Android explains the operation example of sdcard extended card
- 2020-06-01 10:58:41
- OfStack
The Android operation on the sdcard extension carver is just a normal file operation, but there are still some things to be aware of. Such as:
1. Add sdcard operation permission;
2. Confirm the existence of sdcard;
3. You cannot directly create a file in the root directory other than sdcard, but you need to create a directory first and then create a file;
Examples are as follows:
(1) add sdcard operation permission in AndroidManifest.xml
<!-- sdcard permissions -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
(2) variable declaration:
private final static String PATH = "/sdcard/digu";
private final static String FILENAME = "/notes.txt";
(3) write to sdcard:
/**
* Write files
*/
private void onWrite() {
try {
Log.d(LOG_TAG, "Start Write");
//1. To determine if there is sdcard
if (Environment.MEDIA_MOUNTED.equals(Environment
.getExternalStorageState())) {
// directory
File path = new File(PATH);
// file
File f = new File(PATH + FILENAME);
if(!path.exists()){
//2. Create a directory that can be created at application startup
path.mkdirs();
}
if (!f.exists()) {
//3. Create a file
f.createNewFile();
}
OutputStreamWriter osw = new OutputStreamWriter(
new FileOutputStream(f));
//4. Write files from EditView Get the text value
osw.write(editor.getText().toString());
osw.close();
}
} catch (Exception e) {
Log.d(LOG_TAG, "file create error");
}
}