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[[CategoryAPI]], [[CategoryHeader]] [[CategoryAPI]], [[CategorySystem]]

DRAFT

SDL_AndroidGetActivity

Use this function to retrieve the Java instance of the activity class in an Android application.

Syntax

void* SDL_AndroidGetActivity(void)

Return Value

Returns the jobject representing the instance of the Activity class of the Android application, or NULL on error.

The jobject returned by the function is a local reference and must be released by the caller. See the PushLocalFrame()/PopLocalFrame() or DeleteLocalRef() functions of the Java native interface (in Oracle's documentation).

Code Examples

// Calls the void MyActivity.showHome() method of the Java instance of the activity.
void showHome(void)
{
    // retrieve the JNI environment.
    JNIEnv* env = (JNIEnv*)SDL_AndroidGetJNIEnv();

    // retrieve the Java instance of the SDLActivity
    jobject activity = (jobject)SDL_AndroidGetActivity();

    // find the Java class of the activity. It should be SDLActivity or a subclass of it.
    jclass clazz( env->GetObjectClass(activity) );

    // find the identifier of the method to call
    jmethodID method_id = env->GetMethodID( clazz, "showHome", "()V" );

    // effectively call the Java method
    env->CallVoidMethod( activity, method_id );
    
    // clean up the local references.
    env->DeleteLocalRef(activity);
}

Remarks

The prototype of the function in SDL's code actually declares a void* return type, even if the implementation returns a jobject. The rationale being that it allows not to include jni.h in the headers of the SDL.

Version

This function is available in SDL 2.0.0


CategoryAPI, CategorySystem

None: SDL_AndroidGetActivity (last edited 2016-11-20 22:02:28 by PhilippWiesemann)

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