无法在 android studio 中解析符号 com.googlecode.javacv.cpp.opencv_contrib.FaceRecognizer

Question

So I have a project to create an face recognition app. In this project I tried to import :

import com.googlecode.javacv.cpp.opencv_contrib.FaceRecognizer;
import com.googlecode.javacv.cpp.opencv_core.IplImage;
import com.googlecode.javacv.cpp.opencv_core.MatVector;
import com.googlecode.javacv.cpp.opencv_imgproc;

But gradle cannot find the symbol for it. I already import the java module from OpenCV library, but still cannot resolve it. Please help me.Thx

Here is the code for gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.3"
    defaultConfig {
        applicationId "example.com.facerecognation"
        minSdkVersion 21
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets { main { jni.srcDirs = ['src/main/jni', 'src/main/jniLibs/'] } }
}

dependencies {
    implementation project(':openCVLibrary2410')
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    implementation 'com.github.bumptech.glide:glide:4.3.1'
    implementation 'com.github.markushi:circlebutton:1.1'
    implementation "androidx.cardview:cardview:1.0.0"
}

Answer 1

import static is for Methods.

Methods need to be in a class and classes need to be inside a package.

For example, you could have the class MyClass in the package com.example .

You can import this class using import com.example.MyClass .

If you want to statically import a method(eg myMethod ) from this class, you'll need to write import static com.example.MyClass.myMethod

If you can do

import com.googlecode.javacv.cpp.opencv_core.MatVector;

that means that com.googlecode.javacv.cpp.opencv_core is a package.

Methods/constants need to be in a class.

Therefore, com.googlecode.javacv.cpp.opencv_core.IPL_DEPTH_8U cannot be imported statically.