缓存机制
ListView的两级缓存
ListView的缓存和复用由它的父类AbsListView中的RecycleBin实现,设了两个缓存数组mActiveViews和mScrapViews。mActiveViews缓存显示在屏幕中的view,mScrapViews按ViewType缓存离屏的view
class RecycleBin { /** * The position of the first view stored in mActiveViews. */ private int mFirstActivePosition; /** * Views that were on screen at the start of layout. This array is populated at the start of * layout, and at the end of layout all view in mActiveViews are moved to mScrapViews. * Views in mActiveViews represent a contiguous range of Views, with position of the first * view store in mFirstActivePosition. */ private View[] mActiveViews = new View[0]; /** * Unsorted views that can be used by the adapter as a convert view. */ private ArrayList<View>[] mScrapViews; }