Conquering the Second Screen: Porting the Minimal Launcher to a Dangbei Box, and a Long-Press Feature ADB Could Not Test

The first screen’s conquest belonged to the TV; the second belongs to the box. The same philosophy had to replay on a newer Android — and in replaying it, what decided success was never the port itself but the constraints that only surfaced on the target platform.

I. Full Box Scan: All 45 Uninstalls Held

Moving to the Dangbei box (192.168.5.17), the first task was a full scan, focused on whether last time’s uninstalls had been reinstalled by OTA. Two “reinstalls” needed distinguishing: com.android.music was very likely a substring false positive (matching the retained com.android.musicfx), and com.android.modulemetadata was deliberately restored at the time (to fix the Wi-Fi crash). Exact-match recheck excluded both.

All 45 uninstalls held, zero reinstalls. The system was DBOX-A2, Android 12, firmware unchanged, available memory 977MB, storage 20GB left (1.67GB of app cache cleanable).

The ranking of current consumers was telling: system framework 160MB immovable, Dangbei launcher 110MB (with content promotion), ktcp.video 81MB plus daemon 21MB (autostart), 小电视 55MB plus statistics process 37MB (autostart). The actionable list remained fully valid from the previous deep dig, and the single biggest win was replacing the Dangbei launcher.

II. Porting: Android 12 Simpler, but One Critical Trap

Could the minimal launcher from the TV be adapted? Yes, and simpler than the TV — the box ran Android 12 where the original minSdk 26 was natively satisfied, no downgrade. But there were three adaptation points, one of them critical:

Android 11+ package visibility limits. The original manifest’s <queries> declared only the LEANBACK_LAUNCHER category, so apps declaring only the ordinary LAUNCHER category would not be listed. First query app categories with dumpsys package — on Android 12 it contains no resolved tables — then switch to cmd package query-activities, which is exactly the list the launcher can see.

The key confirmation: app categories were mixed — ktcp, Bilibili, btelly and others were LEANBACK, but 小电视 (tv.yst) had only the ordinary LAUNCHER category, as did Dangbei’s own launcher and settings. The original queries declared only LEANBACK, so on the box 小电视 would not be listed.

The adaptation was therefore clear: add the ordinary LAUNCHER category to <queries>. The Dock config also changed to the box’s four main apps — 云视听极光, bilibili, TVBox OSC, 小电视.

Adaptation	TV (Android 6)	Box (Android 12)
minSdk	26→23 (downgrade port)	26 natively satisfied
App visibility	Dual-category query	queries adds ordinary LAUNCHER
Dock config	TV apps	Four main apps
Boot focus	Fixed preselected cursor	Same effect
Input-source button	Hidden (no input)	Auto-hidden

Build, install, cmd package set-home-activity to set as default in one step. HOME popped the chooser, driven by key presses. The launcher was running — box apps carried cover art, much nicer than the TV’s icons.

Reboot verification: after reboot the box’s ADB auto-recovered (persist properties effective, no manual re-enabling like the TV), and boot went straight into our launcher. Available memory reached 1.05GB (initial 866MB → 977MB after uninstalling bloat → 1.05GB after swapping launchers). The original Dangbei launcher stayed installed, just no longer default, switchable back at any time.

III. Move Mode: Turning “Change Config and Rebuild” Into One Sentence

The owner asked: could drag-to-reorder or changing Dock apps be made into an actual feature?

Yes, and it should be — that is the complete launcher experience. Changing the Dock currently required a rebuild, which is indeed anti-human. So a remote move mode was added: long-press OK to pick up an app → directional keys to move (the first row is the Dock, move in to join, move out to leave) → OK to drop, order auto-saved.

Implementation started with a persistence storage class, then AppAdapter (interface with two callbacks, long-press routing, persistent ordering, move methods), the Holder’s directional-key listener gained OK handling, reload’s ordering logic was changed to prefer a user-saved order if present, and finally MainActivity gained the full move-mode implementation plus back-key cancel, with string resources in Chinese and English.

One small compile snag: AppAdapter.java:248 could not find the symbol — the lambda sat inside the Adapter’s onBindViewHolder, and getBindingAdapterPosition() is a Holder method, so it had to be called as h.. Fixed and it passed.

IV. A Feature ADB Could Not Test

Move mode done, verification hit a wall: the long-press test actually became a tap — input --longpress had no effect and directly launched the first Dock app. Trying again, it still launched bilibili on tap. Checking input --help, no long-press parameter. Confirmed: this box’s input --longpress does not support long press.

ADB cannot test long press. But a backup entry could be added: the MENU key — some remotes have a menu key, also testable by ADB. Double insurance.

The MENU key worked — the launcher stayed in the foreground (no app launched), move mode activated, and the prompt displayed correctly: “方向键移动位置（第一行是 Dock），OK 保存，返回取消”, with 云视听极光 in the picked-up state. Persistence confirmed: after restarting the launcher the Dock order held as bilibili first, 云视听极光 second — the swap was saved.

So the final state was: the MENU key entry verified fully usable; the long-press OK entry could not be simulated by ADB, and needs a real remote test. If long-press does not work, the MENU key is a fully functional alternative.

V. An Incidental Find: The In-App Splash Ad

During testing, the long-press not working accidentally launched ktcp.video (云视听极光), which popped a full-screen JD ad (Quoduo, the ReachMax ad network).

This was the app’s own splash ad, not a system ad. The owner’s “no ads on the box” referred to the system level — this was internal ktcp behaviour. Whether to handle it was the owner’s call; his apps were not touched.

VI. To-Do and Rollback

The TV’s launcher is still the old version (no move mode), with ADB disabled by firmware; re-enabling once syncs it over. Three rollback paths were left: switch back to the Dangbei launcher with one set-home-activity, change Dock apps with a word and a two-minute rebuild, uninstall the minimal launcher with one adb uninstall.

The second screen’s conquest is complete. And the lesson it left is worth more than the first: the same idea on a new platform is never hard because of the port, but because of discovering the constraint that only surfaces there — this time, one category missing from <queries>.