重写ViewPager实施单一交有关切换到这个问题，并没有缓存

我们需要解决这个问题：切换时，可以实现单独的消息到左和右，但我不知道的情况下根据岗位总数。只是不知道ViewPagerAdapter的getCount数量。

因为帖子内容的数据图片和布局比較复杂。所以不让ViewPager缓存。否则消耗内存太大。

重写ViewPager

public class LazyViewPager extends ViewGroup {
	
	private boolean isCanScroll = true;
	
    public boolean isCanScroll() {
		return isCanScroll;
	}

	public void setCanScroll(boolean isCanScroll) {
		this.isCanScroll = isCanScroll;
	}

	private static final String TAG = "LazyViewPager";
    private static final boolean DEBUG = false;

    private static final boolean USE_CACHE = false;

    <span style="color:#ff0000;">private static final int DEFAULT_OFFSCREEN_PAGES = 0;//默认的载入页面,ViewPager是1个,所以会载入两个Fragment</span>
    private static final int MAX_SETTLE_DURATION = 600; // ms

重写ViewPager的setAdapter能够实现单个帖子指定跳转到的页数

public void setAdapter(PagerAdapter adapter,int position) {
        if (mAdapter != null) {
            mAdapter.unregisterDataSetObserver(mObserver);
            mAdapter.startUpdate(this);
            for (int i = 0; i < mItems.size(); i++) {
                final ItemInfo ii = mItems.get(i);
                mAdapter.destroyItem(this, ii.position, ii.object);
            }
            mAdapter.finishUpdate(this);
            mItems.clear();
            removeAllViews();
            mCurItem = 0;
            scrollTo(0, 0);
        }

        mAdapter = adapter;

        if (mAdapter != null) {
            if (mObserver == null) {
                mObserver = new PagerObserver();
            }
            mAdapter.registerDataSetObserver(mObserver);
            mPopulatePending = false;
            if (mRestoredCurItem >= 0) {
                mAdapter.restoreState(mRestoredAdapterState, mRestoredClassLoader);
               <span style="color:#ff0000;"> if(position>0){
                	setCurrentItemInternal(position, false, true);
                }else{
                	setCurrentItemInternal(mRestoredCurItem, false, true);
                }</span>
                mRestoredCurItem = -1;
                mRestoredAdapterState = null;
                mRestoredClassLoader = null;
            } else {
                populate(position);
            }
        }
    }

只是前提是设置这个ViewPager的Adapter的getCount的数量为1000或者Integer.Max

假设要实现ViewPager的Fragment不反复运行onCreateView方法，须要重写destroyItem

private class MyFragmentAdapter extends FragmentPagerAdapter{

		public MyFragmentAdapter(FragmentManager fm) {
			super(fm);
			// TODO Auto-generated constructor stub
		}

		@Override
		public Fragment getItem(int arg0) {
			// TODO Auto-generated method stub
			MyFragment fragment = new MyFragment(arg0);
			return fragment;
		}

		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return 10;
		}
		
		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			// TODO Auto-generated method stub
//			super.destroyItem(container, position, object);
		}
		
		@Override
		public void destroyItem(View container, int position, Object object) {
			// TODO Auto-generated method stub
//			super.destroyItem(container, position, object);
		}
	}

假设要设置ViewPager实现左右无限切换，能够通过重写Adapter的getItem（）方法。

@Override
		public Fragment getItem(int arg0) {
			// TODO Auto-generated method stub
			MyFragment fragment = fragments.get(arg0%4);
			return fragment;
		}

前提是getCount是个非常大的数

复制去Google翻译翻译结果

新MyFragment（为arg0）

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