首页 > 其他分享> 文章详细

Android 自定义View-Canvas

2021-04-07 23:59:04 阅读：298 来源： 互联网

标签：Canvas 自定义 Paint onDraw canvas paint 100 绘制 Android

文章目录

Canvas的使用

Canvas的使用

Paint简单介绍

画笔，用于绘制内容的具体效果，如：颜色、文字大小、线条粗细、阴影，实心空心等。

常用API

Paint.setStyle(Style style) 设置绘制模式
Style 具体来说有三种： FILL, STROKE 和 FILL_AND_STROKE 。FILL 是填充模式，STROKE 是画线模式（即勾边模式


Paint.setColor(int color) 设置颜色
Paint.setStrokeWidth(float width) 设置线条宽度
Paint.setTextSize(float textSize) 设置文字大小
Paint.setAntiAlias(boolean aa) 设置抗锯齿开关

Canvas绘制

drawColor 绘制颜色

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //canvas.drawColor(Color.GREEN);
    //canvas.drawColor(Color.parseColor("#88880000"));
    canvas.drawRGB(100, 200, 100);
    //canvas.drawARGB(100, 100, 200, 100);
}

drawCircle 绘制圆形

private void init() {
    paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setColor(Color.RED);
}

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStyle(Paint.Style.FILL);
    //圆心坐标，半径，画笔
    canvas.drawCircle(110, 110, 100, paint);

    paint.setStrokeWidth(10);
    paint.setStyle(Paint.Style.STROKE);
    canvas.drawCircle(110, 320, 100, paint);
}

drawRect 绘制矩形

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStyle(Paint.Style.FILL);
    //左上右下四个顶点坐标，画笔
    canvas.drawRect(100, 100, 200, 200, paint);

    paint.setStrokeWidth(10);
    paint.setStyle(Paint.Style.STROKE);
    canvas.drawRect(100, 250, 200, 350, paint);
}

drawRoundRect 绘制圆角矩形

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStyle(Paint.Style.FILL);
    //左上右下四个顶点，圆角半径
    canvas.drawRoundRect(100, 100, 500, 300, 50, 50, paint);

    paint.setStrokeWidth(10);
    paint.setStyle(Paint.Style.STROKE);
    canvas.drawRoundRect(100, 400, 500, 600, 50, 50, paint);
}

drawPoint 绘制点

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStrokeWidth(20);
    //点的样式
    paint.setStrokeCap(Paint.Cap.ROUND);
    //点的坐标，画笔
    canvas.drawPoint(100, 100, paint);

    paint.setStrokeWidth(20);
    paint.setStrokeCap(Paint.Cap.SQUARE);
    canvas.drawPoint(150, 150, paint);
}

drawPoints 绘制多个点

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStrokeWidth(20);
    paint.setStrokeCap(Paint.Cap.ROUND);
    float[] points = {10, 10, 50, 50, 100, 100, 150, 150, 200, 200};
    //所有点坐标，跳过前几个，一共绘制8个数（4个点）
    canvas.drawPoints(points, 2, 8, paint);
}

drawOval 绘制椭圆

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStyle(Paint.Style.FILL);
    //左上右下四个坐标
    canvas.drawOval(50, 100, 250, 250, paint);

    paint.setStyle(Paint.Style.STROKE);
    canvas.drawOval(50, 300, 250, 450, paint);
}

drawArc 绘制弧线或扇形

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //左上右下四个顶点
    RectF rectF = new RectF(100F, 100F, 400F, 300F);
    //设置填充模式
    paint.setStyle(Paint.Style.FILL);
    //startAngle：弧形开始角度，sweepAngle：弧形划过角度
    //useCenter：是否连接圆心
    canvas.drawArc(rectF, -100, 100, true, paint);
    canvas.drawArc(rectF, 30, 90, false, paint);
    paint.setStyle(Paint.Style.STROKE);
    canvas.drawArc(rectF, 130, 50, false, paint);
}

drawLine 绘制线

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStrokeWidth(20);
    canvas.drawLine(200, 200, 500, 500, paint);
}

drawLines 绘制多条线

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setStrokeWidth(5);
    float[] points = {20, 20, 120, 20, 70, 20, 70, 100, 20, 100, 120, 100};
    canvas.drawLines(points, paint);
}

drawBitmap 绘制Bitmap

canvas.drawBitmap(bitmap, 200, 200, new Paint());

drawText 绘制文本

protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    paint.setTextSize(30);
    canvas.drawText("hello", 100, 100, paint);
}

代码下载

标签：Canvas,自定义,Paint,onDraw,canvas,paint,100,绘制,Android
来源： https://blog.csdn.net/qq_14876133/article/details/115499341

本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享；
2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关；
3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关；
4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除；
5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。

ICode9