Android Listview滑动时不加载数据，停下来时加载数据，让App更优

转载：http://blog.csdn.NET/yy1300326388/article/details/45153813

数据源配置（Adapter）

PRivate  boolean scrollState=false;        public void setScrollState(boolean scrollState) {          this.scrollState = scrollState;      }          public MyAdapter(Context context, List<UserEnity> lists) {          this.context=context;          this.inflater=LayoutInflater.from(context);          this.lists=lists;      }        @Override      public int getCount() {          return lists!=null?lists.size():0;      }        @Override      public Object getItem(int position) {          return lists.get(position);      }        @Override      public long getItemId(int position) {          return position;      }        @Override      public View getView(int position, View convertView, ViewGroup parent) {          ViewHolder viewHolder;          if (convertView == null) {              convertView=inflater.inflate(R.layout.main_item,null,true);              viewHolder=new ViewHolder();              viewHolder.iv_icon= (ImageView) convertView.findViewById(R.id.main_item_iv_icon);              viewHolder.tv_name= (TextView) convertView.findViewById(R.id.main_item_tv_name);              convertView.setTag(viewHolder);          } else {              viewHolder= (ViewHolder) convertView.getTag();          }              UserEnity userEnity=lists.get(position);            String img_url=userEnity.getIcon();          if (!scrollState){              viewHolder.tv_name.setText(userEnity.getName());              viewHolder.tv_name.setTag(null);              ImageLoader.getInstance().displayImage(img_url,viewHolder.iv_icon);              viewHolder.iv_icon.setTag("1");            }else{              viewHolder.tv_name.setText("加载中");              viewHolder.tv_name.setTag(userEnity.getName());              viewHolder.iv_icon.setTag(img_url);              viewHolder.iv_icon.setImageResource(R.mipmap.ic_launcher);            }          return convertView;        }        static class ViewHolder{          TextView tv_name;          ImageView iv_icon;      }  }  这个Adapter中重要的代码如下:

[java]%20view%20plain%20copy%20//定义当前listview是否在滑动状态  private  boolean scrollState=false;  public void setScrollState(boolean scrollState) {      this.scrollState = scrollState;  }  [java]%20view%20plain%20copy%20//实体类  UserEnity userEnity=lists.get(position);    if (!scrollState){//如果当前不是滑动的状态，我们填充真数据              //填充数据              viewHolder.tv_name.setText(userEnity.getName());              //设置Tag中数据为空表示数据已填充              viewHolder.tv_name.setTag(null);              //加载图片              ImageLoader.getInstance().displayImage(img_url,viewHolder.iv_icon);              //设置tag为1表示已加载过数据              viewHolder.iv_icon.setTag("1");    }else{//如果当前是滑动的状态，我们填充假数据              viewHolder.tv_name.setText("加载中");              //将数据name保存在Tag当中              viewHolder.tv_name.setTag(userEnity.getName());              //将数据image_url保存在Tag当中              viewHolder.iv_icon.setTag(img_url);              //设置默认显示图片（最好是本地资源的图片）              viewHolder.iv_icon.setImageResource(R.mipmap.ic_launcher);    }  我们在看看Activity中的代码，主要是监听listview的onscrolllistener方法

[java]%20view%20plain%20copy%20@Override      public void onScrollStateChanged(AbsListView view, int scrollState) {          switch (scrollState){                case AbsListView.OnScrollListener.SCROLL_STATE_IDLE://停止滚动              {                  //设置为停止滚动                  myAdapter.setScrollState(false);                  //当前屏幕中listview的子项的个数                  int count = view.getChildCount();                  Log.e("MainActivity",count+"");                    for (int i = 0; i < count; i++) {                      //获取到item的name                      TextView tv_name = (TextView) view.getChildAt(i).findViewById(R.id.main_item_tv_name);                      //获取到item的头像                      ImageView iv_show= (ImageView) view.getChildAt(i).findViewById(R.id.main_item_iv_icon);                        if (tv_name.getTag() != null) { //非null说明需要加载数据                          tv_name.setText(tv_name.getTag().toString());//直接从Tag中取出我们存储的数据name并且赋值                          tv_name.setTag(null);//设置为已加载过数据                      }                        if (!iv_show.getTag().equals("1")){//!="1"说明需要加载数据                          String image_url=iv_show.getTag().toString();//直接从Tag中取出我们存储的数据image——url                          ImageLoader.getInstance().displayImage(image_url, iv_show);//显示图片                          iv_show.setTag("1");//设置为已加载过数据                      }                  }                  break;              }              case AbsListView.OnScrollListener.SCROLL_STATE_FLING://滚动做出了抛的动作              {                  //设置为正在滚动                  myAdapter.setScrollState(true);                  break;              }                case AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL://正在滚动              {                  //设置为正在滚动                  myAdapter.setScrollState(true);                  break;              }          }      }  最后记得给listview加上滑动的监听

listview.setOnScrollListener(this);效果