一、概述&＃xff1a;在日常的app使用中&＃xff0c;我们会在android 的app中看见 热门标签等自动换行的流式布局&＃xff0c;今天&＃xff0c;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&＃xff1a;
1.流式布局的特点以及应用场景
特点&＃xff1a;当上面一行的空间不够容纳新的TextView时候&＃xff0c;
才开辟下一行的空间
原理图&＃xff1a;
场景&＃xff1a;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&＃xff0c;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&＃xff0c;来为子view设置测量模式和测量值
测量&＃61;测量模式&＃43;测量值&＃xff1b;
测量模式有3种&＃xff1a;
EXACTLY&＃xff1a;表示设置了精确的值&＃xff0c;一般当childView设置其宽、高为精确值、match_parent时&＃xff0c;ViewGroup会将其设置为EXACTLY&＃xff1b;
AT_MOST&＃xff1a;表示子布局被限制在一个最大值内&＃xff0c;一般当childView设置其宽、高为wrap_content时&＃xff0c;ViewGroup会将其设置为AT_MOST&＃xff1b;
UNSPECIFIED&＃xff1a;表示子布局想要多大就多大&＃xff0c;一般出现在AadapterView的item的heightMode中、ScrollView的childView的heightMode中&＃xff1b;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&＃xff0c;就是如下&＃xff1a;
子View.getLayoutParams 得到的LayoutParams对应的就是 子View所在的父控件的LayoutParams;
例如&＃xff0c;LinearLayout 里面的子view.getLayoutParams ->LinearLayout.LayoutParams
所以 咱们的FlowLayout 也需要一个LayoutParams&＃xff0c;由于上面的效果图是子View的 margin&＃xff0c;
所以应该使用MarginLayoutParams。即FlowLayout->MarginLayoutParams
4.最后来看看实现的最终效果图&＃xff1a;
二、热门标签的流式布局的实现&＃xff1a;
1. 自定义热门标签的ViewGroup实现
根据上面的技术分析&＃xff0c;自定义类继承于ViewGroup&＃xff0c;并重写 onMeasure和onLayout等方法。具体实现代码如下&＃xff1a;
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;
/**
*
* &＃64;author caizhiming
* &＃64;created on 2015-4-13
*/
public class XCFlowLayout extends ViewGroup{
//存储所有子View
private List> mAllChildViews &＃61; new ArrayList<>();
//每一行的高度
private List mLineHeight &＃61; 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
}
&＃64;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 &＃61; MeasureSpec.getSize(widthMeasureSpec);
int modeWidth &＃61; MeasureSpec.getMode(widthMeasureSpec);
int sizeHeight &＃61; MeasureSpec.getSize(heightMeasureSpec);
int modeHeight &＃61; MeasureSpec.getMode(heightMeasureSpec);
//如果当前ViewGroup的宽高为wrap_content的情况
int width &＃61; 0;//自己测量的 宽度
int height &＃61; 0;//自己测量的高度
//记录每一行的宽度和高度
int lineWidth &＃61; 0;
int lineHeight &＃61; 0;
//获取子view的个数
int childCount &＃61; getChildCount();
for(int i &＃61; 0;i
View child &＃61; getChildAt(i);
//测量子View的宽和高
measureChild(child, widthMeasureSpec, heightMeasureSpec);
//得到LayoutParams
MarginLayoutParams lp &＃61; (MarginLayoutParams) getLayoutParams();
//子View占据的宽度
int childWidth &＃61; child.getMeasuredWidth() &＃43; lp.leftMargin &＃43; lp.rightMargin;
//子View占据的高度
int childHeight &＃61; child.getMeasuredHeight() &＃43; lp.topMargin &＃43; lp.bottomMargin;
//换行时候
if(lineWidth &＃43; childWidth > sizeWidth){
//对比得到最大的宽度
width &＃61; Math.max(width, lineWidth);
//重置lineWidth
lineWidth &＃61; childWidth;
//记录行高
height &＃43;&＃61; lineHeight;
lineHeight &＃61; childHeight;
}else{//不换行情况
//叠加行宽
lineWidth &＃43;&＃61; childWidth;
//得到最大行高
lineHeight &＃61; Math.max(lineHeight, childHeight);
}
//处理最后一个子View的情况
if(i &＃61;&＃61; childCount -1){
width &＃61; Math.max(width, lineWidth);
height &＃43;&＃61; lineHeight;
}
}
//wrap_content
setMeasuredDimension(modeWidth &＃61;&＃61; MeasureSpec.EXACTLY ? sizeWidth : width,
modeHeight &＃61;&＃61; MeasureSpec.EXACTLY ? sizeHeight : height);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
&＃64;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 &＃61; getWidth();
int lineWidth &＃61; 0;
int lineHeight &＃61; 0;
//记录当前行的view
List lineViews &＃61; new ArrayList();
int childCount &＃61; getChildCount();
for(int i &＃61; 0;i
View child &＃61; getChildAt(i);
MarginLayoutParams lp &＃61; (MarginLayoutParams) child.getLayoutParams();
int childWidth &＃61; child.getMeasuredWidth();
int childHeight &＃61; child.getMeasuredHeight();
//如果需要换行
if(childWidth &＃43; lineWidth &＃43; lp.leftMargin &＃43; 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 &＃61; 0;
lineHeight &＃61; childHeight &＃43; lp.topMargin &＃43; lp.bottomMargin;
//重置view的集合
lineViews &＃61; new ArrayList();
}
lineWidth &＃43;&＃61; childWidth &＃43; lp.leftMargin &＃43; lp.rightMargin;
lineHeight &＃61; Math.max(lineHeight, childHeight &＃43; lp.topMargin &＃43; 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 &＃61; 0;
int top &＃61; 0;
//获取行数
int lineCount &＃61; mAllChildViews.size();
for(int i &＃61; 0; i
//当前行的views和高度
lineViews &＃61; mAllChildViews.get(i);
lineHeight &＃61; mLineHeight.get(i);
for(int j &＃61; 0; j
View child &＃61; lineViews.get(j);
//判断是否显示
if(child.getVisibility() &＃61;&＃61; View.GONE){
continue;
}
MarginLayoutParams lp &＃61; (MarginLayoutParams) child.getLayoutParams();
int cLeft &＃61; left &＃43; lp.leftMargin;
int cTop &＃61; top &＃43; lp.topMargin;
int cRight &＃61; cLeft &＃43; child.getMeasuredWidth();
int cBottom &＃61; cTop &＃43; child.getMeasuredHeight();
//进行子View进行布局
child.layout(cLeft, cTop, cRight, cBottom);
left &＃43;&＃61; child.getMeasuredWidth() &＃43; lp.leftMargin &＃43; lp.rightMargin;
}
left &＃61; 0;
top &＃43;&＃61; lineHeight;
}
}
/**
* 与当前ViewGroup对应的LayoutParams
*/
&＃64;Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
// TODO Auto-generated method stub
return new MarginLayoutParams(getContext(), attrs);
}
}
2.相关的布局文件&＃xff1a;
引用自定义控件&＃xff1a;
xmlns:tools&＃61;"http://schemas.android.com/tools"
android:id&＃61;"&＃64;&＃43;id/container"
android:layout_width&＃61;"match_parent"
android:layout_height&＃61;"match_parent" >
android:id&＃61;"&＃64;&＃43;id/flowlayout"
android:layout_width&＃61;"match_parent"
android:layout_height&＃61;"match_parent" >
TextView的样式文件&＃xff1a;
android:left&＃61;"5dp"
android:right&＃61;"5dp"
android:top&＃61;"5dp"
android:bottom&＃61;"5dp"
/>
三、使用该自定义布局控件类
最后&＃xff0c;如何使用该自定义的热门标签控件类呢&＃xff1f;很简单&＃xff0c;请看下面实例代码&＃xff1a;
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;
/**
*
* &＃64;author caizhiming
* &＃64;created on 2015-4-13
*/
public class MainActivity extends Activity {
private String mNames[] &＃61; {
"welcome","android","TextView",
"apple","jamy","kobe bryant",
"jordan","layout","viewgroup",
"margin","padding","text",
"name","type","search","logcat"
};
private XCFlowLayout mFlowLayout;
&＃64;Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initChildViews();
}
private void initChildViews() {
// TODO Auto-generated method stub
mFlowLayout &＃61; (XCFlowLayout) findViewById(R.id.flowlayout);
MarginLayoutParams lp &＃61; new MarginLayoutParams(
LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
lp.leftMargin &＃61; 5;
lp.rightMargin &＃61; 5;
lp.topMargin &＃61; 5;
lp.bottomMargin &＃61; 5;
for(int i &＃61; 0; i
TextView view &＃61; new TextView(this);
view.setText(mNames[i]);
view.setTextColor(Color.WHITE);
view.setBackgroundDrawable(getResources().getDrawable(R.drawable.textview_bg));
mFlowLayout.addView(view,lp);
}
}
}
四、源码下载
此源码下载完之后&＃xff0c;往往有个要点我们容易忽略&＃xff0c;那就是源码的安全性问题&＃xff0c;此处可点击移动应用安全智能服务提供商爱加密的Android加密&＃xff0c;源码保护&＃xff01;
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