Qt5.13 on android alternative to Qcameraviewfinder

[dedetuga]

hi,

I testing the sample from QTCreator Called "Camera Example" on android, but when i deploy to my android phone I get no preview image of the camera, some how the QcameraViewfinder is not compatible with android,
there is some alternative to solve this?

Thanks

[jsulm]

@dedetuga said in Qt5.13 on android alternative to Qcameraviewfinder:

there is some alternative to solve this?

More recent Qt version maybe?

[dedetuga]

Didn't work I try the same example with QT5.15

[J.Hilk]

@dedetuga Is that the widget example?

yeah, that was never ported properly to android, use the QML example, that one works

[dedetuga]

hi @jsulm,
It works in QML but I don't know programe in QML and my project is in c++ (QTWidgets),
I will use opencv but I have no choise I'm forced to use a vewfinder i get an error if i dont set a view finder.

This is why I'm looking for alternatives

[HemantSuryawanshi]

@J-Hilk I tried qml example (i.e. declarative_camera) for QT Android. but its giving same issue to me.

[Jacques L.]

@dedetuga said in Qt5.13 on android alternative to Qcameraviewfinder:

It works in QML but I don't know programe in QML and my project is in c++ (QTWidgets),

I'm trying to use the Java native alternative but I don't know much of JNI and I'm stuck. Googling quite a lot didn't help much yet. It throw an exception just after on cursor
Probably it is already on uri.
i.e.:

QAndroidJniObject uri = data.callObjectMethod("getData", "()Landroid/net/Uri;")

Because logging statement __DV(uri.isValid()); already prints false:

D myapp: CImageCaptureAndroid::shootPicture
D myapp: CImageCaptureAndroid::handleActivityResult
D myapp: data.isValid()  = > true <
D myapp: data.toString()  = > Intent { act=inline-data (has extras) } <
D myapp: uri.isValid()  = > false <   /// <== Already wrong here
D myapp: uri.toString()  = >  <    /// <== thus, meaningless
D myapp: data_android.isValid()  = > true <
D myapp: data_android.toString()  = > _data <
D myapp: object_data_android  = > 0x95 <
D myapp: contentResolver.isValid()  = > true <
D myapp: contentResolver.toString()  = > android.app.ContextImpl$ApplicationContentResolver@b813db1 <
D myapp: cursor.isValid()  = > false < /// <== Wrong here too
D myapp: cursor.toString()  = >  < /// <== Meaningless too
D myapp: In If9
F mple.myapp: java_vm_ext.cc:561] JNI DETECTED ERROR IN APPLICATION: JNI GetMethodID called with pending exception java.lang.NullPointerException: uri
F mple.myapp: java_vm_ext.cc:561]   at java.lang.Object com.android.internal.util.Preconditions.checkNotNull(java.lang.Object, java.lang.Object) (Preconditions.java:128)

Source: https://stackoverflow.com/questions/63127412/qt-and-android-handleactivityresult-returned-from-a-camera-uri-null

My current header file is:

#pragma once

#include <QObject>
#include <QtAndroidExtras/QAndroidActivityResultReceiver>
#include <QtAndroidExtras/QtAndroid>
#include <QtAndroidExtras/QAndroidJniEnvironment>
#include <QtAndroidExtras/QAndroidJniObject>

#include <QDebug>

class CImageCaptureAndroid : public QObject, public QAndroidActivityResultReceiver
{
      Q_OBJECT

   public:
      CImageCaptureAndroid();

      void shootPicture();

      void handleActivityResult(int receiverRequestCode, int resultCode, const QAndroidJniObject & data) override;

   signals:
      void picturePath(QString);

};

And then the source file:

#include "cimagecaptureandroid.h"

#include "qt_utils.h"

#include <QFile>
#include <QDir>
#include <QStandardPaths>

CImageCaptureAndroid::CImageCaptureAndroid()
{

}

void CImageCaptureAndroid::shootPicture()
{
   __DL("CImageCaptureAndroid::shootPicture");

   QAndroidJniObject ACTION_CAPTURE = QAndroidJniObject::fromString("android.provider.MediaStore.ACTION_IMAGE_CAPTURE");
   QAndroidJniObject ACTION_IMAGE_CAPTURE = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore", "ACTION_IMAGE_CAPTURE", "Ljava/lang/String;");

   QAndroidJniObject intent("android/content/Intent", "(Ljava/lang/String;)V", ACTION_IMAGE_CAPTURE.object<jstring>());

   if (ACTION_CAPTURE.isValid() && intent.isValid()) {
      QtAndroid::startActivity(intent.object<jobject>(), 101, this);
   } else {
      assert( false );
   }
}

void CImageCaptureAndroid::handleActivityResult(int receiverRequestCode, int resultCode, const QAndroidJniObject &data)
{
   __DL("CImageCaptureAndroid::handleActivityResult");
   __DV(data.isValid());
   __DV(data.toString());
   jint RESULT_OK = QAndroidJniObject::getStaticField<jint>("android/app/Activity", "RESULT_OK");
   if (receiverRequestCode == 101 && resultCode == RESULT_OK)  {
      QAndroidJniObject uri = data.callObjectMethod("getData", "()Landroid/net/Uri;");
      __DV(uri.isValid());
      __DV(uri.toString());
      QAndroidJniObject data_android = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore$MediaColumns", "DATA", "Ljava/lang/String;");
      __DV(data_android.isValid());
      __DV(data_android.toString());
      QAndroidJniEnvironment env;
      jobjectArray object = (jobjectArray)env->NewObjectArray(1, env->FindClass("java/lang/String"), NULL);
      jobject object_data_android = env->NewStringUTF(data_android.toString().toStdString().c_str());
      __DV(object_data_android);
      env->SetObjectArrayElement(object, 0, object_data_android);
      QAndroidJniObject contentResolver = QtAndroid::androidActivity().callObjectMethod("getContentResolver", "()Landroid/content/ContentResolver;");
      __DV(contentResolver.isValid());
      __DV(contentResolver.toString());
      QAndroidJniObject cursor = contentResolver.callObjectMethod("query", "(Landroid/net/Uri;[Ljava/lang/String;Ljava/lang/String;[Ljava/lang/String;Ljava/lang/String;)Landroid/database/Cursor;", uri.object<jobject>(), object, NULL, NULL, NULL);
      __DV(cursor.isValid());
      __DV(cursor.toString());
      __DL("In If9");
      jint columnIndex = cursor.callMethod<jint>("getColumnIndex", "(Ljava/lang/String;)I", data_android.object<jstring>());
      __DL("In If10");
      cursor.callMethod<jboolean>("moveToFirst", "()Z");
      __DL("In If11");
      QAndroidJniObject result = cursor.callObjectMethod("getString", "(I)Ljava/lang/String;", columnIndex);
      __DL("In If12");

      QFile imageFile(result.toString());
      QDir dir;
      if(dir.exists("images")){
         __DL("Folder already exists");
      }else {
         dir.mkdir("images");
      }
      QStringList splitedImagePath = result.toString().split("/");
      QString imageName = splitedImagePath.value(splitedImagePath.length() - 1);
      QString dataimgFile = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + "/images/" + imageName;
      // /data/data/org.qtproject.feather/files/images/offLight_Button.png

      if (imageFile.exists()) {
         QFile cdbfile(dataimgFile);
         if (!cdbfile.exists()) {
            if(!imageFile.copy(dataimgFile))
               __DL("Error :copy failed");

            QFile::setPermissions(dataimgFile, QFile::WriteOwner | QFile::ReadOwner);
         } else {
            __DL("image exits already no need to copy");
            QFile::setPermissions(dataimgFile, QFile::WriteOwner | QFile::ReadOwner);
         }
      } else {
         __mDV("img Not exit in Assert ", dataimgFile);
      }

      QString imagePath = "file://" + dataimgFile;

//      this->deleteLater();

      emit picturePath(imagePath);
   }
}