Android: use FileProvider with QDesktopServices::openUrl()

Allow openUrl() to use FileProvider for opening files that are located
under app scoped paths and that use a file scheme for Android sdk 24 or
above.

[ChangeLog][Core][Android] Add FileProvider support for
QDesktopServices::openUrl().
[ChangeLog][Core][Android] Add AndroidX dependency to Gradle builds
by default since it's required by FileProvider.

Fixes: QTBUG-85238
Change-Id: Ia7403f74f2a8fd4886f74dba72e42b318ef5d079
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Nicholas Bennett <nicholas.bennett@qt.io>
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>

src/3rdparty/gradle/gradle.properties

@@ -12,3 +12,6 @@ org.gradle.parallel=true
 # build with the same inputs. However, over time, the cache size will
 # grow. Uncomment the following line to enable it.
 #org.gradle.caching=true
+
+# Allow AndroidX usage
+android.useAndroidX=true

src/android/templates/AndroidManifest.xml

@@ -43,5 +43,15 @@
                 android:name="android.app.extract_android_style"
                 android:value="minimal" />
         </activity>
+
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.qtprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/qtprovider_paths"/>
+        </provider>
     </application>
 </manifest>

src/android/templates/CMakeLists.txt

@@ -14,6 +14,7 @@ add_custom_target(Qt${QtBase_VERSION_MAJOR}AndroidTemplates
     SOURCES
         ${template_files}
         "${CMAKE_CURRENT_SOURCE_DIR}/res/values/libs.xml"
+        "${CMAKE_CURRENT_SOURCE_DIR}/res/xml/qtprovider_paths.xml"
 )
 
 qt_path_join(destination ${QT_INSTALL_DIR} ${INSTALL_DATADIR} "src/android/templates")

src/android/templates/build.gradle

@@ -18,6 +18,7 @@ apply plugin: 'com.android.application'
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar', '*.aar'])
+    implementation 'androidx.core:core:1.8.0'
 }
 
 android {

src/android/templates/res/xml/qtprovider_paths.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths xmlns:android="http://schemas.android.com/apk/res/android">
+    <files-path name="files_path" path="/"/>
+</paths>

src/gui/doc/src/external-resources.qdoc

@@ -46,3 +46,13 @@
     \externalpage https://www.lunarg.com/vulkan-sdk/
     \title LunarG Vulkan SDK
 */
+
+/*!
+    \externalpage https://developer.android.com/reference/androidx/core/content/FileProvider
+    \title Android: FileProvider
+*/
+
+/*!
+    \externalpage https://developer.android.com/training/secure-file-sharing/setup-sharing.html
+    \title Android: Setting up file sharing
+*/

src/gui/util/qdesktopservices.cpp

@@ -162,6 +162,13 @@ void QOpenUrlHandlerRegistry::handlerDestroyed(QObject *handler)
 
     \snippet code/src_gui_util_qdesktopservices.cpp 3
 
+    \note For Android Nougat (SDK 24) and above, URLs with a \c file scheme
+    are opened using \l {Android: FileProvider}{FileProvider} which tries to obtain
+    a shareable \c content scheme URI first. For that reason, Qt for Android defines
+    a file provider with the authority \c ${applicationId}.qtprovider, with \c applicationId
+    being the app's package name to avoid name conflicts. For more information, also see
+    \l {Android: Setting up file sharing}{Setting up file sharing}.
+
     \sa setUrlHandler()
 */
 bool QDesktopServices::openUrl(const QUrl &url)

src/plugins/platforms/android/qandroidplatformservices.cpp

@@ -35,6 +35,11 @@ QAndroidPlatformServices::QAndroidPlatformServices()
             Qt::QueuedConnection);
 }
 
+Q_DECLARE_JNI_TYPE(UriType, "Landroid/net/Uri;")
+Q_DECLARE_JNI_TYPE(FileType, "Ljava/io/File;")
+Q_DECLARE_JNI_CLASS(File, "java/io/File")
+Q_DECLARE_JNI_CLASS(FileProvider, "androidx/core/content/FileProvider");
+
 bool QAndroidPlatformServices::openUrl(const QUrl &theUrl)
 {
     QString mime;
@@ -55,13 +60,36 @@ bool QAndroidPlatformServices::openUrl(const QUrl &theUrl)
     if (url.scheme() == fileScheme)
         mime = QMimeDatabase().mimeTypeForUrl(url).name();
 
+    const QJniObject mimeString = QJniObject::fromString(mime);
+
     using namespace QNativeInterface;
-    QJniObject urlString = QJniObject::fromString(url.toString());
-    QJniObject mimeString = QJniObject::fromString(mime);
-    return QJniObject::callStaticMethod<jboolean>(
-            QtAndroid::applicationClass(), "openURL",
-            "(Landroid/content/Context;Ljava/lang/String;Ljava/lang/String;)Z",
-            QAndroidApplication::context(), urlString.object(), mimeString.object());
+
+    auto openUrl = [mimeString](const QJniObject &url) {
+        return QJniObject::callStaticMethod<jboolean>(QtAndroid::applicationClass(), "openURL",
+            QAndroidApplication::context(), url.object<jstring>(), mimeString.object<jstring>());
+    };
+
+    if (url.scheme() != fileScheme || QNativeInterface::QAndroidApplication::sdkVersion() < 24)
+        return openUrl(QJniObject::fromString(url.toString()));
+
+    // Use FileProvider for file scheme with sdk >= 24
+    const QJniObject context = QAndroidApplication::context();
+    const auto appId = context.callMethod<jstring>("getPackageName").toString();
+    const auto providerName = QJniObject::fromString(appId + ".qtprovider"_L1);
+
+    const auto urlPath = QJniObject::fromString(url.path());
+    const auto urlFile = QJniObject(QtJniTypes::className<QtJniTypes::File>(),
+                                    urlPath.object<jstring>());
+
+    const auto fileProviderUri = QJniObject::callStaticMethod<QtJniTypes::UriType>(
+            QtJniTypes::className<QtJniTypes::FileProvider>(), "getUriForFile",
+            QAndroidApplication::context(), providerName.object<jstring>(),
+            urlFile.object<QtJniTypes::FileType>());
+
+    if (fileProviderUri.isValid())
+        return openUrl(fileProviderUri.callMethod<jstring>("toString"));
+
+    return false;
 }
 
 bool QAndroidPlatformServices::openDocument(const QUrl &url)