android非法字符的判定、表情符号的判定

public class EmojiEditText extends EditText {
// 输入表情前的光标位置
private int cursorPos; // 输入表情前EditText中的文本
private String inputAfterText; // 是否重置了EditText的内容
private boolean resetText;
private Context mContext;

public EmojiEditText(Context context) {
super(context);
this.mContext = context;
initEditText();
}

public EmojiEditText(Context context, AttributeSet attrs) {
super(context, attrs);
this.mContext = context;
initEditText();
}

public EmojiEditText(Context context, AttributeSet attrs,
int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.mContext = context;
initEditText();
} // 初始化edittext 控件

private void initEditText() {
addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start,
int before, int count) {
if (!resetText) {
cursorPos = getSelectionEnd(); // 这里用s.toString()而不直接用s是因为如果用s，
// 那么，inputAfterText和s在内存中指向的是同一个地址，s改变了，
// inputAfterText也就改变了，那么表情过滤就失败了
inputAfterText = s.toString();
}

}

@Override
public void onTextChanged(CharSequence s, int start, int before,
int count) {
if (!resetText) {
if (count >= 2) {// 表情符号的字符长度最小为2
CharSequence input = s.subSequence(cursorPos, cursorPos
+ count);
if (containsEmoji(input.toString())) {
resetText = true;
//暂不支持输入Emoji表情符号
Toast.makeText(mContext, "暂不支持输入表情符号",
Toast.LENGTH_SHORT).show(); // 是表情符号就将文本还原为输入表情符号之前的内容
setText(inputAfterText);
CharSequence text = getText();
if (text instanceof Spannable) {
Spannable spanText = (Spannable) text;
Selection.setSelection(spanText, text.length());
}
}
}
} else {
resetText = false;
}
}

@Override
public void afterTextChanged(Editable editable) {

}
});
}

/**
* 检测是否有emoji表情
* 
* @param source
* @return
*/
public static boolean containsEmoji(String source) {
int len = source.length();
for (int i = 0; i < len; i++) {
char codePoint = source.charAt(i);
if (!isEmojiCharacter(codePoint)) { // 如果不能匹配,则该字符是Emoji表情
return true;
}
}
return false;
}

/**
* 判断是否是Emoji
* 
* @param codePoint
*            比较的单个字符
* @return
*/
private static boolean isEmojiCharacter(char codePoint) {
return (codePoint == 0x0) || (codePoint == 0x9) || (codePoint == 0xA)
|| (codePoint == 0xD)
|| ((codePoint >= 0x20) && (codePoint <= 0xD7FF))
|| ((codePoint >= 0xE000) && (codePoint <= 0xFFFD))
|| ((codePoint >= 0x10000) && (codePoint <= 0x10FFFF));
}

}