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POAndroid NDK: Error while opening a File written to SD card using NDK + SDK android
 

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  1. POAndroid NDK: Error while opening a File written to SD card using NDK + SDK android
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    <p>I am new to android and iam trying to read a file from SD card using NDK and sending that read bytes to SDK and iam writing it to the SD card using SDK (for checking).. I could sucefully make a call from NDK - SDK with the bytes and i could write it to the SD card using SDK.. But i coulnt open the file written to the sd card..</p> <p>I am pasting my code </p> <p>Native C file </p> <pre><code>#include&lt;stdio.h&gt; #include&lt;string.h&gt; #include &lt;jni.h&gt; #include &lt;stdlib.h&gt; #include &lt;android/log.h&gt; #include "com_example_fileupload_NativeLib.h" #define LOG_TAG "testjni" #define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__) JavaVM *m_vm; jobject obj; jclass gFilePermInfoClass; jmethodID gFilePermInfoClsConstructor; jint JNI_OnLoad(JavaVM* vm, void* reserved) { JNIEnv* env; LOGI("JNI INIT"); return JNI_VERSION_1_6; } JNIEXPORT jint JNICALL Java_com_example_fileupload_NativeLib_loop (JNIEnv *env, jobject obj) { LOGI("JNI work !"); jbyteArray data; jbyteArray data_rem; jclass clazz = (*env)-&gt;FindClass(env,"com/example/fileupload/NativeLib"); if (clazz == 0) { LOGI("FindClass error"); return 2; } gFilePermInfoClass = (*env)-&gt;NewGlobalRef(env, clazz); LOGI("JNI before jmethodID"); jmethodID javamethod = (*env)-&gt;GetMethodID(env,gFilePermInfoClass, "callFromCPP", "([B)V"); gFilePermInfoClsConstructor = (*env)-&gt;NewGlobalRef(env, javamethod); if (javamethod == 0) { LOGI("GetMethodID error"); return 3; } LOGI("JNI before calling java "); LOGI(" before File "); FILE *fd = NULL; char buff[1*1024*1024]; char *h; unsigned int nread = 0; unsigned int nread_remaining = 0; int count=0; memset(buff, '\0', sizeof(buff)); fd = fopen("/sdcard/20MB.zip","r+"); fseek ( fd, 0 , SEEK_END ); int fileSize = ftell(fd); LOGI("****SUDARSHAN C SIZE %d",fileSize); if(NULL == fd) // Check for error { LOGI("\n File opening failed\n"); return 1; } nread = (1*1024*1024); // Hard code the number of elements to 50 if(nread_remaining = fileSize%nread) { count = fileSize/nread; LOGI("***** IN IF rem %d",nread_remaining); } else{ count = fileSize/nread; LOGI("***** IN ELSE COUNT %d",count); } data = (*env)-&gt;NewByteArray(env, nread); data_rem = (*env)-&gt;NewByteArray(env, nread_remaining); if(data == NULL){ LOGI("No memory could be allocated for buffer"); return -1; } LOGI("Before While in C "); int count_test=0; int i; for(i=count;i&gt;0;i--) //while(count_test) //while( fread(buff, 1, nread, fd) ) { fread(buff, 1, nread, fd); LOGI("INSIUDE WHILE SUDARSHAN **** %d",i); (*env)-&gt;SetByteArrayRegion(env, data, 0, nread, buff); (*env)-&gt;CallVoidMethod(env, obj, gFilePermInfoClsConstructor, data); } if(nread_remaining){ char buffer[nread_remaining]; fread(buffer, 1, nread_remaining, fd); (*env)-&gt;SetByteArrayRegion(env, data_rem, 0, nread_remaining, buffer); (*env)-&gt;CallVoidMethod(env, obj, gFilePermInfoClsConstructor, data_rem); } if(feof(fd)) { printf("\n Seems like end of file was reached\n"); } else if(ferror(fd)) { printf("\n Some errors on this stream occurred\n"); } // Reset the buffer with NULLs memset(buff, '\0', sizeof(buff)); return (10+11); } </code></pre> <p>NativeLib.java</p> <pre><code>package com.example.fileupload; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import android.os.Environment; public class NativeLib { public int count=0; File someFile = null; FileOutputStream fos = null; File sdDir = new File(Environment.getExternalStorageDirectory().getPath()); public NativeLib() throws FileNotFoundException{ someFile = new File(sdDir.getPath() +"/22MB.zip"); fos = new FileOutputStream(someFile); //fos.flush();fos.close(); } static { System.loadLibrary("com_example_fileupload_NativeLib"); } /** * Adds two integers, returning their sum */ public native int loop(); /** * Returns Hello World string * @throws IOException */ //public native String hello(); public void callFromCPP(byte[] buff) { count=count+buff.length; try { //count=count+buff.length; System.out.println("************ Sudarshan Inside callfromcpp try "+count+" "+buff.length); fos.write(buff); } catch (IOException e) { // TODO Auto-generated catch block System.out.println("************ Sudarshan Inside callfromcpp catch "+e.toString()); e.printStackTrace(); } // count=count+buff.length; //System.out.println("************ Sudarshan Inside callfromcpp 1 "+buff.toString()+" "+count); } </code></pre> <p>Iam calling the native fn. <strong>loop()</strong> from my <strong>MainActivity.java</strong> and the java fn. call from native is <strong>callFromCPP(byte[] buff)</strong> and here only iam writing the byte's to SD card (named <strong>22MB.zip</strong>) returned from native..</p> <p>PLZ help</p> <p>Reagards,</p> <p>Deepak</p>
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    1. USSudarshan
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      1. POAndroid NDK: Error while opening a File written to SD card using NDK + SDK android
      1. USSudarshan
      1. VTFavorite
    1. CO"i coulnt open the file written to the sd card.." what does that mean? Open how and what happens then?
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      1. POAndroid NDK: Error while opening a File written to SD card using NDK + SDK android
      1. USzapl
    2. COi had written a zip file to sdcard.. wen i tried to open that it showing "Bad Zip file cannot open the file"
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      1. POAndroid NDK: Error while opening a File written to SD card using NDK + SDK android
      1. USSudarshan
    3. COlook at your files with a hex editor and check filesizes and so on. Something is wrong, but I can't tell you what. But closing the `FileOutputStream` seems like a good idea since you may not write the end of the file otherwise.
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      1. POAndroid NDK: Error while opening a File written to SD card using NDK + SDK android
      1. USzapl
 

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