问开始Android 4游戏开发错误

EN

FileIO fileIO

fileIO = new AndroidFileIO(getAssets()); 

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.AssetManager;
import android.os.Environment;
import android.preference.PreferenceManager;

import com.example.android4gamedevtut.FileIO;

public class AndroidFileIO implements FileIO{

    Context context;
     AssetManager assets;
     String externalStoragePath;

     public AndroidFileIO(Context assetManager) {
     this.context = assetManager;
     this.assets = assetManager.getAssets();
     this.externalStoragePath = Environment.getExternalStorageDirectory()
     .getAbsolutePath() + File.separator;
     }



    @Override
     public InputStream readAsset(String fileName) throws IOException {
     return assets.open(fileName);
     }
     @Override
     public InputStream readFile(String fileName) throws IOException {
     return new FileInputStream(externalStoragePath + fileName);
     } 

     @Override
     public OutputStream writeFile(String fileName) throws IOException {
     return new FileOutputStream(externalStoragePath + fileName);
     }

     public SharedPreferences getPreferences() {
     return PreferenceManager.getDefaultSharedPreferences(context);
     } 
}