Best Eclipse Shortcuts

There are many sites listing their top Eclipse shortcuts, but for what it's worth I would like to add my most used keyboard shortcuts since starting with Eclipse...

Ctrl + Shift + O = organise and import missing imports
Alt + Shift + R = refactor (rename variable or method)

Ctrl + 1 (one) = Quick fix popup
Ctrl + D = Delete line
Ctrl + O = Outline (easily navigate to parts of project)
Ctrl + M (or double-click tab) = Maximise source when coding
Ctrl + . = Jump next error or warning

Alt + UP / Alt + DOWN = Move selection up or down

Alt + LEFT / Alt + RIGHT = Jump to recently edited sections

Ctrl + Shift + R = open resource (start typing any file name - like indexed search)
Ctrl + Shift + F - Formats code to settings defined under Window > Preferences > Java > Code Style > Formatter

Setting a style on dynamically created view control

How do I set a TextView or Button style in code?
Styling within Android allows you to define a reusable look-and-feel, much like styles in CSS on a web page. These are very easy to assign in your XML layouts, however you cannot set the style of a View control programmatically. This is a pain if you are building a layout dynamically.

To get around this you can create a template layout xml file with the style assigned, for example in res/layout create tvtemplate.xml as with the following content:

res/layout/tvtemplate.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="This is a template"
        style="@style/my_style" />

then inflate this to instantiate your new TextView:

TextView myText = (TextView)getLayoutInflater().inflate(R.layout.tvtemplate, null);

You can then continue to work with your TextView as usual. There may be other workarounds for this, if you have any please feel free to comment. It's also possible that an Android API update will add a property for this in future.

Adding views to a layout dynamically

How do I add a button to my layout in code?

Firstly add the appropriate import to your Activity class for the view to add, in this case a button:

import android.widget.Button;

Then create a new button object within the activity onCreate method:

Button myButton = new Button(this);
myButton.setText("Tap Me");

Finally add the button to the layout:

LinearLayout layout = (LinearLayout) findViewById(R.id.layout1);
layout.addView(myButton);

Obviously the same logic applies to other views (TextViews, etc).

You might also want to apply fonts to your controls, if so take a look at Using a True-Type Font in your Android app.

Official Android Ice Cream Sandwich image

Tweeted by @AndroidDev earlier today at IO2011...

First Steps: Android project structure in Eclipse

Android Project structure in Eclipse

This article is a quick guide to the breakdown of the project structure of a typical, simple Android project within Eclipse. The numbered items below refer to the image to the right.

1. Project root folder (see 7 for details of individual files)
2. src folder. This is where your java code files are stored.
3. package folder. This is organised by package name with the java class files within.
4. Main.java is a java class file, in this case the main activity. Note the exclamation denoting a compilation warning.
5. Web.java is another java class (without warnings or errors).
6. gen folder. The generated compiled files when a project is built. You do not need to venture into this folder.
7. Google APIs folder. The API library folder.
8. assets folder. This is where you place additional assets for use in your project, such as font (ttf) files.
9. res folder. This is where the resource files are stored, such as your drawables (images), layouts and string values.
10. drawable-hdpi folder. High density drawables (images) for use in your project.
11. drawable-ldpi folder. Low density drawables (images) for use in your project.
12. drawable-mdpi folder. Medium density drawables (images) for use in your project.
13. layout folder. This contains the XML layout files that define the screens in your project.
14. main.xml. This is the layout for the Main activity, defined in Main.java.
15. web.xml. This is the layout for the Web activity, defined in Web.java.
16. values folder. This is where your string (text) definitions are stored. To support multiple languages you would find a values folder per language, for example values-fr.
17. strings.xml. A standard XML file containing named string definitions.
18. AndroidManifest.xml - The hub of your project containing the details on the Activities, Permissions within your app.
19. default.properties -An auto-generated configuration file storing the basic project properties.
20. proguard.cfg - ProGuard can be used to obfuscate your code to prevent nasty code thieves from stealing your secrets. By default this is not applied to the code but the configuration file is still present.

Typically you will place any additional referenced Java libraries (.jar files) into a libs folder.

Hopefully this will help an Android newbie opening up a new project for the first time.

Using a True-Type Font in your Android app

Android supports true-type fonts, but these have to be set in code, you cannot specify the fonts in the layout XML.

Firstly copy the font file into your assets folder. I usually create a fonts sub-folder:

project/assets/fonts/myfont.ttf

Second, and finally, apply the font to a TextView in code:

TextView tv = (TextView)findViewById(R.id.TextView1);
Typeface face = Typeface.createFromAsset(getAssets(), "fonts/myfont.ttf");
tv.setTypeface(face);

TextViews, Buttons, CheckedTextView and RadioButtons all have the setTypeface method, but as a note of warning, not all .ttf files will necessarily display in your Android app, if it fails your app will force close with the following error: RuntimeException: native typeface cannot be made.

How to Fix Screen Orientation

How do I stop my Android app rotating?

There are a number of reasons that you may want to prevent your screen from rotating. When an Android device is rotated, by default the currently running activity is restarted. This will often require you to code to maintain the state that the activity was in prior to rotation. Alternatively you may simply want to display only in landscape, perhaps for a game.

To fix your screen orientation, simply set the screenOrientation attribute of the activity within your project manifest, as shown below, to either portrait or landscape:

<activity
    android:name=".myActivity"
    android:screenOrientation="portrait">

You can also do the same thing in code:

myActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

Please refer to the official documentation for more details.