Android自定义view实现动态柱状图

public class Histogram extends View {
 int MAX = 100;//矩形显示的最大值
 int corner = 0; //矩形的角度。 设置为0 则没有角度。
 double data = 0.0;//显示的数
 double tempData = 0; //初始数据
 int textPadding = 50; //字体与矩形图的距离
  Paint mPaint;
 int mColor;
  Context mContext;


 //构造函数
 public Histogram(Context context) {
  super(context);
  mCOntext= context;
 }

 public Histogram(Context context, @Nullable AttributeSet attrs) {
  super(context, attrs);
  mCOntext= context;
  initPaint();
 }

 public Histogram(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  mCOntext= context;
  initPaint();
 }

 //画笔方法
 private void initPaint() {
  mPaint = new Paint();
  mPaint.setAntiAlias(true);
  mColor = mContext.getResources().getColor(R.color.gary);
  mPaint.setColor(mColor);
 }

 @Override
 public void draw(Canvas canvas) {
  super.draw(canvas);

  if (data == 0.0) {
   mPaint.setTextSize(getWidth() / 2);
   RectF oval3 = new RectF(0, getHeight() - DensityUtils.pxTodip(mContext, 20), getWidth(), getHeight());// 设置个新的长方形
   canvas.drawRoundRect(oval3, DensityUtils.pxTodip(mContext, corner), DensityUtils.pxTodip(mContext, corner), mPaint);

   canvas.drawText("0",
     getWidth() * 0.5f - mPaint.measureText("0") * 0.5f,
     getHeight() - DensityUtils.pxTodip(mContext, 20) - 2 * DensityUtils.pxTodip(mContext, textPadding),
     mPaint);
   return;
  }

  //防止数值很大的的时候，动画时间过长
  int step = (int) (data / 100 + 1.0);

  if (tempData 

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 private void initAllViews() {
  column_One= (Histogram) findViewById(R.id.column_one);
  column_two = (Histogram) findViewById(R.id.column_two);
  column_three = (Histogram) findViewById(R.id.column_three);

  column_one.setData( 20.22, 100);
  column_two.setData(30.2, 100);
  column_three.setData(40, 100);
  column_one.mPaint.setColor(getResources().getColor(R.color.colorAccent)); //改变柱状图的颜色
 }