Android Write to File Permission Denied

Question

I'm trying to write to a file in android but i keep getting this error:

java.io.FileNotFoundException: /storage/emulated/0/Notes/TestFile.txt (Permission denied)

Searching this site gives a simple resolution to this problem, which is to add WRITE_EXTERNAL_STORAGE to the app manifest file, but this isnt working for me. I keep getting the same error.

Code to write to file:

try {
                File root = new File(Environment.getExternalStorageDirectory(), "Notes");
                if (!root.exists()) {
                    root.mkdirs();
                }
                File gpxfile = new File(root, "TestFile.txt");
                FileWriter writer = new FileWriter(gpxfile);
                writer.append("Hello World");
                writer.flush();
                writer.close();
                Toast.makeText(getApplicationContext(), "Saved", Toast.LENGTH_SHORT).show();
            } catch (IOException e) {
                e.printStackTrace();
            }

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myapplication">

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

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>
</manifest>

score 1 · Answer 1 · answered Apr 29 '19 at 17:39

1

You have mentioned permission in AndroidManifest.xml but not yet granted it from the user. You need to grant WRITE_EXTERNAL_STORAGE permission through the user in your Android activity.

if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
        }

Next time you launch the Activity, grant it the permission and then you can access external storage. Mind that this will give only write access, not read access.

answered Apr 29 '19 at 17:39

Sushant Somani

1,450
3
13
31

Im getting an error with this code: "error: incompatible type. cannot be converted to Context" and "error: incompatible type. cannot be converted to Activity". Any idea what i can replace "this" with to make it work in my onClick function? I found this thread which is similar, but doesnt fix my issue. https://stackoverflow.com/questions/27704006/error-using-onclicklistener-intent – Some_Dude Apr 29 '19 at 18:05
1

Yes you can replace 'this' with getContext() or getApplicationContext() – Sushant Somani Apr 30 '19 at 00:47

score 1 · Answer 2 · answered Apr 29 '19 at 17:40

1

If your targeted sdk is equal or greater to mashmallow version you must ask for runtime permissions

You can check it here

https://developer.android.com/training/permissions/requesting

answered Apr 29 '19 at 17:40

score 0 · Accepted Answer · answered Apr 29 '19 at 18:13

Fixed it, i had to request permission using this code just above where i wrote to the file:

            ActivityCompat.requestPermissions(MainActivity.this,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                    1);

            ActivityCompat.requestPermissions(MainActivity.this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    1);

The full code looks like this to write to a file in a button click function:

          ActivityCompat.requestPermissions(MainActivity.this,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                    1);

            ActivityCompat.requestPermissions(MainActivity.this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    1);




            try {
                File root = new File(Environment.getExternalStorageDirectory(), "Notes");
                if (!root.exists()) {
                    root.mkdirs();
                }
                File gpxfile = new File(root, "TestFile.txt");
                FileWriter writer = new FileWriter(gpxfile);
                writer.append("Hello World");
                writer.flush();
                writer.close();
                Toast.makeText(getApplicationContext(), "Saved", Toast.LENGTH_SHORT).show();
            } catch (IOException e) {
                e.printStackTrace();
            }

Android Write to File Permission Denied

Code to write to file:

AndroidManifest.xml:

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