Game Development Reference
In-Depth Information
Note
Every time you modify the C/C++ code, you'll have to rebuild the shared libraries with a
call to
ndk-build
. If you have more than one source file, and only modified a subset of files, the
build tool will only recompile the files that changed, thereby reducing the compile time. If you need
to make sure all source files are recompiled, just invoke
ndk-build clean
.
Putting It All Together
We now have everything in place to test our native methods. Let's create a test that invokes
both of the
JniUtils
methods. We call the class
JniUtilsTest
, and it extends the
GLGame
class
and contains a
GLScreen
implementation, as usual. It simply copies a
float[]
array into a direct
ByteBuffer
and then outputs the contents of the
ByteBuffer
to LogCat via the other native
method. Listing 13-6 shows the entire code. Don't forget to add it to the
NdkStarter
class and
the manifest file.
Listing 13-6. JniUtilsTest.java, Testing Our Native Methods
package
com.badlogic.androidgames.ndk;
import
java.nio.ByteBuffer;
import
java.nio.ByteOrder;
import
java.nio.FloatBuffer;
import
com.badlogic.androidgames.framework.Game;
import
com.badlogic.androidgames.framework.Screen;
import
com.badlogic.androidgames.framework.impl.GLGame;
import
com.badlogic.androidgames.framework.impl.GLScreen;
public class
JniUtilsTest
extends
GLGame {
public
Screen getStartScreen() {
return new
JniUtilsScreen(this);
}
class
JniUtilsScreen
extends
GLScreen {
public
JniUtilsScreen(Game game) {
super
(game);
float[]
values = { 1.231f, 554.3f, 348.6f, 499.3f };
ByteBuffer buffer = ByteBuffer.allocateDirect(3 * 4);
buffer.order(ByteOrder.nativeOrder());
JniUtils.copy(buffer, values, 1, 3);
FloatBuffer floatBuffer = buffer.asFloatBuffer();
for
(
int
i = 0; i < 3; i++) {
JniUtils.log("JniUtilsTest", Float.toString(floatBuffer.get(i)));
}
}
