Android M写入SD卡-权限被拒绝 [英] Android M write to SD Card - Permission Denied

问题描述

我正在尝试将应用程序内部的文件复制到SD卡，但出现错误 eacces(权限被拒绝).操作系统为Android M，并且我允许运行时存储权限(已在应用程序信息中检查).我还在AndroidManifest.xml中设置了uses-permission

I'm trying to copy file from within my application to the SD card, but I get the error eacces (permission denied). The OS is Android M and I have allowed runtime Storage permissions (checked in app info). I have also set the uses-permission in AndroidManifest.xml

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

如果我复制到SD卡上不起作用

Doesn't work if I copy to SD card

Source: data/user/0/com.example.myapp/cache/SomeFile.txt
Destination: /storage/1032-2568/SomeFolder/
Error: java.io.FileNotFoundException: /storage/1032-2568/SomeFolder/SomeFile.txt: open failed: EACCES (Permission denied)

如果我复制到内部存储器，则可以使用

Works if I copy to internal storage

Source: data/user/0/com.example.myapp/cache/SomeFile.txt
Destination: /storage/emulated/0/SomeFolder/

将文件从源复制到目标的代码

Code to copy file from source to destination

/*
 * Below are the parameters I have tried
 *
 * inputPath - data/user/0/com.example.myapp/cache or data/user/0/com.example.myapp/cache/
 * inputFile - /SomeFile.txt or SomeFile.txt
 * outputPath - /storage/1032-2568/SomeFolder/ or /storage/1032-2568/SomeFolder
 */
public static void copyFile(String inputPath, String inputFile, String outputPath) {

    InputStream in = null;
    OutputStream out = null;
    try {

        //create output directory if it doesn't exist
        File dir = new File (outputPath);
        if (!dir.exists()) {
            dir.mkdirs();
        }

        in = new FileInputStream(inputPath + inputFile);
        out = new FileOutputStream(outputPath + inputFile);

        byte[] buffer = new byte[1024];
        int read;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
        in.close();


        // write the output file (You have now copied the file)
        out.flush();
        out.close();
    }
    catch (FileNotFoundException fnfe1) {
        /* I get the error here */
        Log.e("tag", fnfe1.getMessage());
    }
    catch (Exception e) {
        Log.e("tag", e.getMessage());
    }
}

ES File Explorer

我看到ES File Explorer也无法在Redmi设备上的SD卡上写入任何内容. 这是包含解决方案的视频.请按照我的设备上适用于ES Explorer的步骤进行操作.可以通过编程方式完成吗?

ES File Explorer

I saw that ES File Explorer also cannot write anything on the SD Card on Redmi devices. Here's a video with solution. Following the steps worked for ES Explorer on my device. Can this be done programmatically?

推荐答案

按照@CommonsWare的建议，我们必须使用android提供的新存储访问框架，并且必须获得用户的许可才能在您写入SD卡文件时使用说这已经写在文件管理器应用程序ES文件浏览器中.

As suggested by @CommonsWare here we have to use the new Storage Access Framework provided by android and will have to take permission from user to write SD card file as you said this is already written in the File Manager Application ES File Explorer.

以下是让用户选择"SD卡"的代码:

Here is the code for Letting the user choose the "SD card" :

startActivityForResult(new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE), requestCode);

看起来会像这样:

并在pickedDir中获取Document路径，并在copyFile块中进一步传递 并使用此路径写入文件:

And get the Document path in pickedDirand pass further in your copyFile block and use this path for writing the file :

public void onActivityResult(int requestCode, int resultCode, Intent resultData) {
    if (resultCode != RESULT_OK)
        return;
    else {
        Uri treeUri = resultData.getData();
        DocumentFile pickedDir = DocumentFile.fromTreeUri(this, treeUri);
        grantUriPermission(getPackageName(), treeUri, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        getContentResolver().takePersistableUriPermission(treeUri, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        copyFile(sdCard.toString(), "/File.txt", path + "/new", pickedDir);
    }
}


public void copyFile(String inputPath, String inputFile, String outputPath, DocumentFile pickedDir) {

    InputStream in = null;
    OutputStream out = null;
    try {

        //create output directory if it doesn't exist
        File dir = new File(outputPath);
        if (!dir.exists()) {
            dir.mkdirs();
        }

        in = new FileInputStream(inputPath + inputFile);
        //out = new FileOutputStream(outputPath + inputFile);

        DocumentFile file = pickedDir.createFile("//MIME type", outputPath);
        out = getContentResolver().openOutputStream(file.getUri());

        byte[] buffer = new byte[1024];
        int read;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
        in.close();


        // write the output file (You have now copied the file)
        out.flush();
        out.close();
    } catch (FileNotFoundException fnfe1) {
    /* I get the error here */
        Log.e("tag", fnfe1.getMessage());
    } catch (Exception e) {
        Log.e("tag", e.getMessage());
    }
}

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