For some reason. In this class I keep getting a NullPointerException. I'm really confused and was wondering if and of you can help me
public class MainActivity extends AppCompatActivity {
private static final String TAG = "OCVSample::Activity";
private static Bitmap bmp, yourSelectedImage, bmpimg1, bmpimg2;
private static ImageView iv1, iv2;
private static TextView tv;
private static String path1, path2;
private static String text;
private static Button start;
private static int imgNo = 0;
private static Uri selectedImage;
private static InputStream imageStream;
private static long startTime, endTime;
private static final int SELECT_PHOTO = 100;
private static int descriptor = DescriptorExtractor.BRISK;
private static String descriptorType;
private static int min_dist = 10;
private static int min_matches = 750;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
public MainActivity() {
Log.i(TAG, "Inititated new " + this.getClass());
}
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS: {
Log.i(TAG, "OpenCV loaded successfully");
}
break;
default: {
super.onManagerConnected(status);
}
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.i(TAG, "called onCreate");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv1 = (ImageView) MainActivity.this.findViewById(R.id.img1);
iv2 = (ImageView) MainActivity.this.findViewById(R.id.img2);
start = (Button) MainActivity.this.findViewById(R.id.button1);
tv = (TextView) MainActivity.this.findViewById(R.id.tv);
run();
}
public void run() {
if (descriptor == DescriptorExtractor.BRISK)
descriptorType = "BRISK";
System.out.println(descriptorType);
tv.setText("Select the two images to be compared.\n" + "DescriptorExtractor:" + descriptorType + "\nHamming distance between descriptors:" + min_dist + "\nMinimum number of good matches:" + min_matches);
iv1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, SELECT_PHOTO);
imgNo = 1;
}
});
iv2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, SELECT_PHOTO);
imgNo = 2;
}
});
start.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
if (bmpimg1 != null && bmpimg2 != null) {
bmpimg1 = Bitmap.createScaledBitmap(bmpimg1, 100, 100, true);
bmpimg2 = Bitmap.createScaledBitmap(bmpimg2, 100, 100, true);
Mat img1 = new Mat();
Utils.bitmapToMat(bmpimg1, img1);
Mat img2 = new Mat();
Utils.bitmapToMat(bmpimg2, img2);
Imgproc.cvtColor(img1, img1, Imgproc.COLOR_RGBA2GRAY);
Imgproc.cvtColor(img2, img2, Imgproc.COLOR_RGBA2GRAY);
img1.convertTo(img1, CvType.CV_32F);
img2.convertTo(img2, CvType.CV_32F);
//Log.d("ImageComparator", "img1:"+img1.rows()+"x"+img1.cols()+" img2:"+img2.rows()+"x"+img2.cols());
Mat hist1 = new Mat();
Mat hist2 = new Mat();
MatOfInt histSize = new MatOfInt(180);
MatOfInt channels = new MatOfInt(0);
ArrayList<Mat> bgr_planes1 = new ArrayList<Mat>();
ArrayList<Mat> bgr_planes2 = new ArrayList<Mat>();
Core.split(img1, bgr_planes1);
Core.split(img2, bgr_planes2);
MatOfFloat histRanges = new MatOfFloat(0f, 180f);
boolean accumulate = false;
Imgproc.calcHist(bgr_planes1, channels, new Mat(), hist1, histSize, histRanges, accumulate);
Core.normalize(hist1, hist1, 0, hist1.rows(), Core.NORM_MINMAX, -1, new Mat());
Imgproc.calcHist(bgr_planes2, channels, new Mat(), hist2, histSize, histRanges, accumulate);
Core.normalize(hist2, hist2, 0, hist2.rows(), Core.NORM_MINMAX, -1, new Mat());
img1.convertTo(img1, CvType.CV_32F);
img2.convertTo(img2, CvType.CV_32F);
hist1.convertTo(hist1, CvType.CV_32F);
hist2.convertTo(hist2, CvType.CV_32F);
double compare = Imgproc.compareHist(hist1, hist2, Imgproc.CV_COMP_CHISQR);
Log.d("ImageComparator", "compare: " + compare);
if (compare > 0 && compare < 1500) {
Toast.makeText(MainActivity.this, "Images may be possible duplicates, verifying", Toast.LENGTH_LONG).show();
new asyncTask(MainActivity.this).execute();
} else if (compare == 0)
Toast.makeText(MainActivity.this, "Images are exact duplicates", Toast.LENGTH_LONG).show();
else
Toast.makeText(MainActivity.this, "Images are not duplicates", Toast.LENGTH_LONG).show();
startTime = System.currentTimeMillis();
} else
Toast.makeText(MainActivity.this,
"You haven't selected images.", Toast.LENGTH_LONG)
.show();
}
});
}
@Override
protected void onNewIntent(Intent newIntent) {
super.onNewIntent(newIntent);
min_dist = newIntent.getExtras().getInt("min_dist");
descriptor = newIntent.getExtras().getInt("descriptor");
min_matches = newIntent.getExtras().getInt("min_matches");
run();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) {
super.onActivityResult(requestCode, resultCode, imageReturnedIntent);
switch (requestCode) {
case SELECT_PHOTO:
if (resultCode == RESULT_OK) {
selectedImage = imageReturnedIntent.getData();
try {
imageStream = getContentResolver().openInputStream(
selectedImage);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
yourSelectedImage = BitmapFactory.decodeStream(imageStream);
if (imgNo == 1) {
iv1.setImageBitmap(yourSelectedImage);
path1 = selectedImage.getPath();
bmpimg1 = yourSelectedImage;
} else if (imgNo == 2) {
iv2.setImageBitmap(yourSelectedImage);
path2 = selectedImage.getPath();
bmpimg2 = yourSelectedImage;
}
}
}
}
@Override
public void onPause() {
super.onPause();
}
@Override
public void onResume() {
super.onResume();
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_4, this, mLoaderCallback);
}
public static class asyncTask extends AsyncTask<Void, Void, Void> {
private static Mat img1, img2, descriptors, dupDescriptors;
private static FeatureDetector detector;
private static DescriptorExtractor DescExtractor;
private static DescriptorMatcher matcher;
private static MatOfKeyPoint keypoints, dupKeypoints;
private static MatOfDMatch matches, matches_final_mat;
private static Bitmap bmp, bmpimg1, bmpimg2;
private static ProgressDialog pd;
private static TextView tv;
private static int descriptor = DescriptorExtractor.BRISK;
private static int min_matches = 750;
private static int min_dist = 10;
private static long endTime;
private static boolean isDuplicate = false;
private MainActivity asyncTaskContext = null;
private static Scalar RED = new Scalar(255, 0, 0);
private static Scalar GREEN = new Scalar(0, 255, 0);
public asyncTask(MainActivity context) {
asyncTaskContext = context;
}
@Override
protected void onPreExecute() {
pd = new ProgressDialog(asyncTaskContext);
pd.setIndeterminate(true);
pd.setCancelable(true);
pd.setCanceledOnTouchOutside(false);
pd.setMessage("Processing...");
pd.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// TODO Auto-generated method stub
compare();
return null;
}
@Override
protected void onPostExecute(Void result) {
try {
Mat img3 = new Mat();
MatOfByte drawnMatches = new MatOfByte();
Features2d.drawMatches(img1, keypoints, img2, dupKeypoints,
matches_final_mat, img3, GREEN, RED, drawnMatches, Features2d.NOT_DRAW_SINGLE_POINTS);
bmp = Bitmap.createBitmap(img3.cols(), img3.rows(),
Bitmap.Config.ARGB_8888);
Imgproc.cvtColor(img3, img3, Imgproc.COLOR_BGR2RGB);
Utils.matToBitmap(img3, bmp);
List<DMatch> finalMatchesList = matches_final_mat.toList();
endTime = System.currentTimeMillis();
if (finalMatchesList.size() > min_matches)// dev discretion for
// number of matches to
// be found for an image
// to be judged as
// duplicates or not
{
tv.setText(finalMatchesList.size()
+ " matches were found. Possible duplicate image.\nTime taken="
+ (endTime - startTime) + "ms");
isDuplicate = true;
} else {
tv.setText(finalMatchesList.size()
+ " matches were found. Images aren't similar.\nTime taken="
+ (endTime - startTime) + "ms");
isDuplicate = false;
}
pd.dismiss();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(asyncTaskContext, e.toString(),
Toast.LENGTH_LONG).show();
}
}
void compare() {
try {
bmpimg1 = bmpimg1.copy(Bitmap.Config.ARGB_8888, true);
bmpimg2 = bmpimg2.copy(Bitmap.Config.ARGB_8888, true);
img1 = new Mat();
img2 = new Mat();
Utils.bitmapToMat(bmpimg1, img1);
Utils.bitmapToMat(bmpimg2, img2);
Imgproc.cvtColor(img1, img1, Imgproc.COLOR_BGR2RGB);
Imgproc.cvtColor(img2, img2, Imgproc.COLOR_BGR2RGB);
detector = FeatureDetector.create(FeatureDetector.PYRAMID_FAST);
DescExtractor = DescriptorExtractor.create(descriptor);
matcher = DescriptorMatcher
.create(DescriptorMatcher.BRUTEFORCE_HAMMING);
keypoints = new MatOfKeyPoint();
dupKeypoints = new MatOfKeyPoint();
descriptors = new Mat();
dupDescriptors = new Mat();
matches = new MatOfDMatch();
detector.detect(img1, keypoints);
Log.d("LOG!", "number of query Keypoints= " + keypoints.size());
detector.detect(img2, dupKeypoints);
Log.d("LOG!", "number of dup Keypoints= " + dupKeypoints.size());
// Descript keypoints
DescExtractor.compute(img1, keypoints, descriptors);
DescExtractor.compute(img2, dupKeypoints, dupDescriptors);
Log.d("LOG!", "number of descriptors= " + descriptors.size());
Log.d("LOG!",
"number of dupDescriptors= " + dupDescriptors.size());
// matching descriptors
matcher.match(descriptors, dupDescriptors, matches);
Log.d("LOG!", "Matches Size " + matches.size());
// New method of finding best matches
List<DMatch> matchesList = matches.toList();
List<DMatch> matches_final = new ArrayList<DMatch>();
for (int i = 0; i < matchesList.size(); i++) {
if (matchesList.get(i).distance <= min_dist) {
matches_final.add(matches.toList().get(i));
}
}
matches_final_mat = new MatOfDMatch();
matches_final_mat.fromList(matches_final);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
Also. What exactly is a NullPointerException and how do I prevent it. Sorry if there isn't enough details, this is my first post on this forum. And what confuses me is the logcat:
09-11 19:32:14.998 1506-3141/duketip.comparatortest W/System.err: java.lang.NullPointerException
09-11 19:32:14.998 1506-3141/duketip.comparatortest W/System.err: at duketip.comparatortest.MainActivity$asyncTask.compare(MainActivity.java:337)
09-11 19:32:14.998 1506-3141/duketip.comparatortest W/System.err: at duketip.comparatortest.MainActivity$asyncTask.doInBackground(MainActivity.java:292)
09-11 19:32:15.008 1506-3141/duketip.comparatortest W/System.err: at duketip.comparatortest.MainActivity$asyncTask.doInBackground(MainActivity.java:256)
09-11 19:32:15.008 1506-3141/duketip.comparatortest W/System.err: at android.os.AsyncTask$2.call(AsyncTask.java:288)
09-11 19:32:15.008 1506-3141/duketip.comparatortest W/System.err: at java.util.concurrent.FutureTask.run(FutureTask.java:237)
09-11 19:32:15.008 1506-3141/duketip.comparatortest W/System.err: at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
09-11 19:32:15.018 1506-3141/duketip.comparatortest W/System.err: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
09-11 19:32:15.018 1506-3141/duketip.comparatortest W/System.err: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
09-11 19:32:15.058 1506-3141/duketip.comparatortest W/System.err: at java.lang.Thread.run(Thread.java:841)
