We released the first version of the Native Development Kit, a development toolchain for building shared libraries in C or C++ that can be used in conjunction with Android applications written in the Java programming language, way back in July of 2009. Since that initial release we’ve steadily improved support for native code; key features such as OpenGL ES support, debugging capabilities, multiple ABI support, and access to bitmaps in native code have arrived with each NDK revision. The result has been pretty awesome: we’ve seen huge growth in certain categories of performance-critical applications, particularly 3D games.
These types of applications are often impractical via Dalvik due to execution speed requirements or, more commonly, because they are based on engines already developed in C or C++. Early on we noted a strong relationship between the awesomeness of the NDK and the awesomeness of the applications that it made possible; at the limit of this function is obviously infinite awesomeness (see graph, right).
With the latest version of the NDK we intend to further increase the awesomeness of your applications, this time by a pretty big margin. With NDK r5, we’re introducing new APIs that will allow you to do more from native code. In fact, with these new tools, applications targeted at Gingerbread or later can be implemented entirely in C++; you can now build an entire Android application without writing a single line of Java.
Of course, access to the regular Android API still requires Dalvik, and the VM is still present in native applications, operating behind the scenes. Should you need to do more than the NDK interfaces provide, you can always invoke Dalvik methods via JNI. But if you prefer to work exclusively in C++, the NDK r5 will let you build a main loop like this:复制内容到剪贴板
代码:
void android_main(struct android_app* state) {
// Make sure glue isn't stripped.
app_dummy();
// loop waiting for stuff to do.
while (1) {
// Read all pending events.
int ident;
int events;
struct android_poll_source* source;
// Read events and draw a frame of animation.
if ((ident = ALooper_pollAll(0, NULL, &events,
(void**)&source)) >= 0) {
// Process this event.
if (source != NULL) {
source->process(state, source);
}
}
// draw a frame of animation
bringTheAwesome();
}
}
