In this tutorial, we will show you how to develop and deploy a Spring 3.0 MVC REST web application in Google App Engine (GAE) environment. Tools and technologies used : Google App Engine Java SDK 1.6.3.1 Spring 3.1.1 JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Note This example is going to reuse this […]
This article shows how to convert an PNG image format to an JPEG image format in Java. 1. PNG Image Below is a PNG image with a transparent background. 2. Java Convert PNG to JPEG Since the JPEG image format doesn’t support the transparent background, we will create a white background as a replacement. Below […]
Often times, you need c or gcc compiler to compile open source projects in Mac OS X. The problem is Mac OS X doesn’t install the gcc compiler by default. If you try to install or compile some projects that required c/gcc compiler, following errors message will be logged : configure: error: C compiler cannot […]
In this tutorial, we will show you how to develop and deploy a JSF 2.0 web application in Google App Engine (GAE) environment. Tools and technologies used : JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 JSF 2.1.7 Note This example is going to reuse this JSF 2.0 […]
Problem Deployed on GAE production environment, when navigate from one page/view to another page/view, GAE shows error message “View xxx could not be restored“? JSF 2.1.7 Google App Engine SDK 1.6.3 P.S No problem at local GAE development. Solution By default, JSF 2 is using server for session management, and it’s not supported in GAE […]
Long live classic Struts 1 framework, in this tutorial, we will show you how to develop a Struts 1.x web application in Google App Engine (GAE) environment. Tools and technologies used : JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 Struts 1.3.10 Note You may also interest at […]
In this tutorial, we will show you how to develop Struts 2 web application in Google App Engine (GAE) environment. Tools and technologies used : JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 Struts 2.3.1.2 Note Before proceed on this tutorial, make sure you read this – GAE […]
Problem JSF application is able to deploy on local GAE environment, with following development environment : JSF 2.1.7 Google App Engine SDK 1.6.3 But hit error message while deployed on GAE production environment. Below is the logged error messages from GAE. com.sun.faces.config.ConfigureListener installExpressionFactory: Unable to instantiate ExpressionFactory ‘com.sun.el.ExpressionFactoryImpl’ E 2012-04-24 03:37:37.989 com.sun.faces.config.ConfigureListener contextInitialized: Critical error […]
Problem Using Eclipse 3.7 + Google Plugin for Eclipse to develop GAE project, when created a .jsp file in “war” directory, Eclipse shows a cross error icon on top of the JSP file. In Eclipse problem view, it show “Your project must be configured to use a JDK in order to use JSPs.“. Solution To […]
Problem Developing Struts2 on Google App Engine, in following environment. Struts 2.3.1.2 freemaker 2.3.18 JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 GAE complaints that javax.swing.tree.TreeNode is a restricted class in local development, if deployed on real GAE production environment, error message is gone. Caused by: java.lang.NoClassDefFoundError: javax.swing.tree.TreeNode […]
Problem Developing JSF (2.1.7) web application with Google App Engine (1.6.3), hits following error message : java.lang.NoClassDefFoundError: javax.naming.InitialContext is a restricted class. Please see the Google App Engine developer’s guide for more details. at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51) at com.sun.faces.config.WebConfiguration.processJndiEntries(WebConfiguration.java:687) at com.sun.faces.config.WebConfiguration.<init>(WebConfiguration.java:134) at com.sun.faces.config.WebConfiguration.getInstance(WebConfiguration.java:194) at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:163) //… Solution Java clsss – javax.naming.InitialContext, is not supported in Google App […]
Problem Developing Struts2 on Google App Engine, in following environment. Struts 2.3.1.2 JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 Just started a simple Struts2 hello world example, when access the action class, hit error “Error: result ‘null’ not found”, in both local development and real production GAE […]
For this tutorial, we will show you how to integrate Google user account in GAE + Java project, via Google Java SDK UserService class. Tools used : JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 1. GAE User service example If user login by using their Google account, […]
You can use command “appcfg download_app” to download uploaded application from GAE, see signature below : AppCfg [options] -A app_id [ -V version ] download_app <out-dir> AppCfg download example Assume you have uploaded an application with app_id “mkyong-springmvc” to GAE, to download it back on your computer, use following command : D:\appengine-java-sdk-1.6.3.1\bin>appcfg -A mkyong-springmvc download_app […]
Problem Forgot what i did, may be installed m2eclipse plguin, it made the M2_REPO classpath variable is unable to edit. Select Windows -> Preferences -> Java -> Build Path -> Classpath Variables. Eclipse come with embedded Maven and have this M2_REPO classpath variable default non modifiable also. Figure – M2_REPO is non modifiable Solution To […]
In this tutorial, we will show you how to use Eclipse to create a Google App Engine (GAE) Python web project (hello world example), run it locally, and deploy it to Google App Engine account. Tools used : Python 2.7 Eclipse 3.7 + PyDev plugin Google App Engine SDK for Python 1.6.4 P.S Assume Python […]
Problem Developing Struts2 (v 2.3.1.2) on Google App Engine (SDK v1.6.3.1), local development, hit “java.security.AccessControlException: access denied” error? Solution Normally, this is because you turn the “devMode on” in struts.xml file. File : struts.xml <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.devMode" value="true" /> //… </struts> […]
In this tutorial, we will show you how to use Eclipse to create a Google App Engine (GAE) Java project (hello world example), run it locally, and deploy it to Google App Engine account. Tools used : JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Google App Engine Java SDK 1.6.3.1 Note GAE supports […]
In this tutorials, we will show you how to install “Google Plugin for Eclipse“, in Eclipse 3.7 (Indigo). 1. Installation In Eclipse 3.7, click “Help” –> “Install New Software…“, copy and paste following URL : http://dl.google.com/eclipse/plugin/3.7 Note For other Eclipse version like 3.3, 3.4, 3.5, 3.6, please refer to this GAE Eclipse documentation. Figure : […]
Problem While installing Google Plugin for Eclipse 3.7, via http://dl.google.com/eclipse/plugin/3.7 , it took almost half and hour and download and stopped at the end. A long list of error messages “.jar has been tampered!” are prompted in Eclipse. An error occurred while collecting items to be installed session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=). No repository […]
1. Problem While installing Google plugin for Eclipse, hit following weird error messages, and caused a long download time and stopped at the end. "Install download" has encountered a problem "Install download1" has encountered a problem "Install download2" has encountered a problem "Install download3" has encountered a problem "Install download4" has encountered a problem See […]
Android tutorial with full example, including Android UI controls, layouts, common application and some FAQs.
In Android, you can use Intent.ACTION_SEND to call an existing email client to send an Email. See following code snippets : Intent email = new Intent(Intent.ACTION_SEND); email.putExtra(Intent.EXTRA_EMAIL, new String[]{"[email protected]"}); email.putExtra(Intent.EXTRA_SUBJECT, "subject"); email.putExtra(Intent.EXTRA_TEXT, "message"); email.setType("message/rfc822"); startActivity(Intent.createChooser(email, "Choose an Email client :")); P.S This project is developed in Eclipse 3.7, and tested with Samsung Galaxy S2 (Android […]
In Android, you can use SmsManager API or device’s Built-in SMS application to send a SMS message. In this tutorial, we show you two basic examples to send SMS message : SmsManager API SmsManager smsManager = SmsManager.getDefault(); smsManager.sendTextMessage("phoneNo", null, "sms message", null, null); Built-in SMS application Intent sendIntent = new Intent(Intent.ACTION_VIEW); sendIntent.putExtra("sms_body", "default content"); sendIntent.setType("vnd.android-dir/mms-sms"); […]
In Android, you can use PackageManager , hasSystemFeature() method to check if a device has camera, gps or other features. See full example of using PackageManager in an activity class. package com.mkyong.android; import android.app.Activity; import android.content.Context; import android.content.pm.PackageManager; import android.os.Bundle; import android.util.Log; public class FlashLightActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); […]
In this tutorial, we show you how to turn on/off the phone camera led or flashlight in Android. See code snippets : 1. Turn on camera = Camera.open(); Parameters p = camera.getParameters(); p.setFlashMode(Parameters.FLASH_MODE_TORCH); camera.setParameters(p); camera.startPreview(); 2. Turn off camera = Camera.open(); Parameters p = camera.getParameters(); p.setFlashMode(Parameters.FLASH_MODE_OFF); camera.setParameters(p); camera.stopPreview(); And, put following permission on AndroidManifest.xml. <uses-permission […]
A small Android tip to show you how to center button on screen. Wrap button in RelativeLayout, and set following attributes to “true“. android:layout_centerVertical="true" android:layout_centerHorizontal="true" Following is a full example to demonstrate the use of above tip to center a button on screen. 1. Android Layout A button in layout. File : res/layout/main.xml <?xml version="1.0" […]
In Android, Toast is a notification message that pop up, display a certain amount of time, and automtaically fades in and out, most people just use it for debugging purpose. Code snippets to create a Toast message : //display in short period of time Toast.makeText(getApplicationContext(), "msg msg", Toast.LENGTH_SHORT).show(); //display in long period of time Toast.makeText(getApplicationContext(), […]
This tutorial will show you how to debug Android application on a real Android-powered device (mobile phone). Tools and environment in this tutorial : Eclipse IDE 3.7 + ADT Plugin Samsung Galaxy S2 Windows 7 Summary steps to debug on device : Download Google USB Driver (if using Android Developer Phones (ADP)) Download OEM USB […]
In this tutorial, we show you how to create a custom dialog in Android. See following steps : Create a custom dialog layout (XML file). Attach the layout to Dialog. Display the Dialog. Done. P.S This project is developed in Eclipse 3.7, and tested with Android 2.3.3. Note You may also interest to read this […]
For Android development on real device like Samsung Galaxy S2, you need to install Samsung OEM driver or USB driver. This Android OEM driver documentation will guide you where to download it… but the guide is not easy to follow. Actually, the “Samsung USB driver” is included in the software called “Samsung Kies or PC […]
In this tutorial, we will enchance the previous AlertDialog example, to make it able to accept user input, just like a PromptDialog. More specific, this is a custom AlertDialog example. See following steps : Create a prompt dialog layout (XML file). Attach the prompt dialog layout to AlertDialog.Builder. Attach the AlertDialog.Builder to AlertDialog. Done. P.S […]
In this tutorial, we show you how to display an alert box in Android. See flowing Steps : First, use the AlertDialog.Builder to create the alert box interface, like title, message to display, buttons, and button onclick function Later attach above builder to AlertDialog and display it. Done. P.S This project is developed in Eclipse […]
In this tutorial, we show you how to make a phone call in Android,and monitor the phone call states via PhoneStateListener. P.S This project is developed in Eclipse 3.7, and tested with Android 2.3.3. 1 Android Layout Files Simpel layout file, to display a button. File : res/layout/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’s WebView allows you to open an own windows for viewing URL or custom html markup page. In this tutorial, you will create two pages, a page with a single button, when you clicked on it, it will navigate to another page and display URL “google.com” in WebView component. P.S This project is developed in […]
In this tutorial, we will demonstrates the use of TabLayout to render 4 tabs – “Android”, “Windows”, “Apple” and “BlackBerry”, each tab contains a textview to display a simple message. P.S This project is developed in Eclipse 3.7, and tested with Android 2.3.3. 1. Tab Images Put 4 tab images in “res/drawable” folder. The tab […]
In Eclipse, to import a single class, you may clicked on the class and press shortcut key “Ctrl + Space” to prompt all the available classes to import. However, if you copied a Java source code from somewhere and more than 20+ classes are not import, are you going to press “Ctrl + Space” one […]
Often times, after code refactor or bug fixed, Eclipse IDE will show a yellow underline for all unsed imports at the top of your class and said “The import xxx is never used“. To remove those unused imports automatically, just click on the class and press the shortcut “Ctrl + Shift + O” to initilize […]
In Android, GridView let you arranges components in a two-dimensional scrolling grid. For detail attribute exaplanation, see GridView reference. In this tutorial, we will show you 2 common GridView examples : Normal way, just display text in GridView layout. Create a custom adapter to display image and text in GridView layout. P.S This project is […]
By default, Eclipse’s editor will not display line numbers, it’s no good for debugging. Here’s a tip to show you how to turn on the “display line numbers” feature in Eclipse. In Eclipse IDE, select “Windows” > “Preference” > “General” > “Editors” > “Text Editors” , check on the “Show line numbers” option. See result.
