ViewPager实现滑动翻页效果

时间：2017-3-8 8:49:29 作者：棋牌资源网来源：棋牌资源网查看：7850 评论：0

内容摘要：实现ViewPager的滑动翻页效果可以使用ViewPager的setPageTransformer方法，如下： import android.content.Context;import android.support.v4.view.ViewPager;import...

实现ViewPager的滑动翻页效果可以使用ViewPager的setPageTransformer方法，如下：


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


public class ReadViewPager extends ViewPager
{
    public ReadViewPager(Context context)
    {
        super(context);
    }

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

    public void setAnima()
    {
        setPageTransformer(true, new PageTransformer()
        {
            private static final float MIN_SCALE = 0.75f;

            @Override
            public void transformPage(View view, float position)
            {

                int pageWidth = view.getWidth();
                int pageHeight =view.getHeight();

                if (position < -1)
                {
                    // [-Infinity,-1)
                    // This page is way off-screen to the left.
                    view.setAlpha(0);

                }
                else if (position <= 0)
                {
                    // [-1,0]
                    // Use the default slide transition when moving to the left page
                    view.setAlpha(1);
                    view.setTranslationX(0);
                    view.setScaleX(1);
                    view.setScaleY(1);
                }
                else if (position <= 1)
                {
                    // (0,1]

                    // Fade the page out.
                    view.setAlpha(1 - position);
//
//                    // Counteract the default slide transition
//                    view.setAlpha(1);
                    view.setTranslationX(pageWidth * -position);
//
//                    // Scale the page down (between MIN_SCALE and 1)
                    float scaleFactor = MIN_SCALE
                            + (1 - MIN_SCALE) * (1 - Math.abs(position));
                    view.setScaleX(scaleFactor);
                    view.setScaleY(scaleFactor);
                }
                else
                {
                    // (1,+Infinity]
                    // This page is way off-screen to the right.
                    view.setAlpha(0);
                }
            }

        });
    }
}

核心代码是android官方demo，以上实现的是翻页效果是：上面一页被滑出界面时，下面一页慢慢显现，透明度慢慢加大，并且大小由小慢慢变大。

不过有一个奇怪的现象，当我做一个答题界面时，刚刚开始我采用ViewPager与View结合实现无限循环切换，并且采用上面的动画效果，可是每当我滑动到最后一张，也就是要开始新的一轮循环的时候，被滑出去的一页也会出现慢慢变透明的情况，而我用ViewPager结合Fragment实现无限循环切换的是就不会出现这种效果

如果想要实现仿造驾考宝典的翻页效果，只要把核心方法改为以下代码便可以了

setPageTransformer(true, new PageTransformer() {
            private static final float MIN_SCALE = 0.75f;

            @Override
            public void transformPage(View view, float position) {

                int pageWidth = view.getWidth();
                 int pageHeight =view.getHeight();

                if (position < -1) { // [-Infinity,-1)
                    // This page is way off-screen to the left.
                    view.setAlpha(0);

                } else if (position <= 0) { // [-1,0]
                    // Use the default slide transition when moving to the left page
                    view.setAlpha(1);
                    view.setTranslationX(0);
                    view.setScaleX(1);
                    view.setScaleY(1);


                } else if (position <= 1) { // (0,1]

                    // Fade the page out.
//                    view.setAlpha(1 - position);
//
//                    // Counteract the default slide transition
                    view.setAlpha(1);
                    view.setTranslationX(pageWidth * -position);
//
//                    // Scale the page down (between MIN_SCALE and 1)
//                    float scaleFactor = MIN_SCALE
//                            + (1 - MIN_SCALE) * (1 - Math.abs(position));
//                    view.setScaleX(scaleFactor);
//                    view.setScaleY(scaleFactor);

                } else { // (1,+Infinity]
                    // This page is way off-screen to the right.
                    view.setAlpha(0);
                }


            }
        });