设置UIBarButtonItem 导航栏返回键

转自:http://www.cnblogs.com/tongyuling/p/5948276.html

    //左键

//    UIButton *backBtn = [UIButton buttonWithType:UIButtonTypeCustom];

//    backBtn.frame = CGRectMake(0, 6, 40, 23);

//    UIImageView *backImg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"back_dark_icon"]];

//    backImg.frame = CGRectMake(-10, 0, 22, 22); //CGRectMake(-10, 0, 22, 22)

//    [backBtn addSubview:backImg];

//    [backBtn addTarget:self action:@selector(leftButtonBackPage:) forControlEvents:UIControlEventTouchUpInside];

//    UIBarButtonItem *leftButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backBtn];

//    self.navigationItem.leftBarButtonItem = leftButtonItem;

    UIButton * leftBtn = [UIButton buttonWithType:UIButtonTypeSystem];

    leftBtn.frame = CGRectMake(0, 0, 25,25);

    [leftBtn setBackgroundImage:[UIImage imageNamed:@"back_dark_icon"] forState:UIControlStateNormal];

    [leftBtn addTarget:self action:@selector(leftButtonBackPage:) forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem * leftBarBtn = [[UIBarButtonItem alloc]initWithCustomView:leftBtn];;

    UIBarButtonItem * spaceItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];

    //将宽度设为负值

    spaceItem.width = -15;

    //将两个BarButtonItem都返回给NavigationItem

    self.navigationItem.leftBarButtonItems = @[spaceItem,leftBarBtn];