变量的非法修饰符

Question

我目前正在从我发现的教程中构建Eclipse中的应用程序，但我的代码中有错误。

我已经包含了下面的主要活动文件（MainActivity.java）：

package com.example.youdothemath;

import android.app.ActionBar;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Fragment;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.R;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View.OnClickListener;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener 
{
    private Button playBtn, helpBtn, highBtn;

    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main); //error

        playBtn = (Button)findViewById(R.id.play_btn); //error
        helpBtn = (Button)findViewById(R.id.help_btn); //error
        highBtn = (Button)findViewById(R.id.high_btn); //error

        playBtn.setOnClickListener(this);
        helpBtn.setOnClickListener(this);
        highBtn.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) 
    {
        //respond to clicks
        if(view.getId()==R.id.play_btn)
        {
            //play button
            private String[] levelNames = {"Easy", "Medium", "Hard"};
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Choose a level")
            .setSingleChoiceItems(levelNames, 0, new DialogInterface.OnClickListener() 
            {
                public void onClick(DialogInterface dialog, int which) 
                {
                    dialog.dismiss();
                    //start gameplay
                    startPlay(which);
                }

            });

            AlertDialog ad = builder.create();
            ad.show();
        }

        else if(view.getId()==R.id.help_btn)
        {
            //how to play button
            Intent helpIntent = new Intent(this, HowToPlay.class);
            this.startActivity(helpIntent);
        }
        else if(view.getId()==R.id.high_btn)
        {
            //high scores button
            Intent highIntent = new Intent(this, HighScores.class);
            this.startActivity(highIntent);
        }
    }

    private void startPlay(int chosenLevel)
    {
        //start gameplay
        Intent playIntent = new Intent(this, PlayGame.class);
        playIntent.putExtra("level", chosenLevel);
        this.startActivity(playIntent);
    }
 }

错误在行

中读取

private String[] levelNames = {"Easy", "Medium", "Hard"}; 

存在“变量levelNames的非法修饰符;仅允许final”

有没有人有任何想法？

Answer 1

这是一个局部变量。您不需要声明它private，因为它已经是其范围的私有。你可以将它移到方法之外但是在类中，并且private修饰符有效。