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android:questions [2010/03/16 18:00]
hevi 		android:questions [2010/03/19 08:32] (current)
ppuro
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 ====== Android Coding Questions ====== ====== Android Coding Questions ======
 +
 +
 +==== Where's an example of layout used by ListActivity? ====
 +
 +<code>
 +
 +<?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"
 +         android:paddingLeft="8dp"
 +         android:paddingRight="8dp">
 + 
 +    <ListView android:id="@id/android:list"
 +               android:layout_width="fill_parent" 
 +               android:layout_height="fill_parent"
 +               android:layout_weight="1"
 +               android:drawSelectorOnTop="false"/>
 + 
 +  <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/AnotherTextView"></TextView>
 +
 +</LinearLayout>
 +
 +</code>
 +
 +==== How do I start another activity? ====
 +
 +<code>
 +  startActivity(new Intent(this, MyAnotherActivity.class));
 +</code>
 ++ Don't forget to add lines in AndroidManifest.xml
 +
 +==== How to add EditText fields to the table's cells? ====
 +<code>
 +<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
 + android:scrollbars="vertical" android:layout_height="fill_parent"
 + android:layout_width="fill_parent" android:stretchColumns="*">
 + <TableRow android:id="@+id/tablerow1">
 + <EditText android:text="1." android:id="@+id/EditText01"
 + android:editable="false"></EditText>
 + <EditText android:id="@+id/EditText11"></EditText>
 + <EditText android:id="@+id/EditText21"></EditText>
 + </TableRow>
 +</TableLayout>
 +</code>
 +
 +==== How to get Eclipse and Android work in Ubuntu? ====
 +For eclipse you need to use sun java packages (gcc gjc java is installed by default but it does not seem to work well)
 +  * https://help.ubuntu.com/community/Java
 +  * get JDK (SDK) package as well
 +
 +Ubuntu 9.10 repositories have Eclipse 3.5.1. It does not work with Android SDK. Get newer Eclipse. Version 3.5.2 seem to work.
 +  * http://www.eclipse.org => Download => Eclipse for Java (or Java EE (not nessessary)).
 +  * Extract it to your self installed software place (eg. /opt) and link eclipse start program to some place in your PATH.
 +
 +Follow general android install [[setup|instructions]].
 +
 +
 +==== How to save XML file after editing (f.e. adding new child) - what class to use? ====
 +
 +To use XmlSerializer is one option to save XML into readable form (string or file). 
 +
 +See the following link [[http://www.ibm.com/developerworks/xml/library/x-android/|Working with XML on Android]] if that is helpful.
 +
 +<code>
 +
 +private String writeXml(List<Message> messages){
 +    XmlSerializer serializer = Xml.newSerializer();
 +    StringWriter writer = new StringWriter();
 +    try {
 +        serializer.setOutput(writer);
 +        serializer.startDocument("UTF-8", true);
 +        serializer.startTag("", "messages");
 +        serializer.attribute("", "number", String.valueOf(messages.size()));
 +        for (Message msg: messages){
 +            serializer.startTag("", "message");
 +            serializer.attribute("", "date", msg.getDate());
 +            serializer.startTag("", "title");
 +            serializer.text(msg.getTitle());
 +            serializer.endTag("", "title");
 +            serializer.startTag("", "url");
 +            serializer.text(msg.getLink().toExternalForm());
 +            serializer.endTag("", "url");
 +            serializer.startTag("", "body");
 +            serializer.text(msg.getDescription());
 +            serializer.endTag("", "body");
 +            serializer.endTag("", "message");
 +        }
 +        serializer.endTag("", "messages");
 +        serializer.endDocument();
 +        return writer.toString();
 +    } catch (Exception e) {
 +        throw new RuntimeException(e);
 +    } 
 +}
 +
 +</code>
 +==== Does anybody know how to launch another application, e.g. "YouTube" from your own program? ====
 +I know how to launch web-browser, if smb needs I can explain. Also I've installed some applications to the emulator, except YouTube :(. By the way we know how to send data from one activity to another and few other features, that could be useful just ask, may be we've faced with it! Vadim.
 +
 +A: A generic answer to this is that you need to know the intent filter of the started activity/application. When you know the intent filter you can always create intent that is going to match to the filter. Then, it is simply just a call on Context.startActivity(intent). All the "standard" platform applications and their AndroidManifest.xml files are in the public repository.
 +
  
 ==== How to add question ? ==== ==== How to add question ? ====
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 </code> </code>
  
 +
 +==== How to answer a question ? ====
 +Just write a solution text into section, after question.
 +
 +If solution is bigger that one paragraph size (having eg. couple screenshots), it is good idea document solution into separate page.
 +<code>
 +  Solution in [[separate page]]
 +</code>