Java Android项目中的动画方法问题-Android studio

我正在Android studio上测试一个小动画示例。在最后一个方法“toggle”中，我遇到一个错误，无法解析符号视图。有人能帮我解决这个问题吗

public class MainActivity extends AppCompatActivity {
private ViewGroup viewGroup;
private TextView textView;
private ImageView imageView, imageView2, imageView3,imageView4,imageView7;
private Button button;

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

    viewGroup=(ViewGroup) findViewById(R.id.viewGroup);
    textView= (TextView) findViewById(R.id.textView);
    textView.setText("It's animating");
    imageView= (ImageView) findViewById(R.id.imageView);
    imageView2= (ImageView) findViewById(R.id.imageView2);
    imageView3= (ImageView) findViewById(R.id.imageView3);
    imageView4= (ImageView) findViewById(R.id.imageView4);
    imageView7= (ImageView) findViewById(R.id.imageView7);


  button = (Button)findViewById(R.id.clickme);
  button.setText("Done");

   button.setOnClickListener(new View.OnClickListener(){
     public void onClick(View v) {
         TransitionManager.beginDelayedTransition(viewGroup, new Explode());
         toggle(textView, imageView, imageView2, imageView3, imageView4, imageView7);
     }
   });


              private static void toggle(View... views) {
                  for (View v : views) {
                      boolean isVisible = v.getVisibility() == View.VISIBLE;
                      v.setVisibility(isVisible ? View.INVISIBLE :
                              View.VISIBLE);
                  }
              }
}}

如果为（视图）设置

，那么？？如果为（视图）

设置

，那么？？