gallery的画廊效果

public class MainActivity extends AppCompatActivity {
  
  

    private ImageSwitcher imageSwitcher;
    private Gallery gallery;
    private ImageAdapter imageAdapter;

    @RequiresApi(api = Build.VERSION_CODES.M)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
  
  
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        imageSwitcher = (ImageSwitcher) findViewById(R.id.imageswitch);
        gallery = (Gallery) findViewById(R.id.gallery);

        imageSwitcher.setInAnimation(this,android.R.anim.fade_in);
        imageSwitcher.setOutAnimation(this,android.R.anim.fade_out);
        imageSwitcher.setFactory(new ViewSwitcher.ViewFactory() {
  
  
            @Override
            public View makeView() {
  
  
                ImageView view = new ImageView(MainActivity.this);
                view.setScaleType(ImageView.ScaleType.FIT_CENTER);
                view.setLayoutParams(new ImageSwitcher.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                        ViewGroup.LayoutParams.MATCH_PARENT ));
                //这种也可以,不过一定是FrameLayout
                View inflate = LayoutInflater.from(MainActivity.this).inflate(R.layout.image_item, null);
                return inflate;
            }
        });

        imageAdapter = new ImageAdapter(MainActivity.this);
        gallery.setAdapter(imageAdapter);

        gallery.setOnItemClickListener(new AdapterView.OnItemClickListener() {
  
  
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
  
  
                Integer[] integers = imageAdapter.getmImageIds();
//                imageSwitcher.setImageResource(integers[position%integers.length]);
                ImageView image = (ImageView) imageSwitcher.findViewById(R.id.image);
                image.setImageResource(integers[position%integers.length]);

            }
        });


    }


}

//视图中间的位置不知怎么获取