修复部分bug

app/src/main/java/com/gh/common/util/FileUtils.java

@@ -37,7 +37,11 @@ public class FileUtils {
 			File file = new File(dir + File.separator + TEST_FILE_NAME);
 			if (!file.exists()) {
 				try {
-					file.createNewFile();
+					if (!file.createNewFile()) {
+						// cannot create file
+						Utils.log("cannot create file");
+						dir = null;
+					}
 				} catch (IOException e) {
 					e.printStackTrace();
 					//cannot create file
@@ -124,7 +128,7 @@ public class FileUtils {
 		return availableBlocks * blockSize / 1024f / 1024f;
 	}
 
-	public static String isCanDownload(String size) {
+	public static String isCanDownload(Context context, String size) {
 		String msg = null;
 		String packageSizeStr = "";
 		for (int i = 0; i < size.length(); i++) {
@@ -136,8 +140,7 @@ public class FileUtils {
 		if (packageSizeStr.length() != 0) {
 			packageSize = Float.valueOf(packageSizeStr);
 		}
-		float freeSpace = getFreeSpaceByPath(Environment
-				.getExternalStorageDirectory().getAbsolutePath());
+		float freeSpace = getFreeSpaceByPath(getDownloadDir(context));
 		if (freeSpace < packageSize) {
 			msg = "手机存储空间不足，无法进行下载！";
 		}