diff --git a/app/build.gradle b/app/build.gradle
index a32ac10..b873162 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -5,7 +5,7 @@ android {
     buildToolsVersion "26.0.1"
     defaultConfig {
         applicationId "com.jiangdg.usbcamera"
-        minSdkVersion 18
+        minSdkVersion 16
         targetSdkVersion 22
         versionCode 1
         versionName "1.0"
@@ -29,6 +29,4 @@ dependencies {
     compile project(':libusbcamera')
     compile 'com.jakewharton:butterknife:8.8.1'
     compile 'com.jakewharton:butterknife-compiler:8.8.1'
-    compile 'com.jakewharton:butterknife:8.8.1'
-    compile 'com.jakewharton:butterknife-compiler:8.8.1'
 }
diff --git a/app/src/main/java/com/jiangdg/usbcamera/view/USBCameraActivity.java b/app/src/main/java/com/jiangdg/usbcamera/view/USBCameraActivity.java
index 2b2d6c5..0ecf3b9 100644
--- a/app/src/main/java/com/jiangdg/usbcamera/view/USBCameraActivity.java
+++ b/app/src/main/java/com/jiangdg/usbcamera/view/USBCameraActivity.java
@@ -47,15 +47,18 @@ public class USBCameraActivity extends AppCompatActivity implements CameraDialog
 
     private boolean isRequest;
 
-    // USB设备监听器
+    /**
+     * USB设备事件监听器
+     * */
     private USBCameraManager.OnMyDevConnectListener listener = new USBCameraManager.OnMyDevConnectListener() {
+        // 插入USB设备
         @Override
         public void onAttachDev(UsbDevice device) {
             if(mUSBManager == null || mUSBManager.getUsbDeviceCount() == 0){
                 showShortMsg("未检测到USB摄像头设备");
                 return;
             }
-
+            // 请求打开摄像头
             if(! isRequest){
                 isRequest = true;
                 if(mUSBManager != null){
@@ -64,23 +67,27 @@ public class USBCameraActivity extends AppCompatActivity implements CameraDialog
             }
         }
 
+        // 拔出USB设备
         @Override
         public void onDettachDev(UsbDevice device) {
             if(isRequest){
+                // 关闭摄像头
                 isRequest = false;
                 mUSBManager.closeCamera();
                 showShortMsg(device.getDeviceName()+"已拨出");
             }
         }
 
+        // 连接USB设备成功
         @Override
         public void onConnectDev(UsbDevice device) {
-            // 处理连接到设备后的逻辑
+
         }
 
+        // 与USB设备断开连接
         @Override
         public void onDisConnectDev(UsbDevice device) {
-            // 处理与设备断开后的逻辑
+
         }
     };
     private FileOutputStream fos;
diff --git a/libusbcamera/build.gradle b/libusbcamera/build.gradle
index ae16b05..84bf920 100644
--- a/libusbcamera/build.gradle
+++ b/libusbcamera/build.gradle
@@ -5,7 +5,7 @@ android {
     buildToolsVersion "26.0.1"
 
     defaultConfig {
-        minSdkVersion 18
+        minSdkVersion 16
         targetSdkVersion 22
         versionCode 1
         versionName "1.0"
diff --git a/libusbcamera/src/main/java/com/jiangdg/usbcamera/USBCameraManager.java b/libusbcamera/src/main/java/com/jiangdg/usbcamera/USBCameraManager.java
index 7774df0..dad39e8 100644
--- a/libusbcamera/src/main/java/com/jiangdg/usbcamera/USBCameraManager.java
+++ b/libusbcamera/src/main/java/com/jiangdg/usbcamera/USBCameraManager.java
@@ -7,7 +7,6 @@ import android.hardware.usb.UsbDevice;
 import android.os.Environment;
 
 import com.jiangdg.libusbcamera.R;
-import com.serenegiant.usb.CameraDialog;
 import com.serenegiant.usb.DeviceFilter;
 import com.serenegiant.usb.USBMonitor;
 import com.serenegiant.usb.common.AbstractUVCCameraHandler;