Caused by: java.lang.NullPointerException错误解析
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editText = (EditText) findViewById(R.id.edit);agnbtn = (Button) findViewById(R.id.agn);reducebtn = (Button) findViewById(R.id.reduce);multbtn = (Button) findViewById(R.id.mul);deletebtn = (Button) findViewById(R.id.delete);dividebtn = (Button) findViewById(R.id.divide);equalbtnButton = (Button) findViewById(R.id.equal);
addbtn.setOnClickListener(new addlis());editText.setOnClickListener(new listener());reducebtn.setOnClickListener(new reducelis());multbtn.setOnClickListener(new multlis());deletebtn.setOnClickListener(new deletelis());dividebtn.setOnClickListener(new dividelis());
运行后系统和会报错:
08-08 00:42:29.422: E/AndroidRuntime(849): Caused by: java.lang.NullPointerException
08-08 00:42:29.422: E/AndroidRuntime(849): at com.example.culcalutor1.MainActivity.onCreate(MainActivity.java:43)
空指针异常,这时就要查看自己的程序中是否存在空指针。
如上例所知,addbtn未初始化,这是一个常见的问题。将addbtn初始化就可以解决了。
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