思路
根据点的数量将Canvas等分，等分后先绘制图表的所有横轴和纵轴。再将数据转化为点坐标，绘制到屏幕上，最后将相邻两点连成线即可。
代码
- 图表函数
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;
class LineGraphicView extends View
{
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;
private Linestyle mStyle = Linestyle.Curve;
private int canvasHeight;
private int canvasWidth;
private int bheight = 0;
private int blwidh;
private boolean isMeasure = true;
private int maxValue;
private int averageValue;
private int marginTop = 20;
private int marginBottom = 40;
private Point[] mPoints;
private ArrayList<Double> yRawData;
private ArrayList<String> xRawDatas;
private ArrayList<Integer> xList = new ArrayList<Integer>();
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);
drawAllYLine(canvas);
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);
}
}
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坐标
drawText(String.valueOf(averageValue * i), blwidh / 2, bheight - (bheight / spacingHeight) * i + marginTop,canvas);
}
}
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坐标
}
}
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<Double> yRawData, ArrayList<String> 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;
}
private int dip2px(float dpValue)
{
return (int) (dpValue * dm.density + 0.5f);
}
}
- 主函数
package com.example;
import java.util.ArrayList;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity
{
LineGraphicView tu;
ArrayList<Double> 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) 2.10);
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("08-01");
xRawDatas.add("08-02");
xRawDatas.add("08-03");
xRawDatas.add("08-04");
xRawDatas.add("08-05");
xRawDatas.add("08-06");
xRawDatas.add("08-07");
xRawDatas.add("08-08");
tu.setData(yList, xRawDatas, 8, 2);
}
}