Android 画笔的使用

private class MyView2 extends View {


        public MyView2(Context context) {


            super(context);


        }


        @Override
        protected void onDraw(Canvas canvas)


        {


            super.onDraw(canvas);


            canvas.drawColor(Color.WHITE);


            Paint paint = new Paint();


            paint.setAntiAlias(true);


            paint.setColor(Color.RED);


            paint.setStyle(Paint.Style.STROKE);//设置为空心


            paint.setStrokeWidth(3);


            canvas.drawCircle(40, 40, 30, paint);


            canvas.drawRect(10, 90, 70, 150, paint);


            canvas.drawRect(10, 170, 70, 200, paint);


            canvas.drawOval(new RectF(10, 220, 70, 250), paint);


            Path path = new Path();//三角形


            path.moveTo(10, 330);


            path.lineTo(70, 330);


            path.lineTo(40, 270);


            path.close();


            canvas.drawPath(path, paint);


            Path path1 = new Path();//梯形


            path1.moveTo(10, 410);//绘画基点


            path1.lineTo(70, 410);


            path1.lineTo(55, 350);


            path1.lineTo(25, 350);


            path1.close();//把开始的点和最后的点连接在一起，构成一个封闭图形
            /*
             * 最重要的就是movtTo和close,如果是Style.FILL的话，不设置close,也没有区别，可是如果是STROKE模式，
             * 如果不设置close,图形不封闭。
             * 
             * 当然，你也可以不设置close，再添加一条线，效果一样。
             */
            canvas.drawPath(path1, paint);
            
            
            
            
            ///第二列


            paint.setColor(Color.BLUE);


            paint.setStyle(Paint.Style.FILL);//设置实心


            canvas.drawCircle(120, 40, 30, paint);


            canvas.drawRect(90, 90, 150, 150, paint);


            canvas.drawRect(90, 170, 150, 200, paint);


            RectF re2 = new RectF(90, 220, 150, 250);


            canvas.drawOval(re2, paint);


            Path path2 = new Path();


            path2.moveTo(90, 330);


            path2.lineTo(150, 330);


            path2.lineTo(120, 270);


            path2.close();


            canvas.drawPath(path2, paint);


            Path path3 = new Path();


            path3.moveTo(90, 410);


            path3.lineTo(150, 410);


            path3.lineTo(135, 350);


            path3.lineTo(105, 350);


            path3.close();


            canvas.drawPath(path3, paint);
            
            
            第三列
            
            /*
             * LinearGradient shader = new LinearGradient(0, 0, endX, endY, new
             * int[]{startColor, midleColor, endColor},new float[]{0 , 0.5f,
             * 1.0f}, TileMode.MIRROR);
             * 参数一为渐变起初点坐标x位置，参数二为y轴位置，参数三和四分辨对应渐变终点
             * 其中参数new int[]{startColor, midleColor,endColor}是参与渐变效果的颜色集合， 
             * 其中参数new float[]{0 , 0.5f, 1.0f}是定义每个颜色处于的渐变相对位置， 这个参数可以为null，如果为null表示所有的颜色按顺序均匀的分布
             */
            Shader mShader = new LinearGradient(0, 0, 100, 100,


            new int[] { Color.RED, Color.GREEN, Color.BLUE, Color.YELLOW },


            null, Shader.TileMode.REPEAT);


            // Shader.TileMode三种模式


            // REPEAT:沿着渐变方向循环重复


            // CLAMP:如果在预先定义的范围外画的话，就重复边界的颜色


            // MIRROR:与REPEAT一样都是循环重复，但这个会对称重复


            paint.setShader(mShader);// 用Shader中定义定义的颜色来话


            canvas.drawCircle(200, 40, 30, paint);


            canvas.drawRect(170, 90, 230, 150, paint);


            canvas.drawRect(170, 170, 230, 200, paint);


            RectF re3 = new RectF(170, 220, 230, 250);


            canvas.drawOval(re3, paint);


            Path path4 = new Path();


            path4.moveTo(170, 330);


            path4.lineTo(230, 330);


            path4.lineTo(200, 270);


            path4.close();


            canvas.drawPath(path4, paint);


            Path path5 = new Path();


            path5.moveTo(170, 410);


            path5.lineTo(230, 410);


            path5.lineTo(215, 350);


            path5.lineTo(185, 350);


            path5.close();


            canvas.drawPath(path5, paint);
            
            //第4列


            paint.setTextSize(24);


            canvas.drawText("圆形", 240, 50, paint);


            canvas.drawText("正方形", 240, 120, paint);


            canvas.drawText("长方形", 240, 190, paint);


            canvas.drawText("椭圆形", 240, 250, paint);


            canvas.drawText("三角形", 240, 320, paint);


            canvas.drawText("梯形", 240, 390, paint);


        }


    }