Which app is in the foreground, and the task and stack structure behind it.
dumpsys activity activitiesdumpsys activity activities | grep -E 'topResumedActivity|mResumedActivity' | head -n 12Get just the foreground component. Filtering on the phone is what keeps the transfer small.
dumpsys activity activitiesThe whole thing — a hundred kilobytes on a phone that has been awake a while.
The full dump prints every task in every stack on every display, so filter it. Four different lines answer "what is in front", and they do not always agree: prefer `topResumedActivity`, which is exactly the question, and treat `mCurrentFocus` as the last resort — it names the focused *window*, which may be the keyboard or a system dialog while the app behind it is still the app the user is running.
| Field | Meaning |
|---|---|
| topResumedActivity= | The one activity with top-resumed state. Android 10 and later. |
| mResumedActivity: / ResumedActivity: | A stack's resumed activity. Several can print; the first is normally the answer. |
| mFocusedApp= | The focused app token. Correct in practice, one indirection from the question. |
| mCurrentFocus= | The focused window — possibly the IME or a dialog rather than an app. |
| u0 com.example/.MainActivity | The Android user id, then the component. Often written relative to the package. |
Android System Monitor runs this command over USB and parses what comes back — a Chromium browser, no SDK, nothing uploaded.
Commands that turn up in the same session as dumpsys activity activities.
| Command | What it does |
|---|---|
| am start | Starts an activity by component or by intent — the fastest way to test whether a deep link resolves. |
| am force-stop | Kills every process and service belonging to one app. |
| top | A one-shot process table: CPU share, memory, state and command line. |
| Command | What it does |
|---|---|
| dumpsys battery | The battery service's live state: level, status, health, voltage and temperature. |
| dumpsys diskstats | Free space per partition, a disk write latency check, and a cached per-app breakdown of what is using storage. |
| dumpsys thermalservice | Whether the phone is throttling, and every thermal zone the hardware layer reports, in degrees Celsius. |
| dumpsys sensorservice | Every sensor the phone has, with its vendor, type, rates and batching — plus a buffer of recent readings. |
| dumpsys meminfo | Which processes are using the most memory, measured as proportional set size. |
| dumpsys package | Everything the package manager knows about one app: version, paths, flags, install source and per-user state. |
| dumpsys dropbox | The platform's ring buffer of crashes, ANRs and tombstones — how you read ANR traces without root. |
Checked against AOSP, toybox and kernel sources while writing the parsers behind our Web ADB tools. Where a behaviour genuinely varies by Android version or manufacturer, this page says so instead of giving a number that would be wrong on half the phones out there.
Switch on developer options and USB debugging on the phone, plug it in, then run `adb shell <command>` from a machine with platform-tools installed — or run `adb shell` on its own to get an interactive prompt and type the command without the prefix. If the command produces binary output, such as a screenshot, use `adb exec-out` instead of `adb shell`: the plain shell service attaches a terminal, which rewrites newline bytes and corrupts the data.
Not the ones on this reference. They run as the `shell` user, which can manage packages for its own Android user, read most `dumpsys` services, write the settings provider, inject input and read shared storage. Root is only needed for things this reference deliberately avoids — reading another app's private data (except through `run-as` on a debuggable build), writing system partitions, or reading `/data/anr` directly.
Either the Android version or the manufacturer. Some flags and fields arrived in a specific release, and those are noted per command. The rest is OEM patching, which hits `dumpsys` hardest: a dump is debug output whose text is whatever the service author last printed, and manufacturers change it and backport their changes. Read fields by name rather than by position, and treat an unfamiliar shape as a difference rather than as a failure.
For many commands, yes — the Web ADB tools on this site talk to a phone over WebUSB from a Chromium-based desktop browser, with no SDK installed and nothing uploaded. Each page links to the tool that runs its command, when one exists. Two limits are worth knowing: only one program can hold the ADB interface at a time, so a desktop `adb server` has to be stopped first, and `adb forward` and `adb reverse` cannot work in a browser at all.
Would rather click than type? The Web ADB Toolkit runs commands like this from a browser over USB. Or browse every command.