Establish App Development Environment

You can develop a Nexacro-based Android app by using Android Studio, the official app development tool of Android. Otherwise, you can use App Builder, which is one of Nexacro products. This chapter explains how to develop an app by using Android Studio. The process of developing a Nexacro-based Android app is basically the same as that of a usual Android app.

The installation file of Android Studio includes a software development kit (SDK). Click on the below link to download the installation file appropriate for your running environment.

https://developer.android.com/studio/index.html

Develop App Project

Once the app development environment is established, open Android Studio to get ready to develop an app running in Android. Before entering an app project, you should find the archive files that you built in Nexacro Studio and locate them in the designated directory.

Create a project

If you want to create a new project with a project already opened, navigate to the below menu.

File > New > New Project

Selection of templates affects an app structure, screen layout as well as the composition of files. Since it is enough for us to have a basic project that just can contain a Nexacro-based app, select Empty Views Activity and click Next.

As the project window is opened, additional necessary files are downloaded and installed automatically.

Set Nexacro libraries

Set the Nexacro Android Archive (AAR) file provided for use in app development in the Android project. No setting is required. Just copy it to the designated path.

If you want to copy the library files to each designated location in your actual project, you should select the Project view option from the dropdown at the top of the Project window. When you install Android Studio, the view mode is set to Android by default. You should change the view mode to Project to see the actual file structure of a project.

Set resources

In this stage, you can set launch images, icons, messages and layouts applied to your app. The Android system can offer optimal settings for screens if you make a list of resources according to device screen sizes and screen densities and then allocate each of them to appropriate folders.

Basic resources are included in the Nexacro Android Archive (AAR) file. If the default resources are used, no specific setup is required.

See the official Android user guide for further details on resources.

Set images

Images used in an app should be placed in each appropriate directory under the res directory according to screen densities. For example, images for a splash screen should be located in drawable folders while app icon images are placed in mipmap folders. Image files should be put in different folders according to the resolution levels that are supported by the relevant app.

Set strings

The default string settings are applied according to the strings.xml file settings included in the Nexacro Android Archive (AAR) file. To change the default string settings, you can create a strings.xml file in the values, values-ko, values-ja, values-zh folders under the res folder and set only the items you want to change.

The code below is the strings.xml file included in the Nexacro Android archive file. The contents may vary depending on the distributed version

$r_title(values\strings.xml)
<?xml version="1.0" encoding="utf-8"?>

<resources>
 <string name="needupdate">It is need to update. \nIt will start after the update is completed.</string>
 <string name="update">Update</string>
 <string name="exit">Exit</string>
 <string name="updateFail">Update is fail. \nPlease restart.</string>
 <string name="loadingFail">First loading is fail. \nPlease restart.</string>
 <string name="updatedone">Update is Completed.</string>
 <string name="checkforupdates">Check for updates.</string>
 <string name="installforupdates">Install for updates.</string>
 <string name="ok">OK</string>
 <string name="downloadingforupdates">Downloading for updates.</string>
 <string name="allow_permission">Allow the permission as the permission is required for the normal function of the engine update.</string>
 <string name="denied_permission">It ends with denial of engine update permission.</string>
 <string name="cancel">Cancel</string>
 <string name="ssl_invalid">The SSL certificate is invalid. Continue?</string>
</resources>

While you can change those strings to suit your situation, you should not change their name attributes because they are predefined for the app.

If you want to add strings written in a non-English language like Korean or Japanese, add a folder under the res directory with a name like values-ko or values-ja. Then, add the strings.xml file to the created folder. See the official Android user guide for further details.

Set Config

Basic config settings are applied according to the settings of the nexacro_config.xml file included in the Nexacro Android Archive (AAR) file. To change the config settings, create and set the nexacro_config.xml file in the xml folder.

The code below is the content of the nexacro_config.xml file included in the Nexacro Android archive file. The contents may vary depending on the distributed version

$r_title(xml\nexacro_config.xml)

<?xml version="1.0" encoding="UTF-8"?>
<nexacro-config>
    <application style="default" dialog-position="bottom" file-logging="true" quiet="false" loglevel="debug" tracemode="none" traceduration="-1"/>
    <notification enable="true" handler="com.nexacro.notification.DefaultHandler"/>
    <xpush-server request-missing-message="false" sender-id="1234567890"/>
    <updator cancelable="true" force="true" restart="false" errormsg="true" quiet="false" failpass="true"/>
    <log filepath="%SD_CARD%nreLog.log" filesize="408960" backupfilecount="5"/>
</nexacro-config>

The below table shows the features that you can set in nexacro_config.xml.

Set build environment

You should modify MainActivity.java and AndroidManifest.xml —default files created in the process of creating an Android project—in a way that suits Nexacro.

MainActivity.java

If you do not specify another name for a main activity at the creation of a project, the activity will be created with the name MainActivity.java. To find the file MainActivity.java, navigate to the folder of the relevant package name under the directory [project > app > src > main > java]. Then, modify the file as below.

$r_title(MainActivity.java)
package com.example.hellonexacroandroid;

import android.os.Bundle;
import com.nexacro.NexacroActivity;

public class MainActivity extends NexacroActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

		// Update Type: Server, Update
        setProjectURL("http://[URL]/");
        setBootstrapURL("http://[URL]/start_android.json");

		// Update Type: Local
		// setBootstrapURL("file:///android_asset/archive/start_android.json");
    }
}

plugin_config.xml

The plugin_config.xml file is located in [Project > app > src > main > res > xml]. It contains basic information about the Device API and necessary information. Refer to the code below to write the required information.

$r_title(plugin_config.xml)


<?xml version="1.0" encoding="UTF-8"?>
<plugin-config>
    <!-- Nexacro Device API -->
    <plugin name="Network" class="com.nexacro.deviceapi.Network" onload="false"/>
    <plugin name="Geolocation" class="com.nexacro.deviceapi.Geolocation" onload="false"/>
    <plugin name="Acceleration" class="com.nexacro.deviceapi.Acceleration" onload="false"/>
    <plugin name="Sound" class="com.nexacro.deviceapi.AudioPlayer" onload="false"/>
    <plugin name="AudioRecorder" class="com.nexacro.deviceapi.AudioRecorder" onload="false"/>
    <plugin name="Camera" class="com.nexacro.deviceapi.Camera" onload="false"/>
    <plugin name="ImagePicker" class="com.nexacro.deviceapi.ImagePicker" onload="false"/>
    <plugin name="ExternalAPI" class="com.nexacro.deviceapi.ExternalAPI" onload="false"/>
    <plugin name="Vibrator" class="com.nexacro.deviceapi.Vibrate" onload="false"/>
    <plugin name="Call" class="com.nexacro.deviceapi.Phone" onload="false"/>
    <plugin name="Sms" class="com.nexacro.deviceapi.SmsManager" onload="false"/>
    <plugin name="ContactSet" class="com.nexacro.deviceapi.Contact" onload="false"/>
    <plugin name="SQLStatement" class="com.nexacro.deviceapi.LiteDBStatement" onload="false"/>
    <plugin name="SQLConnection" class="com.nexacro.deviceapi.LiteDBConnection" onload="false"/>
</plugin-config>

AndroidManifest.xml

The AndroidManifest.xml file, which is located in the directory [project > app > src > main], contains basic information about your app and necessary information for performing specific functionalities. Modify the file as shown in the below sample.

$r_title(AndroidManifest.xml)


<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

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

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.HelloNexacroAndroid"
        android:usesCleartextTraffic="true"
        tools:targetApi="31">

        <activity
            android:name=".MainActivity"
            android:configChanges="orientation|screenSize|keyboardHidden"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <action android:name="OPEN_NEXACRO_ACTIVITY_EXAMPLE" />

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

    </application>

</manifest>

AndroidManifest.xml > Additional privilege settings

Set necessary permissions and other information according to the features that your app is equipped with. For example, add the below sample to the manifest file if you want your app to provide the camera feature.

...
<uses-permission android:name="android.permission.CAMERA" />
<activity android:name="com.nexacro.deviceAPI.CameraListener"
	android:screenOrientation="landscape">
	<intent-filter>
   		<category android:name="android.intent.category.LAUNCHER" />
	</intent-filter>
</activity>
<uses-feature android:name="android.hardware.camera" android:required="false"/>
<uses-feature android:name="android.hardware.camera.autofocus"
	android:required="false"/>
...

The below list contains sets of code to set the permissions for frequently-used features. Pick items necessary for your app and add them to AndroidManifest.xml. If you want to see all the permissions defined in Android, go to Manifest.permission.

<!-- AudioPlayer, AudioRecorder -->
<uses-permission android:name="android.permission.RECORD_AUDIO" /> 
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

<!-- Call -->
<uses-permission android:name="android.permission.CALL_PHONE" />

<!-- Contact -->
<uses-permission android:name="android.permission.READ_CONTACTS" /> 
<uses-permission android:name="android.permission.WRITE_CONTACTS" />

<!-- Camera -->
<uses-permission android:name="android.permission.CAMERA" /> 
<activity android:name="com.nexacro.deviceAPI.CameraListener" android:screenOrientation="landscape">
	<intent-filter>
    	<category android:name="android.intent.category.LAUNCHER" />
	</intent-filter>
</activity>
<uses-feature android:name="android.hardware.camera" android:required="false"/>
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>

<!-- Geolocation -->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />

<!-- Acceleration -->
<uses-permission android:name="android.permission.HIGH_SAMPLING_RATE_SENSORS" tools:ignore="HighSamplingRate" />

<!-- Map -->
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
<uses-library android:name="com.google.android.maps" /> 
<meta-data android:name="com.google.android.maps.v2.API_KEY" android:value="user value" />

<!-- SMS -->
<uses-permission android:name="android.permission.SEND_SMS" /> 
<uses-permission android:name="android.permission.RECEIVE_SMS" /> 
<uses-permission android:name="android.permission.READ_SMS" /> 
<uses-permission android:name="android.permission.WRITE_SMS" />

<receiver android:name="com.nexacro.deviceAPI.SmsRecv">
	<intent-filter>
		<action android:name="android.provider.Telephony.SMS_RECEIVED" />
	</intent-filter>
	<intent-filter>
		<action android:name="android.provider.Telephony.WAP_PUSH_RECEIVED" />
		<data android:mimeType="application/vnd.wap.mms-message" />
	</intent-filter>
</receiver>

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

<!-- Bluetooth -->
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<service
	android:name="com.nexacro.deviceAPI.BluetoothLEAdapterService"
	android:enabled="true"
	android:exported="true">
</service>

<!-- ExternalAPI -->
<uses-permission android:name="android.permission.GET_TASKS" />

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

AndroidManifest.xml > FCM settings

<!-- Adding NexacroNotificationService -->
<service android:name="com.nexacro.notification.NexacroNotificationService">
	<intent-filter>
		<action android:name="com.google.firebase.MESSAGING_EVENT" />
	</intent-filter>
</service>

<!-- Adding NexacroActivity intent-filter -->
<activity android:name="com.nexacro.NexacroActivity"
	android:launchMode="singleTask"
	android:noHistory="false"
	android:hardwareAccelerated="true"
	android:windowSoftInputMode="adjustResize"
	android:configChanges="orientation|keyboard|keyboardHidden|screenSize|navigation|uiMode">
	<intent-filter>
		<action android:name="OPEN_NEXACRO_ACTIVITY_EXAMPLE" />
		<category android:name="android.intent.category.DEFAULT" />
	</intent-filter>
</activity>

If you use FCM, the below code listings should be added to the build.gradle file. Basically, this configuration is automatically performed in Android Studio. If not performed automatically, however, you need to add the below code listings by yourself and download the google-services.json file, which is created in the Firebase console. Then, copy the JSON file to the module directory of your app.

AndroidManifest.xml > ImagePicker, Camera, FileUpload, FileDailog settings

$r_title(file_paths.xml)
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-cache-path name="cache" path="."/>
    <external-files-path name="files" path="./"/>
</paths>

$r_title(AndroidManifest.xml / FileProvider)
<provider
	android:name="android.support.v4.content.FileProvider"
	android:authorities="${applicationId}.fileprovider"
	android:exported="false"
	android:grantUriPermissions="true">
	<meta-data
		android:name="android.support.FILE_PROVIDER_PATHS"
		android:resource="@xml/file_paths"/>
</provider>

<!-- AndroidX -->
<provider
	android:name="androidx.core.content.FileProvider"
	android:authorities="${applicationId}.fileprovider"
	android:exported="false"
	android:grantUriPermissions="true">
	<meta-data
		android:name="android.support.FILE_PROVIDER_PATHS"
		android:resource="@xml/file_paths"/>
</provider>

$r_title(build.gradle / exifinterface)

dependencies {
    implementation 'com.android.support:exifinterface:28.0.0'
	//AndroidX
	implementation 'androidx.exifinterface:exifinterface:1.3.2'
}

Dependency Management

Write the library information in the build.gradle file.

implementation 'androidx.appcompat:appcompat:1.5.1'
implementation 'com.google.android.material:material:1.6.1'
implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
implementation "androidx.room:room-runtime:2.4.3"
implementation 'androidx.exifinterface:exifinterface:1.3.4'
implementation 'com.squareup.okhttp3:okhttp:4.10.0'
annotationProcessor "androidx.room:room-compiler:2.4.3"

When using XPush, add the library information below.

implementation 'org.slf4j:slf4j-api:1.7.36'

When using Firebase, add the library information below.

implementation 'com.google.firebase:firebase-core:21.1.1'
implementation 'com.google.firebase:firebase-messaging:23.0.8'

Set your app stand-alone in disconnected environments

You can run your app without a network connection if you set the update type to "Local" or "Update (Local+Server)" when packing the app in Nexacro Studio. Normally, the Local type is appropriate for users who do not need a network connection while the Update (Local+Server) type suits users who usually maintain communications with servers but still need to operate apps even when networking is in trouble. To make your app stand-alone, you should prepare files necessary for execution and load them onto the app in the building process.

The files necessary for executing an app include modules, sources, resources and start_android.json, which are all obtained through the Packing (Archive&Update) process of Nexacro Studio. If you load those files onto the "archive" folder under the "assets" directory in your Android project before building an app, you can run the app without a network connection.

Right-click on app, the root folder of your project, and select [New > Folder > Assets Folder] from the context menu. Create the assets folder under the directory [project > app > src > main].

Right-click the assets folder under the directory [project > app > src > main] and select [New > Directory] from the context menu to create the "archive" folder under the assets folder.

Copy module, source and resource files to the [project > app > src > main > assets > archive] directory. You can copy and paste files directly from File Explorer into Android Studio.

Go to the project view in Android Studio and check whether the added assets/archive folder and files under the folder are there.

Build

App test

You can test your app by connecting an Android device to your PC using a USB cable. In that case, you need to toggle the USB debugging option in the Developer Options menu in the device and to install a driver for the device.

Select a virtual device or connected device from the device list at the top of Android Studio and execute Run.

You can see the log messages for executing the app through the Logcat window, which is situated at the bottom of the Android Studio screen.

Create installation file

To distribute your app that has been built completely, you should create a keystore that can identify your app and then should create a signed AAB, APK file. You need to create a keystore file just once at the beginning. When the app is updated, you can use the keystore file that you created already.

Click on the below link to go to the official Android user guide where you can learn how to create a keystore and signed APK.

Select the menu [Build > Generate Singed Bundle/APK].

The default setting is to generate AAB files. If needed, you can select an APK item and generate an APK file.