Android: Add enablers for listening to activity results

When you launch an activity through an intent,
data can be provided back from the activity when it has finished
using onActivityResult() in the activity which launched it.

This is okay for applications, since they can easily create their
own activities, but does not work for libraries that need to
use intents. There is no listener API for activity results which
allow external classes to eavesdrop.

In order to support launching intents from third-party or add-on
libraries, we provide a low-level way to hook into the activity
result event. The corresponding public API will be added to
QtAndroidExtras.

Change-Id: I89417f485e2c0e69028dcccc7c155788346a7417
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/corelib/kernel/qjnihelpers.cpp b/src/corelib/kernel/qjnihelpers.cpp
index 74eb6f5b27..311ebaa092 100644
--- a/src/corelib/kernel/qjnihelpers.cpp
+++ b/src/corelib/kernel/qjnihelpers.cpp
@@ -40,6 +40,8 @@
 ****************************************************************************/
 
 #include "qjnihelpers_p.h"
+#include "qmutex.h"
+#include "qlist.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -48,6 +50,39 @@ static jobject g_jActivity = Q_NULLPTR;
 static jobject g_jClassLoader = Q_NULLPTR;
 static jint g_androidSdkVersion = 0;
 
+namespace {
+    class ActivityResultListeners
+    {
+    public:
+        QMutex mutex;
+        QList<QtAndroidPrivate::ActivityResultListener *> listeners;
+    };
+}
+
+Q_GLOBAL_STATIC(ActivityResultListeners, g_activityResultListeners)
+
+void QtAndroidPrivate::registerActivityResultListener(ActivityResultListener *listener)
+{
+    QMutexLocker locker(&g_activityResultListeners()->mutex);
+    g_activityResultListeners()->listeners.append(listener);
+}
+
+void QtAndroidPrivate::unregisterActivityResultListener(ActivityResultListener *listener)
+{
+    QMutexLocker locker(&g_activityResultListeners()->mutex);
+    g_activityResultListeners()->listeners.removeAll(listener);
+}
+
+void QtAndroidPrivate::handleActivityResult(jint requestCode, jint resultCode, jobject data)
+{
+    QMutexLocker locker(&g_activityResultListeners()->mutex);
+    const QList<QtAndroidPrivate::ActivityResultListener *> &listeners = g_activityResultListeners()->listeners;
+    for (int i=0; i<listeners.size(); ++i) {
+        if (listeners.at(i)->handleActivityResult(requestCode, resultCode, data))
+            break;
+    }
+}
+
 static inline bool exceptionCheck(JNIEnv *env)
 {
     if (env->ExceptionCheck()) {