扔物线大神的《Android 开发进阶: 自定义 View 1-

GitHub地址：PracticeDraw1

练习内容1：使用canvas.drawColor()方法把View涂成黄色

canvas.drawColor(Color.YELLOW);

canvas.drawColor()的使用方法汇总：

canvas.drawColor(Color.YELLOW);
canvas.drawColor(Color.parseColor("#00FF00"));
canvas.drawColor(Color.parseColor("#88FF0000"));
canvas.drawRGB(255, 0, 0);
canvas.drawARGB(127, 255, 0, 0);

练习内容2：使用canvas.drawCircle()方法画圆

一共四个圆：1.实心圆2.空心圆3.蓝色实心圆4.线宽为20的空心圆

mPaint.setAntiAlias(true);

canvas.drawCircle(350, 200, 150, mPaint);

mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(4);
canvas.drawCircle(700, 200, 150, mPaint);

mPaint.setColor(Color.BLUE);
mPaint.setStyle(Paint.Style.FILL);
canvas.drawCircle(350, 550, 150, mPaint);

mPaint.setColor(Color.YELLOW);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(50);                   // setStrokeWidth只在STROKE的情况下起作用，FILL情况下不起作用
canvas.drawCircle(700, 550, 150, mPaint);

mPaint.setColor(Color.RED);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(5);
canvas.drawCircle(700, 550, 150, mPaint);

mPaint.reset();

练习内容3：使用canvas.drawRect()方法画矩形

mPaint.setAntiAlias(true);

canvas.drawRect(100, 100, 300, 300, mPaint);

mPaint.setColor(Color.RED);
Rect rect = new Rect(400, 100, 600, 300);
canvas.drawRect(rect, mPaint);

mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(4);
RectF rectF = new RectF(700, 100, 900, 300);
canvas.drawRect(rectF, mPaint);

mPaint.setStyle(Paint.Style.FILL);
mPaint.setColor(Color.GREEN);
canvas.drawRoundRect(100, 400, 300, 600, 50, 50, mPaint);

mPaint.setStyle(Paint.Style.STROKE);
RectF rectF2 = new RectF(400, 400, 600, 600);
canvas.drawRoundRect(rectF2, 50, 80, mPaint);

mPaint.reset();

练习内容4：使用canvas.drawPoint()方法画点

mPaint.setAntiAlias(true);

mPaint.setStrokeWidth(100);
mPaint.setStrokeCap(Paint.Cap.ROUND);
canvas.drawPoint(100, 100, mPaint);

mPaint.setStrokeCap(Paint.Cap.SQUARE);
mPaint.setColor(Color.YELLOW);
canvas.drawPoint(250, 100, mPaint);

mPaint.setStrokeCap(Paint.Cap.BUTT);
mPaint.setColor(Color.RED);
canvas.drawPoint(400, 100, mPaint);

mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setColor(Color.GREEN);
float[] points = {550, 100, 700, 100, 850, 100, 850, 250, 700, 250, 550, 250};
//   canvas.drawPoints(points, mPaint);
canvas.drawPoints(points, 2, 8, mPaint);

mPaint.reset();

练习内容5：使用canvas.drawOval()方法画椭圆

mPaint.setAntiAlias(true);

canvas.drawOval(50, 50, 350, 200, mPaint);

mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(4);
mPaint.setColor(Color.RED);
RectF rectF = new RectF(450, 50, 750, 200);
canvas.drawOval(rectF, mPaint);

mPaint.reset();

练习内容6：使用canvas.drawLine()方法画直线

mPaint.setAntiAlias(true);

mPaint.setStrokeWidth(10);
canvas.drawLine(50, 50, 200, 200, mPaint);

mPaint.setColor(Color.RED);
canvas.drawLine(100, 50, 250, 200, mPaint);

mPaint.setColor(Color.GREEN);
float[] points = {300, 50, 450, 200, 600, 200, 500, 300};
//   canvas.drawLines(points, mPaint);
canvas.drawLines(points, 2, 4, mPaint);

mPaint.reset();

练习内容7：使用canvas.drawRoundRect()方法画圆角矩形

mPaint.setAntiAlias(true);

canvas.drawRoundRect(100, 100, 500, 300, 50, 50, mPaint);

mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(4);
mPaint.setColor(Color.RED);
RectF rectF = new RectF(100, 400, 500, 600);
canvas.drawRoundRect(rectF, 50, 50, mPaint);

mPaint.reset();

练习内容8：使用canvas.drawArc()方法画弧形和扇形

mPaint.setAntiAlias(true);

mPaint.setStyle(Paint.Style.FILL);
canvas.drawArc(200, 100, 800, 500, -110, 100, true, mPaint);
mPaint.setColor(Color.RED);
canvas.drawArc(200, 100, 800, 500, 20, 140, false, mPaint);

mPaint.setStyle(Paint.Style.STROKE);
mPaint.setColor(Color.GREEN);
canvas.drawArc(new RectF(200, 100, 800, 500), 180, 60, false, mPaint);

mPaint.reset();

练习内容9：使用canvas.drawPath()方法画心形

mPaint.setAntiAlias(true);
Path path = new Path();
path.addArc(new RectF(600, 200, 800, 400), -225, 225);
path.arcTo(new RectF(800, 200, 1000, 400), -180, 225, false);
path.lineTo(800, 542);
mPaint.setStyle(Paint.Style.FILL);
canvas.drawPath(path, mPaint);

mPaint.reset();

练习内容10：使用各种Canvas.drawXXX()方法画直方图

mPaint.setAntiAlias(true);

// 画图表坐标轴
Path path = new Path();
path.moveTo(150, 80);
path.lineTo(150, 500);
path.lineTo(900, 500);
mPaint.setColor(Color.WHITE);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(2);
canvas.drawPath(path, mPaint);

// 画矩形
Path path2 = new Path();
path2.addRect(170, 490, 250, 500, Path.Direction.CW);
path2.addRect(270, 430, 350, 500, Path.Direction.CW);
path2.addRect(370, 430, 450, 500, Path.Direction.CW);
path2.addRect(470, 380, 550, 500, Path.Direction.CW);
path2.addRect(570, 350, 650, 500, Path.Direction.CW);
path2.addRect(670, 300, 750, 500, Path.Direction.CW);
path2.addRect(770, 400, 850, 500, Path.Direction.CW);
mPaint.setStyle(Paint.Style.FILL);
mPaint.setColor(Color.parseColor("#72B916"));
canvas.drawPath(path2, mPaint);

// 画文字
mPaint.setColor(Color.WHITE);
mPaint.setTextSize(25);
canvas.drawText("Froyo", 170, 530, mPaint);
canvas.drawText("GB", 290, 530, mPaint);
canvas.drawText("ICS", 390, 530, mPaint);
canvas.drawText("JB", 490, 530, mPaint);
canvas.drawText("KitKat", 580, 530, mPaint);
canvas.drawText("L", 700, 530, mPaint);
canvas.drawText("M", 800, 530, mPaint);

// 画图表文字
mPaint.setTextSize(40);
canvas.drawText("直方图", 450, 650, mPaint);

mPaint.reset();

练习内容11：使用各种Canvas.drawXXX()方法画饼图

mPaint.setAntiAlias(true);

// 画6个扇形
mPaint.setColor(Color.parseColor("#FFC107"));
canvas.drawArc(200, 100, 700, 600, -60, 59, true, mPaint);
mPaint.setColor(Color.parseColor("#9C27B0"));
canvas.drawArc(200, 103, 700, 603, 0, 6, true, mPaint);
mPaint.setColor(Color.parseColor("#9E9E9E"));
canvas.drawArc(200, 106, 700, 606, 8, 6, true, mPaint);
mPaint.setColor(Color.parseColor("#009688"));
canvas.drawArc(200, 109, 700, 609, 16, 45, true, mPaint);
mPaint.setColor(Color.parseColor("#2196F3"));
canvas.drawArc(197, 109, 697, 609, 63, 117, true, mPaint);
mPaint.setColor(Color.parseColor("#F44336"));
canvas.drawArc(190, 95, 690, 595, -180, 120, true, mPaint);
mPaint.setColor(Color.WHITE);
mPaint.setTextSize(40);
canvas.drawText("饼图", 400, 700, mPaint);

mPaint.reset();

最后

扔物线大神的博客地址：HenCoder