Error when Changing to targetSdkVersion 26 from targetSdkVersion 21

Question

latly I changed to targetSdkVersion 26 from targetSdkVersion 21. By doing so several issues arise.

I have written a class and run but gose to throw new RuntimeException(e)

The code is as follows

package com.xxxxxxxxxx.android.webapp.util;

import android.content.Context;
import android.telephony.TelephonyManager;

import com.xxxxxxxxxx.android.webapp.BuildConfig;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


public class Installation {
private static String sID = null;
private static final String INSTALLATION = "INSTALLATION";

public synchronized static String id(Context context) {
    if (sID == null) {
        File installation = new File(context.getFilesDir(), INSTALLATION);
        try {
            if (!installation.exists())
                writeInstallationFile(installation,context);
            sID = readInstallationFile(installation,context);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    return sID;
}

private static String readInstallationFile(File installation,Context context) throws IOException {
    RandomAccessFile f = new RandomAccessFile(installation, "r");
    byte[] bytes = new byte[(int) f.length()];
    f.readFully(bytes);
    f.close();
    return new String(bytes);
}

private static void writeInstallationFile(File installation,Context context) throws IOException {
    FileOutputStream out = new FileOutputStream(installation);
    String id = getUniqueID(context);   //UUID.randomUUID().toString();
    out.write(id.getBytes());
    out.close();
}

private static String getUniqueID(Context context){
    String android_id = android.provider.Settings.Secure.getString(
            context.getContentResolver(), android.provider.Settings.Secure.ANDROID_ID);

    String eid = null;
    try {
        eid = Encryptor.encrypt("gignoGawaAppli", android_id );

        if (BuildConfig.uidEncryptionMd5) {
            eid = md5(eid);
        }

    }catch (Exception e){};
    return eid;
}

public static String md5(String s) {
    try {
        // Create MD5 Hash
        MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
        digest.update(s.getBytes());
        byte messageDigest[] = digest.digest();

        // Create Hex String
        StringBuffer hexString = new StringBuffer();
        for (int i = 0; i < messageDigest.length; i++) {
            if ((0xff & messageDigest[i]) < 0x10) {
                hexString.append("0" + Integer.toHexString((0xFF & messageDigest[i])));
            } else {
                hexString.append(Integer.toHexString(0xFF & messageDigest[i]));
            }
        }
        return hexString.toString();

    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    return "";
}

}

appeard on the console like this

Caused by: java.lang.RuntimeException: java.lang.NullPointerException: Attempt to invoke virtual method byte[] java.lang.String.getBytes() on a null object reference

cant get ANDROID_ID

when my project targetSdkVersion's 21 everthing is ok.

Please help thank you very much.

Try to check if(f !=null) inside readInstallationFile() function before byte[] bytes = new byte[(int) f.length()]; — Ankita, Aug 07 '18 at 06:49
Do you ask for runtime permissions? You're trying to read/write some file to internal storage. Targeting Android 21 doesn't require run-time permissions. — Dmitriy Mitiai, Aug 07 '18 at 06:51
- For targetVersion above 23, you need to add runtime permission check. https://developer.android.com/training/permissions/requesting#java — shizhen, Aug 07 '18 at 06:58

score 0 · Answer 1 · answered Aug 07 '18 at 07:36

0

May be the issue is you don't provide run time permissions.Here is the tutorial

answered Aug 07 '18 at 07:36

Umer Farooq

168
1
12

thank you maybe i need to check run time permissions ill check and i report – iwahei0813 Aug 07 '18 at 09:17
could i ask one question? i understood i need to provide run time permissions but which permissions do i need provide WRITE_EXTERNAL_STORAGE or 　READ_EXTERNAL_STORAGE and then get android_id? thank you very much. – iwahei0813 Aug 09 '18 at 08:29
In your case you need to provide both. – Umer Farooq Aug 09 '18 at 10:35
Thank you very much for helping i will . – iwahei0813 Aug 10 '18 at 07:39

score 0 · Answer 2 · answered Aug 07 '18 at 07:54

「Caused by: java.lang.RuntimeException: java.lang.NullPointerException: Attempt to invoke virtual method 'byte[] java.lang.String.getBytes()' on a null object reference」

This is because below code

String id = getUniqueID(context);   //UUID.randomUUID().toString();

returns a null pointer, which means method getUniqueID is not executed correctly. You need to debug this method to get more details.

Error when Changing to targetSdkVersion 26 from targetSdkVersion 21

2 Answers2