安卓开发——JNI——回调java中的方法

JNI开发中  

在C代码中回调java中的方法 

package com.example.jnitest2;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.view.View;public class HomeActivity extends Activity {private NativeProviefder nativeProviefder;static{System.loadLibrary("jnitest2");}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_home);nativeProviefder = new NativeProviefder(this);}//点击调用一个空参数的方法 public  void showStringOnclick(View view ){nativeProviefder.showStringNative();//showStringNative();}//点击调用一个相加的方法public  void addNumber(View view ){nativeProviefder.addNative();//add();}//点击调用一个打出字符串的方法 public  void printString(View view ){nativeProviefder.printStringNative();}//点击调用一个打出字符串的方法 public  void printStaticString(View view ){nativeProviefder.printStringStaticNative();}}

package com.example.jnitest2;import android.content.Context;import android.widget.Toast;public class NativeProviefder {static{System.loadLibrary("jnitest2");}Context context;public NativeProviefder(Context context) {this.context = context;}public NativeProviefder() {super();}public void showString(){String string = "这是一个空的构造C来调用来显示 ";System.out.println(string);Toast.makeText(context, "这是空的==="+string, 0).show();}public void adds(int a,int b){String string = "这是这是用来计算加法运算的方法 ，计算结果 是 ：  ";int sum = a+b;System.out.println(string+sum);Toast.makeText(context, "这是空的==="+sum, 0).show();}public void printStrings(String string ){String strings = "这是一个输出打印一个字条 串的  方法   输出 的字符串 为  ： ";System.out.println(strings);Toast.makeText(context, "printString==="+strings +"::"+string, 0).show();}public static void printStaticStrings(){String strings = "printStaticStrings： ";System.out.println(strings);}public native void  showStringNative();public native void addNative();public native void printStringNative();public native void printStringStaticNative() ;}

#include <jni.h>#include <stdio.h>#include <stdlib.h>//回调空参数的方法JNIEXPORT void JNICALL Java_com_example_jnitest2_NativeProviefder_showStringNative(JNIEnv * env , jobject obj){// (*FindClass)(JNIEnv*, const char*);jclass  claxx = (*env)->FindClass(env,"com/example/jnitest2/NativeProviefder");//jmethodID   (*GetMethodID)(JNIEnv*, jclass, const char*, const char*);jmethodID  method = (*env)->GetMethodID(env,claxx,"showString","()V");(*env)->CallVoidMethod(env,obj,method);}//回调带int参数的数组JNIEXPORT void JNICALL Java_com_example_jnitest2_NativeProviefder_addNative(JNIEnv * env , jobject obj){jclass claxx = (*env)->FindClass(env,"com/example/jnitest2/NativeProviefder");jmethodID  method = (*env)->GetMethodID(env,claxx,"adds","(II)V");(*env)->CallVoidMethod(env,obj,method,1,2);}//回调带String参数的方法JNIEXPORT void JNICALL Java_com_example_jnitest2_NativeProviefder_printStringNative(JNIEnv * env , jobject obj){//加载类的字节码jclass claxx = (*env)->FindClass(env,"com/example/jnitest2/NativeProviefder");jmethodID method= (*env)->GetMethodID(env,claxx,"printStrings","(Ljava/lang/String;)V");jstring charst = (*env)->NewStringUTF(env,"yhtjhfhy");(*env)->CallVoidMethod(env,obj,method,charst);}//回调静态方法JNIEXPORT void JNICALL Java_com_example_jnitest2_NativeProviefder_printStringStaticNative(JNIEnv * env , jobject obj){//加载类的字节码jclass claxx = (*env)->FindClass(env,"com/example/jnitest2/NativeProviefder");jmethodID method= (*env)->GetStaticMethodID(env,claxx,"printStaticStrings","()V");(*env)->CallVoidMethod(env,obj,method);}//调用其他类的方法//JNIEXPORT void JNICALL Java_com_example_jnitest2_NativeProviefder_printStringStaticNativess//(JNIEnv * env , jobject obj){////加载类的字节码//jclass claxx = (*env)->FindClass(env,"com/example/jnitest2/NativeProviefder");//jmethodID method= (*env)->GetStaticMethodID(env,claxx,"printStaticStrings","()V");////jobject     (*AllocObject)(JNIEnv*, jclass);//jobject mainobi = (*env)->AllocObject(env,"全类名");//(*env)->CallVoidMethod(env,mainobi,method);//}

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE    := jnitest2LOCAL_SRC_FILES := jnitest2.cinclude $(BUILD_SHARED_LIBRARY)

页面配制文件 

<LinearLayout 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:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:orientation="vertical"        tools:context=".HomeActivity" >    <Button        android:onClick="showStringOnclick"        android:id="@+id/bt_showstring"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="C中回调一个空的参数" />    <Button        android:onClick="addNumber"        android:id="@+id/bt_addnumber"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="C中回调相加的方法" />    <Button        android:onClick="printString"        android:id="@+id/bt_printstring"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="C中回调打印字符串" />    <Button        android:onClick="printStaticString"        android:id="@+id/bt_printstaticstring"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="C中回调打印静态方法 字符串" /></LinearLayout>