安卓-如何对ViewPager进行动画处理

Question

这是我制作 ViewPager 的代码。我想在页面切换时添加动画效果，所以编写了以下代码：

ViewPagerAdapter adapter;
                adapter = new ViewPagerAdapter(FistActiivty.this,imges);
                vp.setAdapter(adapter);
                pageSwitcher(2);

try {
                    Field mScroller;
                    mScroller = ViewPager.class.getDeclaredField("mScroller");
                    mScroller.setAccessible(true); 
                    Interpolator sInterpolator = new AccelerateInterpolator();
                    FixedSpeedScroller scroller = new FixedSpeedScroller(vp.getContext(), sInterpolator);
                    // scroller.setFixedDuration(5000);
                    mScroller.set(vp, scroller);
                } catch (Exception e) {
                    Log.v("this",e.getMessage());
                }

public class FixedSpeedScroller extends Scroller {

        private int mDuration = 2000;

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

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

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

        @Override
        public void startScroll(int startX, int startY, int dx, int dy, int duration) {
            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);
        }
    }

    public void pageSwitcher(int seconds) {
        timer = new Timer(); // At this line a new Thread will be created
        timer.scheduleAtFixedRate(new RemindTask(), 0, seconds * 1000);

    }
    class RemindTask extends TimerTask {
        @Override
        public void run() {
            runOnUiThread(new Runnable() {
                public void run() {
                    Log.v("this","change pager " +page);
                    if (page > imges.length) { 
                        vp.setCurrentItem(0);
                        page=1;
                    } else {
                        vp.setCurrentItem(page++);
                    }
                }
            });

        }
    }


    class ViewPagerAdapter extends PagerAdapter {
        Context context;
        String[] img;
        LayoutInflater inflater;
        ImageLoader imageLoader = ImageLoader.getInstance();
        DisplayImageOptions options;
        private ImageLoadingListener imageListener;

        public ViewPagerAdapter(Context context, String[] img) {
            this.context = FistActiivty.this;
            this.img = img;
        }

        @Override
        public int getCount() {
            return img.length;
        }


        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == ((RelativeLayout) object);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            ImageView imgflag;
            inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View itemView = inflater.inflate(R.layout.viewpager_item, container,false);
            imgflag = (ImageView) itemView.findViewById(R.id.flag);
            imageLoader.displayImage(img[position], imgflag,options, imageListener);
            ((ViewPager) container).addView(itemView);

            return itemView;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            // Remove viewpager_item.xml from ViewPager
            ((ViewPager) container).removeView((RelativeLayout) object);

        }

    }

这段代码的结果是这样的。它可以每2秒钟改变一次viewpager，并且正常工作，但在页面改变时没有动画效果，但当我手动改变页面时，它会有动画效果。

如何强制它在改变页面时执行动画？

谢谢。

- mohamad bagheri

---

尝试使用这个库 https://github.com/ToxicBakery/ViewPagerTransforms - Dhaval Patel

请查看此链接：https://dev59.com/kmsz5IYBdhLWcg3wBzfi#9731345 - Aditya Vyas-Lakhan

Answer 1

如果你的意思是要平滑地滚动，请尝试使用smoothscroll选项。
在你的TimerTask中修改为这个。

if (page > imges.length) { 
   vp.setCurrentItem(0, true);
   page=1;
} else {
   vp.setCurrentItem(page++, true);
}

- Goldfish

Answer 2

我认为你应该使用PageTransformer来在页面更改时应用动画。

请访问this链接...

- iMDroid