Flutter 教學

 2019 最新入門零基礎【從零開始學 Flutter 程式設計】線上教學課程目錄

Flutter中文网 (強力推薦)

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一起來學吧~~~

趁空窗期,多吃點新鮮的....不然沒時間進修

flutter doctor cmdline-tools component is missing

 參考來源 Flutter｜環境建置－flutter doctor

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在Android Studio中，點擊SDK Manager

側邊選擇Android SDK

右邊切至 SDK tools頁籤

勾選 Android SDK Command-line Tools(latest)

選擇Apply安裝

再次執行flutter doctor，沒問題後就完成環境建置。

Flutter 官網

 flutter 官網

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比較兩個資料表不同部分

 比較兩個資料表不同部分

在t2表而不在t1表的資料

1、SELECT * FROM t2 WHERE id NOT IN (SELECT id FROM t1);

2、SELECT * FROM t2 WHERE NOT EXISTS(SELECT * FROM t1 WHERE t1.id=t2.id);

3、SELECT t2.* FROM t2 LEFT JOIN t1 ON t2.id=t1.id WHERE t1.id is null;

vb.net jsonconvert.deserializeobject dictionary

 

JSON -> Dictionaries:

Imports System.IO

Imports Newtonsoft.Json

Imports Newtonsoft.Json.Linq

Module Module1

    Sub Main()

        Dim json = File.ReadAllText("data.txt")

        Dim parsed = JsonConvert.DeserializeObject(Of Dictionary(Of String, Object))(json)

        Dim stringValue As String = parsed("string").ToString()

        Dim numberValue As Integer = CInt(parsed("number"))

        Dim arrayValue As JArray = parsed("array")

        Dim subObject As JObject = parsed("otherObject")

        Console.WriteLine("string: {0}", stringValue)

        Console.WriteLine("number: {0}", numberValue)

        Console.WriteLine("Array values:")

        For Each item As Object In arrayValue

            Console.WriteLine(item)

        Next

        Console.WriteLine("otherObject.number:")

        Console.WriteLine(CInt(subObject("number")))

    End Sub

End Module

JSON -> Classes:

Imports System.IO

Imports Newtonsoft.Json

Imports Newtonsoft.Json.Linq

Module Module1

    Sub Main()

        Dim json = File.ReadAllText("data.txt")

        Dim parsed = JsonConvert.DeserializeObject(Of ExampleData)(json)

        Console.WriteLine("number: {0}", parsed.Number)

        Console.WriteLine("string: {0}", parsed.String)

        Console.WriteLine("Array values:")

        For Each item As Integer In parsed.Array

            Console.WriteLine(item)

        Next

        Console.WriteLine("OtherObject.Number: {0}", parsed.OtherObject.Number)

    End Sub

End Module

Public Class ExampleData

    Public Property Number As Integer

    Public Property [String] As String

    Public Property Array As Integer()

    Public Property OtherObject As OtherObject

End Class

Public Class OtherObject

    Public Property Number As Integer

End Class

又開始不下雨了

 在旱地又遇到不下雨,真的很麻煩

上頭水源又被堵掉,不肯放水到我田裡

人在做,真的天會看的

多的水寧改道流掉,也不肯讓水流到我田裡

扯爆了

自己只好用引擎抽水機抽溪水,但真的金錢有限....時間也有限

只能灌溉多少是多少