ZcashLightClientKit/Example/ZcashLightClientSample

iOS demo app

This is a demo app that exercises code in https://github.com/zcash/ZcashLightClientKit, which has all the iOS-related functionalities necessary to build a mobile Zcash shielded wallet.

It relies on Lightwalletd, a backend service that provides a bandwidth-efficient interface to the Zcash blockchain. There is an equivalent Android demo app.

Contents

• Requirements
• Exploring the demo app
  • Demos
• Getting started
• Resources

Requirements

Demo app requires a target device running iOS 12+.

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Exploring the demo app

After building the app, the emulator should launch with a basic app that exercises the SDK (see picture below). To explore the app, click on each menu item, in order, and also look at the associated code.

The demo app is not trying to show what's possible, but to present how to accomplish the building blocks of wallet functionality in a simple way in code. It is comprised of the following self-contained demos. All data is reset between demos in order to keep the behavior repeatable and independent of state.

Demos

Menu Item	Related Code	Description
Get address	GetAddressViewController.swift	Given a seed, display its z-addr
Latest block height	LatestHeightViewController.swift	Given a lightwalletd server, retrieve the latest block height
Sync blocks	SyncBlocksViewController.swift	Download compact blocks from the lightwalletd server.
Get balance	GetBalanceViewController.swift	Calculates the balance of the current wallet address.
Send funds	SendViewController.swift	Send a transaction, the most complex demo.
Transaction details	TransactionDetailViewController.swift	See status of a transaction: pending or confirmed, sent or received.
All transactions	TransactionsTableViewController.swift, TransactionsDataSource.swift	Displays as much available transaction information on the wallet.
Paginated transactions	PaginatedTransactionsViewController.swift	Demonstrates how to paginate transactions.

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Getting started

We’re assuming you already have a brilliant app idea, a vision for the app’s UI, and know the ins and outs of the Android lifecycle. We’ll just stick to the Zcash app part of “getting started.”

Similarly, the best way to build a functioning Zcash shielded app is to implement the functionalities that are listed in the demo app, in roughly that order:

1. Generate and safely store your private key.
2. Get the associated address, and display it to the user on a receive screen. You may also want to generate a QR code from this address.
3. Make sure your app can talk to the lightwalletd server and check by asking for the latest height, and verify that it’s current with the Zcash network.
4. Try interacting with lightwalletd by fetching a block and processing it. Then try fetching a range of blocks, which is much more efficient.
5. Now that you have the blocks process them and list transactions that send to or are from that wallet, to calculate your balance.
6. With a current balance (and funds, of course), send a transaction and monitor its transaction status and update the UI with the results.

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Resources

You don’t need to do it all on your own.

• Chat with the team who built the kit: Zcash discord community channel, wallet
• Discuss ideas with other community members: Zcash forum
• Get funded to build a Zcash app: Zcash foundation grants program
• Follow Zcash-specific best practices: Zcash wallet developer checklist
• Get more information and see FAQs about the wallet: Shielded resources documentation

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