diff --git a/.idea/caches/build_file_checksums.ser b/.idea/caches/build_file_checksums.ser
new file mode 100644
index 0000000..d66561f
Binary files /dev/null and b/.idea/caches/build_file_checksums.ser differ
diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
new file mode 100644
index 0000000..30aa626
--- /dev/null
+++ b/.idea/codeStyles/Project.xml
@@ -0,0 +1,29 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <Objective-C-extensions>
+      <file>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
+      </file>
+      <class>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
+      </class>
+      <extensions>
+        <pair source="cpp" header="h" fileNamingConvention="NONE" />
+        <pair source="c" header="h" fileNamingConvention="NONE" />
+      </extensions>
+    </Objective-C-extensions>
+  </code_scheme>
+</component>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index 4716600..13c4629 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,8 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="EntryPointsManager">
-    <entry_points version="2.0" />
-  </component>
   <component name="NullableNotNullManager">
     <option name="myDefaultNullable" value="android.support.annotation.Nullable" />
     <option name="myDefaultNotNull" value="android.support.annotation.NonNull" />
@@ -27,17 +24,7 @@
       </value>
     </option>
   </component>
-  <component name="ProjectLevelVcsManager" settingsEditedManually="false">
-    <OptionsSetting value="true" id="Add" />
-    <OptionsSetting value="true" id="Remove" />
-    <OptionsSetting value="true" id="Checkout" />
-    <OptionsSetting value="true" id="Update" />
-    <OptionsSetting value="true" id="Status" />
-    <OptionsSetting value="true" id="Edit" />
-    <ConfirmationsSetting value="0" id="Add" />
-    <ConfirmationsSetting value="0" id="Remove" />
-  </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" assert-keyword="true" jdk-15="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">
diff --git a/.idea/modules.xml b/.idea/modules.xml
index 328648b..29b9131 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -3,6 +3,7 @@
   <component name="ProjectModuleManager">
     <modules>
       <module fileurl="file://$PROJECT_DIR$/HenCoderPracticeDraw2.iml" filepath="$PROJECT_DIR$/HenCoderPracticeDraw2.iml" />
+      <module fileurl="file://$PROJECT_DIR$/.idea/PracticeDraw2.iml" filepath="$PROJECT_DIR$/.idea/PracticeDraw2.iml" />
       <module fileurl="file://$PROJECT_DIR$/app/app.iml" filepath="$PROJECT_DIR$/app/app.iml" />
     </modules>
   </component>
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/app/build.gradle b/app/build.gradle
index f3ab172..2a48ee6 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,7 +1,7 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 25
+    compileSdkVersion 24
     buildToolsVersion "25.0.3"
     defaultConfig {
         applicationId "com.hencoder.hencoderpracticedraw2"
@@ -20,7 +20,7 @@ android {
 }
 
 dependencies {
-    compile fileTree(dir: 'libs', include: ['*.jar'])
+    compile fileTree(include: ['*.jar'], dir: 'libs')
     androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
diff --git a/app/src/main/java/com/hencoder/hencoderpracticedraw2/practice/Practice01LinearGradientView.java b/app/src/main/java/com/hencoder/hencoderpracticedraw2/practice/Practice01LinearGradientView.java
index 26596b1..34350f0 100644
--- a/app/src/main/java/com/hencoder/hencoderpracticedraw2/practice/Practice01LinearGradientView.java
+++ b/app/src/main/java/com/hencoder/hencoderpracticedraw2/practice/Practice01LinearGradientView.java
@@ -3,13 +3,16 @@
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
+import android.graphics.LinearGradient;
 import android.graphics.Paint;
+import android.graphics.Shader;
 import android.support.annotation.Nullable;
 import android.util.AttributeSet;
 import android.view.View;
 
 public class Practice01LinearGradientView extends View {
     Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
+    Shader shader = new LinearGradient(100,100,500,500,Color.parseColor("#E91E63"),Color.parseColor("#2196F3"),Shader.TileMode.CLAMP);
 
     public Practice01LinearGradientView(Context context) {
         super(context);
@@ -24,6 +27,13 @@ public Practice01LinearGradientView(Context context, @Nullable AttributeSet attr
     }
 
     {
+        /**
+         * LinearGradient(float x0, float y0, float x1, float y1, int color0, int color1, Shader.TileMode tile) 。
+
+         参数：
+         x0 y0 x1 y1：渐变的两个端点的位置
+         color0 color1 是端点的颜色
+         */
         // 用 Paint.setShader(shader) 设置一个 LinearGradient
         // LinearGradient 的参数：坐标：(100, 100) 到 (500, 500) ；颜色：#E91E63 到 #2196F3
     }
@@ -31,7 +41,7 @@ public Practice01LinearGradientView(Context context, @Nullable AttributeSet attr
     @Override
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);
-
+        paint.setShader(shader);
         canvas.drawCircle(300, 300, 200, paint);
     }
 }