最近項目里要做一個簡單的曲線圖來標識數據，開始以為很簡單，android已經有那么多的開源圖表庫了，什么achartenginee,hellochart，mpandroidchart等等，下載Demo一找，都強大到有點不適合我這個小小的展示功能了，直是無語了。于是只能自已去畫了，繼承自View去重繪。
　下面先看一下效果圖：

思路：根據點的數量將Canvas等分，等分后先繪制圖表的所有橫軸和縱軸。再將數據轉化為點坐標，繪制到屏幕上，最后將相鄰兩點連成線即可。
　源碼如下：
復制代碼
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Path;
import android.graphics.Point;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.WindowManager;

/**********************************************************

• @文件名稱：LineGraphicView.java

• @文件作者：rzq

• @創建時間：2015年5月27日 下午3:05:19

• @文件描述：自定義簡單曲線圖

• @修改歷史：2015年5月27日創建初始版本
  ********************************************************/
  class LineGraphicView extends View
  {
  /

  • 公共部分
    */
    private static final int CIRCLE_SIZE = 10;

  private static enum Linestyle
  {
  Line, Curve
  }

  private Context mContext;
  private Paint mPaint;
  private Resources res;
  private DisplayMetrics dm;

  /**

  • data
    */
    private Linestyle mStyle = Linestyle.Curve;

  private int canvasHeight;
  private int canvasWidth;
  private int bheight = 0;
  private int blwidh;
  private boolean isMeasure = true;
  /**

  • Y軸最大值
    /
    private int maxValue;
    /*
  • Y軸間距值
    */
    private int averageValue;
    private int marginTop = 20;
    private int marginBottom = 40;

  /**

  • 曲線上總點數
    /
    private Point[] mPoints;
    /*
  • 縱坐標值
    /
    private ArrayList yRawData;
    /*
  • 橫坐標值
    */
    private ArrayList xRawDatas;
    private ArrayList xList = new ArrayList();// 記錄每個x的值
    private int spacingHeight;

  public LineGraphicView(Context context)
  {
  this(context, null);
  }

  public LineGraphicView(Context context, AttributeSet attrs)
  {
  super(context, attrs);
  this.mContext = context;
  initView();
  }

  private void initView()
  {
  this.res = mContext.getResources();
  this.mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
  dm = new DisplayMetrics();
  WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
  wm.getDefaultDisplay().getMetrics(dm);
  }

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh)
  {
  if (isMeasure)
  {
  this.canvasHeight = getHeight();
  this.canvasWidth = getWidth();
  if (bheight == 0)
  bheight = (int) (canvasHeight - marginBottom);
  blwidh = dip2px(30);
  isMeasure = false;
  }
  }

  @Override
  protected void onDraw(Canvas canvas)
  {
  mPaint.setColor(res.getColor(R.color.color_f2f2f2));

  drawAllXLine(canvas);// 畫直線（縱向）drawAllYLine(canvas);// 點的操作設置mPoints = getPoints();mPaint.setColor(res.getColor(R.color.color_ff4631));mPaint.setStrokeWidth(dip2px(2.5f));mPaint.setStyle(Style.STROKE);if (mStyle == Linestyle.Curve){drawScrollLine(canvas);}else{drawLine(canvas);}mPaint.setStyle(Style.FILL);for (int i = 0; i < mPoints.length; i++){canvas.drawCircle(mPoints[i].x, mPoints[i].y, CIRCLE_SIZE / 2, mPaint);}

  }

  /**

  • 畫所有橫向表格，包括X軸
    */
    private void drawAllXLine(Canvas canvas)
    {
    for (int i = 0; i < spacingHeight + 1; i++)
    {
    canvas.drawLine(blwidh, bheight - (bheight / spacingHeight) * i + marginTop, (canvasWidth - blwidh),
    bheight - (bheight / spacingHeight) * i + marginTop, mPaint);// Y坐標
    drawText(String.valueOf(averageValue * i), blwidh / 2, bheight - (bheight / spacingHeight) * i + marginTop,
    canvas);
    }
    }

  /**

  • 畫所有縱向表格，包括Y軸
    */
    private void drawAllYLine(Canvas canvas)
    {
    for (int i = 0; i < yRawData.size(); i++)
    {
    xList.add(blwidh + (canvasWidth - blwidh) / yRawData.size() * i);
    canvas.drawLine(blwidh + (canvasWidth - blwidh) / yRawData.size() * i, marginTop, blwidh
    + (canvasWidth - blwidh) / yRawData.size() * i, bheight + marginTop, mPaint);
    drawText(xRawDatas.get(i), blwidh + (canvasWidth - blwidh) / yRawData.size() * i, bheight + dip2px(26),
    canvas);// X坐標
    }
    }

  private void drawScrollLine(Canvas canvas)
  {
  Point startp = new Point();
  Point endp = new Point();
  for (int i = 0; i < mPoints.length - 1; i++)
  {
  startp = mPoints[i];
  endp = mPoints[i + 1];
  int wt = (startp.x + endp.x) / 2;
  Point p3 = new Point();
  Point p4 = new Point();
  p3.y = startp.y;
  p3.x = wt;
  p4.y = endp.y;
  p4.x = wt;

  Path path = new Path();path.moveTo(startp.x, startp.y);path.cubicTo(p3.x, p3.y, p4.x, p4.y, endp.x, endp.y);canvas.drawPath(path, mPaint);}

  }

  private void drawLine(Canvas canvas)
  {
  Point startp = new Point();
  Point endp = new Point();
  for (int i = 0; i < mPoints.length - 1; i++)
  {
  startp = mPoints[i];
  endp = mPoints[i + 1];
  canvas.drawLine(startp.x, startp.y, endp.x, endp.y, mPaint);
  }
  }

  private void drawText(String text, int x, int y, Canvas canvas)
  {
  Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
  p.setTextSize(dip2px(12));
  p.setColor(res.getColor(R.color.color_999999));
  p.setTextAlign(Paint.Align.LEFT);
  canvas.drawText(text, x, y, p);
  }

  private Point[] getPoints()
  {
  Point[] points = new Point[yRawData.size()];
  for (int i = 0; i < yRawData.size(); i++)
  {
  int ph = bheight - (int) (bheight * (yRawData.get(i) / maxValue));

  points[i] = new Point(xList.get(i), ph + marginTop);}return points;

  }

  public void setData(ArrayList yRawData, ArrayList xRawData, int maxValue, int averageValue)
  {
  this.maxValue = maxValue;
  this.averageValue = averageValue;
  this.mPoints = new Point[yRawData.size()];
  this.xRawDatas = xRawData;
  this.yRawData = yRawData;
  this.spacingHeight = maxValue / averageValue;
  }

  public void setTotalvalue(int maxValue)
  {
  this.maxValue = maxValue;
  }

  public void setPjvalue(int averageValue)
  {
  this.averageValue = averageValue;
  }

  public void setMargint(int marginTop)
  {
  this.marginTop = marginTop;
  }

  public void setMarginb(int marginBottom)
  {
  this.marginBottom = marginBottom;
  }

  public void setMstyle(Linestyle mStyle)
  {
  this.mStyle = mStyle;
  }

  public void setBheight(int bheight)
  {
  this.bheight = bheight;
  }

  /**

  • 根據手機的分辨率從 dp 的單位 轉成為 px(像素)
    */
    private int dip2px(float dpValue)
    {
    return (int) (dpValue * dm.density + 0.5f);
    }

}

使用：

package com.example;
import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity
{
LineGraphicView tu;
ArrayList yList;

@Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);tu = (LineGraphicView) findViewById(R.id.line_graphic);yList = new ArrayList<Double>();yList.add((double) 2.103);yList.add(4.05);yList.add(6.60);yList.add(3.08);yList.add(4.32);yList.add(2.0);yList.add(5.0);ArrayList<String> xRawDatas = new ArrayList<String>();xRawDatas.add("05-19");xRawDatas.add("05-20");xRawDatas.add("05-21");xRawDatas.add("05-22");xRawDatas.add("05-23");xRawDatas.add("05-24");xRawDatas.add("05-25");xRawDatas.add("05-26");tu.setData(yList, xRawDatas, 8, 2); }

}
復制代碼

demo下載http://note.youdao.com/yws/public/redirect/share?id=fd4b3bc312e39a915fe865c55cfb561a&type=false
Boxing.zip

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