Widgets are building blocks of ginstr launcher. ginstr widgets have some internal functionality like taking a photo, calling a number.
ginstr widgets are based on Android widgets and their behaviour is similar. For information about Android widgets refer to Android Documentation.
Widgets can be divided into two groups:
- 1. Android widgets
- all native Android widgets (see under “Classes”). Widgets are provided by Android system.
- 2. ginstr widgets
- custom made widgets. They can be composite widgets that consist of multiple Android views or a single view with special functionality.
Widgets can be divided by nesting:
- 1. Container widgets (ViewGroups)
- those widgets are used as containers for other widgets. The purpose is positioning assistance and layout organization. The most important are:
ScrollView(can have one child),
FrameLayout. More are mentioned here.
- 2. Action widgets
- widgets that can’t nest or contain widgets within them. These widgets are used for providing functionality to app (i.e. input text, display text, call phone, send text message…), some of those are (
Widget Library contains all custom ginstr widgets that contain features not provided out of the box by Android.
Attributes define how each widget behaves and what it looks like. Android widgets have attributes described for each widget, for example
EditText (look under XML attributes and Inherited XML attributes). Each attribute has a description what its function is. This is provided for all Android widgets in Android Documentation.
Example Android widget with attributes: <source lang="xml"> <TextView
android:id="@+id/txtView1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginBottom="20dp" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:layout_marginTop="20dp" android:autoLink="email" android:singleLine="false" android:text="@string/test_string" android:textColor="#FFFFFF" android:textColorLink="#82CAFA" android:textSize="14sp" android:textStyle="bold" android:typeface="sans" />
To use ginstr namespace attributes user has to define custom namespace in top (root) element (widget) of the layout.
xmlns:ek=http://schemas.ginstr.com/ginstr. To define custom attributes, the following syntax is used
Example of a ginstr widget with attributes: <source lang="xml"> <de.einakoon.ag.widgets.EnPhoneAction
android:layout_width="50dp" android:layout_height="50dp" ek:s_email="firstname.lastname@example.org" />
!IMPORTANT! Each widget has to have
android:layout_height defined. Custom widgets need custom ginstr attribute defined to work properly, check layout configuration of each widget. An attribute marked with asterisk ( *) is a mandatory parameter when creating widget.
One of the most important things is how to handle widget positioning within container widgets. Positioning depends on each widget within a container, which in turn depends on the container which contains it. If a widget is contained for example in
LinearLayout it will not have the same positioning options as in
- Example: Widget in
RelativeLayouthas the ability to position itself relative to other views by attribute (example under positions widget containing this attribute to right of widget with id mentioned in attribute)
- Example: Widget in
Practice is needed to learn those few containers and their abilities. With combinations of containers any positioning can be achieved.
Widget data persistence
!IMPORTANT! To enable widgets that retrieve data from a user to retain data between orientation changes, a unique id must be provided for a widget within that layout. Id must be identical in both layouts (landscape/portrait). It is encouraged to use portrait mode only due to better visibility on Android phone devices.
Example: <source lang="xml"> <EditText
android:id="@+id/txtView1" android:layout_width="match_parent" android:layout_height="wrap_content"