ios11 UISearchBar占位字和图片不居中问题
创建MySearchBar继承UISearchBar
@interface MySearchBar () <UITextFieldDelegate>
// placeholder 和icon 和 间隙的整体宽度
@property (nonatomic, assign) CGFloat placeholderWidth;
@end
static CGFloat const searchIconW = 20.0;
// icon与placeholder间距
static CGFloat const iconSpacing = 10.0;
// 占位文字的字体大小
static CGFloat const placeHolderFont = 15.0;
@implementation MySearchBar
- (void)layoutSubviews {
[super layoutSubviews];
// 设置背景图片
UIImage *backImage = [UIImage imageWithColor:[UIColor colorWithRed:239/255.0 green:239/255.0 blue:244/255.0 alpha:1]];
[self setBackgroundImage:backImage];
for (UIView *view in [self.subviews lastObject].subviews) {
if ([view isKindOfClass:[UITextField class]]) {
UITextField *field = (UITextField *)view;
// 重设field的frame
field.frame = CGRectMake(15.0, 7.5, self.frame.size.width-30.0, self.frame.size.height-15.0);
[field setBackgroundColor:[UIColor whiteColor]];
field.textColor = [UIColor colorWithRed:51/255.0 green:51/255.0 blue:51/255.0 alpha:1];
field.borderStyle = UITextBorderStyleNone;
field.layer.cornerRadius = 2.0f;
field.layer.masksToBounds = YES;
// 设置占位文字字体颜色
[field setValue:[UIColor colorWithRed:156/255.0 green:156/255.0 blue:156/255.0 alpha:1] forKeyPath:@"_placeholderLabel.textColor"];
[field setValue:[UIFont systemFontOfSize:placeHolderFont] forKeyPath:@"_placeholderLabel.font"];
if (@available(iOS 11.0, *)) {
// 先默认居中placeholder
[self setPositionAdjustment:UIOffsetMake((field.frame.size.width-self.placeholderWidth)/2, 0) forSearchBarIcon:UISearchBarIconSearch];
}
}
}
}
// 开始编辑的时候重置为靠左
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
// 继续传递代理方法
if ([self.delegate respondsToSelector:@selector(searchBarShouldBeginEditing:)]) {
[self.delegate searchBarShouldBeginEditing:self];
}
if (@available(iOS 11.0, *)) {
[self setPositionAdjustment:UIOffsetZero forSearchBarIcon:UISearchBarIconSearch];
}
return YES;
}
// 结束编辑的时候设置为居中
- (BOOL)textFieldShouldEndEditing:(UITextField *)textField {
if ([self.delegate respondsToSelector:@selector(searchBarShouldEndEditing:)]) {
[self.delegate searchBarShouldEndEditing:self];
}
if (@available(iOS 11.0, *)) {
[self setPositionAdjustment:UIOffsetMake((textField.frame.size.width-self.placeholderWidth)/2, 0) forSearchBarIcon:UISearchBarIconSearch];
}
return YES;
}
// 计算placeholder、icon、icon和placeholder间距的总宽度
- (CGFloat)placeholderWidth {
if (!_placeholderWidth) {
CGSize size = [self.placeholder boundingRectWithSize:CGSizeMake(MAXFLOAT, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:placeHolderFont]} context:nil].size;
_placeholderWidth = size.width + iconSpacing + searchIconW;
}
return _placeholderWidth;
}
@end