Android mobile guard-Parse json and message mechanisms to send different types of messages, androidjson

Android mobile guard-Parse json and message mechanisms to send different types of messages, androidjson

URL: http://www.cnblogs.com/wuyudong/p/5900800.html.

1. parse json data

Json parsing code is simple

JSONObject jsonObject = new JSONObject (json); // debug, solve the problem String versionName = jsonObject. getString ("versionName"); mVersionDes = jsonObject. getString ("versionDes"); String versionCode = jsonObject. getString ("versionCode"); mDownloadUrl = jsonObject. getString ("downloadUrl"); // Log print Log. I (tag, versionName); Log. I (tag, mVersionDes); Log. I (tag, versionCode); Log. I (tag, mDownloadUrl );

2. Use the message mechanism to send different types of messages

Obtain the app version number after obtaining the server-side json data, and compare it with the client version number.

// Compare the version (server version> local version, prompting the user to update) if (mLocalVersionCode <Integer. parseInt (versionCode) {// prompt for user updates. the pop-up dialog box (UI) and message mechanism msg are displayed. what = UPDATE_VERSION;} else {// enter the main application interface msg. what = ENTER_HOME ;}

You can use the message mechanism of android to send different types of messages. For details, refer to introduction to Android message mechanism.

Create Handler first

Private Handler mHandler = new Handler () {// public void handleMessage (android. OS. message msg) {switch (msg. what) {case UPDATE_VERSION: // the pop-up dialog box prompts the user to update // showUpdateDialog (); break; case ENTER_HOME: // enter the main interface of the application. enterHome (); break; case URL_ERROR: // ToastUtil. show (getApplicationContext (), "url exception"); enterHome (); break; case IO_ERROR: // ToastUtil. show (getApplicationContext (), "Read exception"); enterHome (); break; case JSON_ERROR: // ToastUtil. show (getApplicationContext (), "json parsing exception"); enterHome (); break; default: break ;}};};

You can define some status codes and error codes when exceptions occur:

/*** Update the status code of the new version */protected static final int UPDATE_VERSION = 100;/*** enter the status code of the main interface of the application */protected static final int ENTER_HOME = 101; /*** url address error Status Code */protected static final int URL_ERROR = 102; // The following are other error status codes protected static final int IO_ERROR = 103; protected static final int maid = 104;

Then implement the enterHome () function. function: Jump to the main interface

/*** Enter the main interface of the application */protected void enterHome () {Intent intent = new Intent (this, HomeActivity. class); startActivity (intent); // after a new interface is enabled, close the navigation interface (the navigation interface is visible only once) finish ();}

So by the way, create a HomeActivity. java

public class HomeActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_home);    }}

Of course, there is also an activity_home.xml file, add a little code, first see the effect, and then modify

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <TextView        android:text="HOMEACTIVITY"        android:textSize="20sp"        android:textColor="#000"        android:layout_width="wrap_content"        android:layout_height="wrap_content" /></LinearLayout>

After running the project, it is found that when no version update is available, the splash interface will stay for a short time, so you can specify the sleep time. When the request network duration exceeds 4 seconds, no processing will be performed, if the request network duration is less than 4 seconds, it is forced to sleep for 4 seconds. In this way, the splash interface will stay for a while and then jump to the HomeActivity interface.

// Specify the sleep time. If the request network duration is greater than 4 seconds, no processing is performed. // The request network duration is less than 4 seconds. Force the request to sleep for 4 seconds. long endTime = System. currentTimeMillis (); if (endTime-startTime <4000) {try {Thread. sleep (4000-(endTime-startTime);} catch (Exception e) {// TODO Auto-generated catch block e. printStackTrace () ;}} mHandler. sendMessage (msg );

The complete code is as follows:

Package com. wuyudong. mobilesafe. activity; import java. io. IOException; import java. io. inputStream; import java.net. httpURLConnection; import java.net. malformedURLException; import java.net. URL; import org. json. JSONException; import org. json. JSONObject; import com. wuyudong. mobilesafe. r; import com. wuyudong. mobilesafe. utils. streamUtil; import android. OS. bundle; import android. OS. handler; import android. OS. message; Import android. app. activity; import android. content. intent; import android. content. pm. packageInfo; import android. content. pm. packageManager; import android. util. log; import android. widget. textView;/*** @ author wuyudong ***/public class SplashActivity extends Activity {protected static final String tag = "SplashActivity "; /*** update the status code of the new version */protected static final int UPDATE_VERSION = 100;/*** enter the application Status Code */protected static final int ENTER_HOME = 101;/*** url address error Status Code */protected static final int URL_ERROR = 102; // The following are other error status codes protected static final int IO_ERROR = 103; protected static final int JSON_ERROR = 104; private TextView TV _version_name; private int mLocalVersionCode; private String mVersionDes; private String mDownloadUrl; private Handler mHandler = new Handler () {// public vo Id handleMessage (android. OS. message msg) {switch (msg. what) {case UPDATE_VERSION: // the pop-up dialog box prompts the user to update // showUpdateDialog (); break; case ENTER_HOME: // enter the main interface of the application. enterHome (); break; case URL_ERROR: // ToastUtil. show (getApplicationContext (), "url exception"); enterHome (); break; case IO_ERROR: // ToastUtil. show (getApplicationContext (), "Read exception"); enterHome (); break; case JSON_ERROR: // ToastUtil. show (ge TApplicationContext (), "json parsing exception"); enterHome (); break; default: break ;};};@ Override protected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); // remove the tittle of the current actinity // requestWindowFeature (Window. FEATURE_NO_TITLE); setContentView (R. layout. activity_splash); // initialize the UI initUI (); // initialize the data initData ();}/*** enter the main interface of the application */protected void enterHome () {Intent intent = New Intent (this, HomeActivity. class); startActivity (intent); // after a new interface is enabled, close the navigation interface (the navigation interface is visible only once) finish ();} /*** method for obtaining data */private void initData () {// 1. application version name TV _version_name.setText ("version name:" + getVersionName (); // checks whether (the local version number is compared with the server version number) is updated. If yes, prompt the user to download // 2. get the local version number mLocalVersionCode = getVersionCode (); // 3, get the server version number (client sends a request, the service returns a response, (json, xml) // http://www.oxxx.com/update74.json? Key = value: the 200 request is returned successfully. The data is read in the stream mode. // The json content includes: /** updated version name | description of the new version | Server version number | New Version apk */checkVersion ();}/*** check version number */private void checkVersion () {new Thread () {public void run () {// send a request to obtain data. The parameter is the URL of the Request json // http: // 192.168.13.99: 8080/update. the json test phase is not optimal // only the simulator accesses the computer tomcat Message msg = Message. obtain (); long startTime = System. currentTimeMillis (); try {// 1, encapsulate the url URL url = new URL ("http: // 169.254.178.87: 8080/update. json "); // 2, enable a link HttpURLConnection connection = (HttpURLConnection) url. openConnection (); // 3. Set common request parameters (request header) // request timeout connection. setConnectTimeout (2000); // read timeout connection. setReadTimeout (2000); // The default value is the get Request Method // connection. setRequestMethod ("POST"); // 4. Obtain the request success response code if (connection. getResponseCode () = 200) {// 5. Get the data in the form of a stream. InputStream is = connection. getInputStream (); // 6, replace the stream with a String (Tool class encapsulation) String json = StreamUtil. streamToString (is); // remember to add permissions --> android. permission. INTERNET Log. I (tag, json); // 7, json parsing JSONObject jsonObject = new JSONObject (json); // debug debugging to Solve the Problem String versionName = jsonObject. getString ("versionName"); mVersionDes = jsonObject. getString ("versionDes"); String versionCode = jsonObject. getString ("versionCode"); mDownloadUrl = jsonObject. getString ("downloadUrl"); // Log print Log. I (tag, versionName); Log. I (tag, mVersionDes); Log. I (tag, versionCode); Log. I (tag, mDownloadUrl); // 8, compare the version number (server version> local version number, prompting the user to update) if (mLocalVersionCode <Integer. parseInt (versionCode) {// prompt for user updates. the pop-up dialog box (UI) and message mechanism msg are displayed. what = UPDATE_VERSION;} else {// enter the main application interface msg. what = ENTER_HOME ;}}} catch (MalformedURLException e) {e. printStackTrace (); msg. what = URL_ERROR;} catch (IOException e) {e. printStackTrace (); msg. what = IO_ERROR;} catch (JSONException e) {e. printStackTrace (); msg. what = JSON_ERROR;} finally {// specifies the sleep time. If the request network duration exceeds 4 seconds, no processing is performed. // The request network duration is less than 4 seconds, force it to sleep for 4 seconds long endTime = System. currentTimeMillis (); if (endTime-startTime <4000) {try {Thread. sleep (4000-(endTime-startTime);} catch (Exception e) {// TODO Auto-generated catch block e. printStackTrace () ;}} mHandler. sendMessage (msg );}};}. start ();}/*** Method for returning the version ** @ return non-0 indicates success */private int getVersionCode () {// 1. manager object packageManager PackageManager pm = getPackageManager (); // 2. obtain the basic information (version name, version number) of the specified package name from the package administrator object. try {PackageInfo packageInfo = pm. getPackageInfo (getPackageName (), 0); // 3. get the version name return packageInfo. versionCode;} catch (Exception e) {e. printStackTrace ();} return 0;}/*** get version name: The ** @ return application version name in the configuration file returns null, indicating an exception */private String getVersionName () {// 1. manager object packageManager PackageManager pm = getPackageManager (); // 2. obtain the basic information (version name, version number) of the specified package name from the package administrator object. try {PackageInfo packageInfo = pm. getPackageInfo (getPackageName (), 0); // 3. get the version name return packageInfo. versionName;} catch (Exception e) {e. printStackTrace ();} return null;}/*** initialize the UI method alt + shift + j */private void initUI () {TV _version_name = (TextView) findViewById (R. id. TV _version_name );}}