diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index afbca6a..6c1c643 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -60,7 +60,7 @@
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@@ -118,7 +118,7 @@
             "state": {
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               "state": {
-                "file": "00. Inbox/01. TODO.md",
+                "file": "04. Programming/Kotlin/AtomicBoolean.md",
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                 "sortOrder": "alphabetical",
@@ -154,7 +154,7 @@
             "state": {
               "type": "outline",
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-                "file": "00. Inbox/01. TODO.md"
+                "file": "04. Programming/Kotlin/AtomicBoolean.md"
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@@ -180,11 +180,11 @@
       "periodic-notes:Open today": false
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-  "active": "3b4577823cedf427",
+  "active": "0c4cc0216ea83049",
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+    "00. Inbox/01. TODO.md",
     "04. Programming/Kotlin/AtomicBoolean.md",
     "04. Programming/Kotlin/run, let, with, also 和 apply.md",
-    "00. Inbox/01. TODO.md",
     "05. 資料收集/軟體工具/git/tag.md",
     "05. 資料收集/讀書筆記/20230206 - 卡片盒筆記.md",
     "01. 個人/00. Informations/Datas.md",
diff --git a/04. Programming/Kotlin/AtomicBoolean.md b/04. Programming/Kotlin/AtomicBoolean.md
index dd97dfe..c7fc23b 100644
--- a/04. Programming/Kotlin/AtomicBoolean.md	
+++ b/04. Programming/Kotlin/AtomicBoolean.md	
@@ -1 +1,19 @@
+[AtomicBoolean  |  Android Developers](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicBoolean)
+
 ## 初始化
+```kotlin
+val init = AtomicBoolean(false)
+or
+val inti = AtomicBoolean() // Default false
+```
+
+## read/write
+用`get()`取值，用`set()`設值
+例：
+```kotlin
+if (init.get()) { ... } // 如果 init 是 true 的話
+
+init.set(true) // 將 init 設為 true
+```
+
+## 其他function