Qt on Android:使用JNI与第三方jar包

wnloadWebPage，Java代码使用asynchttpclient下载一个网页，然后调用ExtendsQtNative通知Qt C++代码。

C++代码

分两部分，一部分是实现JNI方法。另一部分是调用Java类的方法。

实现JNI方法并注册

先看与ExtendsQtNative对应的JNI实现，在main.cpp中，都列出吧：

61#include widget.h

#include

#include

#include

#include

#include ../simpleCustomEvent.h

#include

QObject *g_listener = 0;

// result: -1 failed; 1 success; 0 busy;

static void onDownloaded(JNIEnv *env, jobject thiz,int result, jstring uri, jstring data)

{

QString qstrData;

const char *nativeString = env->GetStringUTFChars(data, 0);

qstrData = nativeString;

env->ReleaseStringUTFChars(data, nativeString);

QCoreApplication::postEvent(g_listener, new SimpleCustomEvent(result, qstrData));

}

bool registerNativeMethods()

{

JNINativeMethod methods[] {

{OnDownloaded, (ILjava/lang/String;Ljava/lang/String;)V, (void*)onDownloaded}

};

const char *classname = an/qt/useJar/ExtendsQtNative;

jclass clazz;

QAndroidJniEnvironment env;

QAndroidJniObject javaClass(classname);

clazz = env->GetObjectClass(javaClass.object());

qDebug() find ExtendsQtNative - clazz;

bool result = false;

if(clazz)

{

jint ret = env->RegisterNatives(clazz,

methods,

sizeof(methods) / sizeof(methods[0]));

env->DeleteLocalRef(clazz);

qDebug() RegisterNatives return - ret;

result = ret >= 0;

}

if(env->ExceptionCheck()) env->ExceptionClear();

return result;

}

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

SimpleCustomEvent::eventType();

registerNativeMethods();

Widget w;

g_listener = qobject_cast

w.show();

return a.exec();

}

注册JNI方法，设置一个全局的对象接收通知。具体的，参考Qt帮助来理解。

调用Java方法

对Java方法的调用在Widget.cpp中。直接看代码吧。

widget.h：

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29#ifndef WIDGET_H

#define WIDGET_H

#include

#include

#include

#include

class Widget : public QWidget

{

Q_OBJECT

public:

Widget(QWidget *parent = 0);

~Widget();

bool event(QEvent *e);

public slots:

void onGet();

private:

QLineEdit * m_urlEdit;

QTextEdit * m_resultView;

QLabel * m_stateLabel;

};

#endif // WIDGET_H

都是界面相关的，没什么好说的。看widget.cpp：

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71#include widget.h

#include

#include

#include ../simpleCustomEvent.h

#include

#include

Widget::Widget(QWidget *parent)

: QWidget(parent)

{

QVBoxLayout *layout = new QVBoxLayout(this);

QHBoxLayout *getLayout = new QHBoxLayout();

layout->addLayout(getLayout);

m_urlEdit = new QLineEdit(http://blog.csdn.net/foruok);

getLayout->addWidget(m_urlEdit, 1);

QPushButton *getButton = new QPushButton(GET);

getLayout->addWidget(getButton);

connect(getButton, SIGNAL(clicked()), this, SLOT(onGet()));

m_resultView = new QTextEdit();

m_resultView->setReadOnly(true);

layout->addWidget(m_resultView, 1);

m_stateLabel = new QLabel();

layout->addWidget(m_stateLabel);

}

Widget::~Widget()

{

}

bool Widget::event(QEvent *e)

{

if(e->type() == SimpleCustomEvent::eventType())

{

e->accept();

SimpleCustomEvent *sce = (SimpleCustomEvent*)e;

switch(sce->m_arg1)

{

case 1:

m_resultView->setText(sce->m_arg2);

m_stateLabel->setText(Success!);

break;

case 0:

m_resultView->setText(sce->m_arg2);

m_stateLabel->setText(Failed!);

break;

case -1:

m_stateLabel->setText(sce->m_arg2);

break;

}

return true;

}

return QWidget::event(e);

}

void Widget::onGet()

{

#ifdef WIN32

m_resultView->setText(Sorry, Just for Android!);

#elif defined(ANDROID)

QString url = m_urlEdit->text();

QAndroidJniObject javaAction = QAndroidJniObject::fromString(url);

QAndroidJniObject::callStaticMethod(an/qt/useJar/ExtendsQtWithJava,