Android: fix mimeTypes handling for file dialog

Since Android native file manager supports mimeTypes, I use
QMimeDatabase to get the correct mime type for the nameFilter
used with the file dialog.

[ChangeLog][Android] Support setting mimetypes and and namefilters for
Android native file dialog.

Task-number: QTBUG-83089
Change-Id: I46545576dc9b51aa872bb37dbf4fe12b2533bdd9
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>

src/android/jar/src/org/qtproject/qt5/android/QtNative.java

@@ -157,6 +157,11 @@ public class QtNative
         }
     }
 
+    public static String[] getStringArray(String joinedString)
+    {
+        return joinedString.split(",");
+    }
+
     private static Uri getUriWithValidPermission(Context context, String uri, String openMode)
     {
         try {

src/plugins/platforms/android/qandroidplatformfiledialoghelper.cpp

@@ -42,6 +42,10 @@
 #include <androidjnimain.h>
 #include <jni.h>
 
+#include <QMimeType>
+#include <QMimeDatabase>
+#include <QRegularExpression>
+
 QT_BEGIN_NAMESPACE
 
 namespace QtAndroidFileDialogHelper {
@@ -147,17 +151,47 @@ void QAndroidPlatformFileDialogHelper::setAllowMultipleSelections(bool allowMult
                               allowMultipleSelections.object(), allowMultiple);
 }
 
+QStringList nameFilterExtensions(const QString nameFilters)
+{
+    QStringList ret;
+#if QT_CONFIG(regularexpression)
+    QRegularExpression re("(\\*\\.?\\w*)");
+    QRegularExpressionMatchIterator i = re.globalMatch(nameFilters);
+    while (i.hasNext())
+        ret << i.next().captured(1);
+#endif // QT_CONFIG(regularexpression)
+    ret.removeAll("*");
+    return ret;
+}
+
 void QAndroidPlatformFileDialogHelper::setMimeTypes()
 {
-    m_intent.callObjectMethod("setType", "(Ljava/lang/String;)Landroid/content/Intent;",
-                              QJNIObjectPrivate::fromString("*/*").object());
+    QStringList mimeTypes = options()->mimeTypeFilters();
+    const QString nameFilter = options()->initiallySelectedNameFilter();
+
+    if (mimeTypes.isEmpty() && !nameFilter.isEmpty()) {
+        QMimeDatabase db;
+        for (const QString &filter : nameFilterExtensions(nameFilter))
+            mimeTypes.append(db.mimeTypeForFile(filter).name());
+    }
+
+    QString type = !mimeTypes.isEmpty() ? mimeTypes.at(0) : QLatin1String("*/*");
+    m_intent.callObjectMethod("setType", "(Ljava/lang/String;)Landroid/content/Intent;",
+                              QJNIObjectPrivate::fromString(type).object());
+
+    if (!mimeTypes.isEmpty()) {
+        const QJNIObjectPrivate extraMimeType = QJNIObjectPrivate::getStaticObjectField(
+                JniIntentClass, "EXTRA_MIME_TYPES", "Ljava/lang/String;");
+
+        QJNIObjectPrivate mimeTypesArray = QJNIObjectPrivate::callStaticObjectMethod(
+                "org/qtproject/qt5/android/QtNative",
+                "getStringArray",
+                "(Ljava/lang/String;)[Ljava/lang/String;",
+                QJNIObjectPrivate::fromString(mimeTypes.join(",")).object());
 
-    const QJNIObjectPrivate extraMimeType = QJNIObjectPrivate::getStaticObjectField(
-            JniIntentClass, "EXTRA_MIME_TYPES", "Ljava/lang/String;");
-    for (const QString &type : options()->mimeTypeFilters()) {
         m_intent.callObjectMethod(
-                "putExtra", "(Ljava/lang/String;Ljava/lang/String;)Landroid/content/Intent;",
-                extraMimeType.object(), QJNIObjectPrivate::fromString(type).object());
+                "putExtra", "(Ljava/lang/String;[Ljava/lang/String;)Landroid/content/Intent;",
+                extraMimeType.object(), mimeTypesArray.object());
     }
 }