弹出一个保存文件的对话框，要控制输入内容限制，同时内容为空时保存按钮不可用。
原文地址请保留http://www.cnblogs.com/rossoneri/p/4140184.html
直接上代码：
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); }});