Added one more Android sample (using OpenCV from native)

samples/android/1-java/.project

 <?xml version="1.0" encoding="UTF-8"?>
 <projectDescription>
-	<name>Sample 1 Java</name>
+	<name>Sample 1 Java API</name>
 	<comment></comment>
 	<projects>
 	</projects>

samples/android/2-native/.classpath

+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="src" path="gen"/>
+	<classpathentry kind="con" path="com.android.ide.eclipse.adt.ANDROID_FRAMEWORK"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

samples/android/2-native/.project

+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Sample 2 Native API</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>com.android.ide.eclipse.adt.ResourceManagerBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>com.android.ide.eclipse.adt.PreCompilerBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>com.android.ide.eclipse.adt.ApkBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>com.android.ide.eclipse.adt.AndroidNature</nature>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

samples/android/2-native/.settings/org.eclipse.jdt.core.prefs

+#Wed Jun 29 04:36:40 MSD 2011
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.5
+org.eclipse.jdt.core.compiler.compliance=1.5
+org.eclipse.jdt.core.compiler.source=1.5

samples/android/2-native/AndroidManifest.xml

+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+      package="org.opencv.samples.s2"
+      android:versionCode="1"
+      android:versionName="1.0">
+
+    <supports-screens android:resizeable="true"
+                      android:smallScreens="true" 
+                      android:normalScreens="true" 
+                      android:largeScreens="true" 
+                      android:anyDensity="true" />
+
+    <application android:label="@string/app_name" android:icon="@drawable/icon">
+        <activity android:name="Sample2Native"
+                  android:label="@string/app_name">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+    
+    <uses-sdk android:minSdkVersion="8" />
+
+    <uses-permission android:name="android.permission.CAMERA"/>
+    <uses-feature android:name="android.hardware.camera" />
+    <uses-feature android:name="android.hardware.camera.autofocus" />
+
+</manifest> 

samples/android/2-native/default.properties

+# This file is automatically generated by Android Tools.
+# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
+#
+# This file must be checked in Version Control Systems.
+#
+# To customize properties used by the Ant build system use,
+# "build.properties", and override values to adapt the script to your
+# project structure.
+
+# Project target.
+target=android-8

samples/android/2-native/jni/Android.mk

+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+OPENCV_MK_BUILD_PATH:=../../../../android/build/OpenCV.mk
+ifeq ("$(wildcard $(OPENCV_MK_BUILD_PATH))","")
+	include $(TOOLCHAIN_PREBUILT_ROOT)/user/share/OpenCV/OpenCV.mk
+else
+	include $(OPENCV_MK_BUILD_PATH)
+endif
+
+LOCAL_MODULE    := native_sample
+LOCAL_SRC_FILES := jni_part.cpp
+LOCAL_LDLIBS +=  -llog -ldl
+
+include $(BUILD_SHARED_LIBRARY)

samples/android/2-native/jni/Application.mk

+APP_STL := gnustl_static
+APP_CPPFLAGS := -frtti -fexceptions
+APP_ABI := armeabi-v7a

samples/android/2-native/jni/jni_part.cpp

+#include <jni.h>
+#include <opencv2/core/core.hpp>
+#include <opencv2/imgproc/imgproc.hpp>
+#include <opencv2/features2d/features2d.hpp>
+#include <vector>
+
+using namespace std;
+using namespace cv;
+
+extern "C" {
+JNIEXPORT void JNICALL Java_org_opencv_samples_s2_Sample2View_FindFeatures(JNIEnv* env, jobject thiz, jint width, jint height, jbyteArray yuv, jintArray rgba)
+{
+    jbyte* _yuv  = env->GetByteArrayElements(yuv, 0);
+    jint*  _rgba = env->GetIntArrayElements(rgba, 0);
+
+    Mat myuv(height + height/2, width, CV_8UC1, (unsigned char *)_yuv);
+    Mat mrgba(height, width, CV_8UC4, (unsigned char *)_rgba);
+    Mat mgray(height, width, CV_8UC1, (unsigned char *)_yuv);
+
+    cvtColor(myuv, mrgba, CV_YUV420i2BGR, 4);
+
+    vector<KeyPoint> v;
+
+    FastFeatureDetector detector(50);
+    detector.detect(mgray, v);
+    for( size_t i = 0; i < v.size(); i++ )
+        circle(mrgba, Point(v[i].pt.x, v[i].pt.y), 10, Scalar(0,0,255,255));
+
+    env->ReleaseIntArrayElements(rgba, _rgba, 0);
+    env->ReleaseByteArrayElements(yuv, _yuv, 0);
+}
+
+}

samples/android/2-native/res/values/strings.xml

+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">Sample 2: Native API</string>
+</resources>

samples/android/2-native/src/org/opencv/samples/s2/Sample2Native.java

+package org.opencv.samples.s2;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.view.Window;
+
+public class Sample2Native extends Activity {
+    /** Called when the activity is first created. */
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        requestWindowFeature(Window.FEATURE_NO_TITLE);
+        setContentView(new Sample2View(this));
+    }
+}

samples/android/2-native/src/org/opencv/samples/s2/Sample2View.java

+package org.opencv.samples.s2;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.hardware.Camera;
+import android.hardware.Camera.PreviewCallback;
+import android.util.Log;
+import android.view.SurfaceHolder;
+import android.view.SurfaceView;
+
+import java.util.List;
+
+class Sample2View extends SurfaceView implements SurfaceHolder.Callback, Runnable {
+    private static final String TAG = "Sample2Native::View";
+    
+    private Camera mCamera;
+    private SurfaceHolder mHolder;
+    private int mFrameWidth;
+    private int mFrameHeight;
+    private byte[] mFrame;
+    private boolean mThreadRun;
+    
+    public Sample2View(Context context) {
+        super(context);
+        mHolder = getHolder();
+        mHolder.addCallback(this);
+    }
+
+    public void surfaceChanged(SurfaceHolder _holder, int format, int width, int height) {
+        if ( mCamera != null) {
+            Camera.Parameters params = mCamera.getParameters();
+            List<Camera.Size> sizes = params.getSupportedPreviewSizes();
+            mFrameWidth = width;
+            mFrameHeight = height;
+            
+            //selecting optimal camera preview size
+            {
+                double minDiff = Double.MAX_VALUE;
+                for (Camera.Size size : sizes) {
+                    if (Math.abs(size.height - height) < minDiff) {
+                        mFrameWidth = size.width;
+                        mFrameHeight = size.height;
+                        minDiff = Math.abs(size.height - height);
+                    }
+                }
+            }
+            params.setPreviewSize(mFrameWidth, mFrameHeight);
+            mCamera.setParameters(params);
+            mCamera.startPreview();
+        }
+    }
+
+    public void surfaceCreated(SurfaceHolder holder) {
+        mCamera = Camera.open();
+        mCamera.setPreviewCallback(
+                new PreviewCallback() {
+                    public void onPreviewFrame(byte[] data, Camera camera) {
+                        synchronized(Sample2View.this) {
+                            mFrame = data;
+                            Sample2View.this.notify();
+                        }
+                    }
+                }
+        );
+        (new Thread(this)).start();
+    }
+
+    public void surfaceDestroyed(SurfaceHolder holder) {
+        mThreadRun = false;
+        if(mCamera != null) {
+            synchronized(Sample2View.this) {
+                mCamera.stopPreview();
+                mCamera.setPreviewCallback(null);
+                mCamera.release();
+                mCamera = null;
+            }
+        }
+    }
+
+    public void run() {
+        mThreadRun = true;
+        Log.i(TAG, "Starting thread");
+        while(mThreadRun) {
+            byte[] data = null;
+            synchronized(this) {
+                try {
+                    this.wait();
+                    data = mFrame;
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+            
+            int frameSize = mFrameWidth*mFrameHeight;
+            int[] rgba = new int[frameSize];
+            
+            FindFeatures(mFrameWidth, mFrameHeight, data, rgba);
+            
+            Bitmap bmp = Bitmap.createBitmap(mFrameWidth, mFrameHeight, Bitmap.Config.ARGB_8888);
+            bmp.setPixels(rgba, 0/*offset*/, mFrameWidth /*stride*/, 0, 0, mFrameWidth, mFrameHeight);
+            
+            Canvas canvas = mHolder.lockCanvas();
+            canvas.drawBitmap(bmp, (canvas.getWidth()-mFrameWidth)/2, (canvas.getHeight()-mFrameHeight)/2, null);
+            mHolder.unlockCanvasAndPost(canvas);
+        }
+    }
+
+    public native void FindFeatures(int width, int height, byte yuv[], int[] rgba);
+
+    static {
+        System.loadLibrary("native_sample");
+    }
+}