EditText限制输入字数，并且禁止输入表情符号

场景：在EditText输入表情符号，但发送到服务器之后，变成了问好，因为服务器无法识别。

解决方案：ContainsEmojiEditText,通过输入字符的长度，判断是否为表情符号。

import android.content.Context;
import android.text.Editable;
import android.text.Selection;
import android.text.Spannable;
import android.text.TextWatcher;
import android.util.AttributeSet;
import android.widget.EditText;
import android.widget.Toast;

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

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

public ContainsEmojiEditText(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;
Toast.makeText(mContext, "不支持输入Emoji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));
}

}

在布局文件中定义：

<com.ak.qmyd.view.ContainsEmojiEditText
android:id="@+id/et_content_edit"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="@drawable/editext_jianjie_border"
android:drawableLeft="@drawable/edit_big"
android:drawablePadding="10dp"
android:gravity="top"
android:hint="说点什么"
android:imeOptions="actionSend"
android:inputType="text"
android:padding="10dp"
android:singleLine="true" />

在Activity中实现输入监听，用于判断输入长度.

et_content_note_edit.addTextChangedListener(new TextWatcher() {
private int cou = 0;
int selectionEnd = 0;

@Override
public void onTextChanged(CharSequence s, int start, int before,
int count) {
cou = before + count;
String editable = et_content_note_edit.getText().toString();
String str = StringUtil.stringFilter(editable); // 过滤特殊字符
if (!editable.equals(str)) {
et_content_note_edit.setText(str);
}
et_content_note_edit.setSelection(et_content_note_edit.length());
cou = et_content_note_edit.length();
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
}

@Override
public void afterTextChanged(Editable s) {
if (cou > mMaxLenth) {
selectionEnd = et_content_note_edit.getSelectionEnd();
s.delete(mMaxLenth, selectionEnd);
ToastManager.show(DongTaiDetailActivity.this,
"评论内容不能超过200个字符");
}
}
});

ok，这样就可以实时监听输入的长度，也可以限制表情符号的输入了。