Add an App Backend

In the Kinvey console click "Add an App", enter the name "TestDrive" when prompted.

Set up TestDrive Project

1. Download the TestDrive project.
2. Download the latest Kinvey library (zip) and extract the downloaded zip file, from: http://devcenter.kinvey.com/android/downloads

###Android Studio

1. In Android Studio, go to File → New → Import Project
2. Browse to the extracted zip from step 1, and click OK
3. Click Next and Finish.
4. Copy all jars in the libs/ folder of the Kinvey Android library zip to the lib/ folder at the root of the project
5. Click the play button to start a build, if you still see compilation errors ensure the versions are correctly defined in the dependencies list

###Finally, for all IDEs

Specify your app key and secret in TestDrive constant variables appKey and appSecret

public class TestDrive extends Activity {
    private String appKey="your_app_key";
    private String appSecret="your_app_secret";

Take a look at our Getting Started guide for more information.

Saving Data

Creating Persistable Objects

With Kinvey's Android library you model data using any class that extends the GenericJson class. The sample project comes with a Entity class that has a string title. When this class is converted to JSON, title will be given the label "_id", which is accomplished by the attribute @Key("_id")

Entity.java looks like this:

public class Entity extends GenericJson {

  @Key("_id")
  private String title;

  public Entity() {}
  
  public Entity(String title) {
    super();
    this.title = title;
  }
  
  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }
}

Saving

The following method is called in the onClickListener of the save_button. When the button is clicked, it will create a new Entity, with the title myEntity. The below code snippet also reveals how to set values directly, without needing to declare them as variables in the Entity. The call to put(Key, Value), in this case, will add a new field labelled description to the entity, with a value defined below.

After creating an entity, the Client is used to access the AppData API, where a call to save will persist the entity with Kinvey. As this call is asyncronous, a callback is provided to indicate the result of the operation.

Entity entity = new Entity("myEntity");
        entity.put("Description","This is a description of a dynamically-added Entity property.");                
        kinveyClient.appData("entityCollection", Entity.class).save(entity, new KinveyClientCallback<Entity>() {
            @Override
            public void onSuccess(Entity result) {
                bar.setVisibility(View.GONE);
                Toast.makeText(TestDrive.this,"Entity Saved\nTitle: " + result.getTitle()
                        + "\nDescription: " + result.get("Description"), Toast.LENGTH_LONG).show();
            }

            @Override
            public void onFailure(Throwable error) {
                bar.setVisibility(View.GONE);
                Log.e(TAG, "AppData.save Failure", error);
                Toast.makeText(TestDrive.this, "Save All error: " + error.getMessage(), Toast.LENGTH_LONG).show();
            }
        });

Load Data

The AsyncAppData object has a get method as a well as a save, and this can be used to load the object by id that was just saved.

        kinveyClient.appData("entityCollection", Entity.class).get(new Query(), new KinveyListCallback<Entity>() {
            @Override
            public void onSuccess(Entity[] result) {
                bar.setVisibility(View.GONE);
                for (Entity entity : result) {
                    Toast.makeText(TestDrive.this,"Entity Retrieved\nTitle: " + entity.getTitle()
                            + "\nDescription: " + entity.get("Description"), Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(Throwable error) {
                bar.setVisibility(View.GONE);
                Log.e(TAG, "AppData.get all Failure", error);
                Toast.makeText(TestDrive.this, "Get All error: " + error.getMessage(), Toast.LENGTH_LONG).show();
            }
        });

This is very similar to Saving data, as the AsyncAppData API is accessed through the client. The call to get supports a query, so this snippet is just sending a new empty query to retrieve all results. Note this snippet uses a KinveyListCallback for async results, as a query will return a list of Entities (as opposed to save, which takes a KinveyClientCallback and only returns a single Entity).

Run the App

Run the sample project and you will have 5 buttons, each showing various usages of the AsyncAppData API. Press the buttons to see what it can do, then read the source to figure out how!

Next steps

• Data Store Guide - How to query for data, delete entities
• Security - How to share data or limit read/write access
• User Guide - How to add users to your app and understand authentication

##License

Copyright (c) 2014 Kinvey Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.