Android learning notes-data Sdcard storage method and sdcard operation tool class, androidsdcard

Android learning notes-data Sdcard storage method and sdcard operation tool class, androidsdcard

(1) file directory

(2) Code of each 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:paddingBottom="@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" >    <ImageView        android:id="@+id/imageView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentTop="true"        android:layout_alignRight="@+id/button1"        android:layout_marginRight="44dp"        android:layout_marginTop="78dp"        android:src="@drawable/ic_launcher" />    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_below="@+id/imageView1"        android:layout_marginLeft="96dp"        android:layout_marginTop="106dp"        android:text="Button" /></RelativeLayout>

FileService. java is the tool class used to operate sdcard:

Package com. example. data_storage_sdcard.file; import java. io. byteArrayOutputStream; import java. io. file; import java. io. fileInputStream; import java. io. fileNotFoundException; import java. io. fileOutputStream; import java. io. IOException; import android. OS. environment;/*** the existence of sdcard is context-independent ** @ author piaodangdehun **/public class FileService {/** the root directory of the sdcard */public boolean saveFileToSdcardRoot (String FileName, byte [] data) {boolean flag = false;/** first, judge whether the sdcard status exists */String state = Environment. getExternalStorageState (); FileOutputStream outputStream = null; File rootFile = Environment. getExternalStorageDirectory (); // get the root path of the sdcard/** indicates that the sdcard is mounted to the mobile phone and can be read and written */if (state. equals (Environment. MEDIA_MOUNTED) {File file = new File (rootFile, fileName); try {outputStream = new FileOutputStream (file); try {OutputStream. write (data, 0, data. length); flag = true;} catch (IOException e) {e. printStackTrace () ;}} catch (FileNotFoundException e) {e. printStackTrace ();} finally {if (outputStream! = Null) {try {outputStream. close ();} catch (IOException e) {e. printStackTrace () ;}}} return flag;}/** custom directory stored in sdcard */public boolean saveFileToSdcardDir (String fileName, byte [] data) {boolean flag = false;/** first, judge whether the sdcard status exists. */String state = Environment. getExternalStorageState (); FileOutputStream outputStream = null; File rootFile = Environment. getExternalStorageDirectory (); // get the root path of the sdcard /** Indicates that the sdcard is mounted to the mobile phone and can read/write */if (state. equals (Environment. MEDIA_MOUNTED) {File file = new File (rootFile. getAbsoluteFile () + "/txt"); if (! File. exists () {file. mkdirs ();} try {outputStream = new FileOutputStream (new File (file, fileName); try {outputStream. write (data, 0, data. length); flag = true;} catch (IOException e) {e. printStackTrace () ;}} catch (FileNotFoundException e) {e. printStackTrace ();} finally {if (outputStream! = Null) {try {outputStream. close ();} catch (IOException e) {e. printStackTrace () ;}}} return flag;}/** data used to read sdcard */public String readContextFromSdcard (String fileName) {String state = Environment. getExternalStorageState (); File rooFile = Environment. getExternalStorageDirectory (); // obtain the sdcard directory FileInputStream inputStream = null; // The stream ByteArrayOutputStream outputStream = new ByteArrayOutputSt Ream (); // if (state. equals (Environment. MEDIA_MOUNTED) {File file = new File (rooFile. getAbsoluteFile () + "/txt/"); // create a txt directory under the sdcard directory File file2 = new File (file, fileName); int len = 0; byte [] data = new byte [1024]; if (file2.exists () {try {inputStream = new FileInputStream (file2); try {while (len = inputStream. read (data ))! =-1) {outputStream. write (data, 0, data. length) ;}} catch (IOException e) {e. printStackTrace ();} return new String (outputStream. toByteArray ();} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke. printStackTrace ();} finally {if (outputStream! = Null) {try {outputStream. close ();} catch (IOException e) {e. printStackTrace () ;}}} return null ;} /*** save files to a fixed file by category ** @ param fileName * @ param data */public void saveFileToSdcardBySuff (String fileName, byte [] data) {// File file = Environment. getExternalStoragePublicDirectory (""); // save the File directory file = null; if (Environment. getExternalStorageState (). equals (Environment. MEDIA_MOUNTED) {/** set Put different files into different categories */if (fileName. endsWith (". mp3 ") {file = Environment. getExternalStoragePublicDirectory (Environment. DIRECTORY_MUSIC);} else if (fileName. endsWith (". jpg ") | fileName. endsWith (". png ") | fileName. endsWith (". gif ") {file = Environment. getExternalStoragePublicDirectory (Environment. DIRECTORY_PICTURES);} else if (fileName. endsWith (". mp4 ") | fileName. endsWith (". avi ") | fileName. endsWith (". 3gp ") {file = Environment. getExternalStoragePublicDirectory (Environment. DIRECTORY_MOVIES);} else {file = Environment. getExternalStoragePublicDirectory (Environment. DIRECTORY_DOWNLOADS);} FileOutputStream outputStream = null; try {outputStream = new FileOutputStream (new File (file, fileName); try {outputStream. write (data, 0, data. length);} catch (IOException e) {e. printStackTrace () ;}} catch (FileNotFo UndException e) {e. printStackTrace ();} finally {if (outputStream! = Null) {try {outputStream. close ();} catch (IOException e) {e. printStackTrace () ;}}}}/** delete a File */public boolean deleteFileFromSdcard (String folder, String fileName) {boolean flag = false; file File = Environment. getExternalStorageDirectory (); if (Environment. getExternalStorageState (). equals (Environment. MEDIA_MOUNTED) {File exitFile = new File (file. getAbsoluteFile () + "/" + folder); if (exitFile. exists () {exitFile. delete () ;}} return flag ;}}

HttpUtils. java

package com.example.data_storage_sdcard.http;import java.io.IOException;import org.apache.http.HttpResponse;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.util.EntityUtils;public class HttpUtils {/* *  */public static byte[] getImage(String path) {byte[] data = null;HttpClient httpClient = new DefaultHttpClient();HttpPost httpPost = new HttpPost(path);try {HttpResponse response = httpClient.execute(httpPost);if (response.getStatusLine().getStatusCode() == 200) {data = EntityUtils.toByteArray(response.getEntity());}} catch (ClientProtocolException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {httpClient.getConnectionManager().shutdown();}return data;}}

ImageCache. java:

Package com. example. data_storage_sdcard.img; import java. io. file; import java. io. fileOutputStream; import java. io. IOException; import android. OS. environment; public class ImageCache {public static String saveImageCache (String fileName, byte [] data) {File file = Environment. getExternalStorageDirectory (); // root directory FileOutputStream outputStream = null; if (Environment. getExternalStorageState (). equals (Environme Nt. MEDIA_MOUNTED) {try {outputStream = new FileOutputStream (new File (file, fileName); outputStream. write (data, 0, data. length); return file. getAbsolutePath () + "/" + fileName;} catch (Exception e) {e. printStackTrace ();} finally {if (outputStream! = Null) {try {outputStream. close () ;}catch (IOException e) {e. printStackTrace () ;}}} return null ;}}

MainActivity. java

Package com. example. data_storage_sdcard; import android. app. activity; import android. app. progressDialog; import android. graphics. bitmap; import android. graphics. bitmapFactory; import android. OS. asyncTask; import android. OS. bundle; import android. view. menu; import android. view. view; import android. view. view. onClickListener; import android. widget. button; import android. widget. imageView; import com. example. data_s Torage_sdcard.http.HttpUtils; import com. example. data_storage_sdcard.img.ImageCache; public class MainActivity extends Activity {private Button button; private ImageView imageView; private ProgressDialog ssprogre; private String imageName; private final String pathString = "http://www.baidu.com/img/bd_logo1.png "; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInsta NceState); setContentView (R. layout. activity_main); button = (Button) this. findViewById (R. id. button1); imageView = (ImageView) this. findViewById (R. id. imageView1); progressDialog = new ProgressDialog (this); progressDialog. setTitle ("Download prompt"); progressDialog. setMessage ("load... "); button. setOnClickListener (new OnClickListener () {@ Overridepublic void onClick (View v) {new mytask(cmd.exe cute (pathString) ;}});} class MyTask extends AsyncTask <String, Void, byte [] >{@ Overrideprotected void onPreExecute () {super. onPreExecute (); progressDialog. show () ;}@ Overrideprotected byte [] doInBackground (String... params) {String name = params [0]; imageName = name. substring (name. lastIndexOf ("/") + 1, name. length (); return HttpUtils. getImage (params [0]);} @ Overrideprotected void onProgressUpdate (Void... values) {super. onProgressUpd Ate (values) ;}@ Overrideprotected void onPostExecute (byte [] result) {super. onPostExecute (result); if (result! = Null) {Bitmap bm = BitmapFactory. decodeByteArray (result, 0, result. length); imageView. setImageBitmap (bm); ImageCache. saveImageCache ("", result);} else {imageView. setImageResource (R. drawable. ic_launcher);} progressDialog. dismiss () ;}@ Overridepublic boolean onCreateOptionsMenu (Menu menu) {// Inflate the menu; this adds items to the action bar if it is present. getMenuInflater (). inflate (R. menu. main, menu); return true ;}}

Test class:

package com.example.data_storage_sdcard;import java.io.FileWriter;import com.example.data_storage_sdcard.file.FileService;import android.nfc.Tag;import android.test.AndroidTestCase;import android.util.Log;public class MyTest extends AndroidTestCase {public void saveFileToSdcardTest() {FileService fileService = new FileService();fileService.saveFileToSdcardRoot("aa.txt","jkhdsfjkhdskjfhdsjf".getBytes());}public void saveFileToSdcardDir() {FileService fileService = new FileService();fileService.saveFileToSdcardRoot("aa.txt","jkhdsfjkhdskjfhdsjf".getBytes());}public void readContextFromSdcardTest() {FileService fileService = new FileService();String msg = fileService.readContextFromSdcard("aa.txt");System.err.println("-->" + msg);}public void saveFileToSdcardBySuffTest() {FileService fileService = new FileService();fileService.saveFileToSdcardBySuff("aa.avi","asdfkajsgdhagsdfhdgsf".getBytes());}public void delFile() {FileService fileService = new FileService();boolean flag = fileService.deleteFileFromSdcard("txt", "aa.txt");}}

You need to add the network access permission, sdcard operation permission, and test permission to the requesting organization.

<? Xml version = "1.0" encoding = "UTF-8"?> <Manifest xmlns: android = "http://schemas.android.com/apk/res/android" package = "com. example. data_storage_sdcard "android: versionCode =" 1 "android: versionName =" 1.0 "> <uses-sdk android: minSdkVersion =" 8 "android: targetSdkVersion = "18"/> <instrumentation android: name = "android. test. instrumentationTestRunner "android: targetPackage =" com. example. data_storage_sdcard "> </instrumentation> <! -- Add the permission to access sdcard --> <uses-permission android: name = "android. permission. WRITE_EXTERNAL_STORAGE"/> <! -- Add Network Access Permissions --> <uses-permission android: name = "android. permission. INTERNET "/> <application android: allowBackup =" true "android: icon =" @ drawable/ic_launcher "android: label =" @ string/app_name "android: theme = "@ style/AppTheme"> <uses-library android: name = "android. test. runner "/> <activity android: name =" com. example. data_storage_sdcard.MainActivity "android: label =" @ string/app_name "> <intent-filter> <action android: name =" android. intent. action. MAIN "/> <category android: name =" android. intent. category. LAUNCHER "/> </intent-filter> </activity> <uses-library> </application> </manifest>