使用UIToolbar的坑

今天下午要做一个需求，点击缴费，弹出一个自定义alterViewController,最后效果如图如下图

Snip20170103_3.png

实现的主要思路是创建一个继承在UIAlertController的自定义类，并将一个自定义Picker添加到上面，点击对号获取选中的值，带回到上一个页面，传值得方式有很多，这里用Block。

碰到的坑：

Snip20170103_2.png

从图中可以看到，我为这个alterVC添加了一个ToolBar，直接创建UIBarButtonSystemItemCancel和UIBarButtonSystemItemDone这两个样式的按钮title竟然无法显示。如图：

//只是创建ToolBar的核心代码
    self.toolbar = [[UIToolbar alloc] init];
    self.toolbar.clipsToBounds = YES;
    [self.view addSubview:self.toolbar];
    
    UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(pickerCancel:)];
    UIBarButtonItem *doneButton =[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(pickerDone:)];
    UIBarButtonItem *flexibleButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    self.titleButton = [[UIBarButtonItem alloc] initWithTitle:self.pickerTitle style:UIBarButtonItemStylePlain target:nil action:nil];
    self.titleButton.tintColor = [UIColor blackColor];

    [self.toolbar setItems:@[cancelButton,flexibleButton,self.titleButton,flexibleButton,doneButton]];

从代码中可以看到toolBar上放置了5个控件，分别是cancelButton，flexibleButton，self.titleButton，flexibleButton，doneButton。flexibleButton为空白按钮，作用是让后面的空间往右移动，从而使self.titleButton正好居中，doneButton正好在最右侧，我为按钮设置tintcolor也依然没法显示文字。

折中的解决方案

给自定义的UIButton设置图片或者文字图片，然后将UIButton转为UIBarButtonItem，在添加到UIToolBar上。代码如下：

    UIToolbar * topView = [[UIToolbar alloc]initWithFrame:CGRectMake(10, 0,   self.view.frame.size.width-40, 40)];
    [topView setBarStyle:UIBarStyleDefault];
    
    //占位空白按钮
    UIBarButtonItem * btnSpace = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil];
    
    //取消按钮
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    btn.frame = CGRectMake(0, 5, 30, 30);
    [btn addTarget:self action:@selector(pickerCancel:) forControlEvents:UIControlEventTouchUpInside];
    [btn setImage:[UIImage imageNamed:@"error"] forState:UIControlStateNormal];
    UIBarButtonItem *cancelBtn = [[UIBarButtonItem alloc]initWithCustomView:btn];
    
    //完成按钮
    UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeCustom];
    btn2.frame = CGRectMake(0, 5, 30, 30);
    [btn2 addTarget:self action:@selector(pickerDone:) forControlEvents:UIControlEventTouchUpInside];
    [btn2 setImage:[UIImage imageNamed:@"right"] forState:UIControlStateNormal];
    UIBarButtonItem *doneBtn = [[UIBarButtonItem alloc]initWithCustomView:btn2];
    
    self.titleButton = [[UIBarButtonItem alloc] initWithTitle:self.pickerTitle style:UIBarButtonItemStylePlain target:nil action:nil];
    self.titleButton.tintColor = [UIColor blackColor];
    
    NSArray * buttonsArray = [NSArray arrayWithObjects:cancelBtn,btnSpace,self.titleButton,btnSpace,doneBtn,nil];
    [topView setItems:buttonsArray];
    [self.view addSubview:topView];

效果：

2017-01-03 21_40_36.gif