- #CREATING A SIMPLE ANDROID APP UPDATE#
- #CREATING A SIMPLE ANDROID APP CODE#
- #CREATING A SIMPLE ANDROID APP PLUS#
Localize your app to different languages by providing alternative definitions for eachīy default, your Android project includes a string resource file at Externalizing the strings also allows you to
#CREATING A SIMPLE ANDROID APP UPDATE#
Which makes it easier to find and update text. String resources allow you to manage all UI text in a single location, When you need to add text in the user interface, you should always specify each string asĪ resource. To resources are always scoped by the resource type (such as id or string), so using Note: This string resource has the same name as the element ID: You'll fix this in the next section by defining the string. However, because you haven't defined the string resource yet, you’ll see aĬompiler error at first. Because this refers to a concrete resource (not just an identifier), it does not String as the value, the value refers to a string resource defined inĪ separate file. android:hint This is a default string to display when the text field is empty. For more information, see the Layouts guide. Were to instead use "match_parent", then the EditTextĮlement would fill the screen, because it would match the size of the parent LinearLayout. Specifies that the view should be only as big as needed to fit the contents of the view. android:layout_width and android:layout_height Instead of using specific sizes for the width and height, the "wrap_content" value Needed for concrete resources such as strings or layouts.
#CREATING A SIMPLE ANDROID APP PLUS#
Using the plus sign is necessary only when specifying a new resource ID and not Once the resource ID is declared once this way, Your project's gen/R.java file that refers to the EditText element. The SDK tools use the ID name to create a new resource ID in The plus sign ( +) before the resource type is needed only when you're defining a It is followed by the resource type ( id in this case), a slash, then the resource name
The at sign ( is required when you're referring to any resource object from You should neverįor more information, read the guide to Providing Resources.Ībout these attributes: android:id This provides a unique identifier for the view, which you can use to reference the objectįrom your app code, such as to read and manipulate the object (you'll see this in the next The SDK tools generate the R.java each time you compile your app. Which allows you to reference that view from other code. You can also create arbitrary resource IDs that you associate with a view using the android:id attribute, Object names in the R class to refer to your resources, such as when you need to specify aĪttribute. Such as a bitmap, layout file, or string.Ĭorresponding resource object defined in your project's gen/R.java file. Here’s how you should declare itĪ resource object is simply a unique integer name that's associated with an app resource, Like every View object, you must define certain XML attributes to specify To create a user-editable text field, add an element inside the. Or height to match the width or height of the parent view.įor more information about layout properties, see the Layout guide. This value declares that the view should expand its width The other two attributes, android:layout_width and android:layout_height, are required for all views in order to specify their size.īecause the LinearLayout is the root view in the layout, it should fillĪvailable to the app by setting the width and height to The screen in the order in which it appears in the XML.
LinearLayout is a view group (a subclass of ViewGroup) that lays out child views in either a vertical or horizontal orientation,Īs specified by the android:orientation attribute. Then add theĪndroid:orientation attribute and set it to "horizontal". The BlankActivity template you chose when you created this project includes theĪctivity_main.xml file with a RelativeLayout root view and a TextView child view.įirst, delete the element and change the element to. The bottom of the screen to open the XML editor.
Lesson, you’re going to work directly with the XML, so click the activity_main.xml tab at This is an editor that helps you build layouts using WYSIWYG tools. Note: In Eclipse, when you open a layout file, you’re first shown Open the activity_main.xml file from the res/layout/ In the following lesson, you'll respond when the button is pressed by sending theĬontent of the text field to another activity. In this lesson, you'll create a layout in XML that includes a text field and aīutton. Illustration of how ViewGroup objects form branches in the layout and contain other View objects. The system to use one on "small" screens and the other on "large" screens. For example, you can create two versions of a layout and tell
#CREATING A SIMPLE ANDROID APP CODE#
Declaring your UI layout in XML rather than runtime code is useful for several reasons,īut it's especially important so you can create different layouts forĭifferent screen sizes.
0 kommentar(er)
