXACTLY ? sizeWidth : width,
  modeHeight == MeasureSpec.EXACTLY ? sizeHeight : height);
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 }
 
 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
 // TODO Auto-generated method stub
 mAllChildViews.clear();
 mLineHeight.clear();
 //获取当前ViewGroup的宽度
 int width = getWidth();
  
 int lineWidth = 0;
 int lineHeight = 0;
 //记录当前行的view
 List<View> lineViews = new ArrayList<View>();
 int childCount = getChildCount();
 for(int i = 0;i < childCount; 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){
  //记录LineHeight
  mLineHeight.add(lineHeight);
  //记录当前行的Views
  mAllChildViews.add(lineViews);
  //重置行的宽高
  lineWidth = 0;
  lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
  //重置view的集合
  lineViews = new ArrayList();
  }
  lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
  lineHeight = Math.max(lineHeight, childHeight + lp.topMargin + lp.bottomMargin);
  lineViews.add(child);
 }
 //处理最后一行
 mLineHeight.add(lineHeight);
 mAllChildViews.add(lineViews);
  
 //设置子View的位置
 int left = 0;
 int top = 0;
 //获取行数
 int lineCount = mAllChildViews.size();
 for(int i = 0; i < lineCount; i ++){
  //当前行的views和高度
  lineViews = mAllChildViews.get(i);
  lineHeight = mLineHeight.get(i);
  for(int j = 0; j < lineViews.size(); j ++){
  View child = lineViews.get(j);
  //判断是否显示
  if(child.getVisibility() == View.GONE){
   continue;
  }
  MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
  int cLeft = left + lp.leftMargin;
  int cTop = top + lp.topMargin;
  int cRight = cLeft + child.getMeasuredWidth();
  int cBottom = cTop + child.getMeasuredHeight();
  //进行子View进行布局
  child.layout(cLeft, cTop, cRight, cBottom);
  left += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
  }
  left = 0;
  top += lineHeight;
 }
  
 }
 /**
 * 与当前ViewGroup对应的LayoutParams
 */
 @Override
 public LayoutParams generateLayoutParams(AttributeSet attrs) {
 // TODO Auto-generated method stub
  
 return new MarginLayoutParams(getContext(), attrs);
 }
}</font></font></font></font>

2.相关的布局文件：

引用自定义控件：

<font color="#362e2b"><font style="background-color:rgb(255, 255, 255)"><font face="Arial"><font style="font-size:14px"><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/container"
 android:layout_width="match_parent"
 android:layout_height="match_parent" >
 
 <com.czm.flowlayout.XCFlowLayout
 android:id="@+id/flowlayout"
 android:layout_width="match_parent"
 android:layout_height="match_parent" >
 
 </com.czm.flowlayout.XCFlowLayout>
 
</RelativeLayout></font></font></font></font>

TextView的样式文件：

<font color="#362e2b"><font style="background-color:rgb(255, 255, 255)"><font face="Arial"><font style="font-size:14px"><?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
 <solid android:color="#666666" />
 <corners android:radius="10dp" />
 <padding 
 android:left="5dp"
 android:right="5dp"
 android:top="5dp"
 android:bottom="5dp"
 />
 
</shape></font></font></font></font>

三、使用该自定义布局控件类

最后，如何使用该自定义的热门标签控件类呢？很简单，请看下面实例代码：

<font color="#362e2b"><font style="background-color:rgb(255, 255, 255)"><font face="Arial"><font style="font-size:14px">package com.czm.flowlayout;
 
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.ViewGroup.LayoutParams;
import android.view.ViewGroup.MarginLayoutParams;
import android.widget.TextView;
/**
 * 
 * @author caizhiming
 * @created on 2015-4-13
 */
public class MainActivity extends Activity {
 
 private String mNames[] = {
  "welcome","android","TextView",
  "apple","jamy","kobe bryant",
  "jordan","layout","viewgroup",
  "margin","padding","text",
  "name","type","search","logcat"
 };
 private XCFlowLayout mFlowLayout;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
  
 initChildViews();
  
 }
 private void initChildViews() {
 // TODO Auto-generated method stub
 mFlowLayout = (XCFlowLayout) findViewById(R.id.flowlayout);
 MarginLayoutParams lp = new MarginLayoutParams(
  LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
 lp.leftMargin = 5;
 lp.rightMargin = 5;
 lp.topMargin = 5;
 lp.bottomMargin = 5;
 for(int i = 0; i < mNames.length; i ++){
  TextView view = new TextView(this);
  view.setText(mNames[i]);
  view.setTextColor(Color.WHITE);
  view.setBackgroundDrawable(getResources().getDrawable(R.drawable.textview_bg));
  mFlowLayout.addView(view,lp);
 }
 }
 
}</font></font></font></font>

以上就是本文的全部内容，下面在给大家一个小福利：

// 流式布局 话不多说，比较简单，注释都写的很清楚


import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;

/**
 * 
 * @author Mr.Himan
 * @version 1.0<br>
 *  2015年11月4日 11:12:06 <br>
 *  流式布局 设置MarginTop 和MarginLeft有效 MarginRight 暂未实现
 */
public class FlowLayout extends ViewGroup {

 /**
 * 存储所有的子View
 */
 private List<List<View>> mAllChildViews = new ArrayList<List<View>>();

 /**
 * 存储每一行的高度
 */
 private List<Integer> mLineHeight = new ArrayList<Integer>();

 public FlowLayout(Context context) {
 this(context, null);
 }

 public FlowLayout(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
 }

 public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 }

 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
 mAllChildViews.clear();
 mLineHeight.clear();
 // 获取当前ViewGroup的宽度
 int width = getWidth();

 int lineWidth = 0;
 int lineHeight = 0;
 // 记录当前行的view
 List<View> lineViews = new ArrayList<View>();
 int childCount = getChildCount();
 for (int i = 0; i < childCount; 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) {
 // 记录LineHeight
 mLineHeight.add(lineHeight);
 // 记录当前行的Views
 mAllChildViews.add(lineViews);
 // 重置行的宽高
 lineWidth = 0;
 lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
 // 重置view的集合
 lineViews = new ArrayList();
 }
 lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
 lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
 + lp.bottomMargin);
 lineViews.add(child);
 }
 // 处理最后一行
 mLineHeight.add(lineHeight);
 mAllChildViews.add(lineViews);

 MarginLayoutParams params = (MarginLayoutParams) this.getLayoutParams();

 // 设置子View的位置
 int left = 0;
 // 添加marginTop
 int top = 0 + params.topMargin;
 // 获取行数
 int lineCount = mAllChildViews.size();
 for (int i = 0; i < lineCount; i++) {
 // 当前行的views和高度
 lineViews = mAllChildViews.get(i);
 lineHeight = mLineHeight.get(i);
 for (int j = 0; j < lineViews.size(); j++) {
 // 为每一列设置marginLeft
 if (j == 0) {
 left = 0 + params.leftMargin;
 }
 View child = lineViews.get(j);
 // 判断是否显示
 if (child.getVisibility() == View.GONE) {
 continue;
 }
 MarginLayoutParams lp = (MarginLayoutParams) child
 .getLayoutParams();
 int cLeft = left + lp.leftMargin;
 int cTop = top + lp.topMargin;
 int cRight = cLeft + child.getMeasuredWidth();
 int cBottom = cTop + child.getMeasuredHeight();
 // 进行子View进行布局
 child.layout(cLeft, cTop, cRight, cBottom);
 left += child.getMeasuredWidth() + lp.leftMargin
 + lp.rightMargin;
 }
 left = 0;
 top += lineHeight;
 }
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

 // 父控件传进来的宽度和高度以及对应的测量模式
 int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
 int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
 int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
 int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

 // 如果当前ViewGroup的宽高为wrap_content的情况
 int width = 0;// 自己测量的 宽度
 int height = 0;// 自己测量的高度
 // 记录每一行的宽度和高度
 int lineWidth = 0;
 int lineHeight = 0;

 // 获取子view的个数
 int childCount = getChildCount();
 
 for (int i = 0; i < childCount; i++) {
 View child = getChildAt(i);
 // 测量子View的宽和高
 measureChild(child, widthMeasureSpec, heightMeasureSpec);
 // 得到LayoutParams

 MarginLayoutParams params = (MarginLayoutParams) child
 .getLayoutParams();
 // 子View占据的宽度
 int childWidth = child.getMeasuredWidth() + params.leftMargin
 + params.rightMargin;
 // 子View占据的高度
 int childHeight = child.getMeasuredHeight() + params.bottomMargin
 + params.topMargin;
 // 换行时候
 if (lineWidth + childWidth > sizeWidth) {
 // 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 {
 // 不换行情况
 // 叠加行宽
 lineWidth += childWidth;
 // 得到最大行高
 lineHeight = Math.max(lineHeight, childHeight);
 }
 // 处理最后一个子View的情况
 if (i == childCount - 1) {
 width = Math.max(width, lineWidth);
 height += lineHeight;
 }
 }
 setMeasuredDimension(modeWidth == MeasureSpec.EXACTLY ? sizeWidth
 : width, modeHeight == MeasureSpec.EXACTLY ? sizeHeight
 : height);

 }

 /**
 * 与当前ViewGroup对应的LayoutParams
 */
 @Override
 public LayoutParams generateLayoutParams(AttributeSet attrs) {
 return new MarginLayoutParams(getContext(), attrs);
 }
}

希望本文所述对大家学习Android实现热门标签的流式布局有所帮助。

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