Android进阶NDKAndroid进阶之旅

Point.java

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package com.darren.ndk.day13;

import java.io.PrintWriter;

public class Point {
	private int x;
	private int y;
	
	public Point(int x,int y){
		this.x = x;
		this.y = y;
	}
	
	public int getX() {
		return x;
	}
	
	public void setX(int x) {
		this.x = x;
	}
	
	public void setY(int y) {
		this.y = y;
	}
	
	public int getY() {
		return y;
	}
}

Simple1.java

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package com.darren.ndk.day13;

import java.util.UUID;

public class Simple1 {

	public static void main(String[] args) {
		// callStaticMethod();
		
		Point point = createPoint();
		
		System.out.println("point: x = "+point.getX()+" , y = "+point.getY());
		
		// android 用反射 ，jni 设置属性值，反射的原理？
	}

	private native static Point createPoint();

	private native static void callStaticMethod();

	// 小的思考：静态获取 uuid 的方法，然后再 c 调用这个方法获取uuid
	public static String getUUID() {
		return UUID.randomUUID().toString();
	}
	
	public static Point test(int x,float y){
		return null;
	}
	
	static{
		System.load("C:/Users/hcDarren/Desktop/android/NDK/NDK_Day13/x64/Debug/NDK_Day13.dll");
	}
}

com_darren_ndk_day13_Simple1.h

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/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_darren_ndk_day13_Simple1 */

#ifndef _Included_com_darren_ndk_day13_Simple1
#define _Included_com_darren_ndk_day13_Simple1
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_darren_ndk_day13_Simple1
 * Method:    callStaticMethod
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_com_darren_ndk_day13_Simple1_callStaticMethod
  (JNIEnv *, jclass);

#ifdef __cplusplus
}
#endif
#endif

Simple.c

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#include "com_darren_ndk_day13_Simple1.h"


JNIEXPORT jobject JNICALL Java_com_darren_ndk_day13_Simple1_createPoint
(JNIEnv *env, jclass jclz){
	// jclz -> Simple1

	// 获取 Point 的 class ,name = "全类名"
	jclass point_clz = (*env)->FindClass(env,"com/darren/ndk/day13/Point");
	// 构建 java 层的 Point 对象，构造函数的id , 构造方法（百度） <init>
	jmethodID j_mid = (*env)->GetMethodID(env,point_clz,"<init>","(II)V");

	jobject point = (*env)->NewObject(env, point_clz, j_mid,11,22);

	// 练习一下 y 重新付个值 ？调用 set 方法
	j_mid = (*env)->GetMethodID(env, point_clz,"setY","(I)V");
	/* va_list 集合
	void (JNICALL *CallVoidMethodV)
		(JNIEnv *env, jobject obj, jmethodID methodID, va_list args);
	// jvalue
	void (JNICALL *CallVoidMethodA)
		(JNIEnv *env, jobject obj, jmethodID methodID, const jvalue * args);
	*/

	(*env)->CallVoidMethod(env, point,j_mid,33);

	// 作业：直接给属性赋值

	return point;
}