Delete a Customer Record in an MDK App

The next step is to store deleted record locally for an offline application or delete directly back to the backed for online applications. You will now create an OData delete action to delete a customer record. You will also show a failure message if the delete action fails.

First, define a failure message action for displaying a message in case deleting of a customer fails.

1. Right-click on the Actions folder | New MDK Action | choose MDK Message Actions in Category | click Message Action | Next.

   

2. Provide the below information:

   Property	Value
   Action Name	DeleteCustomerEntityFailureMessage
   Type	select Message
   Message	Delete entity failure - {{#ActionResults:delete/#Property:error}}
   Title	Delete Customer
   OKCaption	OK
   OnOK	--None--
   CancelCaption	leave it blank
   OnCancel	--None--

   In this expression {{#ActionResults:delete/#Property:error}}, delete is a reference to the Action Result name in the Delete Entity action (you will create this action in following step). This reference is used to pass the results to subsequent actions in the chain. These actions can reference the action result as needed. In this case if there is a failure, you access the error property of the action result to display the OData failure message.

   This is the standard Binding Target Path (also called Dynamic Target Path) syntax used when you need to include a binding with other bindings or within a string as used in the message here.

   You could exclude above expression and can just display a generic message.

   

3. Click Next and then Finish on the Confirmation step.

4. Next, you will create the OData Delete action to delete a customer record.

   You can find more details about Delete Entity Action.

5. Right-click on the Actions folder | New MDK Action | choose MDK Data Actions in Category | click OData Action | Next.

   

   Provide the below information:

   Property	Value
   Action Name	Customers_DeleteEntity
   Type	DeleteEntity
   Service	SampleServiceV2
   EntitySet	Customers
   ReadLink	click on link icon and double click on readLink

   

   The readlink is a direct reference to an individual entity set entry.

   Click Next and Finish on the confirmation screen. The action editor will open with the Customers_DeleteEntity.action loaded.

6. Next, define Success and Failure actions for Customers_DeleteEntity.action.

   In the action editor for the new action, expand the Common Action Properties and provide the below information:

   Property	Value
   Action Result	delete
   Success Action	CloseModalPage_Complete.action
   Failure Action	DeleteCustomerEntityFailureMessage.action

   When Customers_DeleteEntity.action gets executed successfully then CloseModalPage_Complete.action will be triggered or if Customers_DeleteEntity.action fails then DeleteCustomerEntityFailureMessage.action will be triggered.

   delete value for Action Result is reference to DeleteCustomerEntityFailureMessage.action created in step 1.

   You could also show a success message for Success Action or chain a message to success of CloseModalPage_Complete.action.

   

7. Save the changes to the Customers_DeleteEntity.action.

You will add a button to the Customer Detail page called Trash. You will link this button to the Customers_DeleteConfirmation.js rule you just created. This event will display a dialog when the Trash button is pressed by the end-user.

1. In Customers_Detail.page, drag and drop an Action Bar Item to the upper right of the action bar.

   

   Action Bar Item is a button that users can use to fire actions when pressed. You can add an Action Bar Item only to the Action Bar (at the top of the page).

   Click the link icon to open the object browser for the System Item property.

   Double click on the Trash type and click OK.

   

2. Next, click the Events tab, click the link icon for the OnPress property to open the object browser.

   Double Click on the Customers_DeleteConfirmation.js rule and click OK to set it as the OnPress Action.

   You could link OnPress property directly to OData delete action directly instead to this JavaScript file. Idea of linking to JavaScript file is to let you understand another way to achieve similar functionality.

   

3. Save the changes to the Customers_Detail.page.

Deploy the updated application to your MDK client.

1. Right-click on the DemoSampleApp MDK Application in the project explorer pane and select MDK Deploy and Activate.

   

2. Since we have deployed already both the destination and app id should be pre-selected based on the last time you deployed our application.  Confirm the Destination Name is mobileservices_cf and the Application Id is com.sap.mdk.demo and click Next.

   

Make sure you are choosing the right device platform tab above.

1. Re-launch the app on your device, you may asked to authenticate with passcode or Touch ID. You will see a Confirmation pop-up, tap OK.

2. Tap Customer List | tap any record | tap trash icon.

   

3. A confirmation dialog appears for user action, tap OK.

   

   Since this is an Offline application, record has been removed from local store and deletion request has been added to request queue. This has to be sent or uploaded to the backend explicitly.

   MDK base template has added a Sync button on main page of the app to upload local changes from device to the backend and to download the latest changes from backend to the device. Actions | Service | UploadOffline.action & DownloadOffline.action.

4. On Main page, tap Sync, a successful message will be shown.

You can cross verify if this record has been deleted in the backend.

Backend URL can be found in Mobile Services Cockpit.

Mobile Applications | Native/Hybrid | Click on the MDK App com.sap.mdk.demo | Mobile Sample OData ESPM | click Root URL v2 | add /Customers/ at the end of the URL

As Sync is pressed, UploadOffline.action gets trigger to upload local changes from device to the backend and on success of this call, DownloadOffline.action is being called.