android - 使用 __android_log_print 打印 Opencv Mat、Android NDK 的内容

Question

我有以下代码，我想用它来将 trainingLables Mat 的内容打印到 android 控制台:

#include <android/log.h>

JNIEXPORT jintArray JNICALL  Java_com_example_user_activity_MainActivity_generateAssets(JNIEnv* env, jobject thiz, jobject assetManager) {

    .....
    .....

    Mat_<int> trainingLabels(1,10);
    trainingLabels << 0, 0, 0, 1, 1, 1, 0, 1, 1, 1;

    __android_log_print(ANDROID_LOG_ERROR, "TESTING", "%d %d", trainingLabels.???????);

    ......
    ......


}

我有两个问题:

1) 我用什么方法从 trainingLabels 打印一行数据？ (我在代码中用什么代替问号？)

2) 如何在 Android LogCat 中搜索来自 __android_log_print 的内容？

Answer 1

你可以简单地预先用你的数据准备一个字符串

char matRow[100] = ""; // You can calculate how much memory u need, but for debug prints just put a big enough number

Mat_<int> trainingLabels(1,10);
trainingLabels << 0, 0, 0, 1, 1, 1, 0, 1, 1, 1;

for (int i = 0; i < 10; i++) {
    sprintf(matRow + strlen(matRow), "%d ", trainingLabels.at<int>(i)); // You can use data from row you need by accessing trainingLabels.row(...).data
}

android_log_print(ANDROID_LOG_ERROR, "SEARCH FOR THIS TAG", "%s", matRow);

然后在您的 logcat 中查找在我的示例中为“SEARCH FOR THIS TAG”的标签

至于您关于它如何存储在 Mat 对象中的其他问题 - 因为您使用 int 类型创建了 Mat - Mat.data 是 int 数组，您可以通过类似的东西轻松地看到它:

char matRow[100] = ""; // You can calculate how much memory u need, but for debug prints just put a big enough number

Mat_<int> trainingLabels(1,10);
trainingLabels << 0, 0, 0, 1, 1, 1, 0, 1, 1, 1;

int * data = (int*)trainingLabels.data;

for (int i = 0; i < 10; i++) {
    sprintf(matRow + strlen(matRow), "%d ", data[i]); // You can use data from row you need by accessing trainingLabels.row(...).data
}
android_log_print(ANDROID_LOG_ERROR, "SEARCH FOR THIS TAG", "%s", matRow);