Question

写入内部文件（files-folder）时遇到问题。在这里，我试图将我的日志备份到文件夹中的文件。这是我的代码。

package com.rss.feedster.rss_feedster.utility;

import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Environment;
import android.support.v4.content.FileProvider;
import android.util.Log;

import com.rss.feedster.rss_feedster.R;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class LogBackup {

    private static LogBackup log = null;
    private static FileOutputStream fos = null;
    private static Date dateTimeStamp;
    private static final String TAG = Constants.TAG+" : "+LogBackup.class.getSimpleName();

    private LogBackup(){
        dateTimeStamp = new Date();
    }

    private static String getDateTime(Date date) {
        SimpleDateFormat dateFormat = new SimpleDateFormat(
                "dd-MMM-yyyy hh:mm:ss", Locale.getDefault());
        return dateFormat.format(date);
    }

    public static LogBackup getLogBackup(FileOutputStream fos){
        if(log==null)
            log = new LogBackup();

        log.fos = fos;
        return log;
    }

    public static void writeLog(String msg) {
        if(fos!=null) {
            try {
                fos.write((getDateTime(dateTimeStamp)+"  "+msg+"\n").getBytes());
                fos.flush();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        } else {
            Log.e(TAG, "fos = null");
        }
    }

}

这里fos是使用openFileOutput方法获得的。

我收到以下错误

java.io.IOException: write failed: EBADF (Bad file number)
    at libcore.io.IoBridge.write(IoBridge.java:502)
    at java.io.FileOutputStream.write(FileOutputStream.java:186)
    at java.io.OutputStream.write(OutputStream.java:82)
    at **com.rss.feedster.rss_feedster.utility.LogBackup.writeLog(LogBackup.java:47)**
    at com.rss.feedster.rss_feedster.sync.FeedsterSync$2.onDataChange(FeedsterSync.java:107)
    at com.google.firebase.database.zzp.onDataChange(Unknown Source)
    at com.google.android.gms.internal.zzegf.zza(Unknown Source)
    at com.google.android.gms.internal.zzeia.zzbyc(Unknown Source)
    at com.google.android.gms.internal.zzeig.run(Unknown Source)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5254)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: android.system.ErrnoException: write failed: EBADF (Bad file number)
    at libcore.io.Posix.writeBytes(Native Method)
    at libcore.io.Posix.write(Posix.java:258)
    at libcore.io.BlockGuardOs.write(BlockGuardOs.java:313)
    at libcore.io.IoBridge.write(IoBridge.java:497)
    ... 16 more

我还设置了读取和写入权限，如下所示

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

有人可以指出我的代码有什么问题吗？

提前致谢！

以下是使用的代码，我称之为LogBack代码

FileOutputStream fos;
String logMsg;
try {
   fos = getActivity().openFileOutput(Constants.BACKUP_LOG, Context.MODE_APPEND);
 } catch (FileNotFoundException e) {
  e.printStackTrace();
}

下面的代码行是在catch块内部，我在哪里编写任何日志语句..

logMsg = "Error in FetchRssItemsTask : \n" + e.getStackTrace();
Log.e(TAG, logMsg);
LogBackup.getLogBackup(fos).writeLog(TAG+" "+logMsg);

java.io.IOException：写入失败：EBADF（错误的文件号）

0 个答案: