LayoutInflater mInflater = LayoutInflater.from(mActivity);View saveView = mInflater.inflate(R.layout.alert_dlg_save, null);// 设置输入文件名的EditText属性final EditText filename = (EditText) saveView.findViewById(R.id.dlg_save_input_filename);filename.setFilters(new InputFilter[] {new InputFilter.LengthFilter(255), new SpecialFilter() });filename.setText(mStrAsName);TextView defaultPath = (TextView) saveView.findViewById(R.id.dlg_save_default_path);defaultPath.setText(DataStruct.gFloder + "/");AlertDialog.Builder builder = new AlertDialog.Builder(mActivity, AlertDialog.THEME_HOLO_LIGHT);builder.setTitle(R.string.maker_menu_save);builder.setIcon(R.drawable.icon_small);builder.setView(saveView);builder.setPositiveButton(R.string.maker_menu_save,    new DialogInterface.OnClickListener() {        @Override        public void onClick(DialogInterface dialog,int which) {        // TODO Auto-generated method stub        String name = filename.getText().toString().trim();        name += ".astp";        String namePath = DataStruct.gFloder + "/" + name;        if (saveFile(namePath)) {            mStrSavedPath = namePath;            mBtnSave.setEnabled(false);        } else {            ToastFailedSave();        }    }});builder.setNegativeButton(R.string.btn_cancel,    new DialogInterface.OnClickListener() {        @Override        public void onClick(DialogInterface dialog,int which) {        // TODO Auto-generated method stub        }    });Dialog dialog = builder.create();dialog.show();// 获取PositiveButton 重点在这里final Button btn = ((AlertDialog) dialog).getButton(DialogInterface.BUTTON_POSITIVE);// 输入不能为空filename.addTextChangedListener(new TextWatcher() {    @Override    public void onTextChanged(CharSequence s, int start,int before, int count) {        // TODO Auto-generated method stub    }    @Override    public void beforeTextChanged(CharSequence s, int start,int count, int after) {        // TODO Auto-generated method stub    }    @Override    public void afterTextChanged(Editable s) {        // TODO Auto-generated method stub        String name = s.toString().trim();        if (name.isEmpty())            btn.setEnabled(false);        else            btn.setEnabled(true);    }});