Android JNI開發系列(五)Java與JNI數據類型 原

具體的每一個字符的對應關係如下

字符	JAVA類型	C類型
V	void	void
Z	jboolean	boolean
I	jint	int
J	jlong	long
D	jdouble	double
F	jfloat	float
B	jbyte	byte
C	jchar	char
S	jshort	short
[I	jintArray	int[]
[F	jfloatArray	float[]
[B	jbyteArray	byte[]
[C	jcharArray	char[]
[S	jshortArray	short[]
[D	jdoubleArray	double[]
[J	jlongArray	long[]
[Z	jbooleanArray	boolean[]

• Code

public native int add(int a, int b);

public native int sub(int a, int b);

public native double mulit(double a, double b);

public native long divi(long a, long b);

public native char getChar(char a);

public native byte sqrt(byte a);

public native float power(float a);

public native boolean isBoolean(boolean a);

//
// Created by Peng Cai on 2018/9/29.
//
#include <jni.h>
#include <android/log.h>
#include <math.h>

extern "C"  // C 編譯器編譯我的代碼

JNIEXPORT jint JNICALL
Java_org_professor_jni_MainActivity_sub(JNIEnv *env, jobject instance, jint a, jint b) {
    return a - b;
}

JNIEXPORT jdouble JNICALL
Java_org_professor_jni_MainActivity_mulit(JNIEnv *env, jobject instance, jdouble a, jdouble b) {

    return a * b;
}

JNIEXPORT jlong JNICALL
Java_org_professor_jni_MainActivity_divi(JNIEnv *env, jobject instance, jlong a, jlong b) {
    return a / b;
}

JNIEXPORT jchar JNICALL
Java_org_professor_jni_MainActivity_getChar(JNIEnv *env, jobject instance, jchar a) {
    return (jchar) (a + 3);
}

JNIEXPORT jbyte JNICALL
Java_org_professor_jni_MainActivity_sqrt(JNIEnv *env, jobject instance, jbyte a) {

    return (jbyte) sqrt(a);

}

JNIEXPORT jboolean JNICALL
Java_org_professor_jni_MainActivity_isBoolean(JNIEnv *env, jobject instance, jboolean a) {
    return a;
}

JNIEXPORT jfloat JNICALL
Java_org_professor_jni_MainActivity_power(JNIEnv *env, jobject instance, jfloat a) {
    return a * a;
}