1, first to manifest registered SD card read and Write permissions
To illustrate, I'm not using Mainactivity.class as a software portal here.
Copy Code code as follows:
Androidmanifest.xml
<?xml version= "1.0" encoding= "Utf-8"?>
<manifest xmlns:android= "Http://schemas.android.com/apk/res/android"
Package= "COM.TES.TEXTSD"
Android:versioncode= "1"
Android:versionname= "1.0" >
<uses-sdk
Android:minsdkversion= "8"
Android:targetsdkversion= "/>"
<uses-permission android:name= "Android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
Android:allowbackup= "true"
android:icon= "@drawable/ic_launcher"
Android:label= "@string/app_name"
Android:theme= "@style/apptheme" >
<activity
Android:name= "Com.tes.textsd.FileOperateActivity"
Android:label= "@string/app_name" >
<intent-filter>
<action android:name= "Android.intent.action.MAIN"/>
<category android:name= "Android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
</manifest>
2. Create a class to read and write files in SD card
Copy Code code as follows:
Filehelper.java
/**
* @Title: Filehelper.java
* @Package COM.TES.TEXTSD
* @Description: TODO (describe what the file does with a word)
* @author alex.z
* @date 2013-2-26 5:45:40
* @version V1.0
*/
Package COM.TES.TEXTSD;
Import Java.io.DataOutputStream;
Import Java.io.File;
Import Java.io.FileOutputStream;
Import Java.io.FileWriter;
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;
Does the/** SD card exist **/
Private Boolean HASSD = false;
/** SD card Path **/
Private String Sdpath;
/** the current package path **/
Private String Filespath;
Public Filehelper {
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 the 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 ();
}
/**
* Write content to txt text in SD card
* Str as content
*/
public void Writesdfile (String str,string fileName)
{
try {
FileWriter FW = new FileWriter (Sdpath + "//" + fileName);
File F = new file (Sdpath + "//" + fileName);
Fw.write (str);
FileOutputStream OS = new FileOutputStream (f);
DataOutputStream out = new DataOutputStream (OS);
Out.writeshort (2);
Out.writeutf ("");
System.out.println (out);
Fw.flush ();
Fw.close ();
SYSTEM.OUT.PRINTLN (FW);
catch (Exception e) {
}
}
/**
* Read the SD card text file
*
* @param fileName
* @return
*/
public string Readsdfile (string fileName) {
StringBuffer sb = new StringBuffer ();
File File = new file (Sdpath + "//" + fileName);
try {
FileInputStream fis = new FileInputStream (file);
int C;
while ((c = fis.read ())!=-1) {
Sb.append ((char) c);
}
Fis.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;
}
}
3. Write a layout to detect the function of reading and writing
Copy Code code as follows:
Main.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= "Hello"/>
<textview
Android:id= "@+id/sdpathtextview"
Android:layout_width= "Fill_parent"
android:layout_height= "Wrap_content"
android:text= "Hello"/>
<textview
Android:id= "@+id/filespathtextview"
Android:layout_width= "Fill_parent"
android:layout_height= "Wrap_content"
android:text= "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>
4, is the UI of the class
Copy Code code as follows:
Fileoperateactivity.class
/**
* @Title: Fileoperateactivity.java
* @Package COM.TES.TEXTSD
* @Description: TODO (describe what the file does with a word)
* @author alex.z
* @date 2013-2-26 5:47:28
* @version V1.0
*/
Package COM.TES.TEXTSD;
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 ("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 ("Delete file succeeded:"
+ Helper.deletesdfile ("Xx.txt"));
Helper.writesdfile ("1213212", "test.txt");
Readfiletextview.settext ("Read file:" + helper.readsdfile ("test.txt"));
}
}
Look at the effect of the operation:
