Android：为啥会出现这个错误？

Posted 2023-04-17

【中文标题】Android：为啥会出现这个错误？

【英文标题】：Android: Why am i getting this error?Android：为什么会出现这个错误？

【发布时间】：2015-07-01 23:11:27

【问题描述】：

我正在尝试将位图添加到我的目录中。它保存了图像，但我收到了蓝色字样的奇怪错误。

ample.myapplication W/System.err﹕ java.io.FileNotFoundException: /CameraApp: open failed: EROFS (Read-only file system)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at libcore.io.IoBridge.open(IoBridge.java:409)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.io.FileOutputStream.<init>(FileOutputStream.java:88)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.io.FileOutputStream.<init>(FileOutputStream.java:128)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.io.FileOutputStream.<init>(FileOutputStream.java:117)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at com.example.myapplication.MainActivity.save_btn(MainActivity.java:119)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.view.View$1.onClick(View.java:3825)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.view.View.performClick(View.java:4445)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.view.View$PerformClick.run(View.java:18446)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:733)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.os.Looper.loop(Looper.java:136)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5146)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:732)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ Caused by: libcore.io.ErrnoException: open failed: EROFS (Read-only file system)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at libcore.io.Posix.open(Native Method)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ at libcore.io.IoBridge.open(IoBridge.java:393)
04-23 17:07:26.259  12120-12120/com.example.myapplication W/System.err﹕ ... 18 more

这是它用来保存位图的代码。当点击 save_btn 按钮时，它会运行该代码。

 public void save_btn(View v) 
       FileOutputStream out = null;
        try 
            out = new FileOutputStream(filename);
            image.compress(Bitmap.CompressFormat.PNG, 100, out);
         catch (Exception e) 
            e.printStackTrace();
         finally 
            try 
                if (out != null) 
                    out.close();
                
             catch (IOException e) 
                e.printStackTrace();

            

            AlertDialog alertDialog = new AlertDialog.Builder(this).create();
            alertDialog.setTitle("Saved");
            alertDialog.setButton("OK", new DialogInterface.OnClickListener() 
                public void onClick(DialogInterface dialog, int which) 

                
            );
            alertDialog.show();
        
    

相机意图

public void capture_btn(View v) 
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        File file = new File(Environment.getExternalStorageDirectory() + File.separator + "image.jpg");
        takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
        startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
    

【问题讨论】：

请检查您是否在清单中添加了 。

重新安装它..并确保此位图包含目录未在任何其他文件资源管理器上打开。即最好关闭所有应用程序并重新安装。

是的，我的清单确实有这个权限。

我试过重新安装，还是一样的错误

@smither123 将清单添加到您的问题中。

【参考方案1】：

尝试使用以下 sn-p 代码：

public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;

/** Create a File for saving an image or video */
public static File getOutputMediaFile(int type)
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this.

    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES), "App");
    // This locat ion works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists())
        if (! mediaStorageDir.mkdirs())
            android.util.Log.d("log", "failed to create directory");
            return null;
        
    

    // Create a media file name
    File mediaFile;
    if (type == MEDIA_TYPE_IMAGE)
        mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                "IMG_"+ "IdelityPhotoTemp" + ".png");
     else if(type == MEDIA_TYPE_VIDEO) 
        mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                "VID_"+ "idelityVideoTemp" + ".mp4");
     else 
        return null;
    

    return mediaFile;

然后：

try 
    File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
    if (pictureFile == null)
        android.util.Log.d("log", "Error creating media file, check storage permissions");
        return null;
    

    FileOutputStream fos = new FileOutputStream(pictureFile);
    fos.write(photoData);
    fos.close();

 catch (FileNotFoundException e) 
    android.util.Log.d("log", "File not found: " + e.getMessage());
 catch (IOException e) 
    android.util.Log.d("log", "Error accessing file: " + e.getMessage());

如果您使用的是来自相机的 Intent，您可以使用下一个 link 中的方法

【讨论】：

谢谢，由于这两个错误，一切看起来都很好。 i.imgur.com/t7mRvoB.png 抱歉，我对 Java 很陌生。有人可以帮我解决吗？

当然！只需要将它包装到 try catch 中，我会将它添加到答案中

谢谢！所有的错误都消失了。我在“fos.write(photoData);”里面放了什么?

photoData 是一个字节[]，其中包含您的位图。

它会创建文件名，但是当我打开图像时，它会显示“找不到媒体”。