Android calls logcat and androidlogcat in C code

Android calls logcat and androidlogcat in C code

This article adds the function of calling logcat in C code to "passing an array of int type to C in Android java ".

Add the following content to the Android. mk file:

LOCAL_LDLIBS + =-llog

Add the following content to the C code:

#include <android/log.h>#define LOG_TAG "System.out"#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)

Define C macro definition alias # define LOG_TAG "System. out" to "System. out" alias LOG_TAG

# Define LOGI (...) _ android_log_print (ANDROID_LOG_INFO, LOG_TAG, _ VA_ARGS __)
The alias for the _ android_log_print function is written to the first two parameters, the first parameter priority, and the second parameter TAG _ VA_ARGS _ variable parameter.
LOGI (...) is used in the same way as printf () when called.

 JNICALL Java_com_wuyudong_javapassdata_JNI_arrElementsIncrease(        JNIEnv * env, jobject clazz, jintArray jArray){      jsize len = (*env)->GetArrayLength(env, jArray);      LOGD("length = %d", len);     // jboolean iscopy;      int* arrayPointer = (*env)->GetIntArrayElements(env, jArray, NULL);      int i;      for(i = 0; i < len; i++){          *(arrayPointer + i) += 10;      }      return jArray; }

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