java - 如何将变量的值打印到 Textview

Question

这是我的代码(我很初学者) 我试图在这里打印 EditText 上的变量答案 但我收到错误“无法解析符号答案”我不知道如何修复它请帮助:

package com.example.user.test_calculator;


import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

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

public static double main(String[]args){
    int x , y , answer;
    x = 2;
    y = 3;
    answer = y + x;
    return 0;
}
public void buttonOnClick(View v){
    EditText txtoutput = (EditText) findViewById(R.id.editText);
    txtoutput.setText(String.valueOf(answer));


  }

}

Answer 1

您需要在方法 main 之外声明变量answer。

public class MainActivity extends AppCompatActivity {

int answer;

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

public static double main(String[]args){
    int x , y;
    x = 2;
    y = 3;
    this.answer = y + x;
    return 0;
}
public void buttonOnClick(View v){
    EditText txtoutput = (EditText) findViewById(R.id.editText);
    txtoutput.setText(String.valueOf(this.answer));


  }

}