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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [Working with lists]
QStringList getTrackTitles(const QJniObject &album) {
QStringList stringList;
QJniObject list = album.callObjectMethod("getTitles",
"()Ljava/util/List;");
if (list.isValid()) {
const int size = list.callMethod<jint>("size");
for (int i = 0; i < size; ++i) {
QJniObject title = list.callObjectMethod("get", "(I)Ljava/lang/Object;", i);
stringList.append(title.toString());
}
}
return stringList;
}
//! [Working with lists]
//! [QJniObject scope]
void functionScope()
{
QString helloString("Hello");
jstring myJString = 0;
{
QJniObject string = QJniObject::fromString(helloString);
myJString = string.object<jstring>();
}
// Ops! myJString is no longer valid.
}
//! [QJniObject scope]
//! [C++ native methods]
static void fromJavaOne(JNIEnv *env, jobject thiz, jint x)
{
Q_UNUSED(env);
Q_UNUSED(thiz);
qDebug() << x << "< 100";
}
static void fromJavaTwo(JNIEnv *env, jobject thiz, jint x)
{
Q_UNUSED(env);
Q_UNUSED(thiz);
qDebug() << x << ">= 100";
}
void foo()
{
// register the native methods first, ideally it better be done with the app start
const JNINativeMethod methods[] =
{{"callNativeOne", "(I)V", reinterpret_cast<void *>(fromJavaOne)},
{"callNativeTwo", "(I)V", reinterpret_cast<void *>(fromJavaTwo)}};
QJniEnvironment env;
env.registerNativeMethods("my/java/project/FooJavaClass", methods, 2);
// Call the java method which will calls back to the C++ functions
QJniObject::callStaticMethod<void>("my/java/project/FooJavaClass", "foo", "(I)V", 10); // Output: 10 < 100
QJniObject::callStaticMethod<void>("my/java/project/FooJavaClass", "foo", "(I)V", 100); // Output: 100 >= 100
}
//! [C++ native methods]
//! [Java native methods]
class FooJavaClass
{
public static void foo(int x)
{
if (x < 100)
callNativeOne(x);
else
callNativeTwo(x);
}
private static native void callNativeOne(int x);
private static native void callNativeTwo(int x);
}
//! [Java native methods]
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