Android Camera on QT5.12 Opencv4android4.3 c++

[dedetuga]

HI,
I managed to put all together to build android apps on QTCreator with Opencv for Android, but now,
I'm trying get camera image throw opencv using c++ but I have no idea how to do it.
I look to a bunch of tutorials but all are in java and the ones in c++ are not complete.

this is my code:

cout << "Opening camera..." << endl;
       VideoCapture capture(0); // open the first camera
       if (!capture.isOpened())
       {
           ui->label->setText("Failed");
       }
       else
       {
           ui->label->setText("Working");
       }

It returns always true (failed).
why what i'm missing?
Any help?

[dedetuga]

!!!...UPDATE...!!!

Some times the better is restart, this is what i did!

I restart from the bottom by configuring QT Creator
configure qt for android

Now it's building everything...really everything....all QT samples I piped in they work 80 or 90 percent in Android

PS: I'm targeting the samples not designed for Android, I'm targeting all samples without "Android" in the green tags.

For example the sample "Qt Quick Extras - Dashboard" with the kit QT 5.13.0 and it worked 100%

Next stop Rebuilding Opencv4Android....

[jsulm]

@dedetuga On Android your app needs to request access to the camera. I'm not an Android expert, but I think you need to do that in the manifest file.

[dedetuga]

Hi @jsulm thanks for reply.

I add thins to my manifest file:

    <uses-permission android:name="android.permission.CAMERA"/>

    <uses-feature android:name="android.hardware.camera" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.autofocus" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.front" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.front.autofocus" android:required="true"/>

but the app didn't ask for permissions and I still can't get the camera image so I add this code in my mainwindow.cpp

auto  result = QtAndroid::checkPermission(QString("android.permission.CAMERA"));
        if(result == QtAndroid::PermissionResult::Denied){
            QtAndroid::PermissionResultMap resultHash = QtAndroid::requestPermissionsSync(QStringList({"android.permission.CAMERA"}));
            if(resultHash["android.permission.CAMERA"] == QtAndroid::PermissionResult::Denied)
            {

            }
        }

still no camera image, when i check

if (!capture.isOpened())

It return "Not opened"

This is my full Manifest.xml

<?xml version="1.0"?>
<manifest package="org.qtproject.example" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="-- %%INSERT_VERSION_NAME%% --" android:versionCode="-- %%INSERT_VERSION_CODE%% --" android:installLocation="auto">
    <uses-sdk android:minSdkVersion="24" android:targetSdkVersion="28"/>

    <!-- The following comment will be replaced upon deployment with default permissions based on the dependencies of the application.
         Remove the comment if you do not require these default permissions. -->
    <!-- %%INSERT_PERMISSIONS -->
    <uses-permission android:name="android.permission.CAMERA"/>


    <!-- The following comment will be replaced upon deployment with default features based on the dependencies of the application.
         Remove the comment if you do not require these default features. -->
    <!-- %%INSERT_FEATURES -->

    <uses-feature android:name="android.hardware.camera" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.autofocus" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.front" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.front.autofocus" android:required="true"/>

    <supports-screens android:largeScreens="true" android:normalScreens="true" android:anyDensity="true" android:smallScreens="true"/>

    <application android:hardwareAccelerated="true" android:name="org.qtproject.qt5.android.bindings.QtApplication" android:label="-- %%INSERT_APP_NAME%% --">
        <activity android:configChanges="orientation|uiMode|screenLayout|screenSize|smallestScreenSize|layoutDirection|locale|fontScale|keyboard|keyboardHidden|navigation|mcc|mnc|density" android:name="org.qtproject.qt5.android.bindings.QtActivity" android:label="-- %%INSERT_APP_NAME%% --" android:screenOrientation="unspecified" android:launchMode="singleTop">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>

            <!-- Application arguments -->
            <!-- meta-data android:name="android.app.arguments" android:value="arg1 arg2 arg3"/ -->
            <!-- Application arguments -->

            <meta-data android:name="android.app.lib_name" android:value="MyFirstQT_Android_APP"/>
            <meta-data android:name="android.app.qt_sources_resource_id" android:resource="@array/qt_sources"/>
            <meta-data android:name="android.app.repository" android:value="default"/>
            <meta-data android:name="android.app.qt_libs_resource_id" android:resource="@array/qt_libs"/>
            <meta-data android:name="android.app.bundled_libs_resource_id" android:resource="@array/bundled_libs"/>
            <!-- Deploy Qt libs as part of package -->
            <meta-data android:name="android.app.bundle_local_qt_libs" android:value="-- %%BUNDLE_LOCAL_QT_LIBS%% --"/>
            <meta-data android:name="android.app.bundled_in_lib_resource_id" android:resource="@array/bundled_in_lib"/>
            <meta-data android:name="android.app.bundled_in_assets_resource_id" android:resource="@array/bundled_in_assets"/>
            <!-- Run with local libs -->
            <meta-data android:name="android.app.use_local_qt_libs" android:value="-- %%USE_LOCAL_QT_LIBS%% --"/>
            <meta-data android:name="android.app.libs_prefix" android:value="/data/local/tmp/qt/"/>
            <meta-data android:name="android.app.load_local_libs" android:value="-- %%INSERT_LOCAL_LIBS%% --"/>
            <meta-data android:name="android.app.load_local_jars" android:value="-- %%INSERT_LOCAL_JARS%% --"/>
            <meta-data android:name="android.app.static_init_classes" android:value="-- %%INSERT_INIT_CLASSES%% --"/>
            <!-- Used to specify custom system library path to run with local system libs -->
            <!-- <meta-data android:name="android.app.system_libs_prefix" android:value="/system/lib/"/> -->
            <!--  Messages maps -->
            <meta-data android:value="@string/ministro_not_found_msg" android:name="android.app.ministro_not_found_msg"/>
            <meta-data android:value="@string/ministro_needed_msg" android:name="android.app.ministro_needed_msg"/>
            <meta-data android:value="@string/fatal_error_msg" android:name="android.app.fatal_error_msg"/>
            <meta-data android:value="@string/unsupported_android_version" android:name="android.app.unsupported_android_version"/>
            <!--  Messages maps -->

            <!-- Splash screen -->
            <!-- Orientation-specific (portrait/landscape) data is checked first. If not available for current orientation,
                 then android.app.splash_screen_drawable. For best results, use together with splash_screen_sticky and
                 use hideSplashScreen() with a fade-out animation from Qt Android Extras to hide the splash screen when you
                 are done populating your window with content. -->
            <!-- meta-data android:name="android.app.splash_screen_drawable_portrait" android:resource="@drawable/logo_portrait" / -->
            <!-- meta-data android:name="android.app.splash_screen_drawable_landscape" android:resource="@drawable/logo_landscape" / -->
            <!-- meta-data android:name="android.app.splash_screen_drawable" android:resource="@drawable/logo"/ -->
            <!-- meta-data android:name="android.app.splash_screen_sticky" android:value="true"/ -->
            <!-- Splash screen -->

            <!-- Background running -->
            <!-- Warning: changing this value to true may cause unexpected crashes if the
                          application still try to draw after
                          "applicationStateChanged(Qt::ApplicationSuspended)"
                          signal is sent! -->
            <meta-data android:name="android.app.background_running" android:value="false"/>
            <!-- Background running -->

            <!-- auto screen scale factor -->
            <meta-data android:name="android.app.auto_screen_scale_factor" android:value="false"/>
            <!-- auto screen scale factor -->

            <!-- extract android style -->
            <!-- available android:values :
                * default - In most cases this will be the same as "full", but it can also be something else if needed, e.g., for compatibility reasons
                * full - useful QWidget & Quick Controls 1 apps
                * minimal - useful for Quick Controls 2 apps, it is much faster than "full"
                * none - useful for apps that don't use any of the above Qt modules
                -->
            <meta-data android:name="android.app.extract_android_style" android:value="default"/>
            <!-- extract android style -->
    </activity>

    <!-- For adding service(s) please check: https://wiki.qt.io/AndroidServices -->

    </application>

    <uses-feature android:name="android.hardware.camera" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.autofocus" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.front" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.front.autofocus" android:required="true"/>

</manifest>

This is my full mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"


#include <camera/NdkCameraCaptureSession.h>
#include <camera/NdkCameraDevice.h>
#include <camera/NdkCameraError.h>
#include <camera/NdkCameraManager.h>
#include <camera/NdkCameraMetadata.h>
#include <camera/NdkCameraMetadataTags.h>
//#include <camera/NdkCameraWindowType.h>
#include <camera/NdkCaptureRequest.h>

//http://hxr99.blogspot.com/2011/12/opencv-examples-camera-capture.html
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/core.hpp>
#include "opencv2/opencv.hpp"
#include <opencv2/core/mat.hpp>
#include <opencv2/core/mat.inl.hpp>


#include <opencv2/core.hpp>
#include <opencv2/videoio.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>  // cv::Canny()
#include <iostream>

using namespace cv;
using std::cout; using std::cerr; using std::endl;

#include <jni.h>
#include <string>
#include <opencv2/core.hpp>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

#include <QtAndroidExtras/QtAndroid>
#include <QtAndroidExtras/QtAndroid>
#include <QtMultimedia/qmultimedia.h>


MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);


    auto  result = QtAndroid::checkPermission(QString("android.permission.CAMERA"));
        if(result == QtAndroid::PermissionResult::Denied){
            QtAndroid::PermissionResultMap resultHash = QtAndroid::requestPermissionsSync(QStringList({"android.permission.CAMERA"}));
            if(resultHash["android.permission.CAMERA"] == QtAndroid::PermissionResult::Denied)
            {

            }
        }

    //Mat frame;
       cout << "Opening camera..." << endl;
       VideoCapture capture(1099); // open the first camera
       if (!capture.isOpened())
       {
           ui->label->setText("Failed");
       }
       else
       {
           ui->label->setText("Working");
       }



}

MainWindow::~MainWindow()
{
    delete ui;
}

[dedetuga]

!!!...UPDATE...!!!

Some times the better is restart, this is what i did!

I restart from the bottom by configuring QT Creator
configure qt for android

Now it's building everything...really everything....all QT samples I piped in they work 80 or 90 percent in Android

PS: I'm targeting the samples not designed for Android, I'm targeting all samples without "Android" in the green tags.

For example the sample "Qt Quick Extras - Dashboard" with the kit QT 5.13.0 and it worked 100%

Next stop Rebuilding Opencv4Android....