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Android 自定义流式布局 Android自定义流式布局的实现示例

雪芽蓝域zzs 人气:0

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。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:  

在这里插入图片描述

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

(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:

(3)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

3.代码

FlowLayoutView

/**
 * Created by zzs on 20/01/16.
 * 流式布局
 */
public class FlowLayoutView extends ViewGroup{
 public FlowLayoutView(Context context) {
  super(context);
 }

 public FlowLayoutView(Context context, AttributeSet attrs) {
  super(context, attrs);
 }

  //或ViewGroup中所有子元素的属性
 //否则只获取ViewGroup 的属性
 @Override
 public LayoutParams generateLayoutParams(AttributeSet attrs) {
  return new MarginLayoutParams(getContext(),attrs);
 }


 /**
  * 测量控件本身的大小 宽和高 根据子内容获取
  * @param widthMeasureSpec
  * @param heightMeasureSpec
  */
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);

  //获取父布局的模式和尺寸
  int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
  int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
  int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
  int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

  //记录Wrap_content的宽高
  int width = 0;
  int height = 0;

  //没一行的宽和高
  int lineWidth = 0;
  int lineHeight =0;

  //获取子元素的数量
  int cCount = getChildCount();
  //进行遍历子元素
  for(int i=0;i<cCount;i++){
   //获取每一个子元素
   View child = getChildAt(i);
   //测量每一个子元素
   measureChild(child,widthMeasureSpec,heightMeasureSpec);
   //获取每个子元素的属性
   MarginLayoutParams layoutParams = (MarginLayoutParams) child.getLayoutParams();

   //获取当前子元素的宽和高
   int childWidth = child.getMeasuredWidth()+layoutParams.leftMargin+layoutParams.rightMargin;
   int childHeight = child.getMeasuredHeight()+layoutParams.bottomMargin+layoutParams.topMargin;


      if(lineWidth+childWidth>getWidth()-getPaddingLeft()-getPaddingRight()){//换行
    width = Math.max(lineWidth,childWidth);
    lineWidth = childWidth;//重新开一行 当前行的宽度
    //叠加之前的高度
    height += lineHeight;
    //重新开一行 这个新行的高度
    lineHeight = childHeight;
   }else{//不换行
    //记录当前行的宽
    lineWidth += childWidth;
    //记录一行中的高度
    lineHeight = Math.max(lineHeight,childHeight);
   }

   if(i ==cCount-1){//判断是否是最后一个元素
    width = Math.max(width,lineWidth);
    height += lineHeight;
   }
   //设置ViewGrop最终宽高
   setMeasuredDimension(modeWidth==MeasureSpec.EXACTLY?sizeWidth:width+getPaddingRight()+getPaddingLeft(),
        modeHeight==MeasureSpec.EXACTLY?sizeHeight:height+getPaddingBottom()+getPaddingTop());
  }

 }

 //记录所有子元素 按行存取
 List<List<View>> mAllViews = new ArrayList<>();
 //记录每一行中最大的高度
 private List<Integer> mLineHeight = new ArrayList<>();

 //摆放子View ???????????????
 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
  //为了多次执行时 数据正确
  mAllViews.clear();
  mLineHeight.clear();

  //获取父控件的宽度
  int width = getWidth();

  //记录一行中的宽和高
  int lineWidth = 0;
  int lineHeight = 0;

  //记录一行中的 View
  List<View> lineView = new ArrayList<>();

  //获取子元素的个数
  int cCount = getChildCount();
  Log.e("AAA","==AAAA=>"+cCount);
  //遍历所有子元素
  for(int i=0;i<cCount;i++){

   View child = getChildAt(i);
   //获取每个子元素的属性
   MarginLayoutParams layoutParams = (MarginLayoutParams) child.getLayoutParams();

   //获取当前子元素的宽和高
   int childWidth = child.getMeasuredWidth()+layoutParams.leftMargin+layoutParams.rightMargin;
   int childHeight = child.getMeasuredHeight()+layoutParams.bottomMargin+layoutParams.topMargin;

   if(lineWidth+childWidth>width-getPaddingLeft()-getPaddingRight()){//判断是否换行
    //记录一行的高 和一行中的View
    mLineHeight.add(lineHeight);
    mAllViews.add(lineView);

    Log.e("AAA","==>VVV===>"+mAllViews.size());
    //让数据重置
    lineWidth = 0;
    lineView = new ArrayList<>();
   }else{
    //记录一行中的宽 高 view
    lineWidth += childWidth;
    lineHeight = Math.max(lineHeight,childHeight);
    lineView.add(child);
   }



  }
//处理元素 数据以每行的形式处理
  mLineHeight.add(lineHeight);
  mAllViews.add(lineView);


  //获取每个View的padding
  int left = getPaddingLeft();
  int top = getPaddingTop();
  //获取有多少行
  int lineNum = mAllViews.size();
  Log.e("AAA","=BBB=>"+lineNum);
  //展示每一行
  for(int i=0;i<lineNum;i++){
   lineHeight = mLineHeight.get(i);
   lineView = mAllViews.get(i);
   //遍历每一行
   // 取出 每一行的 所有的View
   lineView = mAllViews.get(i);
   lineHeight = mLineHeight.get(i);
   // 循环遍历 每一行的View
   for(int j=0;j<lineView.size();j++){
    View child = lineView.get(j);
    MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

    int lc = left+lp.leftMargin;
    int tc = top+lp.topMargin;
    int rc = lc+child.getMeasuredWidth();
    int bc = tc+child.getMeasuredHeight();
    //摆放 子View的位置
    child.layout(lc, tc, rc, bc);
    //叠加 前一个View 的 实际宽度
    left += child.getMeasuredWidth()+lp.leftMargin+lp.rightMargin;
   }
   //换行了 重置
   left = getPaddingLeft();
   top+=lineHeight;

  }
 }
}

MainActivity

public class MainActivity extends AppCompatActivity {
 private FlowLayoutView flowLayoutView;
 private String[] titils = {"sds", "da", "aa", "fff", "gggggg",
   "hhgghg", "jjhhhh", "aaaaaaaaaaaaaaaaaaaaaaaaaaa", "fff", "gggggg", "hhgghg", "jjhhhh",
   "sds", "da", "aa", "fff", "gggggg", "sds", "da", "aa", "fff", "gggggg"};

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  flowLayoutView = findViewById(R.id.flowLayoutView);

  for (int i = 0; i < titils.length; i++) {
   TextView tv = (TextView) LayoutInflater.from(MainActivity.this)
     .inflate(R.layout.lv_item, flowLayoutView, false);
   tv.setText(titils[i]);
   flowLayoutView.addView(tv);
  }
 }
}

activity_main

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context=".MainActivity">

 <com.zzs.polygon.FlowLayoutView
  android:id="@+id/flowLayoutView"
  android:layout_width="match_parent"
  android:layout_height="wrap_content" />
</LinearLayout>

lv_item

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:background="@drawable/tv_shape"
 android:paddingLeft="10dp"
 android:paddingTop="5dp"
 android:paddingRight="10dp"
 android:paddingBottom="5dp"
 android:layout_marginLeft="10dp"
 android:layout_marginBottom="5dp"
 android:layout_marginRight="10dp"
 android:layout_marginTop="5dp"
 android:text="AAA"
 android:textColor="#ff0000">

</TextView>

drawable / tv_shape.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">

 <corners android:radius="30dp"></corners>
 <solid android:color="#8800ff00"></solid>
 <padding
  android:left="10dp"
  android:right="10dp"
  android:top="10dp"
  android:bottom="10dp"
  ></padding>
</shape>
</TextView>

效果图

在这里插入图片描述

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