Pin generated Gradle wrapper

BUGS_TODO.md

@@ -2,10 +2,8 @@
 
 ## Bugs
 
-- The generated `gradlew` wrapper just forwards to the system `gradle` package. That is convenient in Termux, but it means builds are not pinned to a project-specific Gradle wrapper version.
+No known bugs at the moment.
-- The generated app pins Android Gradle Plugin `8.5.2` without pinning a compatible Gradle wrapper version. That can break when the installed Gradle package changes or is incompatible with that plugin version.
-- The CLI is now split into a dispatcher plus per-command scripts under `lib/commands/`, which improves readability but adds more files to maintain.
 
 ## TODO
 
-- Consider generating a real Gradle wrapper for new projects instead of relying on `gradle` from Termux.
+- Consider vendoring wrapper files so `android-builder new` does not need a system `gradle` binary at generation time.

README.md

@@ -57,9 +57,16 @@ The CLI is now split into smaller scripts for readability and maintenance:
 
 - Gradle settings and properties
 - a single `app` module
+- a real Gradle wrapper for the generated project
 - a minimal `MainActivity`
 - a simple default theme and string resources
 
+The template defaults are controlled in one place through environment variables:
+
+- `ANDROID_BUILDER_GRADLE_VERSION` defaults to `8.7`
+- `ANDROID_BUILDER_AGP_VERSION` defaults to `8.5.2`
+- `ANDROID_BUILDER_GRADLE_DISTRIBUTION_SHA256` defaults to the official checksum for `gradle-8.7-bin.zip`
+
 ## Notes
 
 - The project is designed around Termux.

lib/common.sh

@@ -5,6 +5,9 @@ ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 AB_HOME="${ANDROID_BUILDER_HOME:-$HOME/android-builder}"
 SDK="$HOME/android-sdk"
 PLATFORM="${ANDROID_BUILDER_PLATFORM:-android-33}"
+GRADLE_VERSION="${ANDROID_BUILDER_GRADLE_VERSION:-8.7}"
+AGP_VERSION="${ANDROID_BUILDER_AGP_VERSION:-8.5.2}"
+GRADLE_DISTRIBUTION_SHA256="${ANDROID_BUILDER_GRADLE_DISTRIBUTION_SHA256:-544c35d6bd849ae8a5ed0bcea39ba677dc40f49df7d1835561582da2009b961d}"
 
 ensure_termux() {
   if [ -z "${PREFIX:-}" ] || [ ! -d "/data/data/com.termux/files/usr" ]; then
@@ -13,6 +16,24 @@ ensure_termux() {
   fi
 }
 
+require_gradle() {
+  if ! command -v gradle >/dev/null 2>&1; then
+    echo "Error: gradle is required to generate the project wrapper."
+    echo "Run: android-builder setup"
+    exit 1
+  fi
+}
+
+set_gradle_wrapper_sha256() {
+  WRAPPER_PROPERTIES="$1"
+
+  if grep -q '^distributionSha256Sum=' "$WRAPPER_PROPERTIES"; then
+    sed -i "s/^distributionSha256Sum=.*/distributionSha256Sum=$GRADLE_DISTRIBUTION_SHA256/" "$WRAPPER_PROPERTIES"
+  else
+    printf '\ndistributionSha256Sum=%s\n' "$GRADLE_DISTRIBUTION_SHA256" >> "$WRAPPER_PROPERTIES"
+  fi
+}
+
 get_project_name() {
   if [ -f settings.gradle ]; then
     DETECTED_NAME="$(grep -E '^rootProject.name[[:space:]]*=' settings.gradle \
@@ -38,6 +59,8 @@ get_apk_path() {
 }
 
 create_base_project() {
+  require_gradle
+
   NAME="$1"
   MESSAGE="$2"
   PACKAGE="com.example.$(echo "$NAME" | tr '[:upper:]' '[:lower:]' | tr -cd 'a-z0-9')"
@@ -71,7 +94,7 @@ EOF2
 
   cat > "$NAME/app/build.gradle" <<EOF2
 plugins {
-    id 'com.android.application' version '8.5.2'
+    id 'com.android.application' version '$AGP_VERSION'
 }
 
 android {
@@ -156,13 +179,8 @@ public class MainActivity extends Activity {
 }
 EOF2
 
-  cat > "$NAME/gradlew" <<'EOF2'
+  (cd "$NAME" && gradle wrapper --gradle-version "$GRADLE_VERSION" --distribution-type bin)
-#!/data/data/com.termux/files/usr/bin/bash
+  set_gradle_wrapper_sha256 "$NAME/gradle/wrapper/gradle-wrapper.properties"
-set -e
-exec gradle "$@"
-EOF2
-
-  chmod +x "$NAME/gradlew"
 
   echo "Created project: $NAME"
   echo
@@ -170,4 +188,5 @@ EOF2
   echo "  cd $NAME"
   echo "  android-builder build"
   echo "  android-builder export"
+  echo "  ./gradlew assembleDebug"
 }