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 Activity and click Next.

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

Go to the JDK location option in the menu [File > Project Structure] and select "Use embedded JDK".

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.

You can copy and paste files directly from File Explorer into Android Studio. When you paste a file into each location, the Copy window appears as seen in the below picture to allow you to change the name of the file and the directory where the file is saved. In this sample, just click the OK button without any change.

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

$r_title(values\strings.xml)
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <bool name="is_jellybean_or_higher">false</bool>
    <color name="dim_foreground_dark">#000000</color>
    <string name="AddManifest_Permission">Add or grant permissions to the manifest file.</string>
    <string name="Additional_Permission">Additional authorization is required.</string>
    <string name="AllowUse_Permission">Allow permission to use that feature.</string>
    <string name="Allow_Permission">Allow the permission as the permission is required for the normal function of the engine update.</string>
    <string name="Allow_StoragePermission">Allow *storage* permission in the app permission in the application settings.</string>
    <string name="BeingUpdated">Being updated.</string>
    <string name="Denied_Permission">It ends with denial of engine update permission.</string>
    <string name="Init_nexacro_engine">Initialize Nexacro engine</string>
    <string name="LoadingPleaseWait">Loading... \nPlease Wait...</string>
    <string name="cancel">Cancel</string>
    <string name="check_license">Check License</string>
    <string name="checked">checked</string>
    <string name="checkforupdates">Check for updates.</string>
    <string name="click">click</string>
    <string name="copy">Copy</string>
    <string name="cut">Cut</string>
    <string name="downloadingforupdates">Downloading for updates.</string>
    <string name="editing_delete_description">%1$s deleted</string>
    <string name="editing_description">editing. %1s</string>
    <string name="editing_insert_description">%1$s</string>
    <string name="execute_frameworkscript">Execute Framework Script</string>
    <string name="executing_framework">Load the application (executing the framework)</string>
    <string name="exit">exit</string>
    <string name="fd_cancel">Cancel</string>
    <string name="fd_ok">OK</string>
    <string name="filter">Filter</string>
    <string name="force_close">Update is Completed.</string>
    <string name="home">Home</string>
    <string name="image_description">%1$s image</string>
    <string name="installforupdates">Install for updates.</string>
    <string name="link_description">%1$s link</string>
    <string name="list_description">%1$s selected</string>
    <string name="listitem_description">%1$d of %2$d %3$s</string>
    <string name="listitem_selected_description">%1$d of %2$d selected %3$s</string>
    <string name="load_application">Load Application</string>
    <string name="load_bootstrap">Load the application (bootstrapping)</string>
    <string name="load_extendmodule">Load Extend Module</string>
    <string name="load_failapplication">Load Fail Application Initialize. Click And Close</string>
    <string name="load_frameworkmodule">Load Framework Module</string>
    <string name="loadingFail">First loading is fail. \nPlease restart.</string>
    <string name="loading_application">Load the application (loading the application)</string>
    <string name="move">Move</string>
    <string name="needupdate">It is need to update. \nAfter completing, Please restart.</string>
    <string name="nofilename">No File Name.</string>
    <string name="notexist">Start file is NOT exist. \nPlease restart.</string>
    <string name="ok">OK</string>
    <string name="paste">Paste</string>
    <string name="preparing_framework">Load the application (preparing the framework)</string>
    <string name="selectall">Select All</string>
    <string name="selectword">Select Word</string>
    <string name="spacebar">spacebar</string>
    <string name="ssl_invalid">The SSL certificate is invalid. Continue?</string>
    <string name="start_initialize">Start Initialize</string>
    <string name="unchecked">unchecked</string>
    <string name="updateFail">Update is fail. \nPlease restart.</string>
    <string name="upper">Upper</string>
    <string name="wantreplace">There is a file of the save name. Do you want to replace? </string>
    <style name="AppTheme" parent="android:Theme.Light"/>
</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 a layout

Basic layout settings are applied according to the settings of the nexacro_app.xml file included in the Nexacro Android Archive (AAR) file. To change the layout settings, create and set the nexacro_app.xml file in the layout folder. To add a new layout file, select [File > New > XML > Layout XML File].

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

$r_title(layout\nexacro_app.xml)

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/nexacro_activity"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/transparent" >

    <com.nexacro.view.NexacroLayout
        android:id="@+id/nexacro_layout"
        android:background="@android:color/transparent"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </com.nexacro.view.NexacroLayout>

</FrameLayout>

Font settings

If you select Update (Local+Server) or Local as the Packing Update Type, the UserFont set in the Resource tab can be used. However, if you select Server as the Update Type, you cannot use the UserFont set in the Resource tab, and you must create a fonts folder under the assets folder in the Android Studio project and build the font files together.

Follow the steps below to set up fonts in Android Studio.

For information on creating a UserFont file, refer to the Creating a UserFont File document.

@font-face {
  font-family : 'NOTO';
  font-style : normal;
  src : local("NotoSansCJKkr-Regular");
}

@font-face {
  font-family : 'NOTO';
  font-style : normal;
  src : local("NotoSansCJKkr-Bold");
}

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.helloandroid;

import com.nexacro.NexacroResourceManager;
import com.nexacro.NexacroUpdatorActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends NexacroUpdatorActivity {

    public MainActivity() {
        super();

        setBootstrapURL("http://[URL]/start_android.json");
        setProjectURL("http://[URL]/");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        NexacroResourceManager.createInstance(this);
        NexacroResourceManager.getInstance().setDirect(false);

        Intent intent = getIntent();
        if(intent != null) {
            String bootstrapURL = intent.getStringExtra("bootstrapURL");
            String projectUrl = intent.getStringExtra("projectUrl");
            if(bootstrapURL != null) {
                setBootstrapURL(bootstrapURL);
                setProjectURL(projectUrl);
            }
        }

        super.onCreate(savedInstanceState);
    }

    @Override
    public void setContentView(View view) {
        super.setContentView(view);
    }

}

In the above sample, the text written in bold should be replaced with something appropriate for your settings.

The 15^th and 16^th lines are written to designate two addresses: one is for a bootstrap and the other is for the project's source code. As an argument of the setBootstrapURL method, you should specify the server URL for the start_android.json file, which is created in Nexacro Studio. As an argument of the setProjectURL method, you should specify the server URL for the directory where the source code of the relevant project is generated. You should add a slash (/) at the end of the path to the generated source code.

15 setBootstrapURL("http://192.168.0.1:8080/nexacro/_android_/start_android.json");
16 setProjectURL("http://192.168.0.1:8080/nexacro/_android_/");

The 22^nd and 23^rd lines should be adjusted according to the update type, which is set in the Packing (Archive&Update) stage of Nexacro Studio. If the update type is set to "Server", you should specify "true" as an argument of the setDirect method written in the 23^rd line. If the update type is set to "Update (Local+Server)" or "Local", you should specify "false".

22 NexacroResourceManager.createInstance(this);
23 NexacroResourceManager.getInstance().setDirect(true);

You can change the value of the screenid property by using the setScreenid method with the onCreate callback.

public void onCreate(Bundle savedInstanceState) {
    NexacroResourceManager.createInstance(this);
    NexacroResourceManager.getInstance().setScreenid("Tablet_screen");
}

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. Moreover, the information about the package and main activity—the two pieces of text in bold in the below sample—should be changed according to the settings of your project.

$r_title(AndroidManifest.xml)


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

    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />

    <!-- network access Permission -->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />

	<!-- storage access permission -->
	<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
	<uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />
	<uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />

    <application android:label="@string/app_name"
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:theme="@style/AppTheme"
        android:hasCode="true"
        android:hardwareAccelerated="true"
        android:requestLegacyExternalStorage="true"
        android:usesCleartextTraffic="true">

        <activity
            android:name="com.example.helloandroid.MainActivity"
            android:label="@string/app_name"
            android:theme="@style/Theme.AppCompat.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name="com.nexacro.NexacroActivity"
            android:alwaysRetainTaskState="true"
            android:configChanges="orientation|keyboardHidden|screenSize"
            android:launchMode="singleTop"
            android:theme="@android:style/Theme.NoTitleBar"
            android:windowSoftInputMode="adjustResize" >
        </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" />

<!-- 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.

buildscript {
	// Adding repositories 
	repositories {
		google()  
		jcenter()
	}
	dependencies {
		classpath 'com.android.tools.build:gradle:3.2.1'
		// NOTE: Do not place your application dependencies here; they belong
		// in the individual module build.gradle files
		// Adding google service
		classpath 'com.google.gms:google-services:4.0.1'
	}
}

allprojects {
	// Adding repositories 
	repositories {
		google()
		jcenter()
	}
}

task clean(type: Delete) {
	delete rootProject.buildDir
}

dependencies {
	implementation fileTree(include: ['*.jar'], dir: 'libs')
	implementation 'com.android.support:appcompat-v7:27.1.1'
	implementation 'com.android.support:support-v4:27.1.1'
	implementation 'com.google.android.gms:play-services-maps:16.0.0'
	implementation 'com.google.android.gms:play-services-location:16.0.0'
	implementation 'com.google.firebase:firebase-core:16.0.6'
	implementation 'com.google.firebase:firebase-messaging:17.3.4'
	compile 'com.android.support:multidex:1.0.3'
	implementation 'com.android.support:design:27.1.1'
	implementation files('libs/nexacro.aar')
}
apply plugin: 'com.google.gms.google-services'

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'
}

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

1. 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.

2. Select the Run menu of Android Studio, which allows you to build an APK, install it on your device and then execute the app. Upon selecting the menu, you can choose a device for running your app.

Run > Run 'App'

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.