如图：
WX20230330-111130@2x.png
需要在页面首次加载时候显示，提醒一下用户，后面加载就不需要展示了
这个框是画出来的，单独创建一个继承自UIView的类，下面是代码
一、
#import <CoreGraphics/CoreGraphics.h>
二、
- (void)drawRect:(CGRect)rect {
CGRect frame = rect;
frame.size.height = frame.size.height - 20;
rect = frame;
//绘制带箭头的框框
[self drawArrowRectangle:rect];
}
- (void)drawArrowRectangle:(CGRect) frame {
CGFloat corners = 8.0;
// 获取当前图形，视图推入堆栈的图形，相当于你所要绘制图形的图纸
CGContextRef ctx = UIGraphicsGetCurrentContext();
// 创建一个新的空图形路径。
CGContextBeginPath(ctx);
//启始位置坐标x，y
CGFloat origin_x = frame.origin.x;
CGFloat origin_y = frame.origin.y;
//第一条线的位置坐标(上面横线)
CGFloat line_1_x = frame.size.width;
CGFloat line_1_y = origin_y;
//第二条线的位置坐标（右边竖线）
CGFloat line_2_x = line_1_x;
CGFloat line_2_y = frame.size.height;
//第三条线的位置坐标（底部从右向左的横线，尖角右侧）
CGFloat line_3_x = origin_x + frame.size.width/2+5;//20;
CGFloat line_3_y = line_2_y;
//尖角的顶点位置坐标（尖角右边线）
CGFloat line_4_x = line_3_x - 5;
CGFloat line_4_y = line_3_y + 10;
//第五条线位置坐标（尖角左边线）
CGFloat line_5_x = line_4_x - 5;
CGFloat line_5_y = line_3_y;
//第六条线位置坐标（底部从右向左的横线，尖角左侧）
CGFloat line_6_x = origin_x;
CGFloat line_6_y = line_2_y;
//连接到画笔起始点
CGContextMoveToPoint(ctx, origin_x, origin_y);
CGContextAddArcToPoint(ctx, line_1_x, line_1_y, line_1_x, line_2_y, corners);
CGContextAddLineToPoint(ctx, line_1_x, line_1_y);
CGContextAddArcToPoint(ctx, line_2_x, line_2_y, line_3_x, line_3_y, corners);
CGContextAddLineToPoint(ctx, line_2_x, line_2_y);
CGContextAddLineToPoint(ctx, line_3_x, line_3_y);
CGContextAddLineToPoint(ctx, line_4_x, line_4_y);
CGContextAddLineToPoint(ctx, line_5_x, line_5_y);
CGContextAddArcToPoint(ctx, line_6_x, line_6_y, origin_x, origin_y, corners);
CGContextAddLineToPoint(ctx, line_6_x, line_6_y);
CGContextAddArcToPoint(ctx, origin_x, origin_y, line_1_x, line_1_y, corners);
CGContextClosePath(ctx);
UIColor *costomColor = [[UIColor blackColor] colorWithAlphaComponent:0.7];
CGContextSetFillColorWithColor(ctx, costomColor.CGColor);
CGContextFillPath(ctx);
}
三、只第一次加载页面显示，通过NSUserDefaults来实现
