Android ndk 入门4 - C++实现

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新建工程NDKTest3，新建活动MainActivity

新建MyNDK.java:

package com.zj.ndktest3;/*** Created by root on 15-11-26.*/
public class MyNDK {static {System.loadLibrary("hello-jni-c++");}public static native String hello();
}

修改activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"android:paddingBottom="@dimen/activity_vertical_margin"tools:context="com.zj.ndktest3.MainActivity"><TextViewandroid:id="@+id/text_view"android:layout_width="match_parent"android:layout_height="wrap_content"/></RelativeLayout>

修改MainActivity.java:

package com.zj.ndktest3;import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.widget.TextView;public class MainActivity extends Activity {private TextView mTextView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);mTextView = (TextView)findViewById(R.id.text_view);mTextView.setText(MyNDK.hello());}
}

修改local.propeties，加入：

ndk.dir=/opt/android-ndk-r10e

修改gradle.properties，加入：

android.useDeprecatedNdk=true

修改app/build.gradle，加入：

android {defaultBuild {ndk {moduleName "hello-jni-c++"stl "stlport_shared"ldLibs "log"}}
}

点击MyNDK.java，右键->External Tools->javah，生成com_zj_ndktest3_MyNDK.h:

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_zj_ndktest3_MyNDK */#ifndef _Included_com_zj_ndktest3_MyNDK
#define _Included_com_zj_ndktest3_MyNDK
#ifdef __cplusplus
extern "C" {
#endif
/** Class:     com_zj_ndktest3_MyNDK* Method:    hello* Signature: ()Ljava/lang/String;*/
JNIEXPORT jstring JNICALL Java_com_zj_ndktest3_MyNDK_hello(JNIEnv *, jclass);#ifdef __cplusplus
}
#endif
#endif

新建main.cpp:

#include <jni.h>
#include <iostream>
#include <string.h>
#include "com_zj_ndktest3_MyNDK.h"
#include "MyLog.h"using namespace std;JNIEXPORT jstring JNICALL Java_com_zj_ndktest3_MyNDK_hello(JNIEnv *env, jclass cla) {LOGI("function begins");string ret;LOGI("ok");char s[] = "Golden Global   View,disk * desk";const char *d = " ,*";LOGI("next step is define char *p=NULL");char *p=NULL;LOGI("every thing is ok");p = strtok(s,d);int i=0;LOGI("previous step is ok");while(p){ret += p;ret += " ";p=strtok(NULL,d);}return env->NewStringUTF(ret.c_str());//return env->NewStringUTF("hello jni");
}

新建MyLog.h:

#ifndef _MYLOG_H_
#define _MYLOG_H_#include <android/log.h>#define TAG "test"#define LOGV(...) __android_log_print(ANDROID_LOG_VERBOSE, TAG, __VA_ARGS__)
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, TAG, __VA_ARGS__)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN, TAG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)#endif

新建jni/Android.mk:

LOCAL_PATH := ${call my-dir}
include $(CLEAR_VARS)
LOCAL_MODULE := hello-jni-c++
LOCAL_SRC_FILES := main.cpp
include ${BUILD_SHARED_LIBRARY}

运行：

##################################################################

网上找到两种实现C++的方法：

1.在Application.mk上加入：

APP_STL := stlport_shared

2.在app/build.gradle上加入:

android {defaultConfig {ndk {stl "stlport_shared"}}
}

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