fix lacking json

Author: TTangNingzhi

.idea/workspace.xml

@@ -14,7 +14,7 @@ entire family of [JetBrains IDEs](https://www.jetbrains.com/) and [Tobii eye-tra
 to track developers’ IDE interactions and eye gaze data.
 
 <p align="center">
-    <img src="docs/static/overview.png" width="600" max-width="100^" alt="CodeGRITS Overview">
+    <img src="docs/static/overview.png" width="600px" max-width="100%" alt="CodeGRITS Overview">
 </p>
 
 The data collected by CodeGRITS can be used by empirical SE researchers to understand the behaviors of developers,

README.md

@@ -89,17 +89,23 @@ public ConfigDialog(Project project) throws IOException, InterruptedException {
                 deviceCombo.removeAllItems();
                 deviceCombo.addItem("Mouse");
                 freqCombo.addItem(30.0);
+                freqCombo.addItem(60.0);
+                freqCombo.addItem(120.0);
             }
         }
         Config config = new Config();
-        config.loadFromJson();
-        //load freq
-        freqCombo.setSelectedItem(config.getSampleFreq());
-
+        if (config.configExists()) {
+            config.loadFromJson();
+            // load freq
+            freqCombo.setSelectedItem(config.getSampleFreq());
+        }
     }
 
     private void loadConfig() {
         Config config = new Config();
+        if (!config.configExists()) {
+            return;
+        }
         config.loadFromJson();
 
         List<Boolean> selected = config.getCheckBoxes();