改变viewPager滑动的速度，利用反射完美实现

mScroller

public void setSliderTransformDuration(int duration，ViewPager pager) {
try {
Field mScroller = ViewPager.class.getDeclaredField("mScroller");
mScroller.setAccessible(true);
FixedSpeedScroller scroller = new FixedSpeedScroller(pager.getContext(), null, duration);
mScroller.set(pager, scroller);
} catch (Exception e) {
e.printStackTrace();

}
}

public class FixedSpeedScroller extends Scroller {

private int mDuration = 1500;

public FixedSpeedScroller(Context context) {
super(context);
}

public FixedSpeedScroller(Context context, Interpolator interpolator) {
super(context, interpolator);
}

public FixedSpeedScroller(Context context, Interpolator interpolator, int duration) {
this(context, interpolator);
mDuration = duration;
}

@Override
public void startScroll(int startX, int startY, int dx, int dy, int duration) {
// Ignore received duration, use fixed one instead
super.startScroll(startX, startY, dx, dy, mDuration);
}

@Override
public void startScroll(int startX, int startY, int dx, int dy) {
// Ignore received duration, use fixed one instead
super.startScroll(startX, startY, dx, dy, mDuration);
}
}