Android ListView 多个ItemViewType 导致View类型混乱的解决办法

淡淡的烟草味﹌ 2022-05-13 02:46 211阅读 0赞

关于ListView的基本使用，应该都很清楚。无非就是用一个ViewHolder缓存，然后重用convertView。如下：

@Override
    		public View getView(int position, View convertView, ViewGroup parent) {
    			ViewHolder viewHolder = null;
    			if (convertView == null) {
    				convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.chat_left_item_text, null);
    				viewHolder = new ViewHolder();
    				viewHolder.imageView = (ImageView) convertView.findViewById(R.id.chat_head_iv);
    				convertView.setTag(viewHolder);
    			} else {
    				viewHolder = (ViewHolder) convertView.getTag();
    			}
    			return convertView;
    		}
    
    		class ViewHolder {
    			ImageView imageView;
    		}

但是这次在做一个即时通讯的项目是，ListView中要放的ItemViewType 有十几个之多。然后，同样的使用上面的缓存方法，如下：

private class ChatHeadAdapter extends BaseAdapter {
    
    		@Override
    		public int getCount() {
    			return 50;
    		}
    
    		@Override
    		public Object getItem(int position) {
    			return position;
    		}
    
    		@Override
    		public long getItemId(int position) {
    			return position;
    		}
    
    		@Override
    		public int getItemViewType(int position) {
    			return position % 2;// Type 两种 0和1
    		}
    
    		@Override
    		public int getViewTypeCount() {
    			return 2;
    		}
    
    		@Override
    		public View getView(int position, View convertView, ViewGroup parent) {
    			int viewType = getItemViewType(position);
    			LeftViewHolder leftViewHolder = null;
    			RightViewHolder rightViewHolder = null;
    			if (convertView == null) {
    				if (viewType == 0) {// left
    					convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.chat_left_item_text, null);
    					leftViewHolder = new LeftViewHolder();
    					leftViewHolder.leftImageView = (ImageView) convertView.findViewById(R.id.chat_head_iv);
    					convertView.setTag(leftViewHolder);
    				} else {
    					convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.chat_right_item_text, null);
    					rightViewHolder = new RightViewHolder();
    					rightViewHolder.rightImageView = (ImageView) convertView.findViewById(R.id.chat_head_iv);
    					convertView.setTag(rightViewHolder);
    				}
    			} else {
    				if (viewType == 0) {// left
    					leftViewHolder = (LeftViewHolder) convertView.getTag();
    				} else {
    					rightViewHolder = (RightViewHolder) convertView.getTag();
    				}
    			}
    
    			if (viewType == 0) {// left
    				leftViewHolder.leftImageView.setImageResource(R.drawable.head_temp_left);
    			} else {
    				rightViewHolder.rightImageView.setImageResource(R.drawable.head_temp_right);
    			}
    
    			return convertView;
    		}
    
    		class LeftViewHolder {
    			ImageView leftImageView;
    		}
    
    		class RightViewHolder {
    			ImageView rightImageView;
    		}
    	}

当然实际情况比上面的要复杂的多，上面只是一个简单的例子。

不知道是由于什么原因，用了类似上面的方法来处理我的十几个ItemViewType，还是会经常出现ViewItem的类型不正确，查找很久也没发现原因。

然后只能通过下面的设置，解决这个问题。

@Override
    		public View getView(int position, View convertView, ViewGroup parent) {
    			int viewType = getItemViewType(position);
    			LeftViewHolder leftViewHolder = null;
    			RightViewHolder rightViewHolder = null;
    			if (convertView == null||((Integer) convertView.getTag(R.id.tag_key_chat_item_type))!=viewType) {
    				if (viewType == 0) {// left
    					convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.chat_left_item_text, null);
    					leftViewHolder = new LeftViewHolder();
    					leftViewHolder.leftImageView = (ImageView) convertView.findViewById(R.id.chat_head_iv);
    					convertView.setTag(R.id.tag_key_chat_item_view,leftViewHolder);
    				} else {
    					convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.chat_right_item_text, null);
    					rightViewHolder = new RightViewHolder();
    					rightViewHolder.rightImageView = (ImageView) convertView.findViewById(R.id.chat_head_iv);
    					convertView.setTag(R.id.tag_key_chat_item_view,rightViewHolder);
    				}
    				convertView.setTag(R.id.tag_key_chat_item_type, viewType);
    			} else {
    				if (viewType == 0) {// left
    					leftViewHolder = (LeftViewHolder) convertView.getTag(R.id.tag_key_chat_item_view);
    				} else {
    					rightViewHolder = (RightViewHolder) convertView.getTag(R.id.tag_key_chat_item_view);
    				}
    			}
    			
    			if (viewType == 0) {// left
    				leftViewHolder.leftImageView.setImageResource(R.drawable.head_temp_left);
    			} else {
    				rightViewHolder.rightImageView.setImageResource(R.drawable.head_temp_right);
    			}
    
    			return convertView;
    		}

R.id.tag\_key\_chat\_item\_type和R.id.tag\_key\_chat\_item\_view是在ids.xml中定义的两个普通的id