小编Akh*_*eni的帖子

所有图像类型都可以工作，甚至 gif 也可以，但 tif 和 tiff 图像不会在 android 中使用 React Native 的图像组件显示。

对于 gif，我使用了 fresco:animated-gif，但是对于 tif 和 tiff 还有其他方法吗？我在渲染中只使用了图像，tif 是我的本地图像。

我试图在用户之间的聊天中获取最后一条消息。以下是我的文档中的收藏。

{
"toUser":123,"fromUser":456,"message":"1 from suresh","timeStamp":"2019-10-09 16:39:14:1414 PM +05:30",

"toUser":456,"fromUser":123,"message":"Man super man ","timeStamp":"2019-10-09 16:43:09:0909 PM +05:30",

"toUser":456,"fromUser":123,"message":"Kk","timeStamp":"2019-10-09 18:31:12:1212 PM +05:30"

"toUser":456,"fromUser":123,"message":"It working man","timeStamp":"2019-10-09 18:31:18:1818 PM +05:30"

"toUser":456,"fromUser":123,"message":"2","timeStamp":"2019-10-09 18:31:21:2121 PM +05:30"

"toUser":101,"fromUser":123,"message":"Kk","timeStamp":"2019-10-09 18:31:12:1212 PM +05:30"
} 

我使用 mongo 查询作为

db.chats.aggregate(
[
    {$match:{$or:[{"toUser":123},{"fromUser":123}]}},
    { "$sort": { "timeStamp": -1}},    
    {
        "$group": {
           "_id": {fromUser:"$fromUser",toUser:"$toUser"},
           "fromUser": {"$first":"$fromUser"},
           "toUser" : {"$first":"$toUser"},
           "message": {"$first": "$message" },
            "timeStamp": { "$first": "$timeStamp"}
        }
    },
]
);

我的输出是

{ "_id" : { "fromUser" : 456, "toUser" : 123 }, "fromUser" …