Helper functions needed to run Runnables on Android UI thread easily.

Add two function to allow the users to easily run (a)synchronously Runnables from any thread
directly to Andoroid UI thread. These functions are useful to create java controls and to access
their methods, which must done on Android UI thread.

Change-Id: Iec5437321e6136cc90268cc7ecf091f82fc4cdd3
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>

2 files changed, 52 insertions, 0 deletions

diff --git a/src/androidextras/android/qandroidfunctions.cpp b/src/androidextras/android/qandroidfunctions.cpp
index a4d55c1..5c99642 100644
--- a/src/androidextras/android/qandroidfunctions.cpp
+++ b/src/androidextras/android/qandroidfunctions.cpp
@@ -41,6 +41,7 @@
 #include "qandroidactivityresultreceiver.h"
 #include "qandroidactivityresultreceiver_p.h"
 
+#include <QtCore/private/qjni_p.h>
 #include <QtCore/private/qjnihelpers_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -151,4 +152,50 @@ void QtAndroid::startIntentSender(const QAndroidJniObject &intentSender,
 
 }
 
+/*!
+  \since 5.7
+  \fn void QtAndroid::runOnAndroidThread(const Runnable &runnable)
+
+  Posts the given \a runnable on the android thread.
+  The \a runnable will be queued and executed on the Android UI thread, unless it called on the
+  Android UI thread, in which case the runnable will be executed immediately.
+
+  This function is useful to set asynchronously properties of objects that must be set on on Android UI thread.
+*/
+void QtAndroid::runOnAndroidThread(const QtAndroid::Runnable &runnable)
+{
+    QtAndroidPrivate::runOnAndroidThread(runnable, QJNIEnvironmentPrivate());
+}
+
+/*!
+  \since 5.7
+  \fn void QtAndroid::runOnAndroidThreadSync(const Runnable &runnable, int timeoutMs)
+
+  Posts the \a runnable on the Android UI thread and waits until the runnable is executed,
+  or until \a timeoutMs has passed
+
+  This function is useful to create objects, or get properties on Android UI thread:
+
+  \code
+    QAndroidJniObject javaControl;
+    QtAndroid::runOnAndroidThreadSync([&javaControl](){
+
+        // create our Java control on Android UI thread.
+        javaControl = QAndroidJniObject("android/webkit/WebView",
+                                                    "(Landroid/content/Context;)V",
+                                                    QtAndroid::androidActivity().object<jobject>());
+        javaControl.callMethod<void>("setWebViewClient",
+                                       "(Landroid/webkit/WebViewClient;)V",
+                                       QAndroidJniObject("android/webkit/WebViewClient").object());
+    });
+
+    // Continue the execution normally
+    qDebug() << javaControl.isValid();
+  \endcode
+*/
+void QtAndroid::runOnAndroidThreadSync(const QtAndroid::Runnable &runnable, int timeoutMs)
+{
+    QtAndroidPrivate::runOnAndroidThreadSync(runnable, QJNIEnvironmentPrivate(), timeoutMs);
+}
+
 QT_END_NAMESPACE
diff --git a/src/androidextras/android/qandroidfunctions.h b/src/androidextras/android/qandroidfunctions.h
index dc1d38a..8fde117 100644
--- a/src/androidextras/android/qandroidfunctions.h
+++ b/src/androidextras/android/qandroidfunctions.h
@@ -47,6 +47,8 @@
 #include <QtAndroidExtras/qandroidextrasglobal.h>
 #include <QtAndroidExtras/qandroidjniobject.h>
 
+#include <functional>
+
 QT_BEGIN_NAMESPACE
 
 class QAndroidActivityResultReceiver;
@@ -62,6 +64,9 @@ namespace QtAndroid
                                               int receiverRequestCode,
                                               QAndroidActivityResultReceiver *resultReceiver = 0);
 
+    typedef std::function<void()> Runnable;
+    Q_ANDROIDEXTRAS_EXPORT void runOnAndroidThread(const Runnable &runnable);
+    Q_ANDROIDEXTRAS_EXPORT void runOnAndroidThreadSync(const Runnable &runnable, int timeoutMs = INT_MAX);
 }
 
 QT_END_NAMESPACE