在发送网络请求时，由于用户输入了emoji表情，服务端返回错误提示信息。为了解决服务器不能验证emoji编码的问题，需要在本地进行emoji的输入控制（正常情况下应该由服务器在数据库中添加emoji对应的转码表以支持客户端发送emoji表情），在网上搜了下iOS端解决办法如下：
1.当用户切换键盘为Emoji表情时，输入的表情不响应（即表情符号不显示到UITextView或UITextField）。这里可以通过UITextView或UITextField的回调和是否为emoji键盘：
[[[textView textInputMode] primaryLanguage] isEqualToString:@"emoji"]
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
//不支持系统表情的输入
if ([[[UITextInputMode currentInputMode ]primaryLanguage] isEqualToString:@"emoji"]) {
return NO;
}
return YES;
}
2.通过过滤用户输入的emoji来实现
//过滤表情
+ (NSString *)filterEmoji:(NSString *)string {
NSUInteger len = [string lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
const char *utf8 = [string UTF8String];
char *newUTF8 = malloc( sizeof(char) * len );
int j = 0;
//0xF0(4) 0xE2(3) 0xE3(3) 0xC2(2) 0x30---0x39(4)
for ( int i = 0; i < len; i++ ) {
unsigned int c = utf8;
BOOL isControlChar = NO;
if ( c == 4294967280 ||
c == 4294967089 ||
c == 4294967090 ||
c == 4294967091 ||
c == 4294967092 ||
c == 4294967093 ||
c == 4294967094 ||
c == 4294967095 ||
c == 4294967096 ||
c == 4294967097 ||
c == 4294967088 ) {
i = i + 3;
isControlChar = YES;
}
if ( c == 4294967266 || c == 4294967267 ) {
i = i + 2;
isControlChar = YES;
}
if ( c == 4294967234 ) {
i = i + 1;
isControlChar = YES;
}
if ( !isControlChar ) {
newUTF8[j] = utf8;
j++;
}
}
newUTF8[j] = '\0';
NSString *encrypted = [NSString stringWithCString:(const char*)newUTF8
encoding:NSUTF8StringEncoding];
free( newUTF8 );
return encrypted;
}
3.通过判断用户输入的字符串时候含有表情来进行对应的操作
+ (NSString *)filterEmoji:(NSString *)string {
NSUInteger len = [string lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
const char *utf8 = [string UTF8String];
char *newUTF8 = malloc( sizeof(char) * len );
int j = 0;
//0xF0(4) 0xE2(3) 0xE3(3) 0xC2(2) 0x30---0x39(4)
for ( int i = 0; i < len; i++ ) {
unsigned int c = utf8;
BOOL isControlChar = NO;
if ( c == 4294967280 ||
c == 4294967089 ||
c == 4294967090 ||
c == 4294967091 ||
c == 4294967092 ||
c == 4294967093 ||
c == 4294967094 ||
c == 4294967095 ||
c == 4294967096 ||
c == 4294967097 ||
c == 4294967088 ) {
i = i + 3;
isControlChar = YES;
}
if ( c == 4294967266 || c == 4294967267 ) {
i = i + 2;
isControlChar = YES;
}
if ( c == 4294967234 ) {
i = i + 1;
isControlChar = YES;
}
if ( !isControlChar ) {
newUTF8[j] = utf8;
j++;
}
}
newUTF8[j] = '\0';
NSString *encrypted = [NSString stringWithCString:(const char*)newUTF8
encoding:NSUTF8StringEncoding];
free( newUTF8 );
return encrypted;
}
- emoji在NSUTF8StringEncoding编码下占用4个字节，中文编码占用3个字节,可以根据- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string方法，把string做处理，依据
NSUInteger stringUtf8Length = [string lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
if(stringUtf8Length >= 4 && (stringUtf8Length / string.length != 3)) {
return NO;
}
判断,可排出大多数表情符号，还有少量的符号排除不了，比如_ ，占3个字符。
代码不实用在九宫格键盘上的，可以在输入时打断点查看内容或直接输出%x查看。
