Doodlepop — Photo filter Android app with AdMob

A minimal Kotlin Android app that picks a photo, applies one of three filters (Sketch, B&W, Bubble), saves to the gallery, and monetizes via banner + interstitial AdMob ads — wired up to pass Google's policy review.

Doodlepop = doodle (sketch) + pop (bubble), the two signature effects.

What's in the box

• 3 filters in pure-Kotlin (ImageFilters.kt) — no OpenCV, ~10 MB APK
• Material 3 UI with toolbar + bottom-anchored banner
• AdMob banner (always-on at the bottom)
• AdMob interstitial on Save, with 60-second cooldown
• UMP / GDPR consent gathered before any ad loads
• About / Privacy screen with policy link and "Reset Ad Consent" action
• Debug builds use Google's universal test ad IDs; release builds use your real ones

Build & run

./gradlew :app:assembleDebug
./gradlew :app:installDebug

Or open in Android Studio → Run.

Saved images land in Pictures/Doodlepop/ on the device.

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✅ Pre-launch checklist for AdMob account approval

Google reviews new AdMob publishers when their first app starts serving ads. These are the items they actually check. Everything marked ✓ done is wired in code; everything marked TODO needs an action from you outside the IDE.

In the app (already done)

• ✓ UMP consent gathered before MobileAds.initialize — ConsentManager.kt runs first, ads load only after canRequestAds() returns true.
• ✓ Reset-consent control — required by Google so users can change their mind. Lives in About → Reset Ad Consent.
• ✓ Test IDs in debug, real IDs in release — automatic via buildConfigField in app/build.gradle.kts. Clicking ads in debug is safe; clicking your own production ads will get the account banned.
• ✓ Interstitial at a natural break point — fires on Save, never on app launch, with a 60-second cooldown. Loading ads during app launch or on every action is the #1 cause of policy rejection.
• ✓ Banner doesn't overlap content — image preview is constrained above the banner.
• ✓ App ID in AndroidManifest.xml — ca-app-pub-7343868790309663~1386077355.
• ✓ Interstitial unit ID in app/build.gradle.kts (release) — ca-app-pub-7343868790309663/2507587335.

Before you upload to Play Console

1. Generate a privacy policy (free):
   • https://app-privacy-policy-generator.firebaseapp.com/ → tick "AdMob" and "Google Analytics for Firebase" as third-party services.
   • Host it publicly. Easiest free option: paste into a Notion page (Share → Publish to web) or a GitHub Pages repo.
   • Update app/src/main/res/values/strings.xml → privacy_policy_url with that URL.
2. Create a real AdMob banner unit (you only have an interstitial right now):
   • https://apps.admob.com/ → your app → Ad units → Add ad unit → Banner.
   • Replace admob_banner_unit_id in app/src/main/res/values/strings.xml with the unit ID it gives you (the one with a / not ~).
3. Pick a unique applicationId. com.doodlepop.app is fine if it isn't taken on Play; otherwise change it in app/build.gradle.kts to com.<yourbrand>.doodlepop.
4. Replace the launcher icon. The default vector icon is functional but not distinctive — use Android Studio's File → New → Image Asset to generate a branded one.
5. Sign the release build — see Signing below.

In Play Console

1. Create the app: https://play.google.com/console → Create app. Category: Photography. Free.
2. Upload app-release.aab under Release → Production → Create new release.
3. Data Safety form (under App content):
   • Personal info: None collected.
   • Device or other IDs: Collected, shared → reason: Advertising or marketing. (AdMob uses GAID.)
   • Approximate location: Collected, shared → reason: Advertising or marketing.
   • Mark data as collected via third-party SDK (Google AdMob).
   • Encryption in transit: Yes.
4. Privacy policy URL: paste the URL from step 1 above.
5. Content rating: take the IARC questionnaire → answer honestly (it's a photo editor → "Everyone"). Be sure to mark that the app displays ads.
6. Target audience and content: age 13+ (AdMob ToS minimum).
7. Ads declaration: tick "Yes, my app contains ads."
8. Link your AdMob account in Play Console → Monetize with AdMob → Link.
9. App access: if anything needs login (Doodlepop doesn't), declare it. If not, mark "All functionality is available without restrictions."
10. Submit for review. First review takes 1-7 days. After approval, you can promote to Production.

In AdMob console (post-Play-publish)

1. Verify the app: AdMob auto-links to the Play listing once both use the same package name.
2. Add app-ads.txt to your website root (e.g. https://yourbrand.com/app-ads.txt):
   • AdMob shows you the exact line to add under Apps → app-ads.txt → Set up.
   • Add the same domain to your Play Listing under Developer page → Website.
   • AdMob crawls this within 24 hours; verified = improved fill rate.
3. Payment & tax info — Payments → Settings. Required before Google releases your earnings (threshold is $100).

What gets accounts banned

• Clicking your own live ads. Always test with debug builds (test IDs). After publishing, only check that ads load — never click them on a device tied to your AdMob account.
• Putting real unit IDs in debug builds. Other people's clicks on debug-channel ads count as invalid traffic.
• Showing ads in screens with no user-generated content. Doodlepop only shows ads after the user is interacting with a photo — compliant.
• Stacking ads. One banner + one interstitial-on-save is fine. Two banners on one screen is not.
• Modifying ad views. Don't wrap the AdView in a container that obscures or resizes the ad creative.

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Switching to release IDs

Already wired. app/build.gradle.kts selects:

Build type	Interstitial unit ID	Banner unit ID
debug	Google test (/1033173712)	Google test (/6300978111)
release	Your real (/2507587335)	Test until you create one — TODO above

To swap the banner once you create it, change admob_banner_unit_id in strings.xml (it's read identically in debug and release; if you want to keep testing in debug, move it to a buildConfigField like the interstitial).

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Signing for release

keytool -genkey -v -keystore release.jks \
  -keyalg RSA -keysize 2048 -validity 10000 \
  -alias doodlepop

Create keystore.properties next to app/:

storeFile=/absolute/path/to/release.jks
storePassword=...
keyAlias=doodlepop
keyPassword=...

Wire into app/build.gradle.kts:

import java.util.Properties
import java.io.FileInputStream

val ksProps = Properties().apply {
    val f = rootProject.file("keystore.properties")
    if (f.exists()) load(FileInputStream(f))
}

android {
    signingConfigs {
        create("release") {
            storeFile = file(ksProps.getProperty("storeFile") ?: "/dev/null")
            storePassword = ksProps.getProperty("storePassword")
            keyAlias = ksProps.getProperty("keyAlias")
            keyPassword = ksProps.getProperty("keyPassword")
        }
    }
    buildTypes {
        release {
            signingConfig = signingConfigs.getByName("release")
        }
    }
}

Then build the Play upload bundle:

./gradlew :app:bundleRelease
# app/build/outputs/bundle/release/app-release.aab

Testing the consent flow

UMP only shows the form for users in GDPR regions. To force-test it from a US device, in AdMob Console: Privacy & messaging → GDPR → Add test device IDs (get yours from logcat: adb logcat | grep "Use RequestConfiguration").

To reset consent locally: open Doodlepop → About → Reset Ad Consent → restart the app.

Project layout

app/src/main/
  AndroidManifest.xml                   – Activities, AdMob App ID
  java/com/doodlepop/app/
    MainActivity.kt                     – UI, picker, save, toolbar
    AboutActivity.kt                    – Privacy + reset consent
    ImageFilters.kt                     – Sketch / B&W / Bubble
    InterstitialAdManager.kt            – Load/show/cooldown logic
    ConsentManager.kt                   – UMP GDPR/CCPA flow
  res/
    layout/activity_main.xml            – Toolbar + preview + buttons + AdView
    layout/activity_about.xml
    menu/main_menu.xml
    values/strings.xml                  – Banner unit ID + policy URL
    values/themes.xml