Android自定义控件实现折线图

本文实例实现一个如下图所示的Android折线图，供大家参考，具体内容如下

首先是控件绘图区域的划分，控件左边取一小部分（控件总宽度的八分之一）绘制表头，右边剩余的部分绘制表格

确定表格的行列数，首先绘制一个三行八列的网格，设置好行列的坐标后开始绘制

/*绘制三条横线*/
for(int i=0;i<3;i++){
 canvas.drawLine(textWide, mLineYs[i], totalWidth, mLineYs[i], mPaintLine);
}
/*绘制八条竖线*/
for(int i=0;i<8;i++){
 canvas.drawLine(mLineXs[i], 0, mLineXs[i], totalHeight, mPaintLine);
}

网格绘制完成后，开始绘制折线图

根据输入的节点数据，分别绘制两条折线

通过canvas的drawLine方法依次连接两点即可

在每个数据节点处绘制一个小圆，突出显示

/*绘制第一条折线的路径*/
for (int i = 0; i < mPerformance_1.length - 1; i++) {
 /*折线图的折线的画笔设置粗一点*/
 mPaintLine.setStrokeWidth(5);
 /*计算当前节点的坐标值*/
 float prePointX =mLineXs[i];
 float prePointY =mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_1[i].type]) * animCurrentValue;
 /*计算下一个节点的坐标值*/
 float nextPointX=mLineXs[i + 1];
 float nextPointY=mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_1[i + 1].type]) * animCurrentValue;
 /*连接当前坐标和下一个坐标，绘制线段*/
 canvas.drawLine(prePointX, prePointY, nextPointX, nextPointY, mPaintLine1);
 /*当前节点坐标处绘制小圆*/
 canvas.drawCircle(prePointX, prePointY, mSmallDotRadius, mPointPaint);
}

两条折线重合的地方，需要特殊考虑，比如希望两条折线重合的地方折线变为白色

设置下两条折线的画笔即可

mPaintLine2.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN));
mPaintLine1.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN));

测试代码及效果;

final Random random=new Random();
final LineChartView myView=(LineChartView)findViewById(R.id.custom_view);
final LineChartView.Performance[] performances1=new LineChartView.Performance[8];
final LineChartView.Performance[] performances2=new LineChartView.Performance[8];
myView.setOnClickListener(new View.OnClickListener(){
 @Override
 public void onClick(View v){
   for(int i=0;i<performances1.length;i++){
     switch (random.nextInt(2016)％3){
       case 0:
         performances1[i]= LineChartView.Performance.WIN;
         break;
       case 1:
         performances1[i]= LineChartView.Performance.DRAW;
         break;
       case 2:
         performances1[i]= LineChartView.Performance.LOSE;
         break;
       default:
         performances1[i]= LineChartView.Performance.LOSE;
         break;
     }
     switch (random.nextInt(2016)％3){
       case 0:
         performances2[i]= LineChartView.Performance.WIN;
         break;
       case 1:
         performances2[i]= LineChartView.Performance.DRAW;
         break;
       case 2:
         performances2[i]= LineChartView.Performance.LOSE;
         break;
       default:
         performances1[i]= LineChartView.Performance.LOSE;
         break;
     }
   }
   myView.setPerformances(performances1,performances2);
 }
});

完整代码如下：

public class LineChartView extends View {
 private Context context;
 /*动画插值器*/
 DecelerateInterpolator mDecelerateInterpolator = new DecelerateInterpolator();
 /*动画刷新的次数*/
 private int mDuration = 10;
 /*当前动画进度值*/
 private int mCurrentTime = 0;
 private Performance[] mPerformance_1, mPerformance_2;
 /*两条折线的颜色*/
 private int mLineColor1, mLineColor2;
 /*绘制表头文字画笔*/
 private Paint mPaintText = new Paint();
 /*绘制表格的画笔*/
 private Paint mPaintLine = new Paint();
 /*第一条折线的画笔*/
 private Paint mPaintLine1 =new Paint();
 /*第二条折线的画笔*/
 private Paint mPaintLine2 =new Paint();
 /*坐标点的小圆点画笔*/
 private Paint mPointPaint = new Paint();
 private float mSmallDotRadius = 4;
 private TypedValue typedValue;
 private int mPaintClolor;
 /*Handler刷新界面产生动画效果*/
 private Handler mHandler = new Handler();
 private Runnable mAnimation = new Runnable() {
   @Override
   public void run() {
     if (mCurrentTime < mDuration) {
       mCurrentTime++;
       LineChartView.this.invalidate();
     }
   }
 };

public LineChartView(Context context) {
   super(context);
   this.context=context;
   init();
 }

public LineChartView(Context context, AttributeSet attrs) {
   super(context, attrs);
   this.context=context;
   init();
 }

public LineChartView(Context context, AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
   this.context=context;
   init();
 }

public enum Performance {
   WIN(0),
   DRAW(1),
   LOSE(2);
   public int type;
   Performance(int type) {
     this.type = type;
   }
 }

public void setPerformances(Performance[] performance1, Performance[] performance2) {
   if (performance1 == null) {
     performance1 = new Performance[0];
   }
   if (performance2 == null) {
     performance2 = new Performance[0];
   }
   mPerformance_1 = Arrays.copyOf(performance1, performance1.length > 8 ? 8 : performance1.length);
   mPerformance_2 = Arrays.copyOf(performance2, performance2.length > 8 ? 8 : performance2.length);
   if (isShown()) {
     mCurrentTime = 0;
     this.invalidate();
   }
 }

/**
  * 设置折线1的颜色
  *
  * @param mLineColor1
  */
 public void setLineColor1(int mLineColor1) {
   this.mLineColor1 = mLineColor1;
 }

/**
  * 设置折线2的颜色
  *
  * @param mLineColor2
  */
 public void setLineColor2(int mLineColor2) {
   this.mLineColor2 = mLineColor2;
 }

private void init() {
   mLineColor1=Color.BLUE;
   mLineColor2 = Color.GREEN;
   typedValue=new TypedValue();
   context.getTheme().resolveAttribute(R.attr.title_bar,typedValue,true);
   mPaintClolor =getResources().getColor(typedValue.resourceId);

final LineChartView.Performance[] performances1=new LineChartView.Performance[8];
   final LineChartView.Performance[] performances2=new LineChartView.Performance[8];
   final Random random=new Random();
   for(int i=0;i<performances1.length;i++){
     switch (random.nextInt(2016)％3){
       case 0:
         performances1[i]= LineChartView.Performance.WIN;
         break;
       case 1:
         performances1[i]= LineChartView.Performance.DRAW;
         break;
       case 2:
         performances1[i]= LineChartView.Performance.LOSE;
         break;
       default:
         performances1[i]= LineChartView.Performance.LOSE;
         break;
     }
     switch (random.nextInt(2016)％3){
       case 0:
         performances2[i]= LineChartView.Performance.WIN;
         break;
       case 1:
         performances2[i]= LineChartView.Performance.DRAW;
         break;
       case 2:
         performances2[i]= LineChartView.Performance.LOSE;
         break;
       default:
         performances1[i]= LineChartView.Performance.LOSE;
         break;
     }
   }
   setPerformances(performances1,performances2);
 }

/**
  * @param canvas
  */
 @Override
 protected void onDraw(Canvas canvas) {
   super.onDraw(canvas);
   /*获取控件总宽高*/
   float totalWidth = getWidth();
   float totalHeight = getHeight();
   /*左边取总宽度的八分之一绘制表格头部*/
   float textWide = totalWidth / 8;
   /*左边留一点空白*/
   float left_offset = 10;
   /*折线图的总宽度等于控件的总宽度减去表头和留白*/
   float chartWide = totalWidth - textWide - left_offset;
   /*一共三行，设置每一行的垂直坐标*/
   float[] mLineYs = new float[]{totalHeight / 8, totalHeight / 2, totalHeight * 7 / 8};
   /*一共八列，设置每一列的水平坐标*/
   float[] mLineXs = new float[]{
       textWide + left_offset + chartWide * 0 / 8,
       textWide + left_offset + chartWide * 1 / 8,
       textWide + left_offset + chartWide * 2 / 8,
       textWide + left_offset + chartWide * 3 / 8,
       textWide + left_offset + chartWide * 4 / 8,
       textWide + left_offset + chartWide * 5 / 8,
       textWide + left_offset + chartWide * 6 / 8,
       textWide + left_offset + chartWide * 7 / 8,
   };

/*绘制表头文字*/
   mPaintText.setStyle(Paint.Style.FILL);
   mPaintText.setColor(mPaintClolor);
   mPaintText.setAlpha(226);
   mPaintText.setTextSize(28);
   /*从中间开始绘制*/
   mPaintText.setTextAlign(Paint.Align.CENTER);
   /*测量文字大小，并计算偏移量*/
   Paint.FontMetrics fontMetrics = mPaintText.getFontMetrics();
   float textBaseLineOffset = (fontMetrics.bottom - fontMetrics.top) / 2 - fontMetrics.bottom;
   canvas.drawText("胜场", textWide / 2, mLineYs[0] + textBaseLineOffset, mPaintText);
   canvas.drawText("平局", textWide / 2, mLineYs[1] + textBaseLineOffset, mPaintText);
   canvas.drawText("负场", textWide / 2, mLineYs[2] + textBaseLineOffset, mPaintText);

/*绘制表格画笔设置*/
   mPaintLine.setStyle(Paint.Style.STROKE);
   mPaintLine.setAntiAlias(true);
   mPaintLine.setColor(mPaintClolor);
   mPaintLine.setAlpha(80);
   mPaintLine.setStrokeWidth(1);
   /*开始绘制表格*/
   /*绘制三条横线*/
   for(int i=0;i<3;i++){
     canvas.drawLine(textWide, mLineYs[i], totalWidth, mLineYs[i], mPaintLine);
   }
   /*绘制八条竖线*/
   for(int i=0;i<8;i++){
     canvas.drawLine(mLineXs[i], 0, mLineXs[i], totalHeight, mPaintLine);
   }
   /*折线图画笔设置*/
   mPaintLine1.setStyle(Paint.Style.STROKE);
   /*设置透明度，取值范围为0~255，数值越小越透明，0表示完全透明*/
   mPaintLine1.setAlpha(0);
   mPaintLine1.setAntiAlias(true);
   mPaintLine1.setColor(mLineColor1);
   mPaintLine1.setStrokeWidth(5);
   mPaintLine2.setStyle(Paint.Style.STROKE);
   /*设置透明度，取值范围为0~255，数值越小越透明，0表示完全透明*/
   mPaintLine2.setAlpha(0);
   mPaintLine2.setAntiAlias(true);
   mPaintLine2.setColor(mLineColor2);
   mPaintLine2.setStrokeWidth(5);
   if (typedValue.resourceId==R.color.white){
     /*PorterDuff.Mode.SCREEN 上下层都显示。*/
     mPaintLine2.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN));
     mPaintLine1.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SCREEN));
   }else {
     /*PorterDuff.Mode.DARKEN 上下层都显示。变暗*/
     mPaintLine2.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DARKEN));
     mPaintLine1.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DARKEN));
   }
   /*画节点处的小圆点的画笔设置*/
   mPointPaint.setStyle(Paint.Style.STROKE);
   mPointPaint.setAntiAlias(true);
   mPointPaint.setColor(mPaintClolor);

/*计算当前动画进度对应的数值*/
   float animCurrentValue = mDecelerateInterpolator.getInterpolation(1.0f * mCurrentTime / mDuration);
   mPaintLine.setColor(mLineColor1);
   /*绘制第一条折线的路径*/
   for (int i = 0; i < mPerformance_1.length - 1; i++) {
     /*折线图的折线的画笔设置粗一点*/
     mPaintLine.setStrokeWidth(5);
     /*计算当前节点的坐标值*/
     float prePointX =mLineXs[i];
     float prePointY =mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_1[i].type]) * animCurrentValue;
     /*计算下一个节点的坐标值*/
     float nextPointX=mLineXs[i + 1];
     float nextPointY=mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_1[i + 1].type]) * animCurrentValue;
     /*连接当前坐标和下一个坐标，绘制线段*/
     canvas.drawLine(prePointX, prePointY, nextPointX, nextPointY, mPaintLine1);
     /*当前节点坐标处绘制小圆*/
     canvas.drawCircle(prePointX, prePointY, mSmallDotRadius, mPointPaint);
   }
   /*第一个折线图的最后一个节点的坐标*/
   float lastPointX=mLineXs[mPerformance_1.length - 1];
   float lastPointY= mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_1[mPerformance_1.length - 1].type]) * animCurrentValue;
   /*绘制最后一个节点的外围小圆*/
   canvas.drawCircle(lastPointX,lastPointY ,mSmallDotRadius, mPointPaint);

/*绘制第二条折线*/
   mPaintLine.setColor(mLineColor2);
   for (int i = 0; i < mPerformance_2.length - 1; i++) {
     /*折线图的折线的画笔设置粗一点*/
     mPaintLine.setStrokeWidth(5);
     /*计算当前节点的坐标值*/
     float prePointX =mLineXs[i];
     float prePointY =mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_2[i].type]) * animCurrentValue;
     /*计算下一个节点的坐标值*/
     float nextPointX=mLineXs[i + 1];
     float nextPointY=mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_2[i + 1].type]) * animCurrentValue;
     /*连接当前坐标和下一个坐标，绘制线段*/
     canvas.drawLine(prePointX, prePointY, nextPointX, nextPointY, mPaintLine2);
     /*当前节点坐标处绘制小圆*/
     canvas.drawCircle(prePointX, prePointY, mSmallDotRadius, mPointPaint);
   }
    /*第一个折线图的最后一个节点的坐标*/
   lastPointX=mLineXs[mPerformance_2.length - 1];
   lastPointY= mLineYs[2] - (mLineYs[2] - mLineYs[mPerformance_2[mPerformance_2.length - 1].type]) * animCurrentValue;
   /*绘制最后一个节点的外围小圆*/
   canvas.drawCircle(lastPointX,lastPointY ,mSmallDotRadius, mPointPaint);
   mHandler.postDelayed(mAnimation, 20);
 }
}

来源：https://blog.csdn.net/wangshihui512/article/details/51445506