Wanted Blog: juin 2017

If you come across any mistakes or bugs in this tutorial, please let us know using a Github issue, a post on the DJI forum. Please feel free to send us Github pull request and help us fix any issues.

In this tutorial, you will learn how to use DJI Android UI Library and DJI Android SDK to create a fully functioning mini-DJI Go app easily, with standard DJI Go UIs and functionalities. By the end of this tutorial you will have an app that you can use to show the camera FPV view, check aircraft status, shoot photos, record videos and so on.
You can download the tutorial's final sample code project from this Github Page.
We use Mavic Pro and Nexus 5 as an example to make this demo. For more details of customizing the layouts for iPhone devices, please check the tutorial's Github Sample Project. Let's get started!

Introduction

DJI UI Library is a visual framework consisting of UI Elements. It helps you simplify the creation of DJI Mobile SDK based apps in Android. With similar design to DJI Go,UI Elements allow you to create consistent UX between your apps and DJI apps.
Additionally, with the ease of use, UILibrary let you focus more on business and application logic.
As DJI UI Library is built on top of DJI Mobile SDK and VideoPreviewer, you need to use it with them together in your application development.

Importing DJI SDK and UILibrary with AAR file

1. Now, let's create a new project in Android Studio, open Android Studio and select File -> New -> New Project to create a new project, named 'UILibraryDemo'. Enter the company domain and package name (Here we use "com.dji.uilibrarydemo") you want and press Next. Set the minimum SDK version as API 18: Android 4.3 (Jelly Bean) for "Phone and Tablet" and press Next. Then select "Empty Activity" and press Next. Lastly, leave the Activity Name as "MainActivity", and the Layout Name as "activity_main", press "Finish" to create the project.
2. Next, download the android-uilib-release.aar file from this Github link. Go to File -> New -> New Module on the Android Studio menu:

Choose "Import .JAR/.AAR Package" and click on "Next" button as shown below:

Choose the downloaded android-uilib-release.aar file path in the "File name" field. A "android-uilib-release" name will show in the "Subproject name" field. Press "Finish" button to finish the settings.
Moreover, right click on the 'app' module in the project navigator and click "Open Module Settings" to open the Project Structure window. Navigate to the "Dependencies" tab, click on the "+" sign at the bottom and select "3 Module dependency", then choose the ":android-uilib-release" module and press "OK". You should find the ":android-uilib-release" appear in the list now.

3. Furthermore, double click on the "build.gradle(Module: app)" in the project navigator to open it and replace the content with the following:


apply plugin: 'com.android.application'

android {

compileSdkVersion 23

buildToolsVersion '23.0.1'

defaultConfig {

applicationId "com.dji.uilibrarydemo"

minSdkVersion 18

targetSdkVersion 23

versionCode 1

versionName "1.0"

multiDexEnabled true

}

buildTypes {

release {

minifyEnabled false

proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

}

}

dexOptions {

javaMaxHeapSize "3g"

}

lintOptions{

abortOnError false

}

}

dependencies {

compile fileTree(include: ['*.jar'], dir: 'libs')

compile 'com.android.support:appcompat-v7:23.3.0'

testCompile 'junit:junit:4.12'

compile project(':android-uilib-release')

compile 'com.android.support:recyclerview-v7:23.4.0'

}

In the code above, we update the compileSdkVersion, buildToolsVersion, targetSdkVersion number, etc. Also, we add the "compile 'com.android.support:recyclerview-v7:23.4.0'" at the bottom of "dependencies" to add the necessary recyclerview library.
configureAndroidSDK

Note: We also remove the compile 'com.android.support:design:23.4.0' in the "dependencies" to avoid getting the following errors:

Then, select the Tools -> Android -> Sync Project with Gradle Files on the top bar and wait for Gradle project sync finish.
4. Now, open the MainActivity.java file and add import dji.sdk.sdkmanager.DJISDKManager; at the bottom of the import classes section as shown below:


package com.dji.uilibrarydemo;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import dji.sdk.sdkmanager.DJISDKManager;

Wait for a few seconds and check if the words turn red, if they remain gray color, congrats! You have imported the DJI Android SDK and DJI UI Library into your Android Studio project successfully!

Building the Default Layout using UI Library

Now, let's continue to open the "activity_main.xml" file, and replace the code with the following:


<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:background="@color/background_blue"

android:orientation="horizontal"

tools:context=".MainActivity">

<!--1-->

<!-- Widget to see first person view (FPV) -->

<dji.ui.widget.FPVWidget

android:layout_width="match_parent"

android:layout_height="match_parent"/>

<dji.ui.widget.FPVOverlayWidget

android:layout_width="match_parent"

android:layout_height="match_parent"/>

<!--2-->

<!-- Widgets in top status bar -->

<LinearLayout

android:id="@+id/signal"

android:layout_width="match_parent"

android:layout_height="25dp"

android:background="@color/dark_gray"

android:orientation="horizontal">

<dji.ui.widget.PreFlightStatusWidget

android:id="@+id/status"

android:layout_width="238dp"

android:layout_height="25dp"/>

<dji.ui.widget.FlightModeWidget

android:layout_width="103dp"

android:layout_height="22dp"/>

<dji.ui.widget.GPSSignalWidget

android:layout_width="44dp"

android:layout_height="22dp"/>

<dji.ui.widget.VisionWidget

android:layout_width="22dp"

android:layout_height="22dp"/>

<dji.ui.widget.RemoteControlSignalWidget

android:layout_width="38dp"

android:layout_height="22dp"/>

<dji.ui.widget.VideoSignalWidget

android:layout_width="38dp"

android:layout_height="22dp"/>

<dji.ui.widget.WiFiSignalWidget

android:layout_width="22dp"

android:layout_height="20dp"/>

<dji.ui.widget.BatteryWidget

android:layout_width="56dp"

android:layout_height="22dp"/>

<dji.ui.widget.ConnectionWidget

android:layout_marginTop="5dp"

android:layout_width="22dp"

android:layout_height="22dp"/>

</LinearLayout>

<!--3-->

<LinearLayout

android:id="@+id/camera"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_below="@id/signal"

android:layout_centerHorizontal="true"

android:layout_margin="12dp"

android:background="@color/dark_gray"

android:orientation="horizontal">

<dji.ui.widget.AutoExposureLockWidget

android:layout_width="25dp"

android:layout_height="25dp"/>

<dji.ui.widget.FocusExposureSwitchWidget

android:layout_width="25dp"

android:layout_height="25dp"/>

<dji.ui.widget.FocusModeWidget

android:layout_width="25dp"

android:layout_height="25dp"/>

<dji.ui.widget.config.CameraConfigISOWidget

android:layout_width="50dp"

android:layout_height="25dp"/>

<dji.ui.widget.config.CameraConfigShutterWidget

android:layout_width="50dp"

android:layout_height="25dp"/>

<dji.ui.widget.config.CameraConfigApertureWidget

android:layout_width="50dp"

android:layout_height="25dp"/>

<dji.ui.widget.config.CameraConfigEVWidget

android:layout_width="50dp"

android:layout_height="25dp"/>

<dji.ui.widget.config.CameraConfigWBWidget

android:layout_width="50dp"

android:layout_height="25dp"/>

<dji.ui.widget.CameraConfigStorageWidget

android:layout_width="108dp"

android:layout_height="25dp"/>

<!--4-->

</LinearLayout>

<dji.ui.widget.RemainingFlightTimeWidget

android:layout_alignParentTop="true"

android:layout_marginTop="18dp"

android:layout_width="match_parent"

android:background="@color/transparent"

android:layout_height="20dp"/>

<!--5-->

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:orientation="horizontal"

android:padding="12dp">

<dji.ui.widget.dashboard.DashboardWidget

android:id="@+id/Compass"

android:layout_width="405dp"

android:layout_height="91dp"

android:layout_marginRight="12dp"/>

</LinearLayout>

<!--6-->

<!--Take off and return home buttons on left -->

<LinearLayout

android:layout_width="40dp"

android:layout_height="wrap_content"

android:layout_centerVertical="true"

android:layout_marginStart="12dp"

android:orientation="vertical">

<dji.ui.widget.TakeOffWidget

android:layout_width="40dp"

android:layout_height="40dp"

android:layout_marginBottom="12dp"/>

<dji.ui.widget.ReturnHomeWidget

android:layout_width="40dp"

android:layout_height="40dp"

android:layout_marginTop="12dp"/>

</LinearLayout>

<!--7-->

<dji.ui.widget.controls.CameraControlsWidget

android:id="@+id/CameraCapturePanel"

android:layout_alignParentRight="true"

android:layout_below="@id/camera"

android:layout_width="50dp"

android:layout_height="213dp"/>

<!--8-->

<dji.ui.panel.CameraSettingExposurePanel

android:id="@+id/CameraExposureMode"

android:layout_width="180dp"

android:layout_below="@id/camera"

android:layout_toLeftOf="@+id/CameraCapturePanel"

android:background="@color/transparent"

android:gravity="center"

android:layout_height="263dp"

android:visibility="invisible"/>

<!--9-->

<dji.ui.panel.CameraSettingAdvancedPanel

android:id="@+id/CameraAdvancedSetting"

android:layout_width="180dp"

android:layout_height="263dp"

android:layout_below="@id/camera"

android:layout_toLeftOf="@+id/CameraCapturePanel"

android:background="@color/transparent"

android:gravity="center"

android:visibility="invisible"/>

<!--10-->

<!-- Pre-flight checklist panel -->

<dji.ui.panel.PreFlightCheckListPanel

android:id="@+id/PreflightCheckView"

android:layout_width="400dp"

android:layout_height="wrap_content"

android:layout_below="@id/signal"

android:visibility="gone"/>

</RelativeLayout>

In the xml file above, we implement the following UIs:

Firstly, we add the dji.ui.widget.FPVWidget and dji.ui.widget.FPVOverlayWidget elements to show the first person view (FPV).

Next, on top of the screen, we create a LinearLayout to group the top status bar widgets, like PreFlightStatusWidget, FlightModeWidget, GPSSignalWidget, RemoteControlSignalWidget, etc.

Moreover, we create another LinearLayout to group the camera configurations and config widgets below the status bar widgets, like AutoExposureLockWidget, FocusExposureSwitchWidget, CameraConfigISOWidget, CameraConfigStorageWidget, etc. Also we add the dji.ui.widget.RemainingFlightTimeWidget element to show the remaining flight time widget below the top status bar widgets too.

Below the top status bar, we add a RemainingFlightTimeWidget to show the remaining flight time.

At the bottom of the screen, we add another LinearLayout to group the DashboardWidget. It includes the circular CompassWidget, the DistanceHomeWidget, the HorizontalVelocityWidget, the DistanceRCWidget, the VerticalVelocityWidget and the AltitudeWidget as shown below:

On the left side of the screen, we add a LinearLayout to group the TakeOffWidget and ReturnHomeWidget which will be shown as two buttons.

On the right side of the screen, we add the dji.ui.widget.controls.CameraControlsWidget element to create a CameraControlsWidget to show the camera control widget. Tapping the Menu button on top will toggle between show and hide CameraSettingAdvancedPanel. Tapping the switch button in the middle will toggle camera mode between shoot photo and record video. Tapping the bottom button will toggle between show and hide CameraSettingExposurePanel.

To add the CameraSettingExposurePanel, we add the dji.ui.panel.CameraSettingExposurePanel element and configure its attributes.

To add the CameraSettingAdvancedPanel, we add the dji.ui.panel.CameraSettingAdvancedPanel element and configure its attributes.

Lastly, we add the dji.ui.panel.PreFlightCheckListPanel element to create the PreFlightCheckListPanel. When user press on the PreFlightStatusWidget, it will show up below the top status bar.

Once you finished the steps above, open the "colors.xml" file and replace the content with the following:


<?xml version="1.0" encoding="utf-8"?>

<resources>

<color name="colorPrimary">#3F51B5</color>

<color name="colorPrimaryDark">#303F9F</color>

<color name="colorAccent">#FF4081</color>

<color name="background_blue">#242d34</color>

<color name="transparent">#00000000</color>

<color name="dark_gray">#80000000</color>

</resources>

Moreover, let's open the "styles.xml" file and replace the content with the following:


<resources>

<!-- Base application theme. -->

<style name="AppTheme" parent="@style/Base.Theme.AppCompat.Light.NoActionBar">

</style>

</resources>

With the help of DJI UI Library, it's simple and straightforward to implement the standard DJI Go UIs and functionalities in your own application.

Application Registration

Now let's register our application with the App Key you apply from DJI Developer Website. If you are not familiar with the App Key, please check the Get Started.

Implementing DemoApplication Class

Right click on the 'com.dji.uilibrarydemo' module in the project navigator and select "New -> Java Class" to create a new file, enter "DemoApplication" as the Name. Then replace the code with the same file in this tutorial's Github sample project, here we explain the important parts of it:


@Override

public void onCreate() {

super.onCreate();

mHandler = new Handler(Looper.getMainLooper());

//This is used to start SDK services and initiate SDK.

DJISDKManager.getInstance().registerApp(this, mDJISDKManagerCallback);

}

/**

* When starting SDK services, an instance of interface DJISDKManager.SDKManagerCallback will be used to listen to 

* the SDK Registration result and the product changing.

*/

private DJISDKManager.SDKManagerCallback mDJISDKManagerCallback = new DJISDKManager.SDKManagerCallback() {

//Listens to the SDK registration result

@Override

public void onRegister(DJIError error) {

if(error == DJISDKError.REGISTRATION_SUCCESS) {

DJISDKManager.getInstance().startConnectionToProduct();

Handler handler = new Handler(Looper.getMainLooper());

handler.post(new Runnable() {

@Override

public void run() {

Toast.makeText(getApplicationContext(), "Register Success", Toast.LENGTH_LONG).show();

}

});

} else {

Handler handler = new Handler(Looper.getMainLooper());

handler.post(new Runnable() {

@Override

public void run() {

Toast.makeText(getApplicationContext(), "Register Failed, check network is available", Toast.LENGTH_LONG).show();

}

});

}

Log.e("TAG", error.toString());

}

//Listens to the connected product changing, including two parts, component changing or product connection changing.

@Override

public void onProductChange(BaseProduct oldProduct, BaseProduct newProduct) {

mProduct = newProduct;

if(mProduct != null) {

mProduct.setBaseProductListener(mDJIBaseProductListener);

}

notifyStatusChange();

}

};

private BaseProduct.BaseProductListener mDJIBaseProductListener = new BaseProduct.BaseProductListener() {

@Override

public void onComponentChange(BaseProduct.ComponentKey key, BaseComponent oldComponent, BaseComponent newComponent) {

if(newComponent != null) {

newComponent.setComponentListener(mDJIComponentListener);

}

notifyStatusChange();

}

@Override

public void onConnectivityChange(boolean isConnected) {

notifyStatusChange();

}

};

Here, we implement several features:

We override the onCreate() method to initialize DJISDKManager and register the application.
Implement the two interface methods of SDKManagerCallback. You can use the onRegister() method to check the Application registration status and show text message to inform users. Using the onProductChange() method, we can check the product connection status and invoke the notifyStatusChange() method to notify status changes.
Implement the two interface methods of BaseProductListener. You can use the onComponentChange() method to check the product component change status and invoke the notifyStatusChange() method to notify status changes. Also, you can use the onConnectivityChange() method to notify the product connectivity changes.

For more details, please check this tutorial's Github Sample project.

Modifying AndroidManifest file

Once you finished the steps above, let's open the "AndroidManifest.xml" file and add the following elements on top of the application element:


<!-- DJI SDK need permission -->

<uses-permission android:name="android.permission.BLUETOOTH" />

<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

<uses-permission android:name="android.permission.VIBRATE" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

<uses-permission android:name="android.permission.WAKE_LOCK" />

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

<uses-feature android:name="android.hardware.camera" />

<uses-feature android:name="android.hardware.camera.autofocus" />

<uses-feature

android:name="android.hardware.usb.host"

android:required="false" />

<uses-feature

android:name="android.hardware.usb.accessory"

android:required="true" />

Here, we request permissions that the application must be granted in order for it to register DJI SDK correctly. Also, we declare the camera and USB hardware which are used by the application.
Moreover, let's add the following elements as childs of element on top of the "MainActivity" activity element as shown below:


<!-- DJI SDK -->

<uses-library android:name="com.android.future.usb.accessory" />

<meta-data

android:name="com.dji.sdk.API_KEY"

android:value="Please enter your App Key here." />

<activity

android:name="dji.sdk.sdkmanager.DJIAoaControllerActivity"

android:theme="@android:style/Theme.Translucent">

<intent-filter>

<action android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED" />

</intent-filter>

<meta-data

android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED"

android:resource="@xml/accessory_filter" />

</activity>

<service android:name="dji.sdk.sdkmanager.DJIGlobalService"></service>

<!-- DJI SDK -->

In the code above, you should substitute your App Key of the application for "Please enter your App Key here." in the value attribute under the android:name="com.dji.sdk.API_KEY" attribute. For the "accessory_filter.xml" file, you can get it from this tutorial's Github Sample project.
Lastly, update the "MainActivity" activity elements as shown below:


<activity android:name=".MainActivity"

android:screenOrientation="landscape">

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

In the code above, we add the attributes of "android:screenOrientation" to set "MainActivity" as landscape and add an intent filter for it.

Working on the MainActivity

Finally, let's open the "MainActivity.java" file, replace the code with the following:


public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

// When the compile and target version is higher than 22, please request the

// following permissions at runtime to ensure the

// SDK work well.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

ActivityCompat.requestPermissions(this,

new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.VIBRATE,

Manifest.permission.INTERNET, Manifest.permission.ACCESS_WIFI_STATE,

Manifest.permission.WAKE_LOCK, Manifest.permission.ACCESS_COARSE_LOCATION,

Manifest.permission.ACCESS_NETWORK_STATE, Manifest.permission.ACCESS_FINE_LOCATION,

Manifest.permission.CHANGE_WIFI_STATE, Manifest.permission.MOUNT_UNMOUNT_FILESYSTEMS,

Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.SYSTEM_ALERT_WINDOW,

Manifest.permission.READ_PHONE_STATE,

}

, 1);

}

setContentView(R.layout.activity_main);

}

}

In the onCreate() method, we request several permissions at runtime to ensure the SDK works well when the compile and target SDK version is higher than 22(Like Android Marshmallow 6.0 device and API 23).
Now, let's build and run the project and install it to your Android device. If everything goes well, you should see the "Register Success" textView like the following screenshot when you register the app successfully.

Connecting to the Aircraft and Run the Project

Now, please check this Connect Mobile Device and Run Application guide to run the application and try the mini-DJI Go features of UILibrary based on what we've finished of the application so far!
If you can see the live video feed and test the features like this, congratulations! Using the DJI UI Library is that easy.

Summary

In this tutorial, you have learned how to use the DJI Android UI Library and DJI Android SDK to create a fully functioning mini-DJI Go app easily, with standard DJI Go UIs and functionalities. Hope you enjoy it!

Wanted Blog

samedi 3 juin 2017

les 5 compétences de base d'un hacker

DJI UI Library

Tuto pour bien debuté avec la librairie UI de DJI

Getting Started with DJI UI Library