Android SDcard realizes picture storage, networked download _android

This article introduces the sdcard storage picture Download simple operation, share to everyone for your reference, the specific contents are as follows

Step--After adding network permissions to the configuration manifest

1, Res/layout interface layout

<linearlayout 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:orientation= "vertical" >



  <imageview

    android:id= "@+id/imageview"

    android:layout_ Width= "Wrap_content"

    android:layout_height= "wrap_content"/> <button android:id=

    "@+id/bt_" Download "

    android:layout_width=" wrap_content "

    android:layout_height=" wrap_content "

    android:text" = "Picture Download"

    android:onclick= "Image_download"/>



</LinearLayout>

2, there are 2 classes of one Operation SDcard File tool Class (Fileutil) another mainactivity class

Fileutil class

Operation SDcard's File tool class public class Fileutil {private static final String Cache_dir = Environment.getexternalstoragedirec



 Tory () + "/my_caches/images";

 private static int comp_jpg = 0;

private static int comp_png = 1;

 Determine if SDcard is mounted (whether there is sdcard) public static Boolean ismounted () {String state = Environment.getexternalstoragestate ();

 Return State.equals (environment.media_mounted); //Get the absolute path to the SDcard file root path public static String Getsdcard () {return environment.getexternalstoragedirectory (). GETABSO

 Lutepath ();

 //Get filename public static string getfilename (String URL) {return url.substring (Url.lastindexof ('/') + 1); 

 //Save File Method 1 public static void Sava1 (String url,byte[] Data {//To determine whether there is sdcard if (!ismounted ()) {return;

 ///have SDcard//determine if there is a cached folder file Dir = new file (Cache_dir);

 if (!dir.exists ()) {//No cache folder creation folder exists to save the file Dir.mkdirs ();

 ///Save the file data to sdcard filename = new file (dir,getfilename (URL)); try {fileoutputstream fos = new FileOutputStream (file);

 

 Fos.write (data);

 Fos.close ();

 catch (Exception e) {e.printstacktrace (); //Save File Method 2 public static void Sava2 (String url,bitmap bitmap,int format) {//To determine if there is a sdcard if (!ismounted ())

 {return;

 File dir = new file (Cache_dir);

 if (!dir.exists ()) {dir.mkdirs ();

 //write the file data to sdcard filename = new file (dir,getfilename (URL));

 try {fileoutputstream fos = new FileOutputStream (file); Write the picture file to the cache bitmap.compress (format = = comp_jpg?

 

 CompressFormat.JPEG:CompressFormat.PNG), MB, FOS);

 Fos.close ();

 catch (Exception e) {e.printstacktrace ();

 Read the picture public static Bitmap readimage (String URL) {if (!ismounted ()) {return null;

 File File = new file (cache_dir,getfilename (URL));

 if (file.exists ()) {return bitmapfactory.decodefile (File.getabsolutepath ());

 return null;

 //Empty cache directory public void Clearcaches () {File Dir = new File (cache_dir); file[] File_datas = Dir.listfiles ();

 for (File File:file_datas) {file.delete ();

 }

 }

 

}

Mainactivity class

public class Mainactivity extends activity {private ImageView ImageView;

 Private String URL = "Yun_qi_img/d1160924ab18972bf5f68cc8e0cd7b899f510ae7.gif";

 @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);

 

 Setcontentview (R.layout.activity_main);

 This.imageview = (ImageView) This.findviewbyid (R.id.imageview);

 

 Set default picture Imageview.setimageresource (R.drawable.ic_launcher);

 //Picture Download button Click event Listener public void Image_download (view view) {//Judge whether there is a local picture Bitmap Bitmap = fileutil.readimage (URL);

 if (bitmap!= null) {Imageview.setimagebitmap (bitmap);

 }else{//No pictures on the Send network request new Myasynctask (). Execute (URL); }//Networking tools Class public class Myasynctask extends Asynctask<string, Void, byte[]>{@Override protected byt

 E[] Doinbackground (String ... params) {HttpGet get = new HttpGet (params[0));

 HttpClient client = new Defaulthttpclient ();

 HttpResponse response; try {response = Client.executE (GET);

 if (Response.getstatusline (). Getstatuscode () = () {byte[] data = Entityutils.tobytearray (Response.getentity ());

 FILEUTIL.SAVA1 (Params[0], data);

 return data;

 } catch (Exception e) {e.printstacktrace ();

 return null;

 @Override protected void OnPostExecute (byte[] result) {Super.onpostexecute (result);

 if (result!= null) {Bitmap Bitmap = Bitmapfactory.decodebytearray (result, 0, result.length);

 Imageview.setimagebitmap (bitmap);
 }

 }

 

 }

}

The above is the entire contents of this article, I hope to learn more about Android software programming help.