Android 安卓测验难度

我遇到了这段代码，但不确定它是做什么的，有人能解释一下吗

“啊！”的目的是什么

该代码包括：

int level;
    //get LEVEL from intent. If no LEVEL in intent, LEVEL=-1.
    level = getIntent().getIntExtra("level",-1);

    //if level not equal "-1" (so level was in intent), get questions for this level from database
    if(level!=-1)   {
        db=new QuizHelper(this);
        quesList=db.getAllQuestionsByLevel(level);
    }

---

“！”的意思是不。“！=”表示“不等于”。

您可以研究Java运算符。这确实与安卓系统无关

int level;
    //get LEVEL from intent. If no LEVEL in intent, LEVEL=-1.
    level = getIntent().getIntExtra("level",-1);

    //if level not equal "-1" (so level was in intent), get questions for this level from database
    if(level!=-1)   {
        db=new QuizHelper(this);
        quesList=db.getAllQuestionsByLevel(level);
    }