check camera usable

app/src/main/java/cn/finalteam/rxgalleryfinal/utils/CameraUtil.java

@@ -115,7 +115,12 @@ public class CameraUtil {
     }
 
     public static boolean hasCamera() {
-        return hasBackFacingCamera() || hasFrontFacingCamera();
+        Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
+        if (captureIntent.resolveActivity(SheepApp.getInstance().getPackageManager()) == null) {
+            G.shortToast("相机不可用");
+            return false;
+        }
+        return true;
     }
 
     public static boolean hasBackFacingCamera() {