负载ListView

拼搏现实的明天。 2022-08-05 05:20 89阅读 0赞

复杂的ListView的实现：

/**
    	 * ListView的适配器
    	 */
    	private class AppManagerAdapter extends BaseAdapter{
    		@Override
    		public int getCount() {
    			return userAppInfos.size()+1+systemAppInfos.size()+1;
    		}
    		@Override
    		public View getView(int position, View convertView, ViewGroup parent) {
    			AppInfo appInfo;
    			if(position == 0){ //显示用户程序有多少个的小标签
    				TextView tv = new TextView(getApplication());
    				tv.setTextColor(Color.WHITE);
    				tv.setBackgroundColor(Color.GRAY);
    				tv.setText("用户程序:"+userAppInfos.size()+"个");
    				return tv;
    			}else if(position == (userAppInfos.size()+1)){
    				TextView tv = new TextView(getApplicationContext());
    				tv.setTextColor(Color.WHITE);
    				tv.setBackgroundColor(Color.GRAY);
    				tv.setText("系统程序:"+systemAppInfos.size()+"个");
    				return tv;
    			}else if(position <= userAppInfos.size()){
    				int newPosition = position-1;
    				appInfo = userAppInfos.get(newPosition);
    			}else{
    				int newPosition = position-1-userAppInfos.size()-1;
    				appInfo = systemAppInfos.get(newPosition);
    			}
    			View view;
    			ViewHolder holder;
    			// 不仅需要检查是否为空，还要判断是否是合适的类型去复用
    			if(convertView != null && convertView instanceof RelativeLayout){
    				view = convertView;
    				holder = (ViewHolder) view.getTag();
    			}else{
    				view = View.inflate(getApplicationContext(),R.layout.list_item_appinfo,null);
    				holder = new ViewHolder();
    				holder.iv_icon = (ImageView) view.findViewById(R.id.iv_app_icon);
    				holder.tv_location = (TextView) view.findViewById(R.id.tv_app_location);
    				holder.tv_name = (TextView) view.findViewById(R.id.tv_app_name);
    				view.setTag(holder);
    			}
    			holder.iv_icon.setImageDrawable(appInfo.getIcon());
    			holder.tv_name.setText(appInfo.getName());
    			if(appInfo.isInRom()){
    				holder.tv_location.setText("手机内存");
    			}else{
    				holder.tv_location.setText("外部存储");
    			}
    			return view;
    		}
    		@Override
    		public Object getItem(int position) {
    			return null;
    		}
    		@Override
    		public long getItemId(int position) {
    			return 0;
    		}
    	}
    	static class ViewHolder {
    		TextView tv_name;
    		TextView tv_location;
    		ImageView iv_icon;
    	}