android：调整日志，添加 onDestroy()；

src/android/ShutoApi.java

@@ -124,7 +124,7 @@ public class ShutoApi extends CordovaPlugin {
             pluginResult.setKeepCallback(true);
             this.eventCallbackContext.sendPluginResult(pluginResult);
         } catch (JSONException e) {
-            e.printStackTrace();
+            LOG.w(TAG, e);
         }
     }
 
@@ -156,7 +156,7 @@ public class ShutoApi extends CordovaPlugin {
             pluginResult.setKeepCallback(true);
             this.eventCallbackContext.sendPluginResult(pluginResult);
         } catch (JSONException e) {
-            e.printStackTrace();
+            LOG.w(TAG, e);
             if (callback != null) {
                 callback.onError("Failed to create event data: " + e.getMessage());
             }
@@ -195,6 +195,14 @@ public class ShutoApi extends CordovaPlugin {
         callbackContext.success();
     }
 
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        if (eventCallbacks != null) {
+            eventCallbacks.clear();
+        }
+    }
+
     // 提供给原生代码查询就绪状态的接口
     public boolean isIonicReady() {
         return isIonicReady;