Android-Pin

An easy drop-in PIN controller for Android

Usage

PinFragment is the primary class provided by this library. A PinFragment should be instantiated either for a PIN creation, or for PIN validation.

Fragment toShow = PinHelper.hasDefaultPinSaved(this) ?
                PinFragment.newInstanceForVerification() : 
                PinFragment.newInstanceForCreation();

getFragmentManager().beginTransaction()
                .replace(android.R.id.container, toShow)
                .commit();

A hosting Activity should implement PinFragment.Listener to perform actions when a PIN has been created or validated.

public interface Listener {
    public void onValidated();
    public void onPinCreated();
}

By default, a user's PIN is saved in the default SharedPreference store, and validated against that store. To override this behavior, instantiate your PinFragment with a PinFragmentConfiguration that provides . An example of a configuration might be

PinFragmentConfiguration config = 
    new PinFragmentConfiguration(context)
      .pinSaver(new PinSaver(){
          public void onSave(String pin) {
              // ...do some saving
          }
      }).validator(new Validator(){
          public boolean isValid(String submission){
              boolean valid = // ...check against where you saved the pin
              return valid;
          }
        });

Then, instantiation of your PinFragment might look like this

Fragment toShow = doesHavePinSavedSomewhere() ?
                PinFragment.newInstanceForVerification(config) :
                PinFragment.newInstanceForCreation(config);

getFragmentManager().beginTransaction()
                .replace(android.R.id.container, toShow)
                .commit();

In general, any time a custom PinSaver is defined, it should follow that a custom Validator is also defined. This may be more strictly enforced in the future.

Asynchronous Handling

A very common use case for providing an alternative Validator and PinSaver is if you persist a user's PIN remotely and validate by making a request to your server. In this case, PinFragment can execute your saving and checking on a background thread and show a ProgressBar while executing. To utilize this, pass implementations of AsyncSaver and AsyncValidator to your configuration.

PinFragmentConfiguration config = 
  new PinFragmentConfiguration(context)
    .pinSaver(new AsyncPinSaver(){
        public void onSave(String pin){
            HttpClient client = //...
            client.savePin(pin);
        }
    }).validator(new AsyncValidator(){
        public boolean isValid(String submission){
            // HttpClient client = ...
            // boolean valid = client.comparePin(submission);
            return valid;
      }
    });

This configuration will instruct your PinFragment instance to run onSave() and isValid() in the background and post to your PinFragment.Listener only when a PIN has been successfully created or verified, meaning you don't need to think about scheduling things to happen in the background.

Including in your project

This library is hosted on Maven Central; to include add the following to your pom.xml

<dependency>
  <groupId>com.venmo.android.pin</groupId>
  <artifactId>library</artifactId>
  <version>0.1</version>
</dependency>

For gradle builds, add the following to your build.gradle

repositories {
    mavenCentral()
}

dependencies {
    compile 'com.venmo.android.pin:library:0.1@aar'
}

Contributing

Contributions are encouraged! If you would like to contribute, fork this repository and send a pull request. Please make sure to follow the project code style if possible. .iml/codeStyleSettings is provided for your convenience in Android Studio/IntelliJ.