Android技术12：NDK模拟登陆

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical" >
 6     <EditText 
 7         android:id="@+id/et1"
 8         android:layout_width="fill_parent"
 9         android:layout_height="wrap_content"
10         android:hint="用户名"/>
11      <EditText 
12         android:id="@+id/et2"
13         android:layout_width="fill_parent"
14         android:layout_height="wrap_content"
15         android:hint="密码"/>
16      <Button
17         android:id="@+id/bt1"
18         android:layout_width="wrap_content"
19         android:layout_height="wrap_content"
20         android:hint="登录"/>
21 </LinearLayout>

 1 /* DO NOT EDIT THIS FILE - it is machine generated */
 2 #include <jni.h>
 3 /* Header for class com_forsta_login_MainActivity */
 4 
 5 #ifndef _Included_com_forsta_login_MainActivity
 6 #define _Included_com_forsta_login_MainActivity
 7 #ifdef __cplusplus
 8 extern "C" {
 9 #endif
10 /*
11  * Class:     com_forsta_login_MainActivity
12  * Method:    login
13  * Signature: (Ljava/lang/String;Ljava/lang/String;)I
14  */
15 JNIEXPORT jint JNICALL Java_com_forsta_login_MainActivity_login
16   (JNIEnv *, jobject, jstring, jstring);
17 
18 #ifdef __cplusplus
19 }
20 #endif
21 #endif

 1 #include <stdio.h>
 2 #include <jni.h>
 3 #include <malloc.h>
 4 #include <string.h>
 5 #include "com_forsta_login_MainActivity.h"
 6 
 7 /**
 8  * 返回值 char* 这个代表char数组的首地址
 9  *  Jstring2CStr 把java中的jstring的类型转化成一个c语言中的char 字符串
10  */
11 char*   Jstring2CStr(JNIEnv*   env,   jstring   jstr)
12 {
13      char*   rtn   =   NULL;
14      jclass   clsstring   =   (*env)->FindClass(env,"java/lang/String"); //String
15      jstring   strencode   =   (*env)->NewStringUTF(env,"GB2312");  // 得到一个java字符串 "GB2312"
16      jmethodID   mid   =   (*env)->GetMethodID(env,clsstring,   "getBytes",   "(Ljava/lang/String;)[B"); //[ String.getBytes("gb2312");
17      jbyteArray   barr=   (jbyteArray)(*env)->CallObjectMethod(env,jstr,mid,strencode); // String .getByte("GB2312");
18      jsize   alen   =   (*env)->GetArrayLength(env,barr); // byte数组的长度
19      jbyte*   ba   =   (*env)->GetByteArrayElements(env,barr,JNI_FALSE);
20      if(alen   >   0)
21      {
22       rtn   =   (char*)malloc(alen+1);         //"\0"
23       memcpy(rtn,ba,alen);
24       rtn[alen]=0;
25      }
26      (*env)->ReleaseByteArrayElements(env,barr,ba,0);  //
27      return rtn;
28 }
29 
30 //登录判断逻辑
31 int login(char*username,char*password)
32 {
33     char*user="forsta";
34     char*pwd="123456";
35     int i=0,j=0;
36     if(strcmp(user,username)!=0 ||strcmp(password,pwd)!=0){
37         return 404;
38     }
39     return 200;
40 }
41 
42 JNIEXPORT jint JNICALL Java_com_forsta_login_MainActivity_login
43   (JNIEnv *env, jobject obj, jstring username, jstring pwd){
44     char*name=Jstring2CStr(env,username);
45     char*password=Jstring2CStr(env,pwd);
46     return login(name,password);
47 
48 }

1 LOCAL_PATH := $(call my-dir)
2 include $(CLEAR_VARS)
3 LOCAL_MODULE    := login
4 LOCAL_SRC_FILES := login.c
5 include $(BUILD_SHARED_LIBRARY)

 1 bt.setOnClickListener(new OnClickListener() {
 2             
 3             @Override
 4             public void onClick(View v) {
 5                 String username=t1.getText().toString().trim();
 6                 String pwd=t2.getText().toString().trim();
 7                 int result =login(username,pwd);
 8                 if(result==200)
 9                 {
10                     Toast.makeText(getApplicationContext(), "登录成功，code=200", 1).show();
11                 }else{
12                     
13                     Toast.makeText(getApplicationContext(), "登录失败，code=404", 1).show();
14                 }
15                 
16             }
17         });