<Gridview <br/> Android: Id = "@ + ID/gv_apps" <br/> Android: layout_height = "fill_parent" <br/> Android: layout_width = "fill_parent" <br/> Android: numcolumns = "3" <br/> Android: horizontalspacing = "10px" <br/> Android: verticalspacing = "10px" <br/> Android: listselector = "@ drawable/choose_gridview" <br/> Android: layout_margintop = "28px" <br/> Android: layout_marginbottom = "58px" <br/> Android: layout_marginleft = "5px" <br/> Android: layout_marginright = "5px" <br/> </gridview>
The background image displayed when a field in the gridview is clicked: Android: listselector = "@ drawable/choose_gridview"
Android: numcolumns = "3" specifies the number of columns in each row of the gridview.
Android: horizontalspacing = "10px" horizontal interval between items in the gridview
Android: verticalspacing = "10px" vertical interval between items in the gridview
Remove title: requestwindowfeature (window. feature_no_title );
Full Screen Display:
1. Obtain the window object of the activity.
A) window win = getwindow ()
2. Set flag for this window object
A) win. setflags (windowmanager. layoutparams. flag_fullscreen,
Windowmanager. layoutparams. flag_fullscreen );
Set an adapter for a gridview
1. Prepare a layout file for each item in the gridview
2. Write a class to inherit the baseadapter
I. Explanation: A class inherits the baseadapter and needs to override several methods, including getcount (), getitem (), getitemid (), and getview ()
II. The most important methods are getcount and getview. Each item in the gridview is a view. This view is obtained through getview. When an item needs to be displayed, it will call the getview method in the adapter to obtain the view to be displayed. Therefore, if there are several items in the gridview, The getview method will be called several times to determine the number of items, which is obtained through the getcount method. Therefore, we should return the size of a list in getcount. In getview, an object at position in the list is obtained based on the parameter position. Layoutinflater is used to render the layout file into a view and assign a value to the control in the view.
3. About packageinfo
A) obtain information about all the installation programs in the system, including those installed by the user and those of the system itself:
I. Get packagemanager PM = getpackagemanager ()
Ii. List list = PM. getinstalledpackages (packagemanager. get_uninstalled_packages)
B) What information is encapsulated by packageinfo: packageinfo corresponds to a manifest file, and packageinfo encapsulates minifest files.
I. packagename
Ii. Version Information: versioncode and versionname
Iii. activity information in this package
Iv. Worker er information in this package
V. Information about providers in this package
VI. The service information in this package is encapsulated into xxxinfo, through which you can get the corresponding information
VII. You can also obtain applicationinfo.
1. Obtain the application name applicationinfo. loadlabel (getpackagemanager)
2. Obtain the drawable of the application)
Applicationinfo. loadicon (getpackagemanager)