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首页 > 软件编程 > Android > android recycleView实现指定范围的拖动

Android之RecycleView实现指定范围的拖动效果

作者：chen.yu

这篇文章主要介绍了Android之RecycleView实现指定范围的拖动效果的实例代码，本文通过实例代码给大家介绍的非常详细，对大家的学习或工作具有一定的参考借鉴价值,需要的朋友可以参考下

1 问题

在RecycleView里面实现指定位置的拖动效果，（这里是实现线性布局的，不是网格布局的）

 @Override
  public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
    Log.i(TAG, "onMove viewHolder.getAdapterPosition() is:" + viewHolder.getAdapterPosition());
    int itemViewType = viewHolder.getAdapterPosition();
    Log.i(TAG, "onMove---------------------------------itemViewType is:" + itemViewType);
//    if (itemViewType == 0 || itemViewType == 1 || itemViewType == 16) {
//      Log.i(TAG, "onMove---------------------------------itemViewType is:" + itemViewType);
//      return false;
//    }
    int fromPosition = viewHolder.getAdapterPosition();//得到拖动ViewHolder的position
    int toPosition = target.getAdapterPosition();//得到目标ViewHolder的position
		
    Log.i(TAG, "onMove---------------------------------fromPosition is:" + fromPosition);
    Log.i(TAG, "onMove---------------------------------toPosition is:" + toPosition);
		
		//这里的position如果不是指定范围内的话，直接返回false，就拖动不到其它位置了
    if (DragUtil.INSTANCE.getProhibitDragIndexs().contains(toPosition)) {
      return false;
    }
    itemTouchAdapter.onMove(fromPosition,toPosition);
    return true;
  }

2 关键代码如下

MyItemTouchCallback.java

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.util.Log;
 
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.ItemTouchHelper;
import androidx.recyclerview.widget.RecyclerView;
 
import com.appsinnova.android.keepdrop.manager.FileScanManager;
 
/**
 * Created by Administrator on 2016/4/12.
 */
public class MyItemTouchCallback extends ItemTouchHelper.Callback {
 
  public static final String TAG = MyItemTouchCallback.class.getSimpleName();
  private ItemTouchAdapter itemTouchAdapter;
  public MyItemTouchCallback(ItemTouchAdapter itemTouchAdapter){
    this.itemTouchAdapter = itemTouchAdapter;
  }
 
  @Override
  public boolean isLongPressDragEnabled() {
    return false;
  }
 
  @Override
  public boolean isItemViewSwipeEnabled() {
    return true;
  }
 
 
  @Override
  public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    Log.i(TAG, "getMovementFlags viewHolder.getAdapterPosition() is:" + viewHolder.getAdapterPosition());
    int itemViewType = viewHolder.getAdapterPosition();
    Log.i(TAG, "---------------------------------itemViewType is:" + itemViewType);
//    if (itemViewType == 0 || itemViewType == 1 || itemViewType == 16) {
//      Log.i(TAG, "-getMovementFlags--------------------------------itemViewType is:" + itemViewType);
//      return makeMovementFlags(0, 0);
//    }
    if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
      final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
      final int swipeFlags = 0;
      return makeMovementFlags(dragFlags, swipeFlags);
    } else {
      final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
      //final int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
      final int swipeFlags = 0;
      Log.i(TAG, "makeMovementFlags start");
      return makeMovementFlags(dragFlags, swipeFlags);
    }
  }
 
  @Override
  public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
    Log.i(TAG, "onMove viewHolder.getAdapterPosition() is:" + viewHolder.getAdapterPosition());
    int itemViewType = viewHolder.getAdapterPosition();
    Log.i(TAG, "onMove---------------------------------itemViewType is:" + itemViewType);
//    if (itemViewType == 0 || itemViewType == 1 || itemViewType == 16) {
//      Log.i(TAG, "onMove---------------------------------itemViewType is:" + itemViewType);
//      return false;
//    }
    int fromPosition = viewHolder.getAdapterPosition();//得到拖动ViewHolder的position
    int toPosition = target.getAdapterPosition();//得到目标ViewHolder的position
		
    Log.i(TAG, "onMove---------------------------------fromPosition is:" + fromPosition);
    Log.i(TAG, "onMove---------------------------------toPosition is:" + toPosition);
		
		//这里的position如果不是指定范围内的话，直接返回false，就拖动不到其它位置了
    if (DragUtil.INSTANCE.getProhibitDragIndexs().contains(toPosition)) {
      return false;
    }
    itemTouchAdapter.onMove(fromPosition,toPosition);
    return true;
  }
 
  @Override
  public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
    int position = viewHolder.getAdapterPosition();
    itemTouchAdapter.onSwiped(position);
  }
 
  @Override
  public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
      //滑动时改变Item的透明度
      final float alpha = 1 - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
      viewHolder.itemView.setAlpha(alpha);
      viewHolder.itemView.setTranslationX(dX);
    } else {
      super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }
  }
 
  @Override
  public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
    if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
      if (background == null && bkcolor == -1) {
        Drawable drawable = viewHolder.itemView.getBackground();
        if (drawable == null) {
          bkcolor = 0;
        } else {
          background = drawable;
        }
      }
      viewHolder.itemView.setBackgroundColor(Color.LTGRAY);
    }
    super.onSelectedChanged(viewHolder, actionState);
  }
 
  @Override
  public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    super.clearView(recyclerView, viewHolder);
 
    viewHolder.itemView.setAlpha(1.0f);
    if (background != null) viewHolder.itemView.setBackgroundDrawable(background);
    if (bkcolor != -1) viewHolder.itemView.setBackgroundColor(bkcolor);
    //viewHolder.itemView.setBackgroundColor(0);
 
    if (onDragListener!=null){
      onDragListener.onFinishDrag();
    }
  }
 
  private Drawable background = null;
  private int bkcolor = -1;
 
  private OnDragListener onDragListener;
  public MyItemTouchCallback setOnDragListener(OnDragListener onDragListener) {
    this.onDragListener = onDragListener;
    return this;
  }
  public interface OnDragListener{
    void onFinishDrag();
  }
 
  public interface ItemTouchAdapter {
    void onMove(int fromPosition, int toPosition);
    void onSwiped(int position);
  }
}

 OnRecyclerItemClickListener.java

import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
 
import androidx.core.view.GestureDetectorCompat;
import androidx.recyclerview.widget.RecyclerView;
 
/**
 * Created by Administrator on 2016/4/14.
 */
public class OnRecyclerItemClickListener implements RecyclerView.OnItemTouchListener {
  private GestureDetectorCompat mGestureDetector;
  private RecyclerView recyclerView;
 
  public OnRecyclerItemClickListener(RecyclerView recyclerView){
    this.recyclerView = recyclerView;
    mGestureDetector = new GestureDetectorCompat(recyclerView.getContext(),new ItemTouchHelperGestureListener());
  }
 
  @Override
  public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
    mGestureDetector.onTouchEvent(e);
    return false;
  }
 
  @Override
  public void onTouchEvent(RecyclerView rv, MotionEvent e) {
    mGestureDetector.onTouchEvent(e);
  }
 
  @Override
  public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
 
  }
 
  private class ItemTouchHelperGestureListener extends GestureDetector.SimpleOnGestureListener {
 
    @Override
    public boolean onSingleTapUp(MotionEvent e) {
      View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
      if (child!=null) {
        RecyclerView.ViewHolder vh = recyclerView.getChildViewHolder(child);
        onItemClick(vh);
      }
      return true;
    }
 
    @Override
    public void onLongPress(MotionEvent e) {
      View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
      if (child!=null) {
        RecyclerView.ViewHolder vh = recyclerView.getChildViewHolder(child);
        onLongClick(vh);
      }
    }
  }
 
  public void onLongClick(RecyclerView.ViewHolder vh){}
  public void onItemClick(RecyclerView.ViewHolder vh){}
}

 适配器里面实现接口

MyItemTouchCallback.ItemTouchAdapter

import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
 
import org.greenrobot.eventbus.EventBus;
 
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
 
import static com.appsinnova.android.keepdrop.recommend.entity.ChannelHead.channelType;
 
public class ChannelManagerAdapter extends BaseMultiItemQuickAdapter<MultiItemEntity, BaseViewHolder> implements MyItemTouchCallback.ItemTouchAdapter {
 
  public static final String TAG = ChannelManagerAdapter.class.getSimpleName();
  public static final int MY_VEDIO_TYPE = 0;
  public static final int MORE_VEDIO_TYPE = 1;
  public static final int CAN_EDITABLE = 1;
  public static final int CAN_NOT_EDITABLE = 0;
 
  public List<MultiItemEntity> results = null;
 
  public ChannelManagerAdapter(List<MultiItemEntity> data) {
    super(data);
    addItemType(ChannelHead.channelHeadType, R.layout.item_channel_head);
    addItemType(channelType, R.layout.item_channel);
    this.results = data;
  }
 
  @Override
  protected void convert(BaseViewHolder helper, MultiItemEntity item) {
    switch (helper.getItemViewType()) {
    
		}
  }
 
  @Override
  public void onMove(int fromPosition, int toPosition) {
    if (fromPosition==results.size()-1 || toPosition==results.size()-1){
      return;
    }
    if (fromPosition < toPosition) {
      for (int i = fromPosition; i < toPosition; i++) {
        Collections.swap(results, i, i + 1);
      }
    } else {
      for (int i = fromPosition; i > toPosition; i--) {
        Collections.swap(results, i, i - 1);
      }
    }
		//这个数据是移动后的数据，会更新原始数据
    int size = results.size();
    List<RecommendVedioModel.RecommendVedioItem> items = new ArrayList<RecommendVedioModel.RecommendVedioItem>();
    RecommendVedioModel recommendVedioModel = SPHelper.getInstance().getObject(SpConstants.RECOMMEND_VEDIO_CATETGORY, RecommendVedioModel.class);
    for (int i = 0; i < size; ++i) {
      if (results.get(i).getItemType() == channelType) {
        RecommendVedioModel.RecommendVedioItem item = (RecommendVedioModel.RecommendVedioItem)results.get(i);
        items.add(item);
      }
    }
    if (recommendVedioModel != null) {
      recommendVedioModel.items = items;
    } else {
      Log.i(TAG, "recommendVedioModel is null");
    }
    SPHelper.getInstance().putObject(SpConstants.RECOMMEND_VEDIO_CATETGORY, recommendVedioModel);
    notifyItemMoved(fromPosition, toPosition);
  }
 
  @Override
  public void onSwiped(int position) {
 
  }
}

然后在页面显示的地方

 channelManagerAdapter = ChannelManagerAdapter(allDatas)
    val layoutManager = LinearLayoutManager(this)
    layoutManager.orientation = LinearLayoutManager.VERTICAL
    channelRecycleview.setLayoutManager(layoutManager)
    channelRecycleview.setAdapter(channelManagerAdapter)
    val itemTouchHelper = ItemTouchHelper(MyItemTouchCallback(channelManagerAdapter))
    itemTouchHelper.attachToRecyclerView(channelRecycleview)
 
    channelRecycleview.addOnItemTouchListener(object : OnRecyclerItemClickListener(channelRecycleview) {
      override fun onLongClick(vh: RecyclerView.ViewHolder) {
        LogUtil.i(TAG, "onLongClick vh.layoutPosition is：" + vh.layoutPosition)
        var index = vh.layoutPosition
        if (!prohibitDragIndexs.contains(index)) {
          itemTouchHelper.startDrag(vh)
        }
      }
    })

到此这篇关于Android之RecycleView实现指定范围的拖动效果的文章就介绍到这了,更多相关android recycleView实现指定范围的拖动内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！

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