Internal storage of Android learning notes data reading and writing of internship data

(1) directory structure

(2) Layout file:

<relativelayout xmlns:android= "http://schemas.android.com/apk/res/android" xmlns:tools= "http// Schemas.android.com/tools "android:layout_width=" match_parent "android:layout_height=" Match_parent "Android:paddi ngbottom= "@dimen/activity_vertical_margin" android:paddingleft= "@dimen/activity_horizontal_margin" Android: paddingright= "@dimen/activity_horizontal_margin" android:paddingtop= "@dimen/activity_vertical_margin" tools: Context= ". Mainactivity "> <edittext android:id=" @+id/edittext1 "android:layout_width=" Wrap_content "an droid:layout_height= "Wrap_content" android:layout_alignparentleft= "true" android:layout_alignparenttop= "true "Android:layout_marginleft=" 28DP "android:layout_margintop=" 17DP "android:ems=" ten "/> <butt         On android:id= "@+id/button1" android:layout_width= "wrap_content" android:layout_height= "Wrap_content"   android:layout_alignleft= "@+id/edittext1"     android:layout_below= "@+id/edittext1" android:layout_margintop= "54DP" android:text= "Save Information"/></rel Ativelayout>

(3) The tool class for saving data and reading data: Fileservice.java

Package Com.example.data_storage_interal.file;import Java.io.bytearrayoutputstream;import Java.io.FileInputStream ; Import Java.io.filenotfoundexception;import Java.io.fileoutputstream;import Java.io.ioexception;import android.content.context;/** * Use internal storage, you can make the application uninstall the time to clear all the relevant information * @author Piaodangdehun * */public class Fileservice { Private context Context;public Fileservice (context context) {This.context = context;} /** * Save content to file * @param filename * @param mode * @param data buffer * @return returns the true and False value */public Boolean Savecontenttof Ile (String fileName, int mode, byte[] data) {Boolean flag = false; FileOutputStream OutputStream = null;try {outputstream = Context.openfileoutput (fileName, mode); try { Outputstream.write (data, 0, data.length);} catch (IOException e) {e.printstacktrace ();} Flag = true;} catch (FileNotFoundException e) {e.printstacktrace ();} finally {if (outputstream! = null) {try {outputstream.close ();} CA TCH (Exception E2) {}}}return true;} /** * Read Data * @param fileName * @return */public string Readcontentfromfile (String fileName) {string result = ""; FileInputStream fileinputstream = null; Bytearrayoutputstream outputstream = new Bytearrayoutputstream (); try {FileInputStream = Context.openfileinput ( fileName); int len = 0;byte[] data = new Byte[1024];while (len = fileinputstream.read (data))! =-1) {Outputstream.write (da TA, 0, Len);} return new String (Outputstream.tobytearray ());} catch (Exception e) {e.printstacktrace ();} Return "";}}

(4) Mainactivity.java

Package Com.example.data_storage_interal;import Com.example.data_storage_interal.file.fileservice;import Android.os.bundle;import Android.app.activity;import Android.content.context;import Android.view.Menu;import Android.view.view;import Android.view.view.onclicklistener;import Android.widget.button;import Android.widget.edittext;import Android.widget.toast;public class Mainactivity extends Activity {private button button; Private EditText edittext;private fileservice fileservice; @Overrideprotected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (r.layout.activity_main); button = (Button) This.findviewbyid ( R.id.button1) EditText = (editText) This.findviewbyid (R.ID.EDITTEXT1); fileservice = new Fileservice (this);/* * When the button is clicked, it is stored in the file */button.setonclicklistener (new Onclicklistener () {@Overridepublic void OnClick (View v) {String valuestring = Edittext.gettext (). toString (). Trim (); Boolean flag = Fileservice.savecontenttofile ("Bb.txt", Context.mode_appenD, Valuestring.getbytes ()); if (flag) {Toast.maketext (Mainactivity.this, "saved successfully! ", Toast.length_short). Show ();}});} @Overridepublic boolean Oncreateoptionsmenu (Menu menu) {//Inflate the menu; This adds items to the action bar if it is PR Esent.getmenuinflater (). Inflate (R.menu.main, menu); return true;}}

(5) Test class (to add the appropriate information in the resource file, do not say here)

Package Com.example.data_storage_interal;import Com.example.data_storage_interal.file.fileservice;import Android.app.service;import Android.content.context;import Android.test.androidtestcase;import Android.util.Log; public class MyTest extends Androidtestcase {private static final String TAG = "MyTest";/* * Save data */public void Save () {Fi Leservice fileservice = new Fileservice (GetContext ()), Boolean flag = Fileservice.savecontenttofile ("Aa.txt", Context.mode_private + context.mode_append, "Nihao". GetBytes ()); LOG.I (TAG, "--->>" + flag);} /* * Save data */public void Read () {Fileservice fileservice = new Fileservice (GetContext ()); String msg = fileservice.readcontentfromfile ("Bb.txt"); LOG.I (TAG, "--->>" + msg);}}

After the save is successful, the corresponding file will be found in the DATA-DATA-APK installation directory:

Internal storage of Android learning notes data reading and writing of internship data