diff --git a/README-CHN.md b/README-CHN.md
index 0db01c4..f56e3b7 100644
--- a/README-CHN.md
+++ b/README-CHN.md
@@ -22,7 +22,19 @@ Android 加载控件库，简洁、易用、可定制性强。用于快速实现
 * 1.2.1
 
 ## 使用方式
-* gradle: `compile 'cc.cloudist.acplibrary:library:1.2.1'`
+1. 在工程目录下添加maven
+```
+allprojects {
+    repositories {
+        maven { url "https://jitpack.io" }       
+        ...
+    }
+}
+```
+2. module下添加gradle依赖
+```
+implementation 'com.github.chenzhenlindx:ACProgressLite:1.2.2'
+```
 
 ## 示例代码
 * 花瓣类型
diff --git a/README.md b/README.md
index e8e4a55..cb0d8a0 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,17 @@ Similar to iOS [MBProgressHUD](https://github.com/jdg/MBProgressHUD)
 * 1.2.1
 
 ## Usage
-* gradle: `compile 'cc.cloudist.acplibrary:library:1.2.1'`
+```
+allprojects {
+    repositories {
+        maven { url "https://jitpack.io" }       
+        ...
+    }
+}
+```
+```
+implementation 'com.github.chenzhenlindx:ACProgressLite:1.2.2'
+```
 
 ## Sample Code
 * Flower
diff --git a/build.gradle b/build.gradle
index b618568..f7286ab 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2,14 +2,15 @@
 
 buildscript {
     repositories {
+        google()
         jcenter()
         maven {
             url "https://plugins.gradle.org/m2/"
         }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.2.3'
-        classpath 'com.github.dcendents:android-maven-plugin:1.2'
+        classpath 'com.android.tools.build:gradle:3.2.0'
+        classpath 'com.github.dcendents:android-maven-gradle-plugin:2.0'
         classpath "com.jfrog.bintray.gradle:gradle-bintray-plugin:1.2"
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -18,6 +19,7 @@ buildscript {
 
 allprojects {
     repositories {
+        google()
         jcenter()
     }
 }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0c71e76..47225de 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
-#Wed Apr 10 15:27:10 PDT 2013
+#Wed Oct 10 08:43:27 CST 2018
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip
diff --git a/library/build.gradle b/library/build.gradle
index 1a43ebf..f85f77f 100644
--- a/library/build.gradle
+++ b/library/build.gradle
@@ -6,7 +6,7 @@ version = "1.2.1"
 
 android {
     compileSdkVersion 21
-    buildToolsVersion "21.1.2"
+    buildToolsVersion '28.0.2'
 
     defaultConfig {
         minSdkVersion 9
@@ -23,7 +23,7 @@ android {
 }
 
 dependencies {
-    compile fileTree(dir: 'libs', include: ['*.jar'])
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
 }
 
 //def siteUrl = 'https://github.com/Cloudist/ACProgressLite'
diff --git a/library/src/main/java/cc/cloudist/acplibrary/ACProgressFlower.java b/library/src/main/java/cc/cloudist/acplibrary/ACProgressFlower.java
index e89daf7..5f7f4ff 100644
--- a/library/src/main/java/cc/cloudist/acplibrary/ACProgressFlower.java
+++ b/library/src/main/java/cc/cloudist/acplibrary/ACProgressFlower.java
@@ -51,9 +51,13 @@ public void show() {
             public void run() {
                 int result = mSpinCount % mBuilder.mPetalCount;
                 if (mBuilder.mDirection == ACProgressConstant.DIRECT_CLOCKWISE) {
-                    mFlowerView.updateFocusIndex(result);
+                    if (null != mFlowerView) {
+                        mFlowerView.updateFocusIndex(result);
+                    }
                 } else {
-                    mFlowerView.updateFocusIndex(mBuilder.mPetalCount - 1 - result);
+                    if (null != mFlowerView) {
+                        mFlowerView.updateFocusIndex(mBuilder.mPetalCount - 1 - result);
+                    }
                 }
                 if (result == 0) {
                     mSpinCount = 1;
diff --git a/sample/build.gradle b/sample/build.gradle
index e7cfd1a..427547e 100644
--- a/sample/build.gradle
+++ b/sample/build.gradle
@@ -2,7 +2,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 21
-    buildToolsVersion "21.1.2"
+    buildToolsVersion '28.0.2'
 
     defaultConfig {
         applicationId "cc.cloudist.acpsample"
@@ -20,6 +20,6 @@ android {
 }
 
 dependencies {
-    compile fileTree(dir: 'libs', include: ['*.jar'])
-    compile project(':library')
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation project(':library')
 }