RecyclerView
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原文: http://blog.csdn.net/Rozol/article/details/50225593
微博: http://weibo.com/u/2524456400
RecyclerView是ListView和GridView的代替者.
RecyclerView有一套自己的回收规则,不再需要自己手动写代码去回收.
基本使用
基本代码:
XML布局:
<android.support.v7.widget.RecyclerView android:id="@+id/recycle" android:layout_width="fill_parent" android:layout_height="fill_parent" > </android.support.v7.widget.RecyclerView>Activity代码:
public class RecyclerViewDemo extends Activity { private RecyclerView recycle; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_recycleview); initView(); initData(); } private void initView() { recycle = (RecyclerView) findViewById(R.id.recycle); } private void initData() { LinearLayoutManager layoutManager = new LinearLayoutManager(this); layoutManager.setOrientation(RecyclerView.VERTICAL); recycle.setLayoutManager(layoutManager); recycle.setAdapter(new RecycleAdapter(this)); } }Adapter代码:
public class RecycleAdapter extends RecyclerView.Adapter<ViewHolder>{ String[] contents = new String[]{"纵向列表","横向列表","纵向网格","横向网格","纵向瀑布流","横向瀑布流"}; private Context context; public RecycleAdapter(Context context) { this.context = context; } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(context).inflate(R.layout.item_recycle_menu, parent, false); return new RecyclerHolder(view); } @Override public void onBindViewHolder(ViewHolder holder, int position) { ((RecyclerHolder) holder).setData(position); } @Override public int getItemCount() { return contents.length; } class RecyclerHolder extends RecyclerView.ViewHolder{ private TextView content; public RecyclerHolder(View itemView) { super(itemView); content = (TextView) itemView.findViewById(R.id.content); } public void setData(int position) { content.setText(contents[position]); } } }效果:
- 你所看到的长方格是子条目的CardView控件,RecyclerView默认没有分隔线.
- 不管是想实现ListView/GridView/瀑布流,基本代码不变,你只需要改写layoutManager的孩子就可实现ListView(LinearLayoutManager)/GridView(GridLayoutManager)/瀑布流(StaggeredGridLayoutManager).
源码研究
Code方法研究:
public class RecyclerView extends ViewGroup implements ScrollingView, NestedScrollingChild { public static final int HORIZONTAL = 0; public static final int VERTICAL = 1; public static final int NO_POSITION = -1; public static final long NO_ID = -1; public static final int INVALID_TYPE = -1; public static final int TOUCH_SLOP_DEFAULT = 0; public static final int TOUCH_SLOP_PAGING = 1; public static final int SCROLL_STATE_IDLE = 0; public static final int SCROLL_STATE_DRAGGING = 1; public static final int SCROLL_STATE_SETTLING = 2; public RecyclerViewAccessibilityDelegate getCompatAccessibilityDelegate() { } public void setAccessibilityDelegateCompat(RecyclerViewAccessibilityDelegate accessibilityDelegate) { } //XXX未知XXX public void setHasFixedSize(boolean hasFixedSize) { } //true:不允许Adapter改变RecyclerView的大小 {重要} public boolean hasFixedSize() { } public void setScrollingTouchSlop(int slopConstant) { } //设置touch越界 [TOUCH_SLOP_DEFAULT/TOUCH_SLOP_PAGING] public void swapAdapter(Adapter adapter, boolean removeAndRecycleExistingViews) { } // 更换Adapter public void setAdapter(Adapter adapter) { } // 更换Adapter public Adapter getAdapter() { } public void setRecyclerListener(RecyclerListener listener) { } // 设置回收监听 public void addOnChildAttachStateChangeListener(OnChildAttachStateChangeListener listener) { } // 监听孩子的关联和脱离 public void removeOnChildAttachStateChangeListener(OnChildAttachStateChangeListener listener) { } public void clearOnChildAttachStateChangeListeners() { } public void setLayoutManager(LayoutManager layout) { } // 设置布局管理者{重要} public LayoutManager getLayoutManager() { } public RecycledViewPool getRecycledViewPool() { } public void setRecycledViewPool(RecycledViewPool pool) { } // 设置回收池 public void setViewCacheExtension(ViewCacheExtension extension) { } // 扩张缓存/null清除现有缓存 public void setItemViewCacheSize(int size) { } // 设置条目缓存大小,这些条目不做任何修改直接使用 public int getScrollState() { } //获取滚动状态 [SCROLL_STATE_IDLE/SCROLL_STATE_DRAGGING/SCROLL_STATE_SETTLING] {重要} public void addItemDecoration(ItemDecoration decor, int index) { } // 添加条目的装饰 public void addItemDecoration(ItemDecoration decor) { } public void removeItemDecoration(ItemDecoration decor) { } public void setChildDrawingOrderCallback(ChildDrawingOrderCallback childDrawingOrderCallback) { } //设置孩子绘画回调 public void addOnScrollListener(OnScrollListener listener) { } // 添加滚动监听 {重要} public void removeOnScrollListener(OnScrollListener listener) { } // {重要} public void clearOnScrollListeners() { } public void scrollToPosition(int position) { } // 滚动到某个位置 {重要} public void smoothScrollToPosition(int position) { } // 平滑的滚动到某个位置 {重要} public void setLayoutFrozen(boolean frozen) { } // true:冻结布局和滚动; false:释放冻结 (冻结后仍可调用scrollToPosition/smoothScrollToPosition) {重要} public boolean isLayoutFrozen() { } public void smoothScrollBy(int dx, int dy) { } public boolean fling(int velocityX, int velocityY) { } // true:在抛(速度快) {重要} public void stopScroll() { } // 停止滚动 public int getMinFlingVelocity() { } // 最小的抛速度 public int getMaxFlingVelocity() { } public void addOnItemTouchListener(OnItemTouchListener listener) { } // 添加条目touch监听 public void removeOnItemTouchListener(OnItemTouchListener listener) { } public boolean isComputingLayout() { } // true:是现在在处理的布局 public ItemAnimator getItemAnimator() { } // 条目动画/null:没有动画 public boolean isAnimating() { } public void invalidateItemDecorations() { } // 刷新条目装饰 public ViewHolder getChildViewHolder(View child) { } // 获取孩子的ViewHolder public int getChildAdapterPosition(View child) { } //孩子在适配器中的位置 public int getChildLayoutPosition(View child) { } public long getChildItemId(View child) { } // 获取条目id public ViewHolder findViewHolderForLayoutPosition(int position) { } public ViewHolder findViewHolderForAdapterPosition(int position) { } public ViewHolder findViewHolderForItemId(long id) { } public View findChildViewUnder(float x, float y) { } //给定的点下找到的最上面的子view public void offsetChildrenVertical(int dy) { } // 垂直滚动 public void onChildAttachedToWindow(View child) { } public void onChildDetachedFromWindow(View child) { } public void offsetChildrenHorizontal(int dx) { } // 水平滚动 public boolean hasPendingAdapterUpdates() { } // 是否有未更新的布局 public static class RecycledViewPool { } // 回收池 public static abstract class Adapter<VH extends ViewHolder> { } // 适配器 {重要} public static abstract class LayoutManager { } // 布局管理 {重要} public static abstract class ItemDecoration {} public static class SimpleOnItemTouchListener implements RecyclerView.OnItemTouchListener { } public static abstract class ViewHolder { } // ViewHolder {重要} public static class LayoutParams extends android.view.ViewGroup.MarginLayoutParams { } //LayoutParams public static abstract class AdapterDataObserver { } // 观察者 public static abstract class SmoothScroller { } // 滚动类 {重要} static class AdapterDataObservable extends Observable<AdapterDataObserver> { } // 观察者 public static class State {} public static abstract class ItemAnimator { } // 条目动画类 {重要} }从源码的方法上可以看出,RecyclerView与传统的ListView还是有些区别的:
- RecyclerView没有了对孩子的onClick的监听方法;
- 想要实现点击监听其实很简单,你只需要在控件上实现点击监听后,然后把事件通过接口传递给外面调用.
参考代码:
public class RecyclerHolder extends RecyclerView.ViewHolder implements OnClickListener{
public TextView content;
public int position;
private CardView cardview;public RecyclerHolder(View itemView) { super(itemView); content = (TextView) itemView.findViewById(R.id.item_content); cardview = (CardView) itemView.findViewById(R.id.item_cardview); cardview.setOnClickListener(this); } public void setData(int position) { this.position = position; content.setText(contents[position]); } @Override public void onClick(View v) { if(onItemClickListener != null) onItemClickListener.onItemClick(this, position); }}
public void setOnItemClickListener(OnItemClickListener onItemClickListener){
this.onItemClickListener = onItemClickListener;
}public static interface OnItemClickListener {
void onItemClick(RecyclerHolder recyclerHolder, int position);
}效果:
