ImageSwitcher现在显示图像

Question

我正在尝试运行一个简单的应用程序，它会在按钮上单击动画显示图像。我看到的是一个白色的屏幕。我正在使用教程中的确切代码。任何人都可以告诉我这是什么问题？ 这是教程https://www.tutorialspoint.com/android/android_imageswitcher.htm

这是MainActivity.java

import...
public class MainActivity extends AppCompatActivity {
   ImageSwitcher imageSwitcher;
    Button btn;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

         imageSwitcher=(ImageSwitcher)findViewById(R.id.img);
        btn=(Button)findViewById(R.id.button);
        imageSwitcher.setFactory(new ViewSwitcher.ViewFactory() {
            @Override
            public View makeView() {
                ImageView view = new ImageView(getApplicationContext());
                view.setScaleType(ImageView.ScaleType.CENTER);
                view.setLayoutParams(new
                        ImageSwitcher.LayoutParams(ActionBar.LayoutParams.WRAP_CONTENT,
                        ActionBar.LayoutParams.WRAP_CONTENT));

                return view;
            }
        });
        Animation in = AnimationUtils.loadAnimation(this,android.R.anim.slide_in_left);
        Animation out = AnimationUtils.loadAnimation(this,android.R.anim.slide_out_right);
        imageSwitcher.setInAnimation(in);
        imageSwitcher.setOutAnimation(out);

       btn.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               Toast.makeText(MainActivity.this, "s", Toast.LENGTH_SHORT).show();
               imageSwitcher.setImageResource(R.drawable.m1);
           }
       });



    }

}

这是我的xml文件。

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="vaibhav.com.game.MainActivity">

    <ImageSwitcher
        android:id="@+id/img"
        android:layout_width="324dp"
        android:layout_height="419dp"
        android:layout_margin="0dp"
        android:layout_marginBottom="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginTop="5dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.454"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0"
        tools:layout_editor_absoluteX="57dp" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        android:layout_marginRight="8dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="8dp"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="8dp"
        app:layout_constraintHorizontal_bias="0.439"
        app:layout_constraintVertical_bias="0.946" />
</android.support.constraint.ConstraintLayout>