private void printResult(String result){
		try {//getLength+1 ӦΪ зû
			mDocument.insertString(mDocument.getLength(), result+"\n>", null);
		} catch (BadLocationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//²ɱ༭ݵĳ
		mUnableEditLength=mDocument.getLength();
		this.setCaretPosition(mDocument.getLength());
	}