【iOS】iOS13 UISearchbar适配之路

最大的坑还是iOS13系统不让 KVC 的方式来取或修改一些私有属性，目前是遇到 UISearchBar 的坑，其他还在测试中。

crash修复

2019.06.04 下载了Xcode_11_Beta，跑起来项目后，直接crash。

原本 searchbar 的样子：

生成 UISearchBar 的代码:

- (void)initSearchBar
{
    _searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 0, kSearchBarHeight)];
    self.searchBar.delegate = self;
    self.searchBar.enablesReturnKeyAutomatically = NO;
    self.searchBar.layer.masksToBounds = YES;
    self.searchBar.layer.cornerRadius = kSearchBarHeight / 2;
    self.searchBar.backgroundColor = [UIColor colorWithRGBHex:0xF1F3F6];
    
    // 设置bar的前景色(背景色), 不要使用backgroundColor, 表现不出来
    self.searchBar.barTintColor = [UIColor colorWithRGBHex:0xF1F3F6];
    
    // 设置字体颜色、默认字体颜色
    UITextField *textField = [self.searchBar valueForKey:@"_searchField"];
    textField.backgroundColor = [UIColor colorWithRGBHex:0xF1F3F6];
    textField.textColor = [UIColor colorWithRGBHex:0x000000 alpha:0.85];
    [textField setValue:[UIColor colorWithRGBHex:0x000000 alpha:0.35] forKeyPath:@"_placeholderLabel.textColor"];
    textField.font = [UIFont systemFontOfSize:14.0];

    // 修改放大镜
    UIImage *image = LOAD_DEFAULT_ICON_USE_POOL(@"search_custom_bar_search_icon.png");
    [self.searchBar setImage:image forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
    // 放大镜往左移一点，也得往下一点
    [self.searchBar setPositionAdjustment:UIOffsetMake(-5, 1) forSearchBarIcon:UISearchBarIconSearch];
    // 删除按钮往右移一点
    [self.searchBar setPositionAdjustment:UIOffsetMake(7, 0) forSearchBarIcon:UISearchBarIconClear];
    
    // 方法镜图片的大小是24px，结果系统给放大了，所以这里重设一下，这里设置的y不影响，系统会重新对y居中。
    textField.leftView.frame = CGRectMake(textField.leftView.left, textField.leftView.top, image.size.width, image.size.height);
    
    [self addSubview:self.searchBar];
}

crash原因：

1	*** Terminating app due to uncaught exception 'NSGenericException', reason: 'Access to UISearchBar's _searchField ivar is prohibited. This is an application bug'

问题代码：

1	UITextField *textField = [self.searchBar valueForKey:@"_searchField"];

看来iOS13不允许用 valueForKey 来取私有属性。那就改成遍历取值：

1	UITextField textField = (UITextField)[self.searchBar findSubview:@"UITextField" resursion:YES];

findSubview:resursion 是 UIView 的自定义分类实现的方法，实现为：

- (UIView *)findSubview:(NSString *)name resursion:(BOOL)resursion
{
    Class class = NSClassFromString(name);
    for (UIView *subview in self.subviews) {
        if ([subview isKindOfClass:class]) {
            return subview;
        }
    }
	
    if (resursion) {
        for (UIView *subview in self.subviews) {
            UIView *tempView = [subview findSubview:name resursion:resursion];
            if (tempView) {
                return tempView;
            }
        }
    }
	
    return nil;
}

然后再跑，接着crash。

1	*** Terminating app due to uncaught exception 'NSGenericException', reason: 'Access to UITextField's _placeholderLabel ivar is prohibited. This is an application bug'

1	[textField setValue:[UIColor colorWithRGBHex:0x000000 alpha:0.35] forKeyPath:@"_placeholderLabel.textColor"];

给 textField 设置 placeholder 字体颜色也不行了，这就很尴尬。

原本设置placeholder的方法：

- (void)setPlaceholderStr:(NSString *)placeholderStr
{
    _placeholderStr = [placeholderStr copy];
    _searchBar.placeholder = _placeholderStr;
}

只好改为设置 UITextField 的 @property(nullable, nonatomic,copy) NSAttributedString *attributedPlaceholder API_AVAILABLE(ios(6.0)); // default is nil 属性。

- (void)setPlaceholderStr:(NSString *)placeholderStr
{
    _placeholderStr = [placeholderStr copy];
    if (_placeholderStr.length > 0)
    {
        NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:_placeholderStr];
        [attributedString setAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:kSearchBarFontSize], NSForegroundColorAttributeName:[UIColor colorWithRGBHex:0x000000 alpha:0.35]} range:NSMakeRange(0, _placeholderStr.length)];
        UITextField *textField = (UITextField*)[self.searchBar findSubview:@"UITextField" resursion:YES];
        textField.attributedPlaceholder = attributedString;
    }
    
}

至此，crash修复了。

背景色重叠问题

但是searchBar的背景色又出了问题。

看了下层级是 _UISearchBarSearchFieldBackgroundView ，尝试这个方案：

1 2	UIView textFieldBackgroundView = (UIView )[self.searchBar findSubview:@"_UISearchBarSearchFieldBackgroundView" resursion:YES]; [textFieldBackgroundView removeFromSuperview];

失败。取出来是nil。尝试另一种方案：

for (UIView *view in self.searchBar.subviews) {
    if ([view isKindOfClass:NSClassFromString(@"UIView")] && view.subviews.count > 0) {
        [[view.subviews objectAtIndex:0] removeFromSuperview];
        break;
    }
}

干是干掉了，但是直接crash了：

1	*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Missing or detached view for search bar layout'

看来干掉后系统布局找不到这个view就挂了。

最后在layoutUI 布局的方法里面设置一下image

- (void)layoutUI
{
    // ...上面计算searchBar宽度代码省略
    [self.searchBar setSearchFieldBackgroundImage:[UIImage imageWithColor:[UIColor colorWithRGBHex:0x000000 alpha:0] size:CGSizeMake(self.searchBar.width, self.searchBar.height)] forState:UIControlStateNormal];
}

但这就出现了以前遇到的问题，searchbar的背景色通过设置 self.searchBar.barTintColor 来搞定的。但这样上下就会有条黑线：

改成设置backgroundImage。

1	[self.searchBar setBackgroundImage:[UIImage imageWithColor:[UIColor colorWithRGBHex:0xF1F3F6]]];

最后代码整体改为：

- (void)initSearchBar
{
    _searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 0, kSearchBarHeight)];
    self.searchBar.delegate = self;
    self.searchBar.enablesReturnKeyAutomatically = NO;
    self.searchBar.layer.masksToBounds = YES;
    self.searchBar.layer.cornerRadius = kSearchBarHeight / 2;
    
    // 不要设置 self.searchBar.barTintColor ，上下会有黑线，直接 setBackgroundImage
    [self.searchBar setBackgroundImage:[UIImage imageWithColor:[UIColor colorWithRGBHex:0xF1F3F6]]];

    // 设置字体颜色、默认字体颜色
    UITextField *textField = (UITextField*)[self.searchBar findSubview:@"UITextField" resursion:YES];
    textField.textColor = [UIColor colorWithRGBHex:0x000000 alpha:0.85];
    textField.font = [UIFont systemFontOfSize:kSearchBarFontSize];

    // 修改放大镜
    UIImage *image = LOAD_DEFAULT_ICON_USE_POOL(@"search_custom_bar_search_icon.png");
    [self.searchBar setImage:image forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
    // 放大镜往左移一点，也得往下一点
    [self.searchBar setPositionAdjustment:UIOffsetMake(-5, 1) forSearchBarIcon:UISearchBarIconSearch];
    // 删除按钮往右移一点
    [self.searchBar setPositionAdjustment:UIOffsetMake(7, 0) forSearchBarIcon:UISearchBarIconClear];
    
    // 方法镜图片的大小是24px，结果系统给放大了，所以这里重设一下，这里设置的y不影响，系统会重新对y居中。
    textField.leftView.frame = CGRectMake(textField.leftView.left, textField.leftView.top, image.size.width, image.size.height);
    
    [self addSubview:self.searchBar];
}

- (void)setPlaceholderStr:(NSString *)placeholderStr
{
    _placeholderStr = [placeholderStr copy];
    if (_placeholderStr.length > 0)
    {
        // iOS13不能KVC设置颜色了，所以不能直接设置 self.searchBar.placeholder = _placeholderStr; 。需要通过下面方式来设置颜色
        NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:_placeholderStr];
        [attributedString setAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:kSearchBarFontSize], NSForegroundColorAttributeName:[UIColor colorWithRGBHex:0x000000 alpha:0.35]} range:NSMakeRange(0, _placeholderStr.length)];
        UITextField *textField = (UITextField*)[self.searchBar findSubview:@"UITextField" resursion:YES];
        textField.attributedPlaceholder = attributedString;
    }
    
}

- (void)layoutUI
{
    // ...上面计算searchBar宽度代码省略
    [self.searchBar setSearchFieldBackgroundImage:[UIImage imageWithColor:[UIColor colorWithRGBHex:0x000000 alpha:0] size:CGSizeMake(self.searchBar.width, self.searchBar.height)] forState:UIControlStateNormal];
}

适配结束。

总结

最大的坑还是iOS13系统不让 KVC 的方式来取或修改一些私有属性，目前是遇到 UISearchBar 的坑，其他还在测试中。
UISearchBar 的背景色，内部 UITextField 的背景色，这几个设置起来都是组合比较多，坑也比较多。