本文主要是介绍AndroidUI系列-ViewGroup流式布局,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
很多时候,我们会遇见各种各样的需求,流式布局算是非常常见的一种。像各种菜单啊,展示之类的。其实这个很简单,可以自己手写一个,顺便练练自定义控件。先看看效果。
那么先来分析一下,满足这个需求,应该需要做哪些准备。
就像备注写的一样,
首先需要准备的条件:
一个List<List< View > >
来缓存多少行。
一个List<Integer>
来缓存每一行的高度。
一个List<View>
来缓存每一行的子控件View。
相对于每一行来说,需要一个变量缓存当前行的宽度,一个变量缓存当前行的最大高度。
换行的条件:
当前行的宽度加上下一个子控件的宽度,超过了当前控件允许的最大宽度。那就换行。
那么直接开始撸吧。
package com.example.administrator.flowlayout;import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;import java.util.ArrayList;
import java.util.List;/*** Created by ShuWen on 2017/6/1.*/public class FlowLayout extends ViewGroup {//用于缓存的多少行private List<List<View>> mLineViewsList = new ArrayList<>();//用于缓存每一行最大的高度private List<Integer> mLinesHieights = new ArrayList<>();public FlowLayout(Context context) {super(context);}public FlowLayout(Context context, AttributeSet attrs) {super(context, attrs);}public FlowLayout(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);}//为了获取子控件的margin属性值@Overridepublic LayoutParams generateLayoutParams(AttributeSet attrs) {return new MarginLayoutParams(getContext(),attrs);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);//获取测量模式int meaWidthMode = MeasureSpec.getMode(widthMeasureSpec);int meaHeightMode = MeasureSpec.getMode(heightMeasureSpec);//获得允许的宽高int meaWidthSize = MeasureSpec.getSize(widthMeasureSpec);int meaHeightSize = MeasureSpec.getSize(heightMeasureSpec);//最后测量的宽高int measuredWidth = 0;int measuredHeight = 0;if (meaHeightMode == MeasureSpec.EXACTLY && meaWidthMode == MeasureSpec.EXACTLY){measuredHeight = meaHeightSize;measuredWidth = meaWidthSize;}else {int iCurLineW = 0;int iCurLineH = 0;int childWidth = 0;int childHeight = 0;int childCount = getChildCount();//用于缓存每一行的子控件List<View> childsList = new ArrayList<>();for (int i = 0; i < childCount; i++) {View childView = getChildAt(i);//测量子控件,获得子控件的宽高和margin值measureChild(childView,widthMeasureSpec,heightMeasureSpec);MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();//自控件的宽高childWidth = params.leftMargin + childView.getMeasuredWidth() + params.rightMargin;childHeight = params.topMargin + childView.getMeasuredHeight() + params.bottomMargin;//当前行的宽度,加上下一个控件的宽度大于允许值,则换行if (childWidth + iCurLineW > meaWidthSize){//换行操作,记录测量的父控件宽高measuredWidth = Math.max(measuredWidth,iCurLineW);measuredHeight += iCurLineH;//保存该行的数据mLineViewsList.add(childsList);mLinesHieights.add(iCurLineH);//重新记录新的一行iCurLineH = childHeight;iCurLineW = childWidth;//开始缓存新一行数据childsList = new ArrayList<>();childsList.add(childView);}else {//未换行操作,记录该行宽高iCurLineH = Math.max(iCurLineH,childHeight);iCurLineW += childWidth;//保存到该行集合childsList.add(childView);}//当该行是最后一行并且需要换行时,进行换行数据处理if (i == childCount - 1){measuredHeight += iCurLineH;measuredWidth = Math.max(measuredWidth,iCurLineW);mLinesHieights.add(iCurLineH);mLineViewsList.add(childsList);}}}setMeasuredDimension(measuredWidth,measuredHeight);}@Overrideprotected void onLayout(boolean b, int i, int i1, int i2, int i3) {int left,top,right,bottom;int curLeft = 0;int curTop = 0;int linesCount = mLineViewsList.size();for (int j = 0; j < linesCount; j++) {List<View> childViews = mLineViewsList.get(j);int childsCount = childViews.size();for (int k = 0; k < childsCount; k++) {View childView = childViews.get(k);MarginLayoutParams params = (MarginLayoutParams) childView.getLayoutParams();left = curLeft + params.leftMargin;top = curTop + params.topMargin;right = left + childView.getMeasuredWidth();bottom = top + childView.getMeasuredHeight();//为子控件布局childView.layout(left,top,right,bottom);curLeft += params.leftMargin + childView.getMeasuredWidth() + params.rightMargin;}curLeft = 0;curTop += mLinesHieights.get(j);}mLinesHieights.clear();mLineViewsList.clear();}public interface onItemClick{void click(View view,int position);}public void setOnItemClickListener(final onItemClick onItemClick){int childCount = getChildCount();for (int i = 0; i < childCount; i++) {View childView = getChildAt(i);final int finalI = i;childView.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View view) {onItemClick.click(view, finalI);}});}}
}
其中用到的flag背景:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"><corners android:radius="10dp"/><padding android:bottom="2dp"android:top="2dp"android:right="10dp"android:left="10dp"/><solid android:color="@color/colorPrimary"/>
</shape>
textView的样式.
<style name="text_flag"><item name="android:background">@drawable/flag</item><item name="android:layout_width">wrap_content</item><item name="android:layout_height">wrap_content</item><item name="android:layout_margin">4dp</item><item name="android:textColor">#fff</item></style>
activity的布局:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/activity_main"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"tools:context="com.example.administrator.flowlayout.MainActivity"><com.example.administrator.flowlayout.FlowLayout
android:id="@+id/flowlayout"android:layout_width="fill_parent"android:layout_height="wrap_content"><TextView
style="@style/text_flag"android:text="阿萨德 "/><TextView
style="@style/text_flag"android:text="我阿萨德阿萨德的"/><TextView
style="@style/text_flag"android:textSize="16sp"android:text="你阿萨德阿萨德的"/><TextView
style="@style/text_flag"android:textSize="19sp"android:text="阿萨德 阿萨德"/><TextView
style="@style/text_flag"android:text="阿萨德阿萨德"/><TextView
style="@style/text_flag"android:text="阿大声道"/><TextView
style="@style/text_flag"android:text="阿大声道"/><TextView
style="@style/text_flag"android:text="为全文完请二位"/><TextView
style="@style/text_flag"android:text="谁是谁"/><TextView
style="@style/text_flag"android:text="撒大声地"/><TextView
style="@style/text_flag"android:text="阿大声道"/><TextView
style="@style/text_flag"android:text="大法师"/><TextView
style="@style/text_flag"android:text="12123"/><TextView
style="@style/text_flag"android:text="sadsa"/></com.example.administrator.flowlayout.FlowLayout>
</LinearLayout>
就这么简单,自己撸一遍吧,总能学到一点的。
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