Android编程实现实时监听EditText文本输入的方法

class EditChangedListener implements TextWatcher {    private CharSequence temp;//监听前的文本    private int editStart;//光标开始位置    private int editEnd;//光标结束位置    private final int charMaxNum = 10;    @Override    public void beforeTextChanged(CharSequence s, int start, int count, int after) {      if (DEBUG)        Log.i(TAG, "输入文本之前的状态");      temp = s;    }    @Override    public void onTextChanged(CharSequence s, int start, int before, int count) {      if (DEBUG)        Log.i(TAG, "输入文字中的状态，count是一次性输入字符数");      mTvAvailableCharNum.setText("还能输入" + (charMaxNum - s.length()) + "字符");    }    @Override    public void afterTextChanged(Editable s) {      if (DEBUG)        Log.i(TAG, "输入文字后的状态");            editStart = mEditTextMsg.getSelectionStart();      editEnd = mEditTextMsg.getSelectionEnd();      if (temp.length() > charMaxNum) {        Toast.makeText(getApplicationContext(), "你输入的字数已经超过了限制！", Toast.LENGTH_LONG).show();        s.delete(editStart - 1, editEnd);        int tempSelection = editStart;        mEditTextMsg.setText(s);        mEditTextMsg.setSelection(tempSelection);      }    }};