core :: union_find
union–find algorithm using an efficient disjoint-set data structureapp.nit
on Android using a custom Java entry point
gamnit :: camera_control_android
Two fingers camera manipulation, pinch to zoom and slide to scroll
# Java related services specific to Android and its Dalvik VM
module dalvik
import activities
redef class App
# Main Java Activity of this application
#
# Require: A Nit activity is currently running.
fun native_activity: NativeActivity is abstract
# Current reference context, either an activity or a service
fun native_context: NativeContext do return native_activity
end
redef class Sys
# We cannot create a JVM on Android
#
# This method is not reachable on this platform anyway.
# `Sys::jvm` is implemented by the main activity modules.
redef fun create_default_jvm do abort
redef fun jni_env do return jvm.attach_current_thread
private var class_loader: nullable JavaObject = null
private var class_loader_method: nullable JMethodID = null
redef fun load_jclass(name)
do
var class_loader = self.class_loader
if class_loader == null then
find_class_loader app.native_context
class_loader = self.class_loader
assert class_loader != null
end
var class_loader_method = self.class_loader_method
assert class_loader_method != null
return load_jclass_intern(class_loader, class_loader_method, name)
end
private fun find_class_loader(native_context: NativeContext) import jni_env, class_loader=, JavaObject.as nullable, class_loader_method=, JMethodID.as nullable `{
JNIEnv *env = Sys_jni_env(self);
// Retrieve main activity
jclass class_context = (*env)->GetObjectClass(env, native_context);
if (class_context == NULL) {
__android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve activity class");
(*env)->ExceptionDescribe(env);
exit(1);
}
jmethodID class_activity_getClassLoader = (*env)->GetMethodID(env, class_context, "getClassLoader", "()Ljava/lang/ClassLoader;");
if (class_activity_getClassLoader == NULL) {
__android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve 'getClassLoader' method");
(*env)->ExceptionDescribe(env);
exit(1);
}
// Call activity.getClassLoader
jobject instance_class_loader = (*env)->CallObjectMethod(env, native_context, class_activity_getClassLoader);
if (instance_class_loader == NULL) {
__android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve class loader instance");
(*env)->ExceptionDescribe(env);
exit(1);
}
jclass class_class_loader = (*env)->GetObjectClass(env, instance_class_loader);
if (class_class_loader == NULL) {
__android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve class of class loader");
(*env)->ExceptionDescribe(env);
exit(1);
}
// Get the method ClassLoader.findClass
jmethodID class_class_loader_findClass = (*env)->GetMethodID(env, class_class_loader, "findClass", "(Ljava/lang/String;)Ljava/lang/Class;");
if (class_class_loader_findClass == NULL) {
__android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve 'findClass' method");
(*env)->ExceptionDescribe(env);
exit(1);
}
// Return the values to Nit
Sys_class_loader__assign(self, JavaObject_as_nullable((*env)->NewGlobalRef(env, instance_class_loader)));
Sys_class_loader_method__assign(self, JMethodID_as_nullable(class_class_loader_findClass));
// Clean up
(*env)->DeleteLocalRef(env, class_context);
(*env)->DeleteLocalRef(env, instance_class_loader);
(*env)->DeleteLocalRef(env, class_class_loader);
`}
private fun load_jclass_intern(instance_class_loader: JavaObject, class_loader_findClass: JMethodID, name: CString): JClass import jni_env `{
JNIEnv *env = Sys_jni_env(self);
jobject class_name = (*env)->NewStringUTF(env, name);
jclass java_class = (*env)->CallObjectMethod(env, instance_class_loader, class_loader_findClass, class_name);
if (java_class == NULL) {
__android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed loading targeted class");
(*env)->ExceptionDescribe(env);
exit(1);
}
(*env)->DeleteLocalRef(env, class_name);
return java_class;
`}
end
lib/android/dalvik.nit:17,1--127,3