diff --git a/src/.gradle/5.4.1/executionHistory/executionHistory.lock b/src/.gradle/5.4.1/executionHistory/executionHistory.lock
index 41eb9fd..539cb4c 100644
Binary files a/src/.gradle/5.4.1/executionHistory/executionHistory.lock and b/src/.gradle/5.4.1/executionHistory/executionHistory.lock differ
diff --git a/src/.gradle/5.4.1/fileHashes/fileHashes.lock b/src/.gradle/5.4.1/fileHashes/fileHashes.lock
index cd85a9b..87d8af9 100644
Binary files a/src/.gradle/5.4.1/fileHashes/fileHashes.lock and b/src/.gradle/5.4.1/fileHashes/fileHashes.lock differ
diff --git a/src/.gradle/buildOutputCleanup/buildOutputCleanup.lock b/src/.gradle/buildOutputCleanup/buildOutputCleanup.lock
index 9d3f598..551f969 100644
Binary files a/src/.gradle/buildOutputCleanup/buildOutputCleanup.lock and b/src/.gradle/buildOutputCleanup/buildOutputCleanup.lock differ
diff --git a/src/.idea/workspace.xml b/src/.idea/workspace.xml
index 568089d..0f59503 100644
--- a/src/.idea/workspace.xml
+++ b/src/.idea/workspace.xml
@@ -6,7 +6,14 @@
     </shared>
   </component>
   <component name="ChangeListManager">
-    <list default="true" id="c8515555-ebbc-49d5-889b-0c59bd6c3b6d" name="默认更改列表" comment="" />
+    <list default="true" id="c8515555-ebbc-49d5-889b-0c59bd6c3b6d" name="默认更改列表" comment="ziji wu comment">
+      <change beforePath="$PROJECT_DIR$/.gradle/5.4.1/executionHistory/executionHistory.lock" beforeDir="false" afterPath="$PROJECT_DIR$/.gradle/5.4.1/executionHistory/executionHistory.lock" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.gradle/5.4.1/fileHashes/fileHashes.lock" beforeDir="false" afterPath="$PROJECT_DIR$/.gradle/5.4.1/fileHashes/fileHashes.lock" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.gradle/buildOutputCleanup/buildOutputCleanup.lock" beforeDir="false" afterPath="$PROJECT_DIR$/.gradle/buildOutputCleanup/buildOutputCleanup.lock" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Notes.java" beforeDir="false" afterPath="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Notes.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java" beforeDir="false" afterPath="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java" afterDir="false" />
+    </list>
     <option name="EXCLUDED_CONVERTED_TO_IGNORED" value="true" />
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -29,7 +36,7 @@
       <file pinned="false" current-in-tab="false">
         <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Contact.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="322">
+            <state relative-caret-position="620">
               <caret line="52" column="17" selection-start-line="52" selection-start-column="17" selection-end-line="52" selection-end-column="17" />
               <folding>
                 <element signature="imports" expanded="true" />
@@ -41,8 +48,8 @@
       <file pinned="false" current-in-tab="true">
         <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Notes.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="445">
-              <caret line="286" lean-forward="true" selection-start-line="286" selection-end-line="286" />
+            <state relative-caret-position="216">
+              <caret line="68" column="39" selection-start-line="68" selection-start-column="39" selection-end-line="68" selection-end-column="39" />
             </state>
           </provider>
         </entry>
@@ -50,7 +57,7 @@
       <file pinned="false" current-in-tab="false">
         <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/model/Note.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="360">
+            <state relative-caret-position="-1908">
               <caret line="48" column="28" selection-start-line="48" selection-start-column="28" selection-end-line="48" selection-end-column="28" />
               <folding>
                 <element signature="e#2949#2950#0" expanded="true" />
@@ -71,8 +78,8 @@
       <file pinned="false" current-in-tab="false">
         <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="140">
-              <caret line="29" column="13" selection-start-line="29" selection-start-column="13" selection-end-line="29" selection-end-column="13" />
+            <state relative-caret-position="355">
+              <caret line="49" column="36" lean-forward="true" selection-start-line="49" selection-start-column="36" selection-end-line="49" selection-end-column="36" />
             </state>
           </provider>
         </entry>
@@ -80,7 +87,7 @@
       <file pinned="false" current-in-tab="false">
         <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesProvider.java">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="-132">
+            <state relative-caret-position="300">
               <caret line="44" column="38" selection-start-line="44" selection-start-column="38" selection-end-line="44" selection-end-column="38" />
             </state>
           </provider>
@@ -107,6 +114,9 @@
     </option>
     <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$/.." />
   </component>
+  <component name="HighlightingSettingsPerFile">
+    <setting file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java" root0="FORCE_HIGHLIGHTING" />
+  </component>
   <component name="IdeDocumentHistory">
     <option name="CHANGED_PATHS">
       <list>
@@ -119,13 +129,14 @@
         <option value="$PROJECT_DIR$/app/src/main/java/net/micode/notes/tool/BackupUtils.java" />
         <option value="$PROJECT_DIR$/app/src/main/res/xml/widget_4x_info.xml" />
         <option value="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Contact.java" />
+        <option value="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java" />
         <option value="$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Notes.java" />
       </list>
     </option>
   </component>
-  <component name="ProjectFrameBounds" extendedState="7">
-    <option name="x" value="85" />
-    <option name="y" value="25" />
+  <component name="ProjectFrameBounds" extendedState="6">
+    <option name="x" value="-9" />
+    <option name="y" value="-9" />
     <option name="width" value="1750" />
     <option name="height" value="1030" />
   </component>
@@ -135,6 +146,8 @@
       <foldersAlwaysOnTop value="true" />
     </navigator>
     <panes>
+      <pane id="ProjectPane" />
+      <pane id="PackagesPane" />
       <pane id="Scope" />
       <pane id="AndroidView">
         <subPane>
@@ -228,8 +241,6 @@
           <select />
         </subPane>
       </pane>
-      <pane id="ProjectPane" />
-      <pane id="PackagesPane" />
     </panes>
   </component>
   <component name="PropertiesComponent">
@@ -239,7 +250,7 @@
     <property name="SHARE_PROJECT_CONFIGURATION_FILES" value="true" />
     <property name="SONARLINT_PRECOMMIT_ANALYSIS" value="true" />
     <property name="android.sdk.path" value="D:/Android_SDK/SDK" />
-    <property name="settings.editor.selected.configurable" value="AndroidSdkUpdater" />
+    <property name="settings.editor.selected.configurable" value="preferences.pluginManager" />
   </component>
   <component name="RunDashboard">
     <option name="ruleStates">
@@ -392,7 +403,7 @@
     <editor active="true" />
     <layout>
       <window_info id="Captures" order="0" side_tool="true" weight="0.25" />
-      <window_info active="true" content_ui="combo" id="Project" order="1" visible="true" weight="0.1842448" />
+      <window_info active="true" content_ui="combo" id="Project" order="1" visible="true" weight="0.16601562" />
       <window_info id="设计器" order="2" />
       <window_info id="Resources Explorer" order="3" weight="0.3297587" />
       <window_info id="Structure" order="4" side_tool="true" />
@@ -410,7 +421,7 @@
       <window_info anchor="bottom" id="Terminal" order="7" weight="0.3297587" />
       <window_info anchor="bottom" id="Event Log" order="8" side_tool="true" weight="0.3294271" />
       <window_info anchor="bottom" id="Version Control" order="9" weight="0.3297587" />
-      <window_info anchor="bottom" id="Build" order="10" weight="0.32931727" />
+      <window_info anchor="bottom" id="Build" order="10" visible="true" weight="0.3059896" />
       <window_info anchor="bottom" id="Messages" order="11" weight="0.3297587" />
       <window_info anchor="right" id="Gradle" order="0" />
       <window_info anchor="right" id="Device File Explorer" order="1" side_tool="true" />
@@ -554,16 +565,33 @@
         </state>
       </provider>
     </entry>
+    <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Contact.java">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="620">
+          <caret line="52" column="17" selection-start-line="52" selection-start-column="17" selection-end-line="52" selection-end-column="17" />
+          <folding>
+            <element signature="imports" expanded="true" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
     <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesProvider.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="-132">
+        <state relative-caret-position="300">
           <caret line="44" column="38" selection-start-line="44" selection-start-column="38" selection-end-line="44" selection-end-column="38" />
         </state>
       </provider>
     </entry>
+    <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java">
+      <provider selected="true" editor-type-id="text-editor">
+        <state relative-caret-position="355">
+          <caret line="49" column="36" lean-forward="true" selection-start-line="49" selection-start-column="36" selection-end-line="49" selection-end-column="36" />
+        </state>
+      </provider>
+    </entry>
     <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/model/Note.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="360">
+        <state relative-caret-position="-1908">
           <caret line="48" column="28" selection-start-line="48" selection-start-column="28" selection-end-line="48" selection-end-column="28" />
           <folding>
             <element signature="e#2949#2950#0" expanded="true" />
@@ -580,27 +608,10 @@
         </state>
       </provider>
     </entry>
-    <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="140">
-          <caret line="29" column="13" selection-start-line="29" selection-start-column="13" selection-end-line="29" selection-end-column="13" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Contact.java">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="322">
-          <caret line="52" column="17" selection-start-line="52" selection-start-column="17" selection-end-line="52" selection-end-column="17" />
-          <folding>
-            <element signature="imports" expanded="true" />
-          </folding>
-        </state>
-      </provider>
-    </entry>
     <entry file="file://$PROJECT_DIR$/app/src/main/java/net/micode/notes/data/Notes.java">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="445">
-          <caret line="286" lean-forward="true" selection-start-line="286" selection-end-line="286" />
+        <state relative-caret-position="216">
+          <caret line="68" column="39" selection-start-line="68" selection-start-column="39" selection-end-line="68" selection-end-column="39" />
         </state>
       </provider>
     </entry>
diff --git a/src/app/src/main/java/net/micode/notes/data/Notes.java b/src/app/src/main/java/net/micode/notes/data/Notes.java
index 6f9a420..923f395 100644
--- a/src/app/src/main/java/net/micode/notes/data/Notes.java
+++ b/src/app/src/main/java/net/micode/notes/data/Notes.java
@@ -66,7 +66,7 @@ public class Notes {
 
 
     /**
-     *该类声明了一系列关于便签的final变量，没有定义方法
+     *该类声明了一系列关于便签的final变量，用于再数据库中标识便签，没有定义方法
      */
     public interface NoteColumns {
         /**
diff --git a/src/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java b/src/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java
index ffe5d57..0b3b80a 100644
--- a/src/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java
+++ b/src/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java
@@ -42,6 +42,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper {
 
     private static NotesDatabaseHelper mInstance;
 
+    //创建SQL便签表表项，String类型
     private static final String CREATE_NOTE_TABLE_SQL =
         "CREATE TABLE " + TABLE.NOTE + "(" +
             NoteColumns.ID + " INTEGER PRIMARY KEY," +