Android实现GridView中的item自由拖动效果
之前的工作中，需要实现一个功能就是GridView中的item可以自由拖动，思考了一下，其实实现起来不是很困难，主要工作就是交换节点，以及拖动时的移动效果，下面讲讲具体的实现：
首先声明一个BaseAdapter:
packagecom.dafasoft.dragablegridview;
importandroid.content.Context;
importandroid.view.LayoutInflater;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.AbsListView;
importandroid.widget.AdapterView;
importandroid.widget.BaseAdapter;
importjava.util.ArrayList;
importjava.util.List;
/**
*Createdbyzhangyulongon16/9/22.
*/
publicabstractclassBaseDragableAdapter<T>extendsBaseAdapter{
protectedList<T>mList;
protectedContextmContext;
protectedLayoutInflatermInflater;
//初始化需隐藏的位置信息
protectedintmHidePosition=AdapterView.INVALID_POSITION;
publicBaseDragableAdapter(Contextcontext){
this.mContext=context;
this.mInflater=LayoutInflater.from(context);
mList=newArrayList<T>();
}
@Override
publicintgetCount(){
returnmList==null?0:mList.size();
}
@Override
publicObjectgetItem(inti){
returnmList==null?0:mList.get(i);
}
@Override
publiclonggetItemId(inti){
returni;
}
@Override
publicabstractViewgetView(inti,Viewview,ViewGroupviewGroup);
publicvoidsetList(List<T>list){
if(this.mList!=null)this.mList.clear();//避免脏数据
if(list==null){
return;
}
this.mList=list;
}
publicvoidsetList(T[]list){
ArrayList<T>arrayList=newArrayList<T>(list.length);
for(Tt:list){
arrayList.add(t);
}
setList(arrayList);
}
publicList<T>getList(){
returnthis.mList;
}
publicvoidaddAll(List<T>list){
if(list==null||list.size()==0)return;
this.mList.addAll(list);
}
publicvoidaddAll(intlocation,List<T>list){
if(list==null||list.size()==0)return;
this.mList.addAll(location,list);
}
publicvoidclean(){
if(getCount()==0)return;
mList.clear();
}
publicvoidhideView(intposition){
mHidePosition=position;
notifyDataSetChanged();
}
publicvoidshowHideView(){
//重置hideposition
mHidePosition=AdapterView.INVALID_POSITION;
notifyDataSetChanged();
}
/**
*交换节点
*@paramdraggedPos拖拽的起始节点
*@paramcurrentPos拖拽的当前节点
*/
publicvoidswapView(intdraggedPos,intcurrentPos){
//从前往后拖
if(draggedPos<currentPos){
//将被拖拽的节点移动至当前节点
mList.add(currentPos+1,mList.get(draggedPos));
//删除拖拽前的节点
mList.remove(draggedPos);
}
//从后往前拖
elseif(draggedPos>currentPos){
//将被拖拽的节点移动至当前节点
mList.add(currentPos,mList.get(draggedPos));
//删除拖拽前的节点
mList.remove(draggedPos+1);
}
mHidePosition=currentPos;
notifyDataSetChanged();
}
}
其次实现DragableGridView:
packagecom.dafasoft.dragablegridview;
importandroid.content.Context;
importandroid.graphics.Bitmap;
importandroid.graphics.PixelFormat;
importandroid.util.AttributeSet;
importandroid.util.Log;
importandroid.view.Gravity;
importandroid.view.MotionEvent;
importandroid.view.View;
importandroid.view.WindowManager;
importandroid.widget.AdapterView;
importandroid.widget.GridView;
importandroid.widget.ImageView;
/**
*Createdbyzhangyulongon16/9/22.
*/
publicclassDragableGridViewextendsGridView{
privatestaticfinalintDRAG_IMG_SHOW=1;
privatestaticfinalintDRAG_IMG_NOT_SHOW=0;
privatestaticfinalStringLOG_TAG="DragGridView";
privatestaticfinalfloatAMP_FACTOR=1.2f;
privateImageViewdragImageView;
privateWindowManager.LayoutParamsdragImageViewParams;
privateWindowManagerwindowManager;
privatebooleanisViewOnDrag=false;
/**previousdraggedoverposition*/
privateintpreDraggedOverPositon=AdapterView.INVALID_POSITION;
privateintdownRawX;
privateintdownRawY;
publicDragableGridView(Contextcontext){
super(context);
initView();
}
publicDragableGridView(Contextcontext,AttributeSetattrs){
super(context,attrs);
initView();
}
publicDragableGridView(Contextcontext,AttributeSetattrs,intdefStyleAttr){
super(context,attrs,defStyleAttr);
initView();
}
publicvoidinitView(){
setOnItemLongClickListener(mOnItemLongClickListener);
//setOnItemClickListener(onItemClickListener);
//setOnItemSelectedListener(onItemSelectedListener);
//初始化显示被拖动item的imageview
dragImageView=newImageView(getContext());
dragImageView.setTag(DRAG_IMG_NOT_SHOW);
//初始化用于设置dragImageView的参数对象
dragImageViewParams=newWindowManager.LayoutParams();
//获取窗口管理对象，用于后面向窗口中添加dragImageView
windowManager=(WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE);
}
privateOnItemLongClickListenermOnItemLongClickListener=newOnItemLongClickListener(){
@Override
publicbooleanonItemLongClick(AdapterView<?>parent,Viewview,intposition,longid){
//记录长按item位置
preDraggedOverPositon=position;
//获取被长按item的drawingcache
view.destroyDrawingCache();
view.setDrawingCacheEnabled(true);
//通过被长按item，获取拖动item的bitmap
BitmapdragBitmap=Bitmap.createBitmap(view.getDrawingCache());
//设置拖动item的参数
dragImageViewParams.gravity=Gravity.TOP|Gravity.LEFT;
//设置拖动item为原item1.2倍
dragImageViewParams.width=(int)(AMP_FACTOR*dragBitmap.getWidth());
dragImageViewParams.height=(int)(AMP_FACTOR*dragBitmap.getHeight());
//设置触摸点为绘制拖动item的中心
dragImageViewParams.x=(downRawX-dragImageViewParams.width/2);
dragImageViewParams.y=(downRawY-dragImageViewParams.height/2);
dragImageViewParams.flags=WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
|WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
|WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
|WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;
//设置窗口支持透明度
dragImageViewParams.format=PixelFormat.TRANSLUCENT;
dragImageViewParams.windowAnimations=0;
//dragImageView为被拖动item的容器，清空上一次的显示
if((int)dragImageView.getTag()==DRAG_IMG_SHOW){
windowManager.removeView(dragImageView);
dragImageView.setTag(DRAG_IMG_NOT_SHOW);
}
//设置本次被长按的item
dragImageView.setImageBitmap(dragBitmap);
//添加拖动item到屏幕
windowManager.addView(dragImageView,dragImageViewParams);
dragImageView.setTag(DRAG_IMG_SHOW);
isViewOnDrag=true;
//设置被长按item不显示
((BaseDragableAdapter)getAdapter()).hideView(position);
returntrue;
}
};
@Override
publicbooleanonTouchEvent(MotionEventev){
//被按下时记录按下的坐标
if(ev.getAction()==MotionEvent.ACTION_DOWN){
//获取触摸点相对于屏幕的坐标
downRawX=(int)ev.getRawX();
downRawY=(int)ev.getRawY();
}
//dragImageView处于被拖动时，更新dragImageView位置
elseif((ev.getAction()==MotionEvent.ACTION_MOVE)&&(isViewOnDrag==true)){
Log.i(LOG_TAG,""+ev.getRawX()+""+ev.getRawY());
//设置触摸点为dragImageView中心
dragImageViewParams.x=(int)(ev.getRawX()-dragImageView.getWidth()/2);
dragImageViewParams.y=(int)(ev.getRawY()-dragImageView.getHeight()/2);
//更新窗口显示,移动dragImageView的位置
windowManager.updateViewLayout(dragImageView,dragImageViewParams);
//获取当前触摸点的itemposition
intcurrDraggedPosition=pointToPosition((int)ev.getX(),(int)ev.getY());
//如果当前停留位置item不等于上次停留位置的item，交换本次和上次停留的item
if((currDraggedPosition!=AdapterView.INVALID_POSITION)&&(currDraggedPosition!=preDraggedOverPositon)){
((BaseDragableAdapter)getAdapter()).swapView(preDraggedOverPositon,currDraggedPosition);
preDraggedOverPositon=currDraggedPosition;
}
}
//释放dragImageView
elseif((ev.getAction()==MotionEvent.ACTION_UP)&&(isViewOnDrag==true)){
((BaseDragableAdapter)getAdapter()).showHideView();
if((int)dragImageView.getTag()==DRAG_IMG_SHOW){
windowManager.removeView(dragImageView);
dragImageView.setTag(DRAG_IMG_NOT_SHOW);
}
isViewOnDrag=false;
}
returnsuper.onTouchEvent(ev);
}
}
实现一个adapter继承自BaseDragableAdapter:
packagecom.dafasoft.dragablegridview;
importandroid.content.Context;
importandroid.view.LayoutInflater;
importandroid.view.View;
importandroid.view.ViewGroup;
importandroid.widget.TextView;
/**
*Createdbyzhangyulongon16/9/22.
*/
publicclassMyAdapterextendsBaseDragableAdapter<String>{
publicMyAdapter(Contextcontext){
super(context);
}
@Override
publicViewgetView(inti,Viewview,ViewGroupviewGroup){
ViewHolderviewHolder;
if(view==null){
viewHolder=newViewHolder();
view=mInflater.inflate(R.layout.adapter_my,null);
viewHolder.mItemTv=(TextView)view.findViewById(R.id.tv_item);
view.setTag(viewHolder);
}else{
viewHolder=(ViewHolder)view.getTag();
}
if(mHidePosition==i){
view.setVisibility(View.GONE);
}else{
view.setVisibility(View.VISIBLE);
}
viewHolder.mItemTv.setText(mList.get(i));
returnview;
}
classViewHolder{
TextViewmItemTv;
}
}
在activity中使用：
packagecom.dafasoft.dragablegridview;
importandroid.app.Activity;
importandroid.support.v7.app.AppCompatActivity;
importandroid.os.Bundle;
importjava.util.ArrayList;
importjava.util.List;
publicclassMainActivityextendsActivity{
privateDragableGridViewmDragableGv;
@Override
protectedvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDragableGv=(DragableGridView)findViewById(R.id.drag_grid_view);
MyAdapteradapter=newMyAdapter(this);
List<String>list=newArrayList<String>();
for(inti=0;i<30;i++){
list.add("position"+i);
}
adapter.setList(list);
mDragableGv.setAdapter(adapter);
}
}
以上所述是小编给大家介绍的Android实现GridView中的item自由拖动效果,实现一个模拟后台数据登入的效果，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对毛票票网站的支持！
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