Add this WRITE_EXTERNAL_STORAGE permission to your applications manifest.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="your.company.package"
android:versionCode="1"
android:versionName="0.1">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<!-- ... -->
</application>
<uses-sdk android:minSdkVersion="7" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>
You should always check for availability first. A snippet from the official android documentation on external storage.
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// We can read and write the media
mExternalStorageAvailable = mExternalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// We can only read the media
mExternalStorageAvailable = true;
mExternalStorageWriteable = false;
} else {
// Something else is wrong. It may be one of many other states, but all we need
// to know is we can neither read nor write
mExternalStorageAvailable = mExternalStorageWriteable = false;
}
At last but not least forget about the FileOutputStream and use a FileWriter instead. More information on that class form the FileWriter javadoc. You'll might want to add some more error handling here to inform the user.
// get external storage file reference
FileWriter writer = new FileWriter(getExternalStorageDirectory());
// Writes the content to the file
writer.write("This\n is\n an\n example\n");
writer.flush();
writer.close();