QJniObject: add callStaticMethod overload that takes class as type

Equivalent to get/setStaticField.

Add a test, and tighten up the surrounding test code a bit.

Change-Id: Ic0993c5d6223f4de271cb01baf727459b5167f94
Reviewed-by: Tinja Paavoseppä <tinja.paavoseppa@qt.io>
Reviewed-by: Petri Virkkunen <petri.virkkunen@qt.io>
Reviewed-by: Zoltan Gera <zoltan.gera@qt.io>

src/corelib/kernel/qjniobject.cpp

@@ -970,7 +970,7 @@ QByteArray QJniObject::className() const
     \since 6.4
 
     Calls the static method \a methodName on \a clazz and returns the value of type \c Ret
-    (unless c Ret is \c void).  If \c Ret if a jobject type, then the returned value will
+    (unless \c Ret is \c void).  If \c Ret is a jobject type, then the returned value will
     be a QJniObject.
 
     \code
@@ -982,6 +982,18 @@ QByteArray QJniObject::className() const
     The method signature is deduced at compile time from \c Ret and the types of \a args.
 */
 
+/*!
+    \fn template <typename Klass, typename Ret, typename ...Args> auto QJniObject::callStaticMethod(const char *methodName, Args &&...args)
+    \since 6.7
+
+    Calls the static method \a methodName on the class \c Klass and returns the value of type
+    \c Ret (unless \c Ret is \c void).  If \c Ret is a jobject type, then the returned value will
+    be a QJniObject.
+
+    The method signature is deduced at compile time from \c Ret and the types of \a args.
+    \c Klass needs to be a C++ type with a registered type mapping to a Java type.
+*/
+
 /*!
     \fn QJniObject QJniObject::callObjectMethod(const char *methodName, const char *signature, ...) const
 

src/corelib/kernel/qjniobject.h

@@ -127,7 +127,8 @@ public:
     static auto callStaticMethod(jclass clazz, const char *methodName, const char *signature, Args &&...args)
     {
         QJniEnvironment env;
-        jmethodID id = getMethodID(env.jniEnv(), clazz, methodName, signature, true);
+        jmethodID id = clazz ? getMethodID(env.jniEnv(), clazz, methodName, signature, true)
+                             : 0;
         return callStaticMethod<Ret>(clazz, id, std::forward<Args>(args)...);
     }
 
@@ -181,6 +182,21 @@ public:
         constexpr auto signature = QtJniTypes::methodSignature<Ret, Args...>();
         return callStaticMethod<Ret>(clazz, methodName, signature.data(), std::forward<Args>(args)...);
     }
+    template <typename Klass, typename Ret, typename ...Args
+#ifndef Q_QDOC
+        , QtJniTypes::ValidSignatureTypes<Ret, Args...> = true
+#endif
+    >
+    static auto callStaticMethod(const char *methodName, Args &&...args)
+    {
+        QJniEnvironment env;
+        const jclass clazz = QJniObject::loadClass(QtJniTypes::className<Klass>().data(),
+                                                   env.jniEnv());
+        const jmethodID id = clazz ? getMethodID(env.jniEnv(), clazz, methodName,
+                                         QtJniTypes::methodSignature<Ret, Args...>().data(), true)
+                                   : 0;
+        return callStaticMethod<Ret>(clazz, id, std::forward<Args>(args)...);
+    }
 
     static QJniObject callStaticObjectMethod(const char *className, const char *methodName,
                                              const char *signature, ...);
@@ -547,6 +563,8 @@ private:
     static constexpr void callStaticMethodForType(JNIEnv *env, T &res, jclass clazz,
                                                   jmethodID id, ...)
     {
+        if (!clazz || !id)
+            return;
         va_list args = {};
         va_start(args, id);
         if constexpr (std::is_same_v<T, jboolean>)
@@ -572,6 +590,8 @@ private:
 
     static void callStaticMethodForVoid(JNIEnv *env, jclass clazz, jmethodID id, ...)
     {
+        if (!clazz || !id)
+            return;
         va_list args;
         va_start(args, id);
         env->CallStaticVoidMethodV(clazz, id, args);

tests/auto/corelib/kernel/qjniobject/tst_qjniobject.cpp

@@ -8,6 +8,8 @@
 #include <QtCore/QJniObject>
 #include <QtTest>
 
+using namespace Qt::StringLiterals;
+
 static const char testClassName[] = "org/qtproject/qt/android/testdatapackage/QtJniObjectTestClass";
 Q_DECLARE_JNI_CLASS(QtJniObjectTestClass, testClassName)
 
@@ -310,7 +312,8 @@ void tst_QJniObject::callStaticObjectMethod()
     jclass cls = env->FindClass("java/lang/String");
     QVERIFY(cls != 0);
 
-    QJniObject formatString = QJniObject::fromString(QLatin1String("test format"));
+    const QString string = u"test format"_s;
+    QJniObject formatString = QJniObject::fromString(string);
     QVERIFY(formatString.isValid());
 
     QJniObject returnValue = QJniObject::callStaticObjectMethod(cls,
@@ -319,20 +322,14 @@ void tst_QJniObject::callStaticObjectMethod()
                                                                 formatString.object<jstring>(),
                                                                 jobjectArray(0));
     QVERIFY(returnValue.isValid());
-
+    QCOMPARE(returnValue.toString(), string);
-    QString returnedString = returnValue.toString();
-
-    QCOMPARE(returnedString, QString::fromLatin1("test format"));
 
     returnValue = QJniObject::callStaticObjectMethod<jstring>(cls,
                                                               "format",
                                                               formatString.object<jstring>(),
                                                               jobjectArray(0));
     QVERIFY(returnValue.isValid());
-
+    QCOMPARE(returnValue.toString(), string);
-    returnedString = returnValue.toString();
-
-    QCOMPARE(returnedString, QString::fromLatin1("test format"));
 
     // from 6.4 on we can use callStaticMethod
     returnValue = QJniObject::callStaticMethod<jstring>(cls,
@@ -340,10 +337,15 @@ void tst_QJniObject::callStaticObjectMethod()
                                                         formatString.object<jstring>(),
                                                         jobjectArray(0));
     QVERIFY(returnValue.isValid());
+    QCOMPARE(returnValue.toString(), string);
 
-    returnedString = returnValue.toString();
+    // from 6.7 we can use callStaticMethod without specifying the class string
+    returnValue = QJniObject::callStaticMethod<jstring, jstring>("format",
+                                                                 formatString.object<jstring>(),
+                                                                 jobjectArray(0));
+    QVERIFY(returnValue.isValid());
+    QCOMPARE(returnValue.toString(), string);
 
-    QCOMPARE(returnedString, QString::fromLatin1("test format"));
 }
 
 void tst_QJniObject::callStaticObjectMethodById()