Android action files on SD card

(1) Description: The operation of the file on the SD card needs to add the following permissions

Create and delete file permissions on an SD card

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

Permission to write data on an SD card
<uses-permission android:name= "Android.permission.WRITE_EXTERNAL_STORAGE"/>

The file on the SD card operation and my previous article almost, if there is not understand can see my previous article

Android Read-write file Example

http://blog.csdn.net/liuzuyi200/article/details/25049183

Just added a way to determine if the SD card exists

Environment.getexternalstoragestate (). Equals (environment.media_mounted)

(2) Layout file

<?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 "&G    T <relativelayout android:layout_width= "fill_parent" android:layout_height= "Wrap_content" Android:or ientation= "vertical" > <textview android:id= "@+id/label_01" android:layout_width= "Wrap_ Content "android:layout_height=" wrap_content "android:text=" @string/name "Android:textsiz            E= "20DP"/> <edittext android:id= "@+id/filename" android:layout_width= "160DP" android:layout_height= "Wrap_content" android:layout_aligntop= "@id/label_01" android:layout_toright of= "@id/label_01"/> </RelativeLayout> <textview android:id= "@+id/label_02" android:layout        _width= "Wrap_content"android:layout_height= "Wrap_content" android:text= "@string/neirong"/> <edittext android:id= "@+id/c        Ontent "android:layout_width=" fill_parent "android:layout_height=" 120px "android:ems=" > <requestfocus/> </EditText> <linearlayout android:layout_width= "Fill_parent" Android: layout_height= "wrap_content" android:orientation= "horizontal" > <button android:id= "@+id/sa Vebutton "android:layout_width=" wrap_content "android:layout_height=" Wrap_content "Androi            D:gravity= "Right" android:text= "@string/save"/> <button android:id= "@+id/readbutton" Android:layout_width= "Wrap_content" android:layout_height= "Wrap_content" android:gravity= " Right "android:text=" @string/read "/> </LinearLayout> <textview android:id=" @+id/textc Ontent "Android:lAyout_width= "Match_parent" android:layout_height= "Wrap_content" android:layout_weight= "0.10"/></Linea Rlayout>

(3) Code

Package Com.liuzuyi.file;import Java.io.bytearrayoutputstream;import Java.io.file;import java.io.FileInputStream; Import Java.io.fileoutputstream;import Java.io.inputstream;import Java.io.outputstream;import Android.support.v7.app.actionbaractivity;import Android.support.v7.app.actionbar;import Android.support.v4.app.fragment;import Android.app.activity;import Android.content.context;import Android.os.bundle;import Android.os.environment;import Android.util.log;import Android.view.LayoutInflater;import Android.view.menu;import Android.view.menuitem;import Android.view.view;import Android.view.View.OnClickListener; Import Android.view.viewgroup;import Android.widget.button;import Android.widget.edittext;import Android.widget.textview;import Android.widget.toast;import Android.os.build;public class MainActivity extends Activity {private EditText filename;private EditText context;private TextView textcontent;private static final String TA G= "Simplefile";p rotected void OnCreate (Bundle savedInstancestate) {super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); Filename= (EditText) This.findviewbyid (R.id.filename); context= (EditText) This.findviewbyid (r.id.content); textcontent= (TextView) This.findviewbyid (r.id.textcontent); Button savebtn= (button) This.findviewbyid (R.id.savebutton); Button viewbtn= (button) This.findviewbyid (R.id.readbutton); Savebtn.setonclicklistener (L);   Viewbtn.setonclicklistener (l);} Private View.onclicklistener L =new Onclicklistener () {public void OnClick (View v) {button button = (button) v;//filter out the opening end of the empty Lattice String namestr = Filename.gettext (). toString (). Trim ();  String contentstr =context.gettext (). toString (); Switch (Button.getid ()) {case R.id.savebutton:string resid_s = "Success"; OutputStream Fileos = null;try {if (environment. Getexternalstoragestate (). Equals (environment.media_mounted)) {FileOutputStream OutStream = new FileOutputStream ("/  sdcard/"+namestr+". txt ") Outstream.write (Contentstr.getbytes ()); Outstream.close (); }elsereturn;} Catch (Exception e) {resid_s = "faile"; E.printstacktrace ();} Toast.maketext (Mainactivity.this, Resid_s,toast.length_long). Show (); LOG.I (TAG, NAMESTR); LOG.I (TAG, contentstr); break;case r.id.readbutton:string resid_v = "Success"; InputStream filsis= null; String contentst = null;try {if (Environment.getexternalstoragestate (). Equals (environment.media_mounted)) {File Sdcarddir=environment.getexternalstoragedirectory (); File SaveFile = new file (sdcarddir,namestr+ ". txt"); FileInputStream instream = new FileInputStream (saveFile);  Bytearrayoutputstream Ostream = new Bytearrayoutputstream (); byte[] buffer = new Byte[1024];int len =-1;  while (len = instream.read (buffer))! =-1) {ostream.write (Buffer,0,len);  } CONTENTST = Ostream.tostring ();  Ostream.close ();   Instream.close (); }else{toast.maketext (Mainactivity.this, "SD card not Present", Toast.length_long). Show ();}} catch (Exception e) {resid_v = "faile"; E.printstacktrace ();} Textcontent.settext (CONTENTST); LOG.I (TAG, CONTENTST); Toast.maketext (MainactivitY.this, Resid_v,toast.length_long). Show ();  LOG.I (TAG,NAMESTR); break;} }    };}