Android Application Development Basics (9)-----sharedpreferences

<span id="Label3"></p><p><p>Link Address: http://www.cnblogs.com/lknlfy/archive/2012/02/27/2370319.html</p></p><p><p><strong>I. Overview</strong></p></p><p><p>For sharedpreferences, I'm it. It is understood as a simple database that can store data like a file in the system or read it, but it only stores some simple numerical pairs, such as the Key-values form. If some apps need to save some simple data on exit to restore the data they need to be opened again, you can do so with Sharedpreferences.</p></p><p><p></p></p><p><p><strong>second, The requirements</strong></p></p><p><p>Write a simple app that requires the app to save some of the data it needs when it exits, and restore the data when the app is opened Again.</p></p><p><p></p></p><p><p><strong>third, the realization</strong></p></p><p><p>New Project myshared, Modify The/res/layout/main.xml file, Add a edittext in it, two buttons and a textview, complete the Main.xml file as Follows:</p></p><span class="cnblogs_code_copy"><span class="cnblogs_code_copy"></span></span><pre>1 <?xml version= "1.0" encoding= "utf-8"?><br>2 <linearlayout xmlns:android= "http://schemas.android.com/apk/res/android"<br>3 android:layout_width= "fill_parent"<br>4 android:layout_height= "fill_parent"<br>5 android:orientation= "vertical" ><br>6<br>7 <edittext<br>8 android:id= "@+id/edittext"<br>9 Android:layout_width= "fill_parent"<br>Ten android:layout_height= "wrap_content"<br>android:hint= "please Enter content"<br>/><br>13<br><button<br>Android:id= "@+id/wbutton"<br>Android:layout_width= "fill_parent"<br>android:layout_height= "wrap_content"<br>android:text= "write"<br>/><br>20<br><button<br>Android:id= "@+id/rbutton"<br>Android:layout_width= "fill_parent"<br>android:layout_height= "wrap_content"<br>android:text= "read"<br>/><br>27<br><textview<br>Android:id= "@+id/textview"<br>Android:layout_width= "fill_parent"<br>android:layout_height= "wrap_content"<br>android:gravity= "center_horizontal"<br>Android:textsize= "20dip"<br>/><br>35<br></LinearLayout></pre><span class="cnblogs_code_copy"><span class="cnblogs_code_copy"></span></span><p><p>Then Modify the Mysharedactivity.java file, the main definition of a Sharedpreferences object and a sharedpreferences.editor object, the implementation of two buttons to listen, the complete Mysharedactivity.java file as Follows:</p></p><p><p></p></p><span class="cnblogs_code_copy"><span class="cnblogs_code_copy"></span></span><pre>1 package com.nan.shared;<br>2<br>3 Import android.app.Activity;<br>4 Import android.content.SharedPreferences;<br>5 Import android.os.Bundle;<br>6 Import android.view.View;<br>7 Import android.widget.Button;<br>8 Import android.widget.EditText;<br>9 Import android.widget.TextView;<br>Ten Import android.widget.Toast;<br>11<br>public class Mysharedactivity extends Activity<br>13 {<br>The private EditText Medittext = null;<br>The private Button Writebutton = null;<br>Private Button Readbutton = null;<br>+ Private TextView Mtextview = null;<br>18<br>Private Sharedpreferences msharedpreferences = null;<br>Private Sharedpreferences.editor Meditor = null;<br>21st<br>/** called when the activity is first Created. */<br>@Override<br>public void OnCreate (Bundle Savedinstancestate)<br>25 {<br>Super.oncreate (savedinstancestate);<br>Setcontentview (r.layout.main);<br>28<br>Medittext = (EditText) This.findviewbyid (r.id.edittext);<br>Writebutton = (Button) This.findviewbyid (r.id.wbutton);<br>Readbutton = (Button) This.findviewbyid (r.id.rbutton);<br>Mtextview = (TextView) This.findviewbyid (r.id.textview);<br>33<br>msharedpreferences = getsharedpreferences ("myshare", mode_private);<br>Meditor = Msharedpreferences.edit ();<br>36<br>Panax Notoginseng writebutton.setonclicklistener (new view.onclicklistener ()<br>38 {<br>39<br>@Override<br>$ public void OnClick (View V)<br>42 {<br>+//TODO auto-generated Method Stub<br>44//get Edittext's Content<br>String Text = Medittext.gettext (). toString ();<br>46//modify<br>Meditor.putstring ("hehe", text);<br>48//submit changes<br>Meditor.commit ();<br>Displaytoast ("write success! ");<br>51}<br>52});<br>53<br>Readbutton.setonclicklistener (new View.onclicklistener ()<br>55 {<br>56<br>@Override<br>(+) public void OnClick (View V)<br>59 {<br>/TODO auto-generated Method Stub<br>61//get the saved data<br>String Text = msharedpreferences.getstring ("hehe", null);<br>63//show the data<br>Mtextview.settext (text);<br>65}<br>66});<br>67<br>68}<br>69//show Toast function<br>+ private void Displaytoast (String S)<br>71 {<br>Toast.maketext (mysharedactivity.this, s, toast.length_short). show ();<br>73}<br>74<br>75}</pre><span class="cnblogs_code_copy"><span class="cnblogs_code_copy"></span></span><p><p>well, Run it, as Follows:</p></p><p><p></p></p><p><p></p></p><p><p>Then enter a line of numbers and click "write", as Follows:</p></p><p><p></p></p><p><p></p></p><p><p>To exit the app, rerun it and click on the "read" button, as Follows:</p></p><p><p></p></p><p><p></p></p><p><p>You can see that the previously saved data is Displayed.</p></p><p><p>OK, Finish.</p></p><p><p>Android Application Development Basics (9)-----sharedpreferences</p></p></span>