UITextField from enterBackground to enterForeground,app crash - ios

Question

custom UITextField: In the click TextField input,After the keyborad popup,enter the background to get enter foreground again,The app crash!
if you don't click TextField input,background or foreground conversion ,It is normal;Part of the code:
#implementatio BKSearchViewController
- (void)setNavgationView {
BKSearchBar *searchBar = [[BKSearchBar alloc] initWithFrame:CGRectMake(20, 27, kScreenWidth - 90, 30)];
searchBar.placeholder = #"输入昵称/拜托号";
searchBar.delegate = self;
[searchBar setKeyboardType:UIKeyboardTypeDefault];
[searchBar setReturnKeyType:UIReturnKeySearch];
[searchBar setPlaceholderColor:kcallColor(#"a4a4a4")];
[searchBar setPlaceholderFont:kFont(14)];
[searchBar addTarget:self action:#selector(SearchTextFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
[navgationView addSubview:searchBar];
}
#end
//BKSearchBar The key code
#implementation BKSearchBar
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// 设置背景
self.backgroundColor = kcallColor(#"7d1d57");
self.returnKeyType = UIReturnKeySearch;
// 设置内容 -- 垂直居中
self.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
[self UI];
}
return self;
}
- (void)UI{
// 设置左边显示一个放大镜
UIImageView *leftView = [[UIImageView alloc] init];
omit...
//右边的view
UIImageView *rightView = [[UIImageView alloc] init];
omit...
}
- (CGRect)placeholderRectForBounds:(CGRect)bounds{
CGRect rect = CGRectMake(self.leftView.right, (self.height - 24) / 2, bounds.size.width, 14);
return rect;
}
- (void)clearText{
self.text = nil;
}
- (void)setPlaceholderColor:(UIColor *)color{
[self setValue:color forKeyPath:#"_placeholderLabel.textColor"];
}
- (void)setPlaceholderFont:(UIFont *)font{
[self setValue:font forKeyPath:#"_placeholderLabel.font"];
}

Answer 1

Thank all！The problem is resolved！because of the runtime！
+ (void)swizzleInstanceMethod:(Class)class originSelector:(SEL)originSelector otherSelector:(SEL)otherSelector
{
Method otherMehtod = class_getInstanceMethod(class, otherSelector);
Method originMehtod = class_getInstanceMethod(class, originSelector);
// 交换2个方法的实现
method_exchangeImplementations(otherMehtod, originMehtod);
}