Java 不幸的是，应用程序已经停止了大脑游戏应用程序中的错误

大家好，社区我是hamza，我是android开发新手，我学习了太多教程，最好的是我的UDEMY中的rob percival先生，我现在正在创建一个简单的大脑游戏应用程序，它可以计算你一分钟内可以解决多少个操作，在完成编码后，应用程序甚至不会在消息中堆叠。不幸的是，应用程序已经停止，谢谢你帮我调试代码，因为我不想看任何人的代码。非常感谢你，我很感激

JAVA主代码：

package com.example.hfpro.braintrainer;

import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.Random;

public class MainActivity extends AppCompatActivity {


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

    // Layouts Pointers
    final TextView counter = (TextView)findViewById(R.id.counter) ;
    final TextView operation = (TextView)findViewById(R.id.operation) ;
    final TextView button1 = (TextView) findViewById(R.id.choice1) ;
    final TextView button2 = (TextView) findViewById(R.id.choice2) ;
    final TextView button3 = (TextView) findViewById(R.id.choice3) ;
    final TextView button4 = (TextView) findViewById(R.id.choice4) ;
    final TextView total = (TextView) findViewById(R.id.total) ;
    final TextView result = (TextView) findViewById(R.id.result) ;
    final Button start = (Button) findViewById(R.id.start) ;



    int counterNumber ;
    int correctResult ;
    int score = 0 ;
    int levels = 1 ;
    Random random = new Random() ;

    public void operation(View view)
    {
        String temp = String.valueOf(score)+" / " + String.valueOf(levels) ;
        total.setText(temp);
        int num1 = Math.abs(random.nextInt()%50) ;
        int num2 = Math.abs(random.nextInt()%50) ;
        correctResult = num1 + num2 ;
        temp = String.valueOf(num1) + " + " +String.valueOf(num2) + "  = ? " ;
        operation.setText(temp);
        // set the correct result in a result suggetoin
        int correctResultPosition = Math.abs(random.nextInt()%4) ;
        switch (correctResultPosition)
        {
            case 0 :
                button1.setText(String.valueOf(correctResult));
                break;
            case 1 :
                button2.setText(String.valueOf(correctResult));
                break;
            case 2 :
                button3.setText(String.valueOf(correctResult));
                break;
            case 3 :
                button4.setText(String.valueOf(correctResult));
                break;
            default:
        }
    }

    public void start(final View view)
    {
        // quetions() ;
        counter.setText("60");
        start.animate().alpha(0).setDuration(500) ;
        // timer
        final Handler handler = new Handler() ;
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                counterNumber = Integer.valueOf((String)counter.getText()) ;
                counterNumber -- ;
                if(counterNumber == 0 )
                {
                    //timeFinished
                    String res =   "Time is up your score is :"+ String.valueOf(score) + " :::";
                    result.setText(res);

                }
                counter.setText(String.valueOf(counterNumber));

                handler.postDelayed(this , 1000) ;
            }
        } ;
        handler.post(runnable) ;

    }


    public void checkResult(View view)
    {
        switch (view.getId())
        {
            case R.id.choice1 :
                if(correctResult == Integer.valueOf((String)button1.getText()))
                    {
                        score++ ;
                        String str = String.valueOf(score) + " / " + String.valueOf(levels) ;
                        total.setText(str);
                    }
                levels++ ;
                break;
            case R.id.choice2 :
                if(correctResult == Integer.valueOf((String)button2.getText()))
                {
                    score++ ;
                    String str = String.valueOf(score) + " / " + String.valueOf(levels) ;
                    total.setText(str);
                }
                levels++ ;
                break;
            case R.id.choice3 :
                if(correctResult == Integer.valueOf((String)button3.getText()))
                {
                    score++ ;
                    String str = String.valueOf(score) + " / " + String.valueOf(levels) ;
                    total.setText(str);
                }
                levels++ ;
                break;
            case R.id.choice4:
                if(correctResult == Integer.valueOf((String)button4.getText()))
                {
                    score++ ;
                    String str = String.valueOf(score) + " / " + String.valueOf(levels) ;
                    total.setText(str);
                }
                levels++ ;
                break;
            default:
        }
        this.operation(view);
    }




}

这是XML代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.hfpro.braintrainer.MainActivity">

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true">

        <TextView
            android:layout_width="150dp"
            android:layout_height="100dp"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/RES1"
            android:id="@+id/choice1"
            android:layout_gravity="left|center_vertical"
            android:background="#e1e2b7" />

        <TextView
            android:layout_width="150dp"
            android:layout_height="100dp"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/RES2"
            android:id="@+id/choice2"
            android:layout_gravity="right|center_vertical"
            android:background="#6b4ec8" />

        <TextView
            android:layout_width="150dp"
            android:layout_height="100dp"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/RES3"
            android:id="@+id/choice3"
            android:layout_gravity="left|bottom"
            android:background="#65ba8c" />

        <TextView
            android:layout_width="150dp"
            android:layout_height="100dp"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/RES4"
            android:id="@+id/choice4"
            android:layout_gravity="right|bottom"
            android:background="#dcb27e" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/start"
            android:id="@+id/start"
            android:layout_gravity="center"
            android:onClick="start" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="43dp"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/operation"
            android:id="@+id/operation"
            android:layout_gravity="center_horizontal|top"
            android:onClick="operation" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/result"
            android:id="@+id/counter"
            android:layout_gravity="left|top" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/counter"
            android:id="@+id/total"
            android:layout_gravity="right|top" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/result"
            android:id="@+id/result"
            android:layout_gravity="center_horizontal|bottom" />

    </FrameLayout>
</RelativeLayout>

我使用string.xml，他在这里：

<resources>
    <string name="app_name">BrainTrainer</string>
    <string name="RES1">RES1</string>
    <string name="RES2">RES2</string>
    <string name="RES3">RES3</string>
    <string name="RES4">RES4</string>
    <string name="operation">operation</string>
    <string name="counter">60</string>
    <string name="level">0/1</string>
    <string name="start">Start</string>
    <string name="result">result</string>



</resources>

脑力训练者
RES1
RES2
RES3
RES4
活动
60
0/1
开始
结果

好吧，将来仍然要发布堆栈跟踪。但是我可以告诉你你的问题-你不能把findviewbyd调用放在这样的函数之外。您需要在onCreate中初始化这些变量，并使它们成为非最终变量。在setContentView设置contentView之前，找不到任何视图，因此findViewById将返回null。

发布堆栈跟踪。它会告诉你问题在哪里，是什么。非常感谢，它现在工作得很好，希望你有一个可怕的一天：）和平。