Highlight Android workarounds more

docs/assets/path_provider/lib/path_provider.dart

@@ -3,3 +3,7 @@ import 'dart:io';
 Future<Directory> getApplicationDocumentsDirectory() {
   throw UnsupportedError('stub!');
 }
+
+Future<Directory> getTemporaryDirectory() {
+  throw UnsupportedError('stub!');
+}

docs/assets/sqlite3_flutter_libs/lib/sqlite3_flutter_libs.dart

@@ -0,0 +1,3 @@
+Future<void> applyWorkaroundToOpenSqlite3OnOldAndroidVersions() async {
+  throw 'stub!';
+}

docs/assets/sqlite3_flutter_libs/pubspec.yaml

@@ -0,0 +1,6 @@
+name: sqlite3_flutter_libs
+publish_to: none
+description: Fake "sqlite3_flutter_libs" package so that we can import it in snippets without depending on Flutter.
+
+environment:
+  sdk: ^2.16.0

docs/lib/snippets/setup/database.dart

@@ -10,6 +10,8 @@ import 'dart:io';
 import 'package:drift/native.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:path/path.dart' as p;
+import 'package:sqlite3/sqlite3.dart';
+import 'package:sqlite3_flutter_libs/sqlite3_flutter_libs.dart';
 
 // ... the TodoItems table definition stays the same
 // #enddocregion open
@@ -47,6 +49,18 @@ LazyDatabase _openConnection() {
     // for your app.
     final dbFolder = await getApplicationDocumentsDirectory();
     final file = File(p.join(dbFolder.path, 'db.sqlite'));
+
+    // Also work around limitations on old Android versions
+    if (Platform.isAndroid) {
+      await applyWorkaroundToOpenSqlite3OnOldAndroidVersions();
+
+      final cachebase = (await getTemporaryDirectory()).path;
+
+      // We can't access /tmp on Android, which sqlite3 would try by default.
+      // Explicitly tell it about the correct temporary directory.
+      sqlite3.tempDirectory = cachebase;
+    }
+
     return NativeDatabase.createInBackground(file);
   });
 }

docs/pages/docs/setup.md

@@ -96,6 +96,11 @@ now looks like this:
 
 {% include "blocks/snippet" snippets = snippets name = 'open' %}
 
+The Android-specific workarounds are necessary because sqlite3 attempts to use `/tmp` to store
+private data on unix-like systems, which is forbidden on Android. We also use this opportunity
+to work around a problem some older Android devices have with loading custom libraries through
+`dart:ffi`.
+
 ## Next steps
 
 Congratulations! With this setup complete, your project is ready to use drift.

docs/pubspec.yaml

@@ -19,9 +19,11 @@ dependencies:
   # used in snippets
   http: ^1.1.0
   sqlite3: ^2.0.0
-  # Fake path_provider for snippets
+  # Fake flutter packages for snippets
   path_provider:
     path: assets/path_provider
+  sqlite3_flutter_libs:
+    path: assets/sqlite3_flutter_libs
   # Used in examples
   rxdart: ^0.27.3
   yaml: ^3.1.1

examples/app/android/app/build.gradle

@@ -48,6 +48,10 @@ android {
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
+
+        ndk {
+            abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86_64'
+        }
     }
 
     buildTypes {

examples/app/lib/database/connection/native.dart

@@ -6,6 +6,8 @@ import 'package:drift_dev/api/migrations.dart';
 import 'package:flutter/foundation.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:path/path.dart' as p;
+import 'package:sqlite3/sqlite3.dart';
+import 'package:sqlite3_flutter_libs/sqlite3_flutter_libs.dart';
 
 Future<File> get databaseFile async {
   // We use `path_provider` to find a suitable path to store our data in.
@@ -17,7 +19,19 @@ Future<File> get databaseFile async {
 /// Obtains a database connection for running drift in a Dart VM.
 DatabaseConnection connect() {
   return DatabaseConnection.delayed(Future(() async {
-    return NativeDatabase.createBackgroundConnection(await databaseFile);
+    if (Platform.isAndroid) {
+      await applyWorkaroundToOpenSqlite3OnOldAndroidVersions();
+
+      final cachebase = (await getTemporaryDirectory()).path;
+
+      // We can't access /tmp on Android, which sqlite3 would try by default.
+      // Explicitly tell it about the correct temporary directory.
+      sqlite3.tempDirectory = cachebase;
+    }
+
+    return NativeDatabase.createBackgroundConnection(
+      await databaseFile,
+    );
   }));
 }