高仿新闻类APP频道管理功能，ItemTouchHelper的实践

package com.goach.tabdemo.adapter; import android.content.Context; import android.graphics.Bitmap; import android.os.Handler; import android.support.v4.view.MotionEventCompat; import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.helper.ItemTouchHelper; import android.util.Log; import android.util.SparseArray; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.animation.Animation; import android.view.animation.LinearInterpolator; import android.view.animation.TranslateAnimation; import android.widget.ImageView; import android.widget.RelativeLayout; import android.widget.TextView; import com.goach.tabdemo.APPConst; import com.goach.tabdemo.R; import com.goach.tabdemo.activity.MyChannelHeaderWidget; import com.goach.tabdemo.activity.MyChannelWidget; import com.goach.tabdemo.activity.RecChannelHeaderWidget; import com.goach.tabdemo.activity.RecChannelWidget; import com.goach.tabdemo.base.EditModeHandler; import com.goach.tabdemo.base.IChannelType; import com.goach.tabdemo.base.ItemDragListener; import com.goach.tabdemo.base.ItemDragVHListener; import com.goach.tabdemo.bean.ChannelBean; import com.goach.tabdemo.view.helper.ItemDragHelperCallback; import com.nineoldandroids.animation.AnimatorSet; import com.nineoldandroids.animation.ObjectAnimator; import java.util.List; /** * Created by goach on 2016/9/28. */ public class ChannelAdapter extends RecyclerView.Adapter<ChannelAdapter.ChannelViewHolder> implements ItemDragListener { private List<ChannelBean> mMyChannelItems; private List<ChannelBean> mOtherChannelItems; private int mMyHeaderCount; private int mRecHeaderCount; private LayoutInflater mInflater; private SparseArray<IChannelType> mTypeMap = new SparseArray(); private boolean isEditMode; private ItemTouchHelper mItemTouchHelper; // touch 点击开始时间 private long startTime; // touch 间隔时间 用于分辨是否是 "点击" private static final long SPACE_TIME = 100; private ChannelItemClickListener channelItemClickListener; public ChannelAdapter(Context context,RecyclerView recyclerView, List<ChannelBean> myChannelItems,List<ChannelBean> otherChannelItems, int myHeaderCount,int recHeaderCount){ this.mItemTouchHelper = new ItemTouchHelper(new ItemDragHelperCallback(this)); mItemTouchHelper.attachToRecyclerView(recyclerView); this.mMyChannelItems = myChannelItems; this.mOtherChannelItems = otherChannelItems; this.mMyHeaderCount = myHeaderCount; this.mRecHeaderCount = recHeaderCount ; mInflater = LayoutInflater.from(context); mTypeMap.put(IChannelType.TYPE_MY_CHANNEL_HEADER,new MyChannelHeaderWidget(new EditHandler())); mTypeMap.put(IChannelType.TYPE_MY_CHANNEL,new MyChannelWidget(new EditHandler())); mTypeMap.put(IChannelType.TYPE_REC_CHANNEL_HEADER,new RecChannelHeaderWidget()); mTypeMap.put(IChannelType.TYPE_REC_CHANNEL,new RecChannelWidget(new EditHandler())); } @Override public ChannelViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { return mTypeMap.get(viewType).createViewHolder(mInflater,parent); } @Override public void onBindViewHolder(ChannelViewHolder holder, int position) { if(getItemViewType(position)==IChannelType.TYPE_MY_CHANNEL){ int myPosition = position-mMyHeaderCount; myPosition = myPosition<0||myPosition>=mMyChannelItems.size()?0:myPosition; mTypeMap.get(getItemViewType(position)).bindViewHolder(holder,position,mMyChannelItems.get(myPosition)); return; } if(getItemViewType(position)==IChannelType.TYPE_REC_CHANNEL){ int otherPosition = position-mMyChannelItems.size()-mMyHeaderCount-mRecHeaderCount; otherPosition = otherPosition<0||otherPosition>=mOtherChannelItems.size()?0:otherPosition; mTypeMap.get(getItemViewType(position)).bindViewHolder(holder,position,mOtherChannelItems.get(otherPosition)); return; } mTypeMap.get(getItemViewType(position)).bindViewHolder(holder,position,null); } @Override public int getItemViewType(int position) { if(position<mMyHeaderCount) return IChannelType.TYPE_MY_CHANNEL_HEADER; if(position>=mMyHeaderCount&&position<mMyChannelItems.size()+mMyHeaderCount) return IChannelType.TYPE_MY_CHANNEL; if(position>=mMyChannelItems.size()+mMyHeaderCount&&position<mMyChannelItems.size()+mMyHeaderCount+mRecHeaderCount) return IChannelType.TYPE_REC_CHANNEL_HEADER; return IChannelType.TYPE_REC_CHANNEL; } @Override public int getItemCount() { return mMyChannelItems.size()+mOtherChannelItems.size()+mMyHeaderCount+mRecHeaderCount; } @Override public void onItemMove(int fromPosition, int toPosition) { if(toPosition > 2){ ChannelBean item = mMyChannelItems.get(fromPosition - mMyHeaderCount); mMyChannelItems.remove(fromPosition - mMyHeaderCount); mMyChannelItems.add(toPosition - mMyHeaderCount, item); notifyItemMoved(fromPosition, toPosition); } } @Override public void onItemSwiped(int position) { } public static class ChannelViewHolder extends RecyclerView.ViewHolder implements ItemDragVHListener { public ChannelViewHolder(View itemView) { super(itemView); } @Override public void onItemSelected() { scaleItem(1.0f , 1.2f , 0.5f); } @Override public void onItemFinished() { scaleItem(1.2f , 1.0f , 1.0f); } public void scaleItem(float start , float end , float alpha) { ObjectAnimator anim1 = ObjectAnimator.ofFloat(itemView, "scaleX", start, end); ObjectAnimator anim2 = ObjectAnimator.ofFloat(itemView, "scaleY", start, end); ObjectAnimator anim3 = ObjectAnimator.ofFloat(itemView, "alpha", alpha); AnimatorSet animSet = new AnimatorSet(); animSet.setDuration(200); animSet.setInterpolator(new LinearInterpolator()); animSet.playTogether(anim1, anim2 ,anim3); animSet.start(); } } private class EditHandler extends EditModeHandler{ @Override public void startEditMode(RecyclerView mRecyclerView) { doStartEditMode(mRecyclerView); } @Override public void cancelEditMode(RecyclerView mRecyclerView) { doCancelEditMode(mRecyclerView); } @Override public void clickMyChannel(RecyclerView mRecyclerView,ChannelAdapter.ChannelViewHolder holder) { RecyclerView.LayoutManager layoutManager = mRecyclerView.getLayoutManager(); int position = holder.getAdapterPosition(); if(isEditMode){ View targetView = layoutManager.findViewByPosition(mMyChannelItems.size() +mMyHeaderCount+mRecHeaderCount); View currentView = mRecyclerView.getLayoutManager().findViewByPosition(position); int targetX ; int targetY; if(mRecyclerView.indexOfChild(targetView)>=0){ int spanCount = ((GridLayoutManager)layoutManager).getSpanCount(); targetX = targetView.getLeft(); targetY = targetView.getTop(); if ((mMyChannelItems.size()) % spanCount == 1) { View preTargetView = la