android viewpager实现竖直滑动效果

public class CustomViewPager extends ViewGroup {
 private static final String TAG = CustomViewPager.class.getSimpleName();
 private float startX = 0;
 private GestureDetector detector;
 int a = 30;
 public CustomViewPager(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 }
 
 public CustomViewPager(Context context, AttributeSet attrs) {
 super(context, attrs);
 init(context);
 }
 private void init(Context context) {
 detector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener(){
 /**
 * distanceX 在屏幕上要移动的距离 而不是坐标
 */
 @Override
 public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
 scrollBy(0, (int)distanceY);
 return true;
 }
 });
 }
 public CustomViewPager(Context context) {
 super(context);
 }
 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
 for(int i=0;i

public class MainActivity extends ActionBarActivity {
 private CustomViewPager custom_view_pager;
 private int[] ids = {R.drawable.a1,R.drawable.a2,R.drawable.a3,R.drawable.a4,R.drawable.a5,R.drawable.a6};
 private List imageViews;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 DisplayUtil.init(this);
 custom_view_pager = (CustomViewPager) findViewById(R.id.custom_view_pager);
 initData();
 }
 private void initData() {
 imageViews = new ArrayList<>();
 for(int i=0;i