fix failed_devices.txt created failure

build.gradle

@@ -27,8 +27,10 @@ ext {
     commonLibVersion= '2.12.4'
     versionCompiler = 27
     versionTarget = 27
+    // if hope supporting 4.4
+    // please modify it to 16
     minSdkVersion = 21
-    versionNameString = '1.0.0'
+    versionNameString = '1.1.0.20190826'
     javaSourceCompatibility = JavaVersion.VERSION_1_8
     javaTargetCompatibility = JavaVersion.VERSION_1_8
 }

libusbcamera/build.gradle

@@ -7,7 +7,7 @@ android {
     defaultConfig {
         minSdkVersion rootProject.ext.minSdkVersion
         targetSdkVersion rootProject.ext.versionTarget
-        versionCode 1
+        versionCode 2
         versionName rootProject.ext.versionNameString
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }

libusbcamera/src/main/java/com/serenegiant/usb/USBMonitor.java

@@ -311,7 +311,7 @@ public final class USBMonitor {
 		// get detected devices
 		final HashMap<String, UsbDevice> deviceList = mUsbManager.getDeviceList();
 		// store those devices info before matching filter xml file
-		String fileName = Environment.getExternalStorageDirectory()+ "/USBCamera/failed_devices.txt";
+		String fileName = Environment.getExternalStorageDirectory().getAbsolutePath()+ "/USBCamera/failed_devices.txt";
 
 		File logFile = new File(fileName);
 		if(! logFile.exists()) {
@@ -323,10 +323,15 @@ public final class USBMonitor {
 		}
 		FileWriter fw = null;
 		PrintWriter pw = null;
-		final List<UsbDevice> result = new ArrayList<UsbDevice>();
 		try {
 			fw = new FileWriter(logFile, true);
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+		if(fw != null) {
 			pw = new PrintWriter(fw);
+		}
+		final List<UsbDevice> result = new ArrayList<UsbDevice>();
 		if (deviceList != null) {
 			if ((filters == null) || filters.isEmpty()) {
 				result.addAll(deviceList.values());
@@ -346,6 +351,7 @@ public final class USBMonitor {
 							String devSystemVersion = android.os.Build.VERSION.RELEASE;
 							String devClass = String.valueOf(device.getDeviceClass());
 							String subClass = String.valueOf(device.getDeviceSubclass());
+							try{
 								if(pw != null) {
 									StringBuilder sb = new StringBuilder();
 									sb.append(devModel);
@@ -357,14 +363,14 @@ public final class USBMonitor {
 									pw.flush();
 									fw.flush();
 								}
+							}catch (IOException e) {
+								e.printStackTrace();
+							}
 						}
 					}
 				}
 			}
 		}
-		} catch (IOException e) {
-			e.printStackTrace();
-		} finally {
 		if (pw != null) {
 			pw.close();
 		}
@@ -375,7 +381,6 @@ public final class USBMonitor {
 				e.printStackTrace();
 			}
 		}
-		}
 		return result;
 	}