Tech

We are all waiting for a stable release of Maven3 with following updates .. faster, more performant .. save us time building our software and some precious memory ;) improved artifact resolution api and plugin api better osgi integration a few bugfixes no mixing of application dependencies and tooling dependencies though it does not matter that much to me: polyglot features .. e.g.: “Writing your pom files in Groovy” version-less parent elements for multi-module or multi-pom projects, no need to define the parent version in every submodule better artifact resolution, which dependency or pom supplied which artifact to the outcome .. got that information from: “Splitter from the world of Java” ...

Since version 1.6 Android offers a library for recognition and handling of new gestures using a touch display. With the gesture builder it is possible to capture new gestures in the emulator. Gestures can be integrated into an activity like that. GestureLibrary gLib = GestureLibraries.fromRawResource(this, R.raw.spells); if (!gLib.load()) { finish(); } Furthermore we need a gesture overlay in the UI: <android.gesture.GestureOverlayView android:id="@+id/gestures" android:layout_width="fill_parent" android:layout_height="0dip" android:layout_weight="1.0" /> In the next step we implement an event handler for the gesture (Source: http://developer.android.com/resources/articles/gestures.html): GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures); gestures.addOnGesturePerformedListener(this); public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) { ArrayList<prediction> predictions = mLibrary.recognize(gesture); if (predictions.size() > 0) { Prediction prediction = predictions.get(0); if (prediction.score > 1.0) { Toast.makeText(this, prediction.name, Toast.LENGTH_SHORT).show(); } } } ...

The integration of gestures into your android app adds some nice functionality and is made very easy using Google’s GestureBuilder application and the integrated GestureLibrary and Gesture Overlay API – so let’s build a sample app. If you need some basic information regarding gestures on android first – take a look at this article. Creating a gesture library First you need to define the gestures that should be captured in the application later. For this reason there’s the GestureBuilder delivered with the Android SDK. You can find the app in the samples directory of your android sdk – e.g. <installation-directory>/android-sdk-linux_86/platforms/android-2.1/samples/GestureBuilder. ...

Sometimes QR codes are a nice way to distribute information like calendar events, contact information, e-mail, geo-locations or internet addresses. In the following article we’re going to encode information to QR code images using the ZXing library and afterwards decode information from a given QR code. Finally we’re taking a look on online QR code generators and how to integrate the ZXing library in a Maven project. The ZXing Library Download the ZXing Libraries from http://code.google.com/p/zxing/downloads/list – the file name is ZXing-<version>.zip Unpack the downloaded archive somewhere Change to the extracted directory and run ant. If you don’t have JavaME installed – and you don’t have to for the samples below – run ant buildwithoutj2me – that will do the job Having compiled the libraries you’re now free to include the core.jar from zxing-<version>/core/ and the javase.jar from zxing-<version>/javase as dependency in your project ...

Sometimes one needs to look up license details of a running Confluence system .. perhaps for creating a commercial plugin or to display recommendations dependant from the license used. For this reason there are a few possibilities for receiving some license information from the Confluence API or the velocity context. Note: This article is outdated since the Atlassian Marketplace was launched and a shiny new licensing API was added. Until this article is updated I strongly recommend to take a closer look at the detailed information that Atlassian is providing in the Developer Documentation. ...

Sound recording and playback is really simple using the MediaRecorder and MediaPlayer classes .. see the example below .. Sample App First some layout .. a button to start/stop recording and a button to play the recorded stuff (main.xml): <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:id="@+id/output" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="" /> <Button android:text="@+string/record" android:id="@+id/btRecord" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button> <Button android:text="@+string/play" android:id="@+id/btPlay" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button> </LinearLayout> Adjusting the externalized strings in the strings.xml <?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">Soundrecorder Tutorial</string> <string name="record">Record!</string> <string name="play">Play</string> </resources> ...

Here is an example on how to use the accelerometer in your Android application. If you want to simulate the acceleration on the emulator I highly recommend the Sensor Simulator on the OpenIntents website. The following example app displays the coordinates received by the sensor. The Acceleration App The activity – AccelerationActivity.java package com.hascode.android; import android.app.Activity; import android.content.Context; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.os.Bundle; import android.widget.TextView; public class AccellerationActivity extends Activity { private TextView result; private SensorManager sensorManager; private Sensor sensor; private float x, y, z; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); sensor = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER).get(0); result = (TextView) findViewById(R.id.result); result.setText("No result yet"); } private void refreshDisplay() { String output = String .format("x is: %f / y is: %f / z is: %f", x, y, z); result.setText(output); } @Override protected void onResume() { super.onResume(); sensorManager.registerListener(accelerationListener, sensor, SensorManager.SENSOR_DELAY_GAME); } @Override protected void onStop() { sensorManager.unregisterListener(accelerationListener); super.onStop(); } private SensorEventListener accelerationListener = new SensorEventListener() { @Override public void onAccuracyChanged(Sensor sensor, int acc) { } @Override public void onSensorChanged(SensorEvent event) { x = event.values[0]; y = event.values[1]; z = event.values[2]; refreshDisplay(); } }; } ...

In this tutorial we are going to build a simple todo app that is able to store simple todos in a database. The user is able to add new todos or delete old ones by clicking on a todo. For this tutorial we won’t use maven to keep it simple – if maven integration is desired – take a look at this tutorial. Steps Create a new android project using the Android SDK and your IDE Create some packages com.hascode.android.activity and com.hascode.android.persistence Create the layout in res/layout/main.xml – the main elements: a listview for the todos-list, a textbox and a button to enter new data. <?xml version="1.0" encoding="utf-8"?> <RelativeLayout android:id="@+id/widget31" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" > <TableRow android:id="@+id/row" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_below="@+id/tasklist" android:layout_alignParentLeft="true" > <EditText android:id="@+id/etNewTask" android:layout_width="200px" android:layout_height="wrap_content" android:text="" android:textSize="18sp" > </EditText> <Button android:id="@+id/btNewTask" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+string/add_button_name" > </Button> </TableRow> <ListView android:id="@+id/tasklist" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_alignParentLeft="true" > </ListView> </RelativeLayout> ...

There is a nice Maven plugin helping you signing your Android app – the Maven Jar Signer Plugin. If you want to learn more about Maven integration in an android project take a look at this article. Maven Profile Setup Add the following code to your pom.xml <?xml version="1.0"?> <profiles> <profile> <id>sign</id> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jarsigner-plugin</artifactId> <version>1.2</version> <executions> <execution> <id>signing</id> <goals> <goal>sign</goal> </goals> <phase>package</phase> <inherited>true</inherited> <configuration> <archiveDirectory/> <includes> <include>target/*.apk</include> </includes> <keystore>path/to/keystore</keystore> <storepass>storepasword</storepass> <keypass>keypassword</keypass> <alias>key-alias</alias> </configuration> </execution> </executions> </plugin> <plugin> <groupId>com.jayway.maven.plugins.android.generation2</groupId> <artifactId>maven-android-plugin</artifactId> <inherited>true</inherited> <configuration> <sign> <debug>false</debug> </sign> </configuration> </plugin> </plugins> </build> </profile> </profiles> ...

Searching for nice coding kata sites I found this one – codingkata.org – I really liked because of the quick start and nice maven integration. Just head over to the kata overview select the kata you wish to try out, copy the generated maven command line option and run it in the console – heres the code for the hello-world sample: Coding Katas from Maven Archetype mvn archetype:generate -DinteractiveMode=false -DarchetypeRepository=http://www.codingkata.org/repo/release -DarchetypeGroupId=org.codingkata.template -DarchetypeArtifactId=solv-java-archetype -DarchetypeVersion=1.04 -DgroupId=org.codingkata.unit -DartifactId=hello-world-solv-java -DkataId=hello-world -DkataVersion=1.02 -DlangVersion=1.6 -DlibVersion=1.3.2 -Dversion=1271358 ...