@ -3,15 +3,17 @@ layout: learn
description: Learn about the Android SDK
permalink: /:collection/:path.html
---
# Android DApps
{:.no_toc}
This tutorial is written for readers who are new to either or both Blockstack
and Android to create a decentralized application. It contains the following
content:
* TOC
{:toc}
- TOC
{:toc}
This tutorial was extensively tested using Android Studio 3.6 on a Dell XPS 13
running Ubuntu 19. If your environment is different, you may encounter
@ -76,8 +78,7 @@ If you don't have these installed, take a moment to install or upgrade as needed
## Build the Blockstack hello-world web app
In this section, you build a Blockstack `hello-world` web application that acts as the companion site to your
Android application.
In this section, you build a Blockstack `hello-world` web application that acts as the companion site to your Android application.
### Generate and launch your hello-blockstack application
@ -88,70 +89,66 @@ In this section, you build an initial React.js application called
1. Create a `hello-blockstack` directory.
```bash
mkdir hello-blockstack
```
```bash
mkdir hello-blockstack
```
2. Change into your new directory.
```bash
cd hello-blockstack
```
```bash
cd hello-blockstack
```
3. Use the Blockstack application generator to create your initial `hello-blockstack` application.
```bash
$ npx generator-blockstack --plain
create package.json
create .gitignore
create webpack.config.js
create netlify.toml
create firebase.json
...
added 812 packages from 575 contributors and audited 813 packages in 13.176s
found 1 high severity vulnerability
run `npm audit fix` to fix them, or `npm audit` for details
```
Depending on your environment you may have some warnings with the installation. Optionally, you can fix these before continuing to the next section.
```
```bash
$ npx generator-blockstack --plain
create package.json
create .gitignore
create webpack.config.js
create netlify.toml
create firebase.json
...
npm WARN ajv-errors@1.0.1 requires a peer of ajv@>=5.0.0 but none is installed. You must install peer dependencies yourself.
added 840 packages from 582 contributors and audited 843 packages in 18.84s
found 0 vulnerabilities
```
4. Respond to the prompts to populate the initial app .
Depending on your environment you may have some warnings with the installation. Optionally, you can fix these before continuing to the next section.
After the process completes successfully, you see a prompt similar to the following:
4. Depending on your environment, respond to the prompts to populate the initial app.
You might see a prompt similar to the following:
```bash
[fsevents] Success:
"/Users/theuser/repos/hello-blockstack/node_modules/fsevents/lib/binding/Release/node-v59-darwin-x64/fse.node"
is installed via remote npm notice created a lockfile as package-lock.json.
You should commit this file. added 1060 packages in 26.901s
```
```bash
[fsevents] Success:
"/Users/theuser/repos/hello-blockstack/node_modules/fsevents/lib/binding/Release/node-v59-darwin-x64/fse.node"
is installed via remote npm notice created a lockfile as package-lock.json.
You should commit this file. added 1060 packages in 26.901s
```
5. R un the initial application.
5. After the initial setup you can now r un the initial application.
```bash
$ npm run start
```bash
$ npm run start
> hello-blockstack@0.0.0 start /Users/user/repos /hello-blockstack
> hello-blockstack-webpack@0.0.0 start /home/user /hello-blockstack
> webpack-dev-server
Project is running at http://localhost:8080/
webpack output is served from /
404s will fallback to /index.html
Hash: 4d2312ba236a4b95dc3a
Version: webpack 2.7.0
Time: 2969ms
Asset Size Chunks Chunk Names
....
Child html-webpack-plugin for "index.html":
chunk {0} index.html 541 kB [entry] [rendered]
[0] ./~/lodash/lodash.js 540 kB {0} [built]
[1] ./~/html-webpack-plugin/lib/loader.js!./src/index.html 533 bytes {0} [built]
[2] (webpack)/buildin/global.js 509 bytes {0} [built]
[3] (webpack)/buildin/module.js 517 bytes {0} [built]
webpack: Compiled successfully.
```
ℹ ｢wds｣: Project is running at http://localhost:9000/
ℹ ｢wds｣: webpack output is served from /
ℹ ｢wds｣: Content not from webpack is served from /home/user/hello-blockstack/dist
ℹ ｢wdm｣: Hash: f5d88efe9c9194f66ddd
Version: webpack 4.43.0
Time: 2733ms
Built at: 05/19/2020 10:44:50 AM
Asset Size Chunks Chunk Names
main.js 5.39 MiB main [emitted] main
....
[./src/index.js] 1.8 KiB {main} [built]
+ 610 hidden modules
ℹ ｢wdm｣: Compiled successfully.
```
The system opens a browser displaying your running application.
@ -164,72 +161,19 @@ In this section, you build an initial React.js application called
The system displays a prompt allowing you to create a new Blockstack ID or restore an existing one.
7. Follow the prompts appropriate to your situation.
If you are restoring an existing ID, you may see a prompt about your user
being nameless, ignore it. At this point you have only a single application
on your test server. So, you should see this single application, with your
own `blockstack.id` , once you are signed in:
### Add a redirect end point to your application
When a user opens the webapp from the Blockstack Browser on an Android phone,
you want the web app to redirect the user to your Android application. The work
you do here will allow it.
1. From the terminal command line, change directory to the root of your sample
application directory.
2. Use the `touch` command to add a redirect endpoint to your application.
This endpoint on the web version of your app will redirect Android users back
to your mobile app.
```bash
$ touch public/redirect.html
```
3. Open `redirect.html` and add code to the endpoint.
```html
<!DOCTYPE html>
< html >
< head >
< title > Hello, Blockstack!< / title >
< script >
function getParameterByName(name) {
var match = RegExp('[?& ]' + name + '=([^&]*)').exec(window.location.search);
return match && decodeURIComponent(match[1].replace(/\+/g, ' '));
}
var authResponse = getParameterByName('authResponse')
window.location="myblockstackapp:" + authResponse
< / script >
< body >
< / body >
< / html >
```
Blockstack apps are identified by their domain names. The endpoint will
receive a get request with the query parameter `authResponse=XXXX` and
should redirect the browser to `myblockstackapp:XXXX` .
`myblockstackapp:` is custom protocol handler. The handler should be unique
to your application. Your app's web-based authentication uses this handler
to redirect the user back to your Android app. Later, you'll add a reference
to this handler in your Android application.
At this point you have only a single application
on your test server. So, you should see this single application, with your
own `blockstack.id` , once you are signed in:
5. Close and save the `redirect.html` file.
6. Ensure your Blockstack compiles successfully.
## Create the hello-android project
In this section, you'll create an Android application in Android Studio. You'll
In this section, you'll create an Android application in Android Studio. You'll
run the application in the emulator to test it.
### Create a simple project
@ -237,79 +181,74 @@ run the application in the emulator to test it.
In this section, you create an inital project. You'll validate the application's
iniatial state by creating an emulator to run it in. Open Android Studio and do the following:
1. Open Android Studio and choose **Start a new Andriod Studio project** .
If studio is already started, choose **File > New > New Project** .
2. Enter these fields in the **Create Android Project** page.
< table class = "uk-table" >
< tr >
< th > Application Name< / th >
< td > < code > hello-android< / code > < / td >
< / tr >
< tr >
< th > Company domain< / th >
< td > < code > < i > USERNAME< / i > .example.com< / code > < / td >
< / tr >
< tr >
< th > Project location< / th >
< td > < code > /Users/< i > USERNAME< / i > /AndroidStudioProjects/helloandroid< / code > < / td >
< / tr >
< tr >
< th > Include Kotlin support< / th >
< td > Set (checked)< / td >
< / tr >
< / table >
3. Press **Next** to display **Target Android Devices** .
4. Check **Phone and Tablet** .
5. Choose API 27: Andriod 8.1 (Oreo) for the target version.
6. Press **Next** .
7. Choose **Empty Activity** and press **Next** .
8. Leave the **Configure Activity** dialog with its defaults.
9. Press **Finish** .
2. Choose a project template: select **Empty Activity** and press **Next**
3. Enter these fields in the **Create Android Project** page.
< table class = "uk-table" >
< tr >
< th > Name< / th >
< td > < code > Hello Android< / code > < / td >
< / tr >
< tr >
< th > Package name< / th >
< td > < code > blockstack.id.< i > USERNAME< / i > .hello< / code > < / td >
< / tr >
< tr >
< th > Project location< / th >
< td > < code > /home/< i > USERNAME< / i > /AndroidStudioProjects/helloandroid< / code > < / td >
< / tr >
< tr >
< th > Language< / th >
< td > Select (Kotlin)< / td >
< / tr >
< tr >
< th > Minimum SDK< / th >
< td > Select (API 21: Android 5.0 (Lollipop))< / td >
< / tr >
< / table >
4. Press **Finish** .
Android studio builds your initial project. This can take a bit the first time you do it.
### Run the app in an emulator
In this section, you run the appliation and create an emulator when prompted.
1. Once the project is imported into studio, click the `app` module in the **Project** window.
2. Then, select **Run > Run** (or click the green arrow in the toolbar).
2. Then, select **Run > Run** (or click the green arrow in the toolbar).
Studio prompts you to **Select Deployment Target** .
3. Choose **Create New Virtual Device** and press **OK** .
Studio prompts you to **Select Hardware** .
Studio prompts you to **Select Hardware** .
4. Choose a Phone running Pixel XL .
4. Choose a Phone device configuration like "Pixel" .
Studio prompts you for a system image.
Studio prompts you for a system image.
5. Choose **Oreo** which is API level 27 and press **Next** .
5. Choose **Q** which is API level 29 and press **Next** .
Studio asks you to verify your new emulator configuration.
Studio asks you to verify your new emulator configuration.
6. Press **Finish** .
The emulation takes a moment to build. Then, studio launches the emulation and opens your application.
The emulation takes a moment to build. Then, studio launches the emulation and opens your application.
### Configure your application with the Blockstack SDK
@ -317,84 +256,79 @@ Now that you have created your initial project and verified it running in an emu
1. In studio, open the `AndroidManifest.xml` file.
2. Add an `<intent-filter>` with the custom handler for Blockstack.
2. Add an `<intent-filter>` with the custom handler for Blockstack. Replace the host ("flamboyant-darwin-d11c17.netlify.app") with your own url once you have hosted your web app publicly.
```XML
< intent-filter >
< action android:name = "android.intent.action.VIEW" / >
< category android:name = "android.intent.category.DEFAULT" / >
< category android:name = "android.intent.category.BROWSABLE" / >
< data android:scheme = "myblockstack app" / >
< / intent-filter >
```
```XML
< intent-filter >
< action android:name = "android.intent.action.VIEW" / >
< category android:name = "android.intent.category.DEFAULT" / >
< category android:name = "android.intent.category.BROWSABLE" / >
< data android:scheme = "https" android:host = "flamboyant-darwin-d11c17.netlify. app" / >
< / intent-filter >
```
2 . Open the Project's `build.gradle` file.
3 . Add the Jitpack repository `maven { url 'https://jitpack.io' }` to the `repositories` section.
3 . Open the Project's `build.gradle` file ("Project: Hello Android") .
4 . Add the Jitpack repository `maven { url 'https://jitpack.io' }` to the `repositories` section. for all projects
When you finish, that section looks like this:
When you finish, that section looks like this:
```JS
allprojects {
repositories {
google()
jcenter()
maven { url 'https://jitpack.io' }
}
}
```
4. Open the Module `build.gradle` file.
5. Set the `defaultConfig minSdkVersion` to `19` .
```JS
allprojects {
repositories {
google()
jcenter()
maven { url 'https://jitpack.io' }
}
}
```
When you are done, you should see (within your own username not `meepers` ):
5. Open the Module `build.gradle` file ("Module: app").
6. Fix a problem with duplicate meta data in the Android SDK: add `packagingOptions`
```JS
android {
compileSdkVersion 27
defaultConfig {
applicationId "com.example.meepers.hello_android"
minSdkVersion 19
targetSdkVersion 27
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
...
packagingOptions {
exclude 'META-INF/*'
}
}
```
```
7. Below this, add the Blockstack Android SDK dependency to your project's `dependencies` list:
When you are done you should see:
When you are done you should see:
```JS
```JS
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
implementation 'com.android.support:appcompat-v7:27.1.1 '
implementation 'com.android.support.constraint:constraint-layout:1.1.3 '
implementation 'com.android.support:design:27.1.1 '
implementation 'androidx.appcompat:appcompat:1.1.0 '
implementation 'androidx.core:core-ktx:1.2.0 '
implementation 'androidx.constraintlayout:constraintlayout:1.1.3 '
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
implementation 'com.github.blockstack:blockstack-android:0.4.0'
androidTestImplementation 'androidx.test.ext:junit:1.1.1'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
implementation 'com.github.blockstack:blockstack-android:7940940'
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.2.0'
}
```
```
**NOTE** : Ignore the warning on the appcompat` dependencies.
**NOTE** : Ignore the warning on the `junit`
8. Sync your project.
Be sure to check the sync completed successfully.
Be sure to check the sync completed successfully.
10 . Run your app in the emulator.
9 . Run your app in the emulator.
You've made a lot of changes, make sure the emulator is still running
correctly.
You've made a lot of changes, make sure the emulator is still running
correctly.
### Add a simple interface
@ -402,48 +336,50 @@ Now that you have created your initial project and verified it running in an emu
The `activity_main.xml` file defines the graphical elements. Some elements are required before you can functionality to your `MainActivity.kt` code.
3. Replace the entire content of the file with the following code:
2. Replace the entire content of the file with the following code:
The new interface includes a `BlockstackSignInButton` which is provided by
the SDK. This SDK includes a themed "Sign in with Blockstack " button
(`BlockstackSignInButton`). You use this button here with the
`org.blockstack.android.sdk.ui.BlockstackSignInButton` class.
The new interface includes a `BlockstackSignInButton` which is provided by
the SDK. This SDK includes a themed "Get Started " button
(`BlockstackSignInButton`). You use this button here with the
`org.blockstack.android.sdk.ui.BlockstackSignInButton` class.
```XML
<?xml version="1.0" encoding="utf-8"?>
< android.support.constraint.ConstraintLayout xmlns:android = "http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
< org.blockstack.android.sdk.ui.BlockstackSignInButton
android:id="@+id/signInButton"
android:layout_width="307dp"
android:layout_height="45dp"
android:layout_margin="4dp"
android:layout_marginEnd="185dp"
android:layout_marginStart="39dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="16dp" />
< TextView
android:id="@+id/userDataTextView"
android:layout_width="370dp"
android:layout_height="27dp"
tools:layout_editor_absoluteX="6dp"
tools:layout_editor_absoluteY="70dp" />
< / android >
< androidx.constraintlayout.widget.ConstraintLayout xmlns:android = "http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="16dp"
tools:context=".MainActivity">
< org.blockstack.android.sdk.ui.BlockstackSignInButton
android:id="@+id/signInButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toTopOf="@id/userDataTextView"/>
< TextView
android:id="@+id/userDataTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@id/signInButton" />
< / androidx.constraintlayout.widget.ConstraintLayout >
```
This codes adds a button and some text to your application.
4. Choose **Run > Apply changes** .
3. Choose **Run > Apply changes** .
5. Choose **Run > Run app** in the emulator.
4. Choose **Run > Run app** in the emulator.
The emulator now contains a new interface with a button:
@ -452,27 +388,35 @@ Now that you have created your initial project and verified it running in an emu
### Add session & authentication code
1. Open the `MainActivity.kt` file.
2. Add some additional imports to the top below the `android.os.Bundle` import.
2. Add some additional imports to the top, replace the `android.os.Bundle` import.
When you are done, your imports should appear as follows:
When you are done, your imports should appear as follows:
```kotlin
```kotlin
import android.content.Intent
import android.os.Bundle
import android.support.v7 .app.AppCompatActivity
import android.view.View
import androidx.appcompat .app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import org.blockstack.android.sdk.BlockstackSession
import org.blockstack.android.sdk.Scope
import org.blockstack.android.sdk.UserData
import org.blockstack.android.sdk.toBlockstackConfig
```
3. Add a variable for the Blockstack session before `onCreate` .
import org.blockstack.android.sdk.BlockstackSignIn
import org.blockstack.android.sdk.SessionStore
import org.blockstack.android.sdk.getBlockstackSharedPreferences
import org.blockstack.android.sdk.model.UserData
import org.blockstack.android.sdk.model.toBlockstackConfig
import org.blockstack.android.sdk.ui.SignInProvider
import org.blockstack.android.sdk.ui.showBlockstackConnect
```
3. Add one variable for the Blockstack sign-in flow and one for the Blockstack session that deals with all other function. This needs to be added before `onCreate` .
```kotlin
class MainActivity : AppCompatActivity() {
private var _blockstackSession: BlockstackSession? = null
private lateinit var blockstackSession: BlockstackSession
private lateinit var blockstackSignIn: BlockstackSignIn
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
@ -481,204 +425,186 @@ Now that you have created your initial project and verified it running in an emu
}
```
4. Replace the existing the `onCreate` function with the following:
```kotlin
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val scopes = arrayOf(Scope.StoreWrite)
val config = "https://flamboyant-darwin-d11c17.netlify.com"
.toBlockstackConfig(scopes)
4. Replace the existing the `onCreate` function with the following, use your own domain if you are already hosting your web app somewhere:
_blockstackSession = BlockstackSession(this, config)
signInButton.isEnabled = true
```kotlin
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val appConfig =
"https://flamboyant-darwin-d11c17.netlify.app".toBlockstackConfig()
val sessionStore = SessionStore(getBlockstackSharedPreferences())
blockstackSession = BlockstackSession(sessionStore, appConfig)
blockstackSignIn = BlockstackSignIn(sessionStore, appConfig)
BlockstackSignIn.shouldLaunchInCustomTabs = false
signInButton.setOnClickListener {
showBlockstackConnect()
}
signInButton.setOnClickListener { view: View ->
blockstackSession().redirectUserToSignIn {
// only called on error
if (intent?.action == Intent.ACTION_VIEW) {
// handle the redirect from sign in
userDataTextView.text = "Signing in now ..."
lifecycleScope.launch(Dispatchers.IO) {
handleAuthResponse(intent)
}
}
if (intent?.action == Intent.ACTION_VIEW) {
// handle the redirect from sign in
handleAuthResponse(intent)
}
}
```
}
}
```
This new `onCreate` does several things:
This new `onCreate` does several things:
* Define the initial state for the `signInButton` .
* Supply authentication information for connecting to your Blockstack app: `appDomain` and `scopes` (for `redirectURI` , `manifestURI` the default values are used)
* Add a listener for the button click .
- Supply authentication information for connecting to your Blockstack app: `appDomain` (for `scopes` , `redirectURI` , `manifestURI` the default values are used)
- Add a listener for the button click.
- Handles the redirect intent from the sign-in flow .
Notice that the application in this example is a URI you have not set up.
Registering and application name takes time, so in time's interest you'll
use an existing app that is identical to the `hello-world` you created
earlier. For a production version, you'll need to replace `appDomain` ,
`redirectURI` , `manifestURI` and `scopes` with values appropriate for your
app.
Notice that the application in this example is a URI you have not set up.
Registering and application name takes time, so in time's interest you'll
use an existing app (https://flamboyant-darwin-d11c17.netlify.app) that is identical to the `hello-world` you created
earlier. For a production version, you'll need to replace `appDomain` ,
`redirectURI` , `manifestURI` and `scopes` with values appropriate for your
app.
5. Add a private function to reflect when a user successfully signs in.
```kotlin
private fun onSignIn(userData: UserData) {
userDataTextView.text = "Signed in as ${userData.decentralizedID}"
signInButton.isEnabled = false
}
```
```kotlin
private fun onSignIn(userData: UserData) {
userDataTextView.text = "Signed in as ${userData.decentralizedID}"
signInButton.isEnabled = false
}
```
6. Handle sign in requests with an `onNewIntent` function if the activity was already opened when signing in
6. Create a handler for the authentication response.
Retrieve the authentication token from the custom protocol handler call and
send it to the Blockstack session.
```kotlin
private fun handleAuthResponse(intent: Intent) {
val authResponse = intent.data?.getQueryParameter("authResponse")
if (authResponse != null) {
val userData = blockstackSession.handlePendingSignIn(authResponse)
if (userData.hasValue) {
// The user is now signed in!
runOnUiThread {
onSignIn(userData.value!!)
}
}
}
}
```
```kotlin
override fun onNewIntent(intent: Intent?) {
super.onNewIntent(intent)
7. Add `SignInProvider` interface for better user onboarding. Let the activity implement the interface and implement the member function `getBlockstackSignIn`
if (intent?.action == Intent.ACTION_VIEW) {
handleAuthResponse(intent)
```kotlin
class MainActivity : AppCompatActivity(), SignInProvider {
...
override fun provideBlockstackSignIn(): BlockstackSignIn {
return blockstackSignIn
}
}
```
8. Verify your final `MainActivity.kt` code looks like this:
```kotlin
package blockstack.id.user.hello
```
import android.content.Intent
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.android.synthetic.main.activity_main.\*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import org.blockstack.android.sdk.BlockstackSession
import org.blockstack.android.sdk.BlockstackSignIn
import org.blockstack.android.sdk.SessionStore
import org.blockstack.android.sdk.getBlockstackSharedPreferences
import org.blockstack.android.sdk.model.UserData
import org.blockstack.android.sdk.model.toBlockstackConfig
import org.blockstack.android.sdk.ui.SignInProvider
import org.blockstack.android.sdk.ui.showBlockstackConnect
class MainActivity : AppCompatActivity(), SignInProvider {
private lateinit var blockstackSession: BlockstackSession
private lateinit var blockstackSignIn: BlockstackSignIn
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val appConfig =
"https://flamboyant-darwin-d11c17.netlify.app".toBlockstackConfig()
val sessionStore = SessionStore(getBlockstackSharedPreferences())
blockstackSession = BlockstackSession(sessionStore, appConfig)
blockstackSignIn = BlockstackSignIn(sessionStore, appConfig)
BlockstackSignIn.shouldLaunchInCustomTabs = false
signInButton.setOnClickListener {
showBlockstackConnect()
}
if (intent?.action == Intent.ACTION_VIEW) {
// handle the redirect from sign in
userDataTextView.text = "Signing in now ..."
lifecycleScope.launch(Dispatchers.IO) {
handleAuthResponse(intent)
}
}
}
}
```
7. Create a handler for the authentication response.
```kotlin
private fun handleAuthResponse(intent: Intent) {
val response = intent.dataString
if (response != null) {
val authResponseTokens = response.split(':')
if (authResponseTokens.size > 1) {
val authResponse = authResponseTokens[1]
blockstackSession().handlePendingSignIn(authResponse, { userData ->
if (userData.hasValue) {
// The user is now signed in!
runOnUiThread {
onSignIn(userData.value!!)
}
}
})
}
}
}
```
private fun onSignIn(userData: UserData) {
userDataTextView.text = "Signed in as ${userData.decentralizedID}"
signInButton.isEnabled = false
}
8. Add the convenience method to access the blockstack session.
private suspend fun handleAuthResponse(intent: Intent) {
val authResponse = intent.data?.getQueryParameter("authResponse")
if (authResponse != null) {
val userData = blockstackSession.handlePendingSignIn(authResponse)
if (userData.hasValue) {
// The user is now signed in!
runOnUiThread {
onSignIn(userData.value!!)
}
}
}
}
```kotlin
fun blockstackSession() : BlockstackSession {
val session = _blockstackSession
if(session != null) {
return session
} else {
throw IllegalStateException("No session.")
override fun provideBlockstackSignIn(): BlockstackSignIn {
return blockstackSignIn
}
}
```
9. Verify your final `MainActivity.kt` code looks like this:
```kotlin
class MainActivity : AppCompatActivity() {
private var _blockstackSession: BlockstackSession? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
signInButton.isEnabled = false
val scopes = arrayOf(Scope.StoreWrite)
val config = "https://flamboyant-darwin-d11c17.netlify.com"
.toBlockstackConfig(scopes)
_blockstackSession = BlockstackSession(this, config)
signInButton.isEnabled = true
signInButton.setOnClickListener { view: View ->
blockstackSession().redirectUserToSignIn {
// only called on error
}
}
if (intent?.action == Intent.ACTION_VIEW) {
handleAuthResponse(intent)
}
}
private fun onSignIn(userData: UserData) {
userDataTextView.text = "Signed in as ${userData.decentralizedID}"
signInButton.isEnabled = false
}
override fun onNewIntent(intent: Intent?) {
super.onNewIntent(intent)
if (intent?.action == Intent.ACTION_VIEW) {
handleAuthResponse(intent)
}
}
private fun handleAuthResponse(intent: Intent) {
val response = intent.dataString
if (response != null) {
val authResponseTokens = response.split(':')
if (authResponseTokens.size > 1) {
val authResponse = authResponseTokens[1]
blockstackSession().handlePendingSignIn(authResponse, { userData ->
if (userData.hasValue) {
// The user is now signed in!
runOnUiThread {
onSignIn(userData.value!!)
}
}
})
}
}
}
fun blockstackSession() : BlockstackSession {
val session = _blockstackSession
if(session != null) {
return session
} else {
throw IllegalStateException("No session.")
}
}
}
```
}
```
### Run the final app in the emulator
1. Choose **Run > Apply changes** .
2. Choose **Run > Run app** in the emulator.
3. When you see the application open, choose **Sign in with Blockstack** .
The system prompts you how to open.
3. When you see the application open, choose **Get Started** .
4. A small information is presented about the sign-in flow
4. Choose **Chrome** and click **ALWAYS** .
5. Move through the rest of the Chrome prompts .
5. Select **Get Started**
The system might prompt you how to select a browser.
The system presents you with your final application.
6. Work through the Blockstack prompts to login.
7. Blockstack redirects you to a web site. Open it with your Android app: Select **Hello Android** and **Always**
6. Work through the Blockstack prompts to log in.
8. The screen after the sign-in flow shows the owner address of the username that was entered during sign-in.
## Where to go next
Congratulations, you've completed your Android app using the Blockstack Android SDK.
Learn more about Blockstack by [trying another tutorial ](https://blockstack.org/tutorials ).
```
Friedger Müffke
5 years ago
Mark Hendrickson
