import android.text.TextWatcher; 
import android.text.Editable;

int mMaxLenth = 20;
InputFilter[] FilterArray = new InputFilter[1];
 FilterArray[0] = new InputFilter() {
  @Override
  public CharSequence filter (CharSequence source, int start, int end, 
   Spanned dest, int dstart, int dend){
  boolean bInvlid = false;
  int sourceLen = getCharacterNum(source.toString());
  int destLen = getCharacterNum(dest.toString());
  if (sourceLen + destLen > mMaxLenth) {
   return "";  }
  return source;
  }
 };
mEditText.setFilters(FilterArray);

 mEditText.addTextChangedListener(new TextWatcher() {
  String tmp = "";
  String digits = "/\\:*?<>|\"\n\t";
  @Override
  public void onTextChanged(CharSequence s, int start, int before,
   int count) {
  mEditText.setSelection(s.length());
  }
  @Override
  public void beforeTextChanged(CharSequence s, int start, int count,
   int after) {
  tmp = s.toString();
  }
  @Override
  public void afterTextChanged(Editable s) {
  String str = s.toString();
  if (str.equals(tmp)) {
   return;
  }
  StringBuffer sb = new StringBuffer();
  for (int i = 0; i < str.length(); i++) {
   if (digits.indexOf(str.charAt(i)) < 0) {
   sb.append(str.charAt(i));
   }
  }
  tmp = sb.toString();
  mEditText.setText(tmp);
  }
 });

import java.util.regex.*;

public static String StringFilter(String str)throws PatternSyntaxException{ 
 String regEx = "[/\\:*?<>|\"\n\t]"; //要过滤掉的字符
 Pattern p = Pattern.compile(regEx); 
 Matcher m = p.matcher(str); 
 return m.replaceAll("").trim(); 
 }

mEditText.addTextChangedListener(new TextWatcher() {
  @Override
  public void onTextChanged(CharSequence s, int start, int before,
   int count) {
  String t = mEditText.getText().toString();
  String editable = mEditText.getText().toString(); 
  String str = stringFilter(editable.toString()); 
  if(!editable.equals(str)){ 
   mEditText.setText(str); 
   mEditText.setSelection(str.length()); //光标置后
  } 
  }
  @Override
  public void beforeTextChanged(CharSequence s, int start, int count,
   int after) {
  }
  @Override
  public void afterTextChanged(Editable s) {
  }
 });

int mMaxLenth = 200;//设置允许输入的字符长度
public static String stringFilter(String str)throws PatternSyntaxException{ 
 String regEx = "[/\\:*?<>|\"\n\t]";
 Pattern p = Pattern.compile(regEx);
 Matcher m = p.matcher(str);
 return m.replaceAll("");
 }
mEditText.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 = mEditText.getText().toString();
  String str = stringFilter(editable); //过滤特殊字符
  if (!editable.equals(str)) {
   mEditText.setText(str);
  }
  mEditText.setSelection(mEditText.length());
  cou = mEditText.length();
  }
  @Override
  public void beforeTextChanged(CharSequence s, int start, int count,
   int after) {
  }
  @Override
  public void afterTextChanged(Editable s) {
  if (cou > mMaxLenth) {
   selectionEnd = mEditText.getSelectionEnd();
   s.delete(mMaxLenth, selectionEnd);
  }
  }
 });