Android SD card file read/write

 

Use the buttons in the upper-right corner to export and import files from the simulator.

Program running result

After running, delete in the file browser is deleted.

 

 

FileHelper. java is a help class for files. It creates, deletes, and reads files.

 

 

Package com. zeph. android. fileoperate;

 

Import java. io. File;

Import java. io. FileInputStream;

Import java. io. FileNotFoundException;

Import java. io. IOException;

 

Import android. content. Context;

Import android. OS. Environment;

 

Public class FileHelper {

 

Private Context context;

/** Whether the SD card exists **/

Private boolean hasSD = false;

/** SD card path **/

Private String SDPATH;

/** Path of the current package **/

Private String FILESPATH;

 

Public FileHelper (Context context ){

This. context = context;

HasSD = Environment. getExternalStorageState (). equals (

Android. OS. Environment. MEDIA_MOUNTED );

SDPATH = Environment. getExternalStorageDirectory (). getPath ();

FILESPATH = this. context. getFilesDir (). getPath ();

}

 

/**

* Create a file on the SD card

*

* @ Throws IOException

*/

Public File createSDFile (String fileName) throws IOException {

File file = new File (SDPATH + "//" + fileName );

If (! File. exists ()){

File. createNewFile ();

}

Return file;

}

 

/**

* Delete files on the SD card

*

* @ Param fileName

*/

Public boolean deleteSDFile (String fileName ){

File file = new File (SDPATH + "//" + fileName );

If (file = null |! File. exists () | file. isDirectory ())

Return false;

Return file. delete ();

}

 

/**

* Read text files from the SD card

*

* @ Param fileName

* @ Return

*/

Public String readSDFile (String fileName ){

StringBuffer sb = new StringBuffer ();

File file = new File (SDPATH + "//" + fileName );

Try {

FileInputStream FCM = new FileInputStream (file );

Int c;

While (c = FCM. read ())! =-1 ){

Sb. append (char) c );

}

FCM. close ();

} Catch (FileNotFoundException e ){

E. printStackTrace ();

} Catch (IOException e ){

E. printStackTrace ();

}

Return sb. toString ();

}

 

Public String getFILESPATH (){

Return FILESPATH;

}

 

Public String getSDPATH (){

Return SDPATH;

}

 

Public boolean hasSD (){

Return hasSD;

}

}

 

Activity Type

 

 

 

Package com. zeph. android. fileoperate;

 

Import java. io. IOException;

 

Import android. app. Activity;

Import android. OS. Bundle;

Import android. widget. TextView;

 

Public class FileOperateActivity extends Activity {

 

Private TextView hasSDTextView;

Private TextView SDPathTextView;

Private TextView FILESpathTextView;

Private TextView createFileTextView;

Private TextView readFileTextView;

Private TextView deleteFileTextView;

Private FileHelper helper;

 

@ Override

Public void onCreate (Bundle savedInstanceState ){

Super. onCreate (savedInstanceState );

SetContentView (R. layout. main );

 

HasSDTextView = (TextView) findViewById (R. id. hasSDTextView );

SDPathTextView = (TextView) findViewById (R. id. SDPathTextView );

FILESpathTextView = (TextView) findViewById (R. id. FILESpathTextView );

CreateFileTextView = (TextView) findViewById (R. id. createFileTextView );

ReadFileTextView = (TextView) findViewById (R. id. readFileTextView );

DeleteFileTextView = (TextView) findViewById (R. id. deleteFileTextView );

 

Helper = new FileHelper (getApplicationContext ());

 

HasSDTextView. setText ("Whether the SD card exists:" + helper. hasSD ());

SDPathTextView. setText ("SD card path:" + helper. getSDPATH ());

FILESpathTextView. setText ("package path:" + helper. getFILESPATH ());

 

Try {

CreateFileTextView. setText ("Create File :"

+ Helper. createSDFile ("test.txt"). getAbsolutePath ());

} Catch (IOException e ){

E. printStackTrace ();

}

 

DeleteFileTextView. setText ("Whether the file is successfully deleted :"

+ Helper. deleteSDFile ("delete.txt "));

 

ReadFileTextView. setText ("Read File:" + helper. readSDFile ("benzeph.txt "));

}

}

 

Layout. xml

 

 

 

<? Xml version = "1.0" encoding = "UTF-8"?>

<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"

Android: layout_width = "fill_parent"

Android: layout_height = "fill_parent"

Android: orientation = "vertical">

 

<TextView

Android: id = "@ + id/hasSDTextView"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: text = "@ string/hello"/>

 

<TextView

Android: id = "@ + id/SDPathTextView"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: text = "@ string/hello"/>

 

<TextView

Android: id = "@ + id/FILESpathTextView"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: text = "@ string/hello"/>

 

<TextView

Android: id = "@ + id/createFileTextView"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: text = "false"/>

<TextView

Android: id = "@ + id/readFileTextView"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: text = "false"/>

<TextView

Android: id = "@ + id/deleteFileTextView"

Android: layout_width = "fill_parent"

Android: layout_height = "wrap_content"

Android: text = "false"/>

 

</LinearLayout>

 

Note that the conditions for reading external devices must be added to the Manifest file. Previously, I forgot to add the file, and the file cannot be created or deleted.

 

 

 

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

 

From Ben Zeph's Code Cloud