Qt 和 Android Gallery - 使用 QAndroidJniObject 的 MediaStore

Posted 2023-02-15

【中文标题】Qt 和 Android Gallery - 使用 QAndroidJniObject 的 MediaStore

【英文标题】：Qt and Android Gallery - MediaStore using QAndroidJniObject

【发布时间】：2015-12-08 18:35:50

【问题描述】：

我正在编写一个需要从 android Gallery 获取图像路径的代码。该代码是使用QAndroidJniObject 编写的，以在Qt 中编写等效的java 代码

我的问题是我没有弄清楚如何让Android MediaStore columns 返回图像路径。我尝试了几种方法都没有成功：

QAndroidJniObject dadosAndroid = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore$MediaColumns", "DATA", "Ljava/lang/String;")
QAndroidJniObject dadosAndroid = QAndroidJniObject::fromString("MediaColumns.DATA")
QAndroidJniObject dadosAndroid = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore", "DATA", "Ljava/lang/String;")
QAndroidJniObject dadosAndroid = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore.Images.Media", "EXTERNAL_CONTENT_URI", "Landroid/net/Uri;")
QAndroidJniObject dadosAndroid = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore.Images.ImageColumns", "BUCKET_DISPLAY_NAME", "Landroid/net/Uri;")

我该怎么做？我的完整代码如下。

void imagePickerAndroid::handleActivityResult(int receiverRequestCode, int resultCode, const QAndroidJniObject &data)

    qDebug() << "Trabalha com os dados";

    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;");

        QAndroidJniObject dadosAndroid = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore", "DATA", "Ljava/lang/String;");

        QAndroidJniObject contentResolver = QtAndroid::androidActivity().callObjectMethod("getContentResolver", "()Landroid/content/ContentResolver;");

        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>(), 0, 0, 0, 0);

        cursor.callMethod<jboolean>("moveToFirst", "()Z");

        jint columnIndex = cursor.callMethod<jint>("getColumnIndexOrThrow", "(Ljava/lang/String;)I", dadosAndroid.object<jstring>());
        //columnIndex returns 0

        QAndroidJniObject result = cursor.callObjectMethod("getString", "(I)Ljava/lang/String;", columnIndex);

    
    else
    
        qDebug() << "Caminho errado";
    

【参考方案1】：

回答我自己的问题。

这是handleActivityResult 的代码，用于使用用Qt 编写的java 等效代码从android gallery 获取完整的image path：

void imagePickerAndroid::handleActivityResult(int receiverRequestCode, int resultCode, const QAndroidJniObject &data)

    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;");
        QAndroidJniObject dadosAndroid = QAndroidJniObject::getStaticObjectField("android/provider/MediaStore$MediaColumns", "DATA", "Ljava/lang/String;");
        QAndroidJniEnvironment env;
        jobjectArray projecao = (jobjectArray)env->NewObjectArray(1, env->FindClass("java/lang/String"), NULL);
        jobject projacaoDadosAndroid = env->NewStringUTF(dadosAndroid.toString().toStdString().c_str());
        env->SetObjectArrayElement(projecao, 0, projacaoDadosAndroid);
        QAndroidJniObject contentResolver = QtAndroid::androidActivity().callObjectMethod("getContentResolver", "()Landroid/content/ContentResolver;");
        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>(), projecao, NULL, NULL, NULL);
        jint columnIndex = cursor.callMethod<jint>("getColumnIndex", "(Ljava/lang/String;)I", dadosAndroid.object<jstring>());
        cursor.callMethod<jboolean>("moveToFirst", "()Z");
        QAndroidJniObject resultado = cursor.callObjectMethod("getString", "(I)Ljava/lang/String;", columnIndex);
        QString imagemCaminho = "file://" + resultado.toString();
        emit imagemCaminhoSignal(imagemCaminho);
    
    else
    
        qDebug() << "Caminho errado";