停止在Android Studio的表情调节器中工作

我在android学习中遇到了一个简单的问题，下面是我的代码

当我在Emulator应用程序中运行时，停止工作。有人能帮我吗

package com.blah-blah.padideh.tamrin3;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;


public class Activityone extends Activity {

    Button calculate=(Button) findViewById(R.id.button);
    TextView firstnumber=(TextView)findViewById(R.id.editText);
    TextView secondnumber=(TextView)findViewById(R.id.editText2);
    TextView Result=(TextView)findViewById(R.id.result);
    double num1,num2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_farshid);
        calculate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                num1=Double.parseDouble(firstnumber.getText().toString());
                num2=Double.parseDouble(secondnumber.getText().toString());
                Result.setText("Sum:\t"+(num1+num2)+"\n"+
                "Multiple:\t"+(num1*num2)+"\n"+
                "Minus:\t"+(num1-num2)+"\n"+
                "Divide:\t"+(num1/num2)+"\n"+"Good Luck");

            }
        });
    }
}

---

包com.blah-blah.padideh.tamrin3

导入android.app.Activity； 导入android.os.Bundle； 导入android.view.view； 导入android.widget.Button； 导入android.widget.TextView

public class Activityone extends Activity {


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

// Now you can find your views
Button calculate=(Button) findViewById(R.id.button);
final TextView firstnumber=(TextView)findViewById(R.id.editText);
final TextView secondnumber=(TextView)findViewById(R.id.editText2);
TextView Result=(TextView)findViewById(R.id.result);
final double num1,num2;

calculate.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        num1=Double.parseDouble(firstnumber.getText().toString());
        num2=Double.parseDouble(secondnumber.getText().toString());
        Result.setText("Sum:\t"+(num1+num2)+"\n"+
        "Multiple:\t"+(num1*num2)+"\n"+
        "Minus:\t"+(num1-num2)+"\n"+
        "Divide:\t"+(num1/num2)+"\n"+"Good Luck");

    }
});
}
}

---

在活动中调用setContentView之前，无法尝试查找视图。

是的。经过几次逻辑检查后，我发现了我的错误。祝你好运

 import android.app.Activity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 import android.widget.TextView;


 public class FarshidActivity extends Activity {




@Override
protected void onCreate(Bundle savedInstanceState) {


    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_farshid);

    Button calculate=(Button) findViewById(R.id.button);
    final TextView firstnumber=(TextView)findViewById(R.id.editText);
    final TextView secondnumber=(TextView)findViewById(R.id.editText2);
    final TextView Result=(TextView)findViewById(R.id.result);



    calculate.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            double num1,num2;


            num1=Double.parseDouble(firstnumber.getText().toString());
            num2=Double.parseDouble(secondnumber.getText().toString());
            Result.setText("Sum:\t"+(num1+num2)+"\n"+
            "Multiple:\t"+(num1*num2)+"\n"+
            "Minus:\t"+(num1-num2)+"\n"+
            "Divide:\t"+(num1/num2)+"\n"+"Good Luck");

        }
    });
}

---

}

你能从Logcat发布日志吗？答案解决了你的问题吗？这也是有错误的。Android Studio告诉我你必须声明num1、num2、结果、firstnumber和secondnumber最终结果@Bashid您应该更多地阅读java，并学习了解logcat。这些都是java和android中的简单概念。谢谢你的评论。你说得对。我需要更仔细地查看我的代码，并考虑逻辑性。