AndroidNDK开发之“文件操作”

亦凉 2022-08-07 01:57 164阅读 0赞

其实和上层没什么关系，主要是通过C来完成文件的基本操作。不好意思大家，时间不够，不多说，贴上关键代码。

关键文件代码：

MainActivity.java

package com.scan.file;  
  
import android.app.Activity;  
import android.os.Bundle;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.widget.Button;  
import android.widget.Toast;  
  
public class MainActivity extends Activity \{  
  
    private static final String TAG = "File";  
    private Button doc = null;  
  
    /\*\* Called when the activity is first created. \*/  
    @Override  
    public void onCreate(Bundle savedInstanceState) \{  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
  
        initControls();  
    \}  
  
    /\*\*  
     \* 初始化控件  
     \*/  
    public void initControls() \{  
        doc = (Button) this.findViewById(R.id.btn\_do\_c);  
        doc.setOnClickListener(new MyButtonOnClickListener());  
    \}  
  
    /\*\*  
     \* 监听ButtonOnClick  
     \*  
     \* @author lxf  
     \*  
     \*/  
    class MyButtonOnClickListener implements OnClickListener \{  
  
        @Override  
        public void onClick(View v) \{  
            switch (v.getId()) \{  
  
            case R.id.btn\_do\_c:  
                String do\_c\_result = doCMethod();  
                displayMessage(do\_c\_result);  
                break;  
            \}  
  
        \}  
  
    \}  
  
    /\*  
     \* Toast显示消息  
     \*/  
    private void displayMessage(String msg) \{  
        Toast.makeText(this, msg, Toast.LENGTH\_SHORT).show();  
    \}  
  
    /\*\*  
     \* 测试方法  
     \*  
     \* @return  
     \*/  
    public native String sayHello();  
  
    /\*\*  
     \* 执行C底层的方法  
     \*  
     \* @return  
     \*/  
    public native String doCMethod();  
  
    /\*  
     \* 载人本地库文件  
     \*/  
    static \{  
        System.loadLibrary("AndroidJni");  
    \}  
\}

file.h

\#include <string.h>  
\#include <stdio.h>  
\#include "define.h"  
  
unsigned short File\_Open(FILE\_HANDLE\*\* FileHandle, char\* name, unsigned short flag,unsigned short mode);  
  
unsigned short File\_Close(FILE\_HANDLE\* FileHandle);  
  
unsigned short File\_GetSize(FILE\_HANDLE\* FileHandle, unsigned long\* FileSize);  
  
unsigned short File\_Read(FILE\_HANDLE\* FileHandle, char\* buf, unsigned long count,unsigned long\* ReadCount);  
  
unsigned short File\_Write(FILE\_HANDLE\* FileHandle, char\* buf, unsigned long count,unsigned long\* WriteCount);  
  
unsigned short File\_Seek(FILE\_HANDLE\* FileHandle, long offset, short origin,unsigned long\* SeekLen);  
  
unsigned short File\_Delete(char\* name);  
  
unsigned short File\_ISExist(char\* path);  
  
unsigned short File\_Create\_Dir(char\* dirName);  
  
unsigned short File\_Delete\_Dir(char\* dirName);

Android.mk

LOCAL\_PATH := $(call my-dir)  
  
include $(CLEAR\_VARS)  
  
LOCAL\_MODULE    := AndroidJni  
LOCAL\_SRC\_FILES := AndroidJni.c File.c SyncmlEngine.c  
  
LOCAL\_LDLIBS += -L$(SYSROOT)/usr/lib -llog  
  
include $(BUILD\_SHARED\_LIBRARY)

AndroidJni.c

\#include <string.h>  
\#include <jni.h>  
\#include <android/log.h>  
\#include "SyncmlEngine.h"  
  
//测试方法sayHello  
jstring Java\_com\_scan\_file\_MainActivity\_sayHello(JNIEnv\* env, jobject thiz) \{  
    //打印信息出来  
    \_\_android\_log\_print(ANDROID\_LOG\_INFO, "JNIMsg", "SayHello");  
    return (\*env)->NewStringUTF(env, "Hello from JNI ! sayHello");  
\}  
  
//执行C底层方法  
jstring Java\_com\_scan\_file\_MainActivity\_doCMethod(JNIEnv\* env, jobject thiz) \{  
    //打印信息出来  
    \_\_android\_log\_print(ANDROID\_LOG\_INFO, "JNIMsg", "doCMethod");  
  
    SyncmlStart();  
  
    return (\*env)->NewStringUTF(env, "Do C Method OK!");  
\}

file.c

\#include <stdio.h>  
\#include <string.h>  
\#include <sys/stat.h>  
\#include <dirent.h>  
\#include <android/log.h>  
\#include "File.h"  
  
/\*\*  
 \* File\_Open--打开文件  
 \* flag--读\\写\\读写\\追加  
 \* mode--如果没有，是否新建  
 \*/  
unsigned short File\_Open(FILE\_HANDLE\*\* FileHandle, char\* name,  
        unsigned short flag, unsigned short mode) \{  
  
    if (FileHandle == NULL) \{  
        return 100;  
    \}  
    if (name == NULL) \{  
        return 100;  
    \}  
    char type\[128\] = "";  
  
    if (flag == FO\_OREAD) \{  
        if (mode != FO\_CREATE) \{  
            strcpy(type, "r"); //只读，不建文件  
        \} else \{  
            strcpy(type, "r+");  
        \}  
    \} else if (flag == FO\_OWRITE) \{  
        if (mode != FO\_CREATE) \{  
            strcpy(type, "w"); //只写，不建文件  
        \} else \{  
            strcpy(type, "w+");  
        \}  
    \} else if (flag == FO\_RW) \{  
        if (mode != FO\_CREATE) \{  
            strcpy(type, "a");  
        \} else \{  
            strcpy(type, "a+");  
        \}  
    \} else if (flag == FO\_APPEND) \{  
        if (mode != FO\_CREATE) \{  
            strcpy(type, "a");  
        \} else \{  
            strcpy(type, "a+");  
        \}  
    \}  
  
    \*FileHandle = fopen(name, type);  
    return 0;  
\}  
  
/\*\*  
 \* File\_Close--关闭文件  
 \* 返回值  
 \* 0--关闭成功;否则失败  
 \*/  
unsigned short File\_Close(FILE\_HANDLE\* FileHandle) \{  
    if (FileHandle == NULL) \{  
        return 100;  
    \}  
    return fclose(FileHandle);  
\}  
  
/\*\*  
 \* File\_GetSize--得到文件长度  
 \* FileSize--返回文件长度  
 \*/  
unsigned short File\_GetSize(FILE\_HANDLE\* FileHandle, unsigned long\* FileSize) \{  
    if (FileHandle == NULL) \{  
        return 100;  
    \}  
    fseek(FileHandle, 0L, SEEK\_END);  
    \*FileSize = ftell(FileHandle);  
    return 0;  
\}  
  
/\*\*  
 \* File\_Read--读取文件到buf  
 \* count--读取的长度  
 \* ReadCount--返回已读取的长度  
 \*/  
unsigned short File\_Read(FILE\_HANDLE\* FileHandle, char\* buf,  
        unsigned long count, unsigned long\* ReadCount) \{  
    if (FileHandle == NULL) \{  
        return 100;  
    \}  
    \*ReadCount = fread(buf, 1, count, FileHandle);  
    \_\_android\_log\_print(ANDROID\_LOG\_INFO, "JNIMsg",  
            "File\_Read           ReadCount=%d", \*ReadCount);  
    return 0;  
\}  
  
/\*\*  
 \* File\_Write--从buf中写入文件  
 \* count--写入的长度  
 \* WriteCount--返回已写入的长度  
 \*/  
unsigned short File\_Write(FILE\_HANDLE\* FileHandle, char\* buf,  
        unsigned long count, unsigned long\* WriteCount) \{  
    if (FileHandle == NULL) \{  
        return 100;  
    \}  
    unsigned short write\_result = fwrite(buf, count, 1, FileHandle); // 返回值是成功写入的项目数  
    if(write\_result == 1) \{  
        \*WriteCount = write\_result \* count;  
    \}  
    return write\_result;  
\}  
  
/\*\*  
 \* File\_Seek--给文件偏移量  
 \* offset--偏移量  
 \* origin--偏移方向  
 \* SeekLen--返回已偏移的长度  
 \* 返回值0--成功,其他失败  
 \*/  
unsigned short File\_Seek(FILE\_HANDLE\* FileHandle, long offset, short origin,  
        unsigned long\* SeekLen) \{  
    unsigned short seek\_result = fseek(FileHandle, offset, origin);  
    if(seek\_result == 0) \{  
        \*SeekLen = offset;  
    \}  
    return seek\_result;  
\}  
  
/\*\*  
 \* File\_Delete--删除文件  
 \* 0--删除成功  -1--删除失败  
 \*/  
unsigned short File\_Delete(char\* name) \{  
    if (name == NULL) \{  
        return 100;  
    \}  
    return remove(name);  
\}  
  
/\*\*  
 \* File\_ISExist--判断文件是否存在  
 \* 0存在  -1不存在  
 \*/  
unsigned short File\_ISExist(char\* path) \{  
    if (path == NULL) \{  
        return 100;  
    \}  
    return access(path, 0);  
\}  
  
/\*\*  
 \* File\_Create\_Dir--创建文件目录  
 \* 返回0--成功  
 \*/  
unsigned short File\_Create\_Dir(char\* dirName) \{  
    if (dirName == NULL) \{  
        return 100;  
    \}  
    return mkdir(dirName, S\_IRWXU);  
\}  
  
/\*\*  
 \* File\_Delete\_Dir--删除文件目录  
 \*/  
unsigned short File\_Delete\_Dir(char\* dirName) \{  
    if (dirName == NULL) \{  
        return 100;  
    \}  
    DIR\* dp = NULL;  
    DIR\* dpin = NULL;  
    char \*pathname = (char\*) malloc(256);  
    memset(pathname, 0, 256);  
    struct dirent\* dirp;  
    dp = opendir(dirName);  
    if (dp == NULL) \{  
        \_\_android\_log\_print(ANDROID\_LOG\_INFO, "JNIMsg",  
                "File\_Delete\_Dir      your input directory is not exist!");  
        return 100;  
    \}  
    while ((dirp = readdir(dp)) != NULL) \{  
        if (strcmp(dirp->d\_name, "..") == 0 || strcmp(dirp->d\_name, ".") == 0)  
            continue;  
        strcpy(pathname, dirName);  
        strcat(pathname, "/");  
        strcat(pathname, dirp->d\_name);  
        dpin = opendir(pathname);  
        if (dpin != NULL) \{  
            closedir(dpin);  
            dpin = NULL;  
            File\_Delete\_Dir(pathname);  
        \} else \{  
            remove(pathname);  
        \}  
    \}  
    rmdir(dirName);  
    closedir(dp);  
    free(pathname);  
    pathname = NULL;  
    dirp = NULL;  
  
    return 0;  
\}

有看不懂的地方可以留言，一起探讨。

分类: [ Android][Android]

标签: [ android][android]

[Android]: http://www.cnblogs.com/luxiaofeng54/category/276200.html
[android]: http://www.cnblogs.com/luxiaofeng54/tag/android/