ViewPager切換滑動速度修改

ViewPager的setCurrentItem 滑動速度是寫死地

下面的方法可以修改，在此以做記錄

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public class FixedSpeedScroller extends Scroller {     private int mDuration = 1500;       public FixedSpeedScroller(Context context) {         super(context);     }       public FixedSpeedScroller(Context context, Interpolator interpolator) {         super(context, interpolator);     }       @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);     }       public void setmDuration(int time) {         mDuration = time;     }       public int getmDuration() {         return mDuration;     } }

使用方法：

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try {                 Field field = ViewPager.class.getDeclaredField("mScroller");                 field.setAccessible(true);                 FixedSpeedScroller scroller = new FixedSpeedScroller(mViewPager.getContext(),                         new AccelerateInterpolator());                 field.set(mViewPager, scroller);                 scroller.setmDuration(2000);             } catch (Exception e) {                 LogUtils.e(TAG, "", e);             }

注意點： 
PagerAdapter 的 destroyItem 每次會刪除上一個頁面，導致，如果做自動切換頁面時會看不到動畫 .

解決辦法:
destoryItem中不做刪除view，instantiateItem中對view是否有parent做爲判斷條件，這種情況適用於，少量的固定的子View，比如一個Banner，banner中做自動循環播放

轉載：http://my.oschina.net/javalover/blog/179003