旋转屏幕时保存活动

Question

我在应用程序中有3个按钮，还有3个带计数器的textview。当您按下电视按钮时，它会根据点击次数以升序记录数字。而且，当您打开设备时，将重置所有内容并重新创建活动。请帮忙，我不知道如何保存当前活动信息？

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.arellomobile.mvp.MvpAppCompatActivity;
import com.arellomobile.mvp.presenter.InjectPresenter;

import com.geekbrains.lesson1.R;

public class MoxyMainActivity extends MvpAppCompatActivity
        implements MoxyExampleView, View.OnClickListener {

    @InjectPresenter
    Presenter presenter;

    private Button btnCounter1;
    private Button btnCounter2;
    private Button btnCounter3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnCounter1 = (Button) findViewById(R.id.btnCounter1);
        btnCounter2 = (Button) findViewById(R.id.btnCounter2);
        btnCounter3 = (Button) findViewById(R.id.btnCounter3);
        btnCounter1.setOnClickListener(this);
        btnCounter2.setOnClickListener(this);
        btnCounter3.setOnClickListener(this);

    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("key", "value");
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);

    }

    @Override
    public void onClick(View v) {
        presenter.buttonClick(v.getId());
    }

    @Override
    public void setButtonText(int btnIndex, int value) {
        switch (btnIndex) {
            case 1:
                btnCounter1.setText("Количество = " + value);
                break;
            case 2:
                btnCounter2.setText("Количество = " + value);
                break;
            case 3:
                btnCounter3.setText("Количество = " + value);
                break;
        }
    }
}

<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/_1" />

    <Button
        android:id="@+id/btnCounter1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Количество = 0" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/_2" />

    <Button
        android:id="@+id/btnCounter2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Количество = 0" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/_3" />

    <Button
        android:id="@+id/btnCounter3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Количество = 0" />
</LinearLayout>