Tutorial by Examples: f

In order to define a string array write in a resources file res/values/filename.xml <string-array name="string_array_name"> <item>text_string</item> <item>@string/string_id</item> </string-array> for example res/values/arrays.xml <?x...

Dimensions are typically stored in a resource file names dimens.xml. They are defined using a <dimen> element. res/values/dimens.xml <?xml version="1.0" encoding="utf-8"?> <resources> <dimen name="small_padding">5dp</dimen> &l...

Integers are typically stored in a resource file named integers.xml, but the file name can be chosen arbitrarily. Each integer is defined by using an <integer> element, as shown in the following file: res/values/integers.xml <?xml version="1.0" encoding="utf-8"?> &...

In order to define an integer array write in a resources file res/values/filename.xml <integer-array name="integer_array_name"> <item>integer_value</item> <item>@integer/integer_id</item> </integer-array> for example res/values/arrays.xm...

Gradle (Module:app) Configuration android { .... dataBinding { enabled = true } } Data model public class Item { public String name; public String description; public Item(String name, String description) { this.name = name; this.descr...

Data model public class Item { private String name; public String getName() { return name; } } Layout XML You must import referenced classes, just as you would in Java. <?xml version="1.0" encoding="utf-8"?> <layout xmlns:android="h...

/** * Interface with default method */ public interface Printable { default void printString() { System.out.println( "default implementation" ); } } /** * Class which falls back to default implementation of {@link #printString()} */ public class WithDefault...

You can as well access other interface methods from within your default method. public interface Summable { int getA(); int getB(); default int calculateSum() { return getA() + getB(); } } public class Sum implements Summable { @Override public int get...

if (i < 2) { System.out.println("i is less than 2"); } else if (i > 2) { System.out.println("i is more than 2"); } else { System.out.println("i is not less than 2, and not more than 2"); } The if block will only run when i is 1 or less. The else if...

for (int i = 0; i < 100; i++) { System.out.println(i); } The three components of the for loop (separated by ;) are variable declaration/initialization (here int i = 0), the condition (here i < 100), and the increment statement (here i++). The variable declaration is done once as if pl...

Java SE 5 With Java 5 and up, one can use for-each loops, also known as enhanced for-loops: List strings = new ArrayList(); strings.add("This"); strings.add("is"); strings.add("a for-each loop"); for (String string : strings) { System.out.println(string); } For each ...

public class MyActivity extends Activity { private static final String PREFS_FILE = "NameOfYourPrefrenceFile"; // PREFS_MODE defines which apps can access the file private static final int PREFS_MODE = Context.MODE_PRIVATE; // you can use live template "key"...

int i = 2; if (i < 2) { System.out.println("i is less than 2"); } else { System.out.println("i is greater than 2"); } An if statement executes code conditionally depending on the result of the condition in parentheses. When condition in parentheses is true it will ...

It is helpful to filter the logcat output because there are many messages which are not of interest. To filter the output, open the "Android Monitor" and click on the drop down on the top-right and select Edit Filter Configuration Now you can add custom filters to show messages which ar...

Using BufferedReader: System.out.println("Please type your name and press Enter."); BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); try { String name = reader.readLine(); System.out.println("Hello, " + name + "!"); } catch(I...

The Arrays.asList() method can be used to return a fixed-size List containing the elements of the given array. The resulting List will be of the same parameter type as the base type of the array. String[] stringArray = {"foo", "bar", "baz"}; List<String> stringL...

All Swing-related operations happen on a dedicated thread (the EDT - Event Dispatch Thread). If this thread gets blocked, the UI becomes non-responsive. Therefore, if you want to delay an operation you cannot use Thread.sleep. Use a javax.swing.Timer instead. For example the following Timer will re...

Updating the state of a Swing component must happen on the Event Dispatch Thread (the EDT). The javax.swing.Timer triggers its ActionListener on the EDT, making it a good choice to perform Swing operations. The following example updates the text of a JLabel each two seconds: //Use a timer to updat...

In the ActionListener attached to a javax.swing.Timer, you can keep track of the number of times the Timer executed the ActionListener. Once the required number of times is reached, you can use the Timer#stop() method to stop the Timer. Timer timer = new Timer( delay, new ActionListener() { priv...

public interface MyInterface { public void foo(); int bar(); public String TEXT = "Hello"; int ANSWER = 42; public class X { } class Y { } } Interface members always have public visibility, even if the public keyword is omitted. So both foo...