Hi!
After installing Android Studio and setting up the OpenCv4Android 3.0, I tried to run a simple application which purpose was to read a image from the emulators hard disk and then show it in the app. Unfortunately I got the error "Null object reference".
This is a sample of code I have been using:
public class MainActivity extends AppCompatActivity {
static {
if (!OpenCVLoader.initDebug()){
Log.i("opencv", "opencv initialization failed");
} else {
Log.i("opencv", "opencv initialization successful"); }
}
@Override
protected void onCreate(Bundle savedInstanceState) {
ImageView imgView = (ImageView) findViewById(R.id.sampleImageView);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Mat imgRGB = imread("../data/androidlogo.jpg");
if(imgRGB==null){
Log.i("opencv","Image read failed");
}
else {
Log.i("opencv", "Image read successful, height: "+ imgRGB.height() + " width: " + imgRGB.width());
Bitmap img = Bitmap.createBitmap(imgRGB.cols(), imgRGB.rows(), Bitmap.Config.ARGB_8888);
Utils.matToBitmap(imgRGB, img);
imgView.setImageBitmap(img);
}
}
**And this is how I declared the imgview object in the xml:**
ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/sampleImageView"
android:layout_centerHorizontal="true"
android:layout_toEndOf="@+id/textView"
**And this is the logcat:**
08-30 08:50:26.925 2715-2715/com.example.robin.opencvexample I/OpenCV/StaticHelper﹕ -----------------------------------------------------------------
08-30 08:50:26.925 2715-2715/com.example.robin.opencvexample I/opencv﹕ opencv initialization successful
08-30 08:50:27.051 2715-2715/com.example.robin.opencvexample I/opencv﹕ Image read successful, height: 350 width: 480
08-30 08:50:27.063 2715-2715/com.example.robin.opencvexample D/AndroidRuntime﹕ Shutting down VM
08-30 08:50:27.063 2715-2715/com.example.robin.opencvexample E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.robin.opencvexample, PID: 2715
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.robin.opencvexample/com.example.robin.opencvexample.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageBitmap(android.graphics.Bitmap)' **on a null object reference**
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**Conclusion:**
From reading the log, the image and the opencv was sucessfully initialized, and the height and width of the image is correct as well. But its when I try to show the image where it fails. Any suggestion?
Regards Robin
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