Android network_network Image Viewer,

Android network_network Image Viewer,

Xml

<? Xml version = "1.0"?> -<LinearLayout tools: context = ". mainActivity "android: paddingTop =" @ dimen/activity_vertical_margin "android: paddingRight =" @ dimen/activity_horizontal_margin "android: paddingLeft =" @ dimen/plugin "android: paddingBottom = "@ dimen/Docs" android: orientation = "vertical" android: layout_height = "match_parent" android: layout_width = "match_parent" xmlns: tools = "http://schemas.android.com/tools" xmlns: android = "http://schemas.android.com/apk/res/android"> <EditText android: id = "@ + id/et_url" android: layout_height = "wrap_content" android: layout_width = "fill_parent" android: text = "http://www.baidu.com"/> <Button android: id = "@ + id/bt_looksource" android: layout_height = "wrap_content" android: layout_width = "fill_parent" android: text = "view image"/>-<ScrollView android: layout_height = "wrap_content" android: layout_width = "wrap_content"> <ImageView android: id = "@ + id/img_pic" android: layout_height = "match_parent" android: layout_width = "match_parent"/> </ScrollView> </LinearLayout>Image Display Control

 

Java

 

Package com. itheima. sourcelook; import java. io. inputStream; import java.net. httpURLConnection; import java.net. URL; import java.net. URLConnection; import android. OS. bundle; import android. OS. handler; import android. OS. logoff; import android. OS. message; import android. app. activity; import android. content. context; import android. graphics. bitmap; import android. graphics. bitmapFactory; import android. text. textUtils; Import android. view. menu; import android. view. view; import android. view. view. onClickListener; import android. widget. button; import android. widget. editText; import android. widget. imageView; import android. widget. textView; import android. widget. toast; import com. itheima. piclook. r; public class MainActivity extends Activity implements OnClickListener {private EditText et_url; private ImageView img_pic; priva Te Context mContext; @ Override protected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); mContext = this; et_url = (EditText) findViewById (R. id. et_url); Button bt_looksource = (Button) findViewById (R. id. bt_looksource); img_pic = (ImageView) findViewById (R. id. img_pic); // 2. set the Click Event bt_looksource.setOnClickListener (this); System. out. Println ("oncreate method Thread:" + Thread. currentThread (). getName ();} // ☆☆☆1. create a Handler object private Handler handler = new Handler () {// ☆☆☆2. override the handlermessage method of handler to receive the public void handleMessage (android. OS. message msg) {// ☆☆☆5. receives data sent by the subthread and processes the data. Bitmap bitmap = (Bitmap) msg. obj; // ☆☆☆6. the current method belongs to the main thread which can be used to update the UI // 5. obtain the content returned by the server and display it on the textview img_pic.setImageBitmap (bitmap); // set the image content of the ImageView };}; @ Override public void onClick (View v) {try {// 3. in the oclick method, obtain the url entered by the user. final String url_str = et_url.getText (). toString (). trim (); if (TextUtils. isEmpty (url_str) {Toast. makeText (mContext, "url cannot be blank", 0 ). show (); return;} System. out. println ("oclick method thread:" + Thre Ad. currentThread (). getName (); // create a subthread for network requests new Thread (new Runnable () {@ Override public void run () {try {System. out. println ("oclick method runnable Thread:" + Thread. currentThread (). getName (); // 4. request url // 1. create a Url object URL = new url (url_str); // 2. obtain the url of the UrlConnection object HttpURLConnection connection = (HttpURLConnection. openConnection (); // 3. set Request Parameters, request methods, and connection timeout for the UrlConnection object. setRequestM Ethod ("GET"); // sets the request method connection. setConnectTimeout (1000*10); // set the timeout time // 4. before obtaining the data of a url request, you need to determine the response code: 200: Successful, 206: access part of the data is successful. 300: jump or redirect: 400: Error 500: Server exception int code = connection. getResponseCode (); if (code = 200) {// 5. obtain valid data and parse the obtained stream data to String InputStream inputStream = connection. getInputStream (); // converts a read stream into an image Drawable, Btimap: bitmap ????? Bitmap bitmap = BitmapFactory. decodeStream (inputStream); // ☆☆☆3. Create a Message object in the subthread to carry the data obtained in the subthread to the main thread. Message msg = Message. obtain (); // gets a Message object. The internal implementation is: if the previous Message exists, it will be returned directly. If no new Message is created, msg will be returned. obj = bitmap; // encapsulate the obtained data into msg. // ☆☆☆4. Use the handler object to send the message to the main thread. Handler. sendMessage (msg) ;}} catch (Exception e) {e. printStackTrace ();}}}). start ();} catch (Exception e) {e. printStackTrace ();}}}MainActivity

 

Byte stream operations

Package com. itheima. sourcelook; import java. io. byteArrayOutputStream; import java. io. inputStream; public class StreamUtils {public static String streamToString (InputStream in) {String result = ""; try {// create a byte array to write the stream ByteArrayOutputStream out = new ByteArrayOutputStream (); byte [] buffer = new byte [1024]; int length = 0; while (length = in. read (buffer ))! =-1) {out. write (buffer, 0, length); out. flush ();} result = out. toString (); // convert byte streams to string out. close ();} catch (Exception e) {e. printStackTrace ();} return result ;}}StreamUtils

 

Instructor notes

04 network image Viewer


Adb shell + input text content; you can input the content to the input box on the mobile phone.

Replace a read flow with a bitmap object:

BitmapFactory: converts a file, read stream, and byte array into a Bitmap object.
Bitmap bitmap = BitmapFactory. decodeStream (InputStream in );

ImageView. setImageBitmap (bitmap); // sets the image content