diff --git a/core/function-impl/mogo-core-function-hmi/src/main/java/com/mogo/eagle/core/function/hmi/ui/carcorder/CarcorderPreviewView.kt b/core/function-impl/mogo-core-function-hmi/src/main/java/com/mogo/eagle/core/function/hmi/ui/carcorder/CarcorderPreviewView.kt
index cb7b0b955d..52b9fb36a5 100644
--- a/core/function-impl/mogo-core-function-hmi/src/main/java/com/mogo/eagle/core/function/hmi/ui/carcorder/CarcorderPreviewView.kt
+++ b/core/function-impl/mogo-core-function-hmi/src/main/java/com/mogo/eagle/core/function/hmi/ui/carcorder/CarcorderPreviewView.kt
@@ -41,7 +41,6 @@ class CarcorderPreviewView private constructor(
 
     init {
         LayoutInflater.from(context).inflate(R.layout.view_carcorder_preview, this, true)
-        initView()
     }
 
     companion object {
@@ -113,6 +112,7 @@ class CarcorderPreviewView private constructor(
 
     private val listener: UVCCameraHelper.OnMyDevConnectListener = object : UVCCameraHelper.OnMyDevConnectListener {
         override fun onAttachDev(device: UsbDevice?) {
+            Log.d(TAG, "onAttachDev")
             // request open permission
             if (!isRequest) {
                 isRequest = true
@@ -121,6 +121,7 @@ class CarcorderPreviewView private constructor(
         }
 
         override fun onDettachDev(device: UsbDevice) {
+            Log.d(TAG, "onDettachDev")
             // close camera
             if (isRequest) {
                 isRequest = false
@@ -130,6 +131,7 @@ class CarcorderPreviewView private constructor(
         }
 
         override fun onConnectDev(device: UsbDevice?, isConnected: Boolean) {
+            Log.d(TAG, "onConnectDev:isConnected=$isConnected")
             if (!isConnected) {
                 showShortMsg("fail to connect,please check resolution params")
                 isPreview = false
@@ -155,13 +157,14 @@ class CarcorderPreviewView private constructor(
         }
 
         override fun onDisConnectDev(device: UsbDevice?) {
+            Log.d(TAG, "onDisConnectDev")
             showShortMsg("相机断开连接")
         }
     }
 
 
     private fun showShortMsg(msg: String) {
-        Toast.makeText(context, msg, Toast.LENGTH_SHORT).show()
+        //Toast.makeText(context, msg, Toast.LENGTH_SHORT).show()
     }
 
     private fun initView() {
@@ -177,6 +180,7 @@ class CarcorderPreviewView private constructor(
 
     override fun onAttachedToWindow() {
         super.onAttachedToWindow()
+        initView()
         // step.2 register USB event broadcast
         if (mCameraHelper != null) {
             mCameraHelper!!.registerUSB()
@@ -189,8 +193,6 @@ class CarcorderPreviewView private constructor(
         if (mCameraHelper != null) {
             mCameraHelper!!.unregisterUSB()
         }
-
-
     }
 
     override fun onSurfaceCreated(view: CameraViewInterface?, surface: Surface?) {
diff --git a/libraries/map-usbcamera/src/main/AndroidManifest.xml b/libraries/map-usbcamera/src/main/AndroidManifest.xml
index 9f80e8f54e..70e75d7b52 100644
--- a/libraries/map-usbcamera/src/main/AndroidManifest.xml
+++ b/libraries/map-usbcamera/src/main/AndroidManifest.xml
@@ -2,7 +2,10 @@
     package="com.mogo.usbcamera">
 
 
-    <uses-feature android:name="android.hardware.usb.host"/>
+    <!-- 声明使用usb -->
+    <uses-feature
+        android:name="android.hardware.usb.host"
+        android:required="true" />
 
     <application>
 
diff --git a/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/USBMonitor.java b/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/USBMonitor.java
index f58754f413..1eea770006 100644
--- a/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/USBMonitor.java
+++ b/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/USBMonitor.java
@@ -108,7 +108,9 @@ public final class USBMonitor {
 		mOnDeviceConnectListener = listener;
 		mAsyncHandler = HandlerThreadHandler.createHandler(TAG);
 		destroyed = false;
-		if (DEBUG) Log.v(TAG, "USBMonitor:mUsbManager=" + mUsbManager);
+		if (DEBUG) {
+			Log.v(TAG, "USBMonitor:mUsbManager=" + mUsbManager);
+		}
 	}
 
 	/**
@@ -116,7 +118,9 @@ public final class USBMonitor {
 	 * never reuse again
 	 */
 	public void destroy() {
-		if (DEBUG) Log.i(TAG, "destroy:");
+		if (DEBUG) {
+			Log.i(TAG, "destroy:");
+		}
 		unregister();
 		if (!destroyed) {
 			destroyed = true;
@@ -149,9 +153,13 @@ public final class USBMonitor {
 	 * @throws IllegalStateException
 	 */
 	public synchronized void register() throws IllegalStateException {
-		if (destroyed) throw new IllegalStateException("already destroyed");
+		if (destroyed) {
+			throw new IllegalStateException("already destroyed");
+		}
 		if (mPermissionIntent == null) {
-			if (DEBUG) Log.i(TAG, "register:");
+			if (DEBUG) {
+				Log.i(TAG, "register:");
+			}
 			final Context context = mWeakContext.get();
 			if (context != null) {
 				mPermissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);
diff --git a/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/common/AbstractUVCCameraHandler.java b/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/common/AbstractUVCCameraHandler.java
index f8630fee5d..00aa36d45a 100644
--- a/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/common/AbstractUVCCameraHandler.java
+++ b/libraries/map-usbcamera/src/main/java/com/serenegiant/usb/common/AbstractUVCCameraHandler.java
@@ -480,6 +480,7 @@ public abstract class AbstractUVCCameraHandler extends Handler {
                     try {
                         mSync.wait();
                     } catch (final InterruptedException e) {
+                        e.printStackTrace();
                     }
                 }
             }