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Two methods in java.util.Collection create an array from a collection: Object[] toArray() <T> T[] toArray(T[] a) Object[] toArray() can be used as follows: Java SE 5 Set<String> set = new HashSet<String>(); set.add("red"); set.add("blue"); ...

Methods can also have generic type parameters. public class Example { // The type parameter T is scoped to the method // and is independent of type parameters of other methods. public <T> List<T> makeList(T t1, T t2) { List<T> result = new ArrayList<T&...

When we create a button in layout, we can use the android:onClick attribute to reference a method in code to handle clicks. Button <Button android:width="120dp" android:height="wrap_content" android:text="Click me" android:onClick="handleCl...

Java SE 5 Since Java 1.5 you can get a String representation of the contents of the specified array without iterating over its every element. Just use Arrays.toString(Object[]) or Arrays.deepToString(Object[]) for multidimentional arrays: int[] arr = {1, 2, 3, 4, 5}; System.out.println(Arrays.toS...

Java 7 introduced the very useful Files class Java SE 7 import java.nio.file.Files; import java.nio.file.Paths; import java.nio.file.Path; Path path = Paths.get("path/to/file"); try { byte[] data = Files.readAllBytes(path); } catch(IOException e) { e.printStackTrace();...

When we create any View in layout, we can use the android:onClick attribute to reference a method in the associated activity or fragment to handle the click events. XML Layout <Button android:id="@+id/button" ... // onClick should reference the method in your activity or fra...

Strings can be internationalised by defining a different strings.xml for each language you support. You add a new language by creating a new values directory with the ISO language code as a suffix. For example, when adding a German set your structure might look like follows: When the system look...

Strings are typically stored in the resource file strings.xml. They are defined using a <string> XML element. The purpose of strings.xml is to allow internationalisation. You can define a strings.xml for each language iso code. Thus when the system looks for the string 'app_name' it first che...

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...

If your model has private methods, the databinding library still allows you to access them in your view without using the full name of the method. Data model public class Item { private String name; public String getName() { return name; } } Layout XML <?xml versi...

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...

From the documentation: The exception that is thrown when an application attempts to perform a networking operation on its main thread. This is only thrown for applications targeting the Honeycomb SDK or higher. Applications targeting earlier SDK versions are allowed to do networking on their ma...

In order to compare Strings for equality, you should use the String object's equals or equalsIgnoreCase methods. For example, the following snippet will determine if the two instances of String are equal on all characters: String firstString = "Test123"; String secondString = "Test...

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...

Java SE 7 Java 7 introduced the Diamond1 to remove some boiler-plate around generic class instantiation. With Java 7+ you can write: List<String> list = new LinkedList<>(); Where you had to write in previous versions, this: List<String> list = new LinkedList<String>()...

package com.example; import android.os.Bundle; import android.support.annotation.Nullable; import android.util.Log; import android.view.View; import android.view.ViewTreeObserver; public class ExampleActivity extends Activity { @Override protected void onCreate(@Nullable final ...