Android实现列表时间轴

public class DividerItemDecoration extends RecyclerView.ItemDecoration{ // 写右边字的画笔(具体信息) private Paint mPaint; // 写左边日期字的画笔( 时间 + 日期) private Paint mPaint1; private Paint mPaint2; private Paint mPaint3; // 左 上偏移长度 private int itemView_leftinterval; private int itemView_topinterval; // 轴点半径 private int circle_radius; // 图标 private Bitmap mIcon; //月份合集(使用时需要设置) private List<String> monthList= new ArrayList<>(); //年份合集(使用时需要设置) private List<String> yearList= new ArrayList<>(); public void setMonthList(List<String> monthList) {  this.monthList = monthList; } public void setYearList(List<String> yearList) {  this.yearList = yearList; } // 在构造函数里进行绘制的初始化，如画笔属性设置等 public DividerItemDecoration(Context context) {  // 轴点画笔(红色)  mPaint = new Paint();  mPaint.setColor(Color.rgb(58, 154, 239));  mPaint.setStyle(Paint.Style.STROKE);  mPaint.setStrokeWidth(3);  // 左边时间文本画笔(蓝色)  // 此处设置了两只分别设置 时分 & 年月  mPaint1 = new Paint();  mPaint1.setColor(Color.BLACK);  mPaint1.setTextSize(30);  mPaint2 = new Paint();  mPaint2.setColor(context.getResources().getColor(R.color.divider));  mPaint2.setTextSize(26);  mPaint3 = new Paint();  mPaint3.setColor(Color.rgb(58, 154, 239));  mPaint3.setTextSize(20);  // 赋值ItemView的左偏移长  itemView_leftinterval = 150;  // 赋值ItemView的上偏移长度  itemView_topinterval = 30;  // 赋值轴点圆的半径为10  circle_radius = 8; } // 重写getItemOffsets（）方法 // 作用：设置ItemView 左 & 上偏移长度 @Override public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {  super.getItemOffsets(outRect, view, parent, state);  // 设置ItemView的左 & 上偏移长度分别为150 px & 30px,即此为onDraw()可绘制的区域  outRect.set(itemView_leftinterval, itemView_topinterval, 0, 0); } // 重写onDraw（） // 作用:在间隔区域里绘制时光轴线 & 时间文本 @Override public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {  super.onDraw(c, parent, state);  // 获取RecyclerView的Child view的个数  int childCount = parent.getChildCount();  // 遍历每个Item，分别获取它们的位置信息，然后再绘制对应的分割线  for (int i = 0; i < childCount; i++) {   // 获取每个Item对象   View child = parent.getChildAt(i);   View lastChild = null;   if (i > 0) {    lastChild = parent.getChildAt(i - 1);   }   /**    * 绘制轴点    */   // 轴点 = 圆 = 圆心(x,y) 位置可以根据需求来调节   float centerx = child.getLeft() - itemView_leftinterval / 4;   float centery = child.getTop() + itemView_topinterval +10;   // 绘制轴点圆   c.drawCircle(centerx, centery, circle_radius, mPaint);   /**    * 绘制上半轴线(x轴是保持不变的)    */   // 上端点坐标(x,y)   float upLine_up_x = centerx;   float upLine_up_y = 0;   if (i>0){     upLine_up_y = lastChild.getBottom();   }else {     upLine_up_y = centery - itemView_topinterval;   }   // 下端点坐标(x,y)   float upLine_bottom_x = centerx;   float upLine_bottom_y = centery - circle_radius;   //绘制上半部轴线   c.drawLine(upLine_up_x, upLine_up_y, upLine_bottom_x, upLine_bottom_y, mPaint);   /**    * 绘制下半轴线,最后一个不画下半轴    */   if (i <childCount-1){    // 上端点坐标(x,y)    float bottomLine_up_x = centerx;    float bottom_up_y = centery + circle_radius;    // 下端点坐标(x,y)    float bottomLine_bottom_x = centerx;    float bottomLine_bottom_y = child.getBottom();    //绘制下半部轴线    c.drawLine(bottomLine_up_x, bottom_up_y, bottomLine_bottom_x, bottomLine_bottom_y, mPaint);   }   /**    * 绘制左边时间文本    */   // 获取每个Item的位置   int index = parent.getChildAdapterPosition(child);   // 设置文本起始坐标   float Text_x = child.getLeft() - itemView_leftinterval * 5 / 6;   float Text_y = upLine_bottom_y;   // 根据Item位置设置时间文本   switch (index) {    case (0):     // 设置日期绘制位置     c.drawText(monthList.get(0), Text_x, Text_y, mPaint1);     c.drawText(yearList.get(0), Text_x + 8, Text_y + 28, mPaint2);     break;    case (1):     // 设置日期绘制位置     c.drawText(monthList.get(1), Text_x, Text_y, mPaint1);     c.drawText(yearList.get(1), Text_x + 8, Text_y + 28, mPaint2);     break;    case (2):     // 设置日期绘制位置     if (TextUtils.isEmpty(yearList.get(2))){      c.drawText(monthList.get(2), Text_x, Text_y, mPaint3);     }else {      c.drawText(monthList.get(2), Text_x, Text_y, mPaint1);      c.drawText(yearList.get(2), Text_x + 8, Text_y + 28, mPaint2);     }     break;    case (3):     // 设置日期绘制位置     c.drawText(monthList.get(3), Text_x, Text_y, mPaint1);     c.drawText(yearList.get(3), Text_x + 8, Text_y + 28, mPaint2);     break;    case (4):     // 设置日期绘制位置     c.drawText(monthList.get(4), Text_x, Text_y, mPaint1);     c.drawText(yearList.get(4), Text_x + 8, Text_y + 28, mPaint2);     break;    default:c.drawText("结束", Text_x, Text_y, mPaint1);   }  } }}

DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(this);  dividerItemDecoration.setMonthList(monthList);  dividerItemDecoration.setYearList(yearList);  mRecyclerView.addItemDecoration(dividerItemDecoration);