TranslucentToolbar.h文件

#import <UIKit/UIKit.h>

@interface TranslucentToolbar :
UIToolbar

@end

TranslucentToolbar.m文件

#import "TranslucentToolbar.h"

@implementation TranslucentToolbar

- (id)initWithFrame:(CGRect)aRect {

if ((self = [super
initWithFrame:aRect])) {

self.opaque =
NO;

self.backgroundColor = [UIColor
colorWithRed:34.0/255.0
green:39.0/255.0
blue:42.0/255.0
alpha:0.8];

self.clearsContextBeforeDrawing =
YES;

}

return
self;

}

- (void)drawRect:(CGRect)rect

{

// Drawing code

}

@end

在须要创建的地方使用子类化的UIToolbar：

_bottomBar =[[TranslucentToolbar
alloc] initWithFrame:CGRectMake(0, height-botH, width, botH)];