矩形
关键元素：左上坐标 和 右下坐标
private void drawRec(Canvas canvas) {
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
float left = 0; float top = 0;
float right = getWidth() / 3;
float buttom = getWidth() / 3;
canvas.drawRect(left, top, right, buttom, paint);
}
圆形
关键元素：圆心坐标 和 半径
private void drawCicle(Canvas canvas) {
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
float cenetrX = getWidth() / 2;
float centerY = getWidth() / 3 / 2;
float radius = getWidth() / 3 / 2;
canvas.drawCircle(cenetrX, centerY, radius, paint);
}
椭圆形或者弧形
关键元素：椭圆容器 ， 起始角度 ， 圆弧角度
注意：这里需要传递一个 RectF 作为椭圆或者弧形的容器
startAngle ： 0度为最右侧
useCenter ： 是否是实心的
private void drawArc(Canvas canvas) {
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);paint.setStrokeWidth(0.1f * getWzidth() / 3);
paint.setStyle(Paint.Style.STROKE);float margin = 0.1f * getWidth() / 3;
float left = 2 * getWidth() / 3 + margin;
float top = 0 + margin;
float right = getWidth() - margin;
float buttom = getWidth() / 3 - margin;
RectF oval = new RectF(left, top, right, buttom);
float startAngle = 270;
float sweepAngle = 285;
boolean useCenter = false;
canvas.drawArc(oval, startAngle, sweepAngle, useCenter, paint);
}
文字
注意：
-
x，y为文字矩形的左下角坐标 - 如果设置
paint.setTextAlign(Paint.Align.CENTER);则x为文字中心的坐标，y不变
canvas.drawText("绘制文字", x, y, paint);
