IntelliJ-创建对象时可以识别类，但是方法不会自动完成或编译

Question

I've got a class defined in a .java file outside of the main activity as follows.

package com.example.someGuy.numbershapes;

class Number {

        public int input;

        public boolean isSquare(){
            int sqrtOfInput = (int) Math.sqrt(input);
            if (input == sqrtOfInput * sqrtOfInput) return true;
            else return false;
        }
        public boolean isTriangle(){
            int sqrtOfInput = (int) Math.sqrt(input * 2);
            if (input == sqrtOfInput * (sqrtOfInput + 1)/2) return true;
            else return false;
        }
}

I then try to access it from the main activity like this.

package com.example.someGuy.numbershapes;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    Number myNumber = new Number();

    myNumber.input = 22;

    if (myNumber.isTriangular()){
        //do something
    }
    else if (myNumber.isSquare()){
        //do something else        
    }
}

When I try to run/build the project in IntelliJ, I get an error saying that there is an identifier expected, and illegal start of type error. What am I doing wrong? I was able to get this class to behave as an object in browxy. What am I doing wrong in this case? I'm trying to set the input to a text field in the layout and get it to run through the functions I have defined so that I can determine if the number input by the user is triangular, a perfect square, both or neither.

Answer 1

You need to put this code

myNumber.input = 22;

if (myNumber.isTriangular()){
    //do something
}
else if (myNumber.isSquare()){
    //do something else        
}

inside the onCreate method, as statements have to appear in a block of code. (The block would be a method for the example)

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Number myNumber = new Number();
    myNumber.input = 22;

    if (myNumber.isTriangular()){
        //do something
    }
    else if (myNumber.isSquare()){
        //do something else        
    }
}