Android 类从抽象类继承的对象的可拆分数组

我有一个抽象类钻取和4个扩展它的类addClass、divClass等。 Drill类实现了parcelable。现在我有了GamePlayActivity，它需要向结果活动传递一系列训练，我有两个编译问题。以下是相关代码：

训练班：

...
    public Drill(Parcel in) {
        readFromParcel(in);
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        // We just need to write each field into the
        // parcel. When we read from parcel, they
        // will come back in the same order
        dest.writeInt(firstNumber);
        dest.writeInt(secondNumber);
        dest.writeInt(answer);
        dest.writeInt(userAnswer);
        dest.writeString(userAnswerString);
        dest.writeString(symbol);
        dest.writeInt(minBound);
        dest.writeInt(maxBound);
        dest.writeInt(drillNumber);
    }

    /**
     *
     * Called from the constructor to create this
     * object from a parcel.
     *
     * @param in parcel from which to re-create object
     */
    protected void readFromParcel(Parcel in) {
        // We just need to read back each
        // field in the order that it was
        // written to the parcel
        firstNumber = in.readInt();
        secondNumber = in.readInt();
        answer = in.readInt();
        userAnswer = in.readInt();
        userAnswerString = in.readString();
        symbol = in.readString();
        minBound = in.readInt();
        maxBound = in.readInt();
    }

    public static final Parcelable.Creator<Drill> CREATOR = new Parcelable.Creator<Drill>() {
        public Drill createFromParcel(Parcel in) {
            return new Drill(in); // compilation error
        }

        public Drill[] newArray(int size) {
            return new Drill[size];
        }
    };

}

这是GamePlayClass，传递数组的类：

package com.simplemathgame;

import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class GamePlayActivity extends Activity {
...

    Drill[] arrayOfDrills;
    int dIndex = 0;
...


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

        ...

        arrayOfDrills = new Drill[addDrills + subDrills + mulDrills + divDrills];

        ...

        finishButton.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
            ...
                Intent resultsActivity = new Intent(GamePlayActivity.this, Results.class);
                resultsActivity.putExtra("drillArray", arrayOfDrills);
                startActivity(resultsActivity);
            }

        });
    }

    public static <T> void shuffle(T[] array) {
        for (int i = array.length; i > 1; i--) {
            T temp = array[i - 1];
            int randIx = (int) (Math.random() * i);
            array[i - 1] = array[randIx];
            array[randIx] = temp;
        }
    }
}

package com.simplemathgame;

import android.os.Bundle;
import android.app.Activity;

public class Results extends Activity {
    Drill[] arrayOfDrills;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_results);

        Bundle extras  = getIntent().getExtras();
        arrayOfDrills = extras.getParcelable("drillArray"); // compilation error
    }
}

在这里，我不知道为什么会发生错误

第一个编译错误： 无法实例化类型Drill

第二个编译错误： 类型不匹配：无法从钻孔[]转换为钻孔[]（&Parcelable）

---

我应该如何修复我的代码？谢谢

训练类是抽象的吗？不能启动抽象类

你能发布LogCat中显示的确切错误消息吗？我已经添加了错误，这是编译错误而不是运行时错误。请共享Drills的可打包实现。没有这样的实现：那么你是如何解决你的问题的？如何为抽象类实现parcelable

package com.simplemathgame;

import android.os.Bundle;
import android.app.Activity;

public class Results extends Activity {
    Drill[] arrayOfDrills;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_results);

        Bundle extras  = getIntent().getExtras();
        arrayOfDrills = extras.getParcelable("drillArray"); // compilation error
    }
}