ViewPager不跳到半屏

import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;

public class HalfScreenViewPager extends ViewPager {
    private boolean allowHalfScreen = false;

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

    public HalfScreenViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (allowHalfScreen) {
            int halfScreenWidth = getWidth() / 2;
            int currentX = (int) event.getX();
            if (currentX >= halfScreenWidth && currentX <= getWidth() - halfScreenWidth) {
                return false; // 不处理滑动事件，停留在半屏位置
            }
        }
        return super.onTouchEvent(event);
    }

    public void setAllowHalfScreen(boolean allowHalfScreen) {
        this.allowHalfScreen = allowHalfScreen;
    }
}