Android实现热门标签的流式布局

2020-04-11 11:06:48

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来源：转载

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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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