> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/nfc-wallet-sdk-android/help/knowledge-base/retrieve-logs-from-an-android-device.md).

# Retrieve logs from an Android device

## Overview

Use Android Debug Bridge (ADB) to capture device logs (`logcat`) for troubleshooting.

If you can reproduce the issue in a controlled environment, capture logs right around the failing flow.

{% hint style="info" %}
If you need SDK runtime logs that stay inside the application sandbox, use `LogService` instead. See [Collect logs with LogService](/nfc-wallet-sdk-android/additional-features/collect-logs-with-secure-logger.md).
{% endhint %}

## Prerequisites

Before you can retrieve the log files from an Android device, ensure that you have done the following setup:

* Install Android Debug Bridge (ADB) on the host machine.
* Enable **USB debugging** on the device under test.
* Connect the Android device to the host machine using a USB cable.
* Install the device USB driver on Windows (if required).

To verify the setup, run:

```bash
adb devices
```

The device is reachable when you see an entry with status `device`:

```
List of devices attached
228b0e100d047ece device
```

If you do not see the device, re-check the prerequisites. For ADB setup and troubleshooting, see the official Android documentation: [Android Debug Bridge (adb)](https://developer.android.com/tools/adb).

{% hint style="warning" %}
Some devices require enabling device logging in a vendor-specific menu.

For example, on some Huawei devices you can access the menu by dialing `*#*#2846579#*#*`. See [Huawei logcat not showing the log for my app](https://stackoverflow.com/questions/18124334/huawei-logcat-not-showing-the-log-for-my-app) for context.
{% endhint %}

## Capture logs (recommended)

1. Clear device log buffers:

   ```bash
   adb logcat -b all -c
   ```
2. Start capturing logs (millisecond timestamps, all priorities):

   ```bash
   adb logcat -v threadtime -b all *:V > TestLogFileName.txt
   ```
3. Reproduce the issue in your **digital wallet application**.
4. Stop capture and collect the file:
   * Press `CTRL+C`.
   * Retrieve `TestLogFileName.txt` from the folder where you ran the command.

{% hint style="info" %}
For the most detailed logs, reproduce using a build of your **digital wallet application** that integrates the NFC Wallet SDK `dev` build.

See [Deliverables](/nfc-wallet-sdk-android/general/deliverables.md) for supported build types.

Capture logs only around the failing flow. Start right before the steps. Stop right after.
{% endhint %}

{% hint style="warning" %}
Avoid [logcat filters](https://developer.android.com/studio/command-line/logcat#filteringOutput). They often hide the lines needed for root-cause analysis.
{% endhint %}

## Verifying the setup

You can verify the setup by running a flow that calls the SDK API, for example **Retrieve card list** in [Display digital cards](/nfc-wallet-sdk-android/implement-nfc-wallet/manage-digital-cards/display-digital-cards.md#retrieve-card-list).

With the recommended command, the log file should have:

* A timestamp with millisecond precision on each line.
* Log priority letters up to `V` (Verbose) after the PID and TID fields.
* A line containing `PublicAPI::Start of DigitalizedCardManager.getAllCards`.

The following example shows the log snippet demonstrating such features:

```
08-06 17:11:21.790 14171 14171 D SDK_ENTRY_POINT: PublicAPI::Start of DigitalizedCardManager.getAllCards
08-06 17:11:21.790 14171 14171 D SDK_ENTRY_POINT: PublicAPI::Start of SDKController.getInstance
08-06 17:11:21.791 14171 14171 D SDK_ENTRY_POINT: PublicAPI::Start of SDKController.getService
08-06 17:11:21.791 14171 14171 V util.h.xy.by.mb: Attempting to retrieve service with name: DigitalizedCardBuinsessService
08-06 17:11:21.791 14171 14171 D util.h.xy.by.mb: business service = util.h.xy.l.a@f9a06e1
08-06 17:11:21.791 14171 14171 V util.h.xy.l.a: getAllCards is called
08-06 17:11:21.791 14171 14171 D util.h.xy.aj.b: [DCM.getAllCards].increment
08-06 17:11:21.791 14171 14171 V util.h.xy.aj.b: [DCM.getAllCards]Ops left is 1
08-06 17:11:21.792 14171 18982 I util.h.xy.n.mb: -----------------------------------------------------------------------GET_ALLCARDS-START----------------------------------------------------------------------

```


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