无法解析符号＆＃39; ThemeSelectionActivity＆＃39;我尝试在Android中实现OnTouchListener时出错

Question

基本上，我试图实现OnTouchListener来监听滑动手势。我为此创建了一个类OnSwipeTouchListener.java，并且我在GalleryActivity.java中调用了这个类，这是发生错误的地方。我一直收到这个错误：无法解析符号＆＃39; ThemeSelectionActivity＆＃39;，我按Alt Enter但没有任何反应。我该如何解决这个问题。

以下是出现错误的GalleryActivity.java的代码：

package com.mydomain.sample;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.ImageButton;
import android.widget.RelativeLayout;
import android.widget.Toast;

import java.util.ArrayList;


public class GalleryActivity extends AppCompatActivity {


    GridView gv_folder, gridView;
    RelativeLayout rootLayout;


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

        gv_folder = (GridView)findViewById(R.id.gallery_gridview_folders);
        rootLayout = (RelativeLayout) findViewById(R.id.galleryRootLayout);

        rootLayout.setOnTouchListener(new OnSwipeTouchListener(ThemeSelectionActivity.this) {

        @Override
            public void onSwipeRight() {
                super.onSwipeRight();

                gv_folder.setVisibility(View.INVISIBLE);
            }
        });
    }
}

这是OnSwipeTouchListener.java类

package com.mydomain.sample;

import android.content.Context;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;


public class OnSwipeTouchListener implements OnTouchListener {

private final GestureDetector gestureDetector;

public OnSwipeTouchListener(Context ctx) {
    gestureDetector = new GestureDetector(ctx, new GestureListener());
}

@Override
public boolean onTouch(View v, MotionEvent event) {
    return gestureDetector.onTouchEvent(event);
}

private final class GestureListener extends SimpleOnGestureListener {

    private static final int SWIPE_THRESHOLD = 1;
    private static final int SWIPE_VELOCITY_THRESHOLD = 1;

    @Override
    public boolean onDown(MotionEvent e) {
        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        boolean result = false;
        try {
            float diffY = e2.getY() - e1.getY();
            float diffX = e2.getX() - e1.getX();
            if (Math.abs(diffX) > Math.abs(diffY)) {
                if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                    if (diffX > 0) {
                        onSwipeRight();
                    } else {
                        onSwipeLeft();
                    }
                }
                result = true;
            } else if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
                if (diffY > 0) {
                    onSwipeBottom();
                } else {
                    onSwipeTop();
                }
            }
            result = true;

        } catch (Exception exception) {
            exception.printStackTrace();
        }
        return result;
    }
}

public void onSwipeRight() {
}

public void onSwipeLeft() {
}

public void onSwipeTop() {
}

public void onSwipeBottom() {
}
}