前言
这里我给大家几组测试用例可以一试，为啥不好用。
1、限制10个字节，输入2个Emoj之后是8个字节(一个Emoj是4个字节)，此时再输入一个中文，看看结果如何(中文的UTF8占3个字节)
2、限制5个字符,一个Emoj是2个字符,其他都是一个。此时输入两个Emoj，再输入中文，然后中文联想试试。
就目前的情况来说，看了很多资料，并没有一个通用的能限制字符数和字节数的封装。这里全面进行了总结，并进行了封装。欢迎大家下载。
一. 字符限制
1. 错误方法
常见的这种方法是错误的，会导致Emoj表情的截取问题
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if(range.length range.location > textField.text.length)
{
return NO;
}
NSUInteger newLength = [textField.text length] [string length] - range.length;
return newLength <= 5;
}
这种限制方法会导致拼音下出现这种情况，且无法输入.无法输入满5个字符。在emoj表情也有问题
2. 推荐方法
使用rangeOfComposedCharacterSequencesForRange, 防止在range范围内整词被截断
- (void)textFieldDidChange:(UITextField *)textField
{
NSString *toBeString = textField.text;
UITextRange *selectedRange = [textField markedTextRange];
UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
// 没有高亮选择的字，则对已输入的文字进行字数统计和限制,防止中文被截断
if (!position){
if (toBeString.length > _maxLength){
//中文和emoj表情存在问题，需要对此进行处理
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, _maxLength)];
textField.text = [toBeString substringWithRange:rangeRange];
}
}
}
二. 字节限制
1. 限制字节数
在UTF8中，英文和数字是1个字节,汉子是3个字节，emoji是3或者4个字节。这里的难度比上面更大，如果截取失败，极有可能出现乱码。这里我们的做法如下
- (void)textFieldDidChange:(UITextField *)textField
{
NSString *toBeString = textField.text;
//---字节处理
NSInteger bytesCount = strlen([textField.text UTF8String]);
if (bytesCount > _maxBytesLength) {
NSString *content = [textField.text subStrWithUtf8Len:(int)_maxBytesLength];
textField.text = content;
}
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
NSString * inputString = [textField.text stringByReplacingCharactersInRange:range withString:string];
//限制字节数
if ([inputString length] > 0){
NSInteger len = strlen([inputString UTF8String]);
if (len > _maxBytesLength){
return NO;
}
else {
return YES;
}
}
return YES;
}
这里不能只在进行限制，在textFieldDidChange中需要对中文联想做处理才行
三. 放弃键盘
1. 能拿到uitextfield的时候用
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
return [textField resignFirstResponder];
}
2. 点击view消失的时候用
[self.view endEditing:YES];
3. 难以获取的时候用
[[UIApplication sharedApplication] sendAction:@selector(resignFirstResponder) to:nil from:nil forEvent:nil];
或者
[[[UIApplication sharedApplication] keyWindow] endEditing:YES];
4.Tableview点击空白处或者滚动时消失
{
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(fingerTapped:)];
[self.view addGestureRecognizer:singleTap];
}
#pragma mark- 键盘消失
-(void)fingerTapped:(UITapGestureRecognizer *)gestureRecognizer{
[self.view endEditing:YES];
}
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
[self.view endEditing:YES];
}
四. 正则表达式限制
请参考 正则表达式语法表 ,这里我提供了两种表达式给大家参考，一个Int,一个无unsignedInt
-(BOOL) isTextFieldMatchWithRegularExpression:(NSString *)exporession{
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",exporession];
return [predicate evaluateWithObject:self];
}
-(BOOL) isTextFieldIntValue{
return [self isTextFieldMatchWithRegularExpression:@"[-]{0,1}[0-9]*"];
}
-(BOOL) isTextFieldUnsignedIntValue{
return [self isTextFieldMatchWithRegularExpression:@"[0-9] "];
}
五. UITextfield的键盘事件多次回调问题
1.键盘高度遮挡问题
一般出现遮挡的时候我们用以下代码,看看当前textfield是否在键盘下面，在的话算出键盘的顶端和textfield的底部的距离，然后做偏移动画
- (void)keyboardWillShow:(NSNotification *)notification {
NSDictionary *userInfo = [notification userInfo];
NSValue* aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
CGRect keyboardRect = [aValue CGRectValue];
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];
CGFloat keyboardTop = keyboardRect.origin.y;
CGFloat offset = self.normalTextField.frame.size.height self.normalTextField.frame.origin.y - keyboardTop;
NSValue *animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
NSTimeInterval animationDuration;
[animationDurationValue getValue:&animationDuration];
if(offset > 0){
// Animate the resize of the text view's frame in sync with the keyboard's appearance.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:animationDuration];
CGRect rect = CGRectMake(0.0f, -offset,self.view.frame.size.width,self.view.frame.size.height);
self.view.frame = rect;
[UIView commitAnimations];
}
}
1、真机
如果使用了中文输入法，注册的keyboardWillShow会回调两次。第一次是键盘默认高度216，第二次则是加了keyboard的导航栏的高度。
2、模拟器
第一次弹出键盘没有问题
打印userinfo:
(lldb) po userInfo
{
UIKeyboardAnimationCurveUserInfoKey = 7;
UIKeyboardAnimationDurationUserInfoKey = "0.25";
UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {414, 226}}";
UIKeyboardCenterBeginUserInfoKey = "NSPoint: {207, 849}";
UIKeyboardCenterEndUserInfoKey = "NSPoint: {207, 623}";
UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 736}, {414, 226}}";
UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 510}, {414, 226}}";
UIKeyboardIsLocalUserInfoKey = 1;
}
此时我们去按123旁边的小圆球会出现如下的图：
打印userinfo:
(lldb) po userInfo
{
UIKeyboardAnimationCurveUserInfoKey = 7;
UIKeyboardAnimationDurationUserInfoKey = "0.25";
UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {414, 271}}";
UIKeyboardCenterBeginUserInfoKey = "NSPoint: {207, 623}";
UIKeyboardCenterEndUserInfoKey = "NSPoint: {207, 600.5}";
UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 510}, {414, 226}}";
UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 465}, {414, 271}}";
UIKeyboardIsLocalUserInfoKey = 1;
}
键盘被遮挡了。
总结:观察结果,发现了这个规律，打印一下时间,还有一个问题就是，中文键盘第一次启动的时候会回调两次。
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];
所以去掉这句话即可
六. 使用封装的XXTextField
UITextView , UITextfield 中如果有keyboard的时候，需要一个自动弹起事件，以及弹起之后的content的偏移对父view的处理。如果每个页面都实现一次会非常复杂。这里我们介绍一种自动化的处理机制。在此之前，先介绍一下文字处理框架.最后给大家推荐一下我写的 XXTextField ,大家也可以在此基础上自己添加一些正则表达式。
1.解决uiview中的textfield 遮挡问题
_textfieldName.keyboardType = UIKeyboardTypeDefault;
_textfieldName.inputType = XXTextFieldTypeOnlyInt;
_textfieldName.maxLength = 5;
_textfieldPwd.inputType = XXTextFieldTypeForbidEmoj;
#import "XXKeyboardManager.h"
@interface XXCorrectVC ()<XXKeyboardManagerShowHiddenNotificationDelegate>
@end
@implementation XXCorrectVC
- (void)viewDidLoad {
[super viewDidLoad];
[[XXKeyboardManager sharedInstance] setDelegate:self];
// Do any additional setup after loading the view from its nib.
}
#pragma mark- KeyBoardShow/Hidden
- (void)showKeyboardWithRect:(CGRect)keyboardRect
withDuration:(CGFloat)animationDuration
{
CGFloat offset = self.textFieldCorrect.frame.size.height self.textFieldCorrect.frame.origin.y - keyboardRect.origin.y;
if(offset < 0){
return;
}
[UIView animateWithDuration:animationDuration
delay:0.f
options:UIViewAnimationOptionCurveEaseInOut animations:^{
CGRect rect = CGRectMake(0.0f, -offset,self.view.frame.size.width,self.view.frame.size.height);
self.view.frame = rect;
} completion:^(BOOL finished) {
}];
}
- (void)hiddenKeyboardWithRect:(CGRect)keyboardRect
withDuration:(CGFloat)animationDuration
{
[UIView animateWithDuration:animationDuration
delay:0.f
options:UIViewAnimationOptionCurveEaseInOut animations:^{
self.textFieldCorrect.frame = self.view.bounds;
} completion:^(BOOL finished) {
}];
}
@end
2.解决uitableview中键盘遮挡问题
/*
* 键盘要显示的时候
*/
- (void)showKeyboardWithRect:(CGRect)keyboardRect
withDuration:(CGFloat)animationDuration{
CGSize kbSize = keyboardRect.size;
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
_baseTableView.contentInset = contentInsets;
_baseTableView.scrollIndicatorInsets = contentInsets;
// If active text field is hidden by keyboard, scroll it so it's visible
// Your app might not need or want this behavior.
CGRect aRect = self.view.frame;
aRect.size.height -= kbSize.height;
if (!CGRectContainsPoint(aRect, _activeCell.frame.origin) ) {
[_baseTableView scrollRectToVisible:_activeCell.frame animated:YES];
}
}
/*
* 键盘要消失的时候
*/
- (void)hiddenKeyboardWithRect:(CGRect)keyboardRect
withDuration:(CGFloat)animationDuration{
_baseTableView.contentInset = UIEdgeInsetsZero;
_baseTableView.scrollIndicatorInsets = UIEdgeInsetsZero;
}
总结
以上就是这篇文章的全部内容了，希望本文的内容对各位Android开发者们能有所帮助，如果有疑问大家可以留言交流。