Illustration of Android app Operation Skills

A TableLayout of the Android application consists of many TableRow. Each TableRow defines a row. In fact, you can define other sub-objects, which will be explained below ).

The TableLayout container does not display the border lines of row, cloumns, or cell. Each row has 0 or more cells, and each cell has one View object. A table consists of columns and rows in multiple cells. The table allows cells to be empty. Cells cannot span columns, which is different from HTML. A TableLayout is displayed, and the dotted lines in the figure represent invisible cell borders.

Columns can be hidden, expanded to fill in available screen space, or forced column contraction until the table matches the screen size. For more information, see the reference documentation for this class. Absolute Layout allows the child element to specify an accurate x/y coordinate value and display it on the screen. (0, 0) is the upper left corner. When you move down or to the right, the coordinate value increases.

AbsoluteLayout has no page border and allows elements to overlap with each other, though not recommended ). We generally do not recommend AbsoluteLayout unless you have a legitimate reason to use it, because it makes the interface code too rigid, so that it can work well on different devices.

Android applications allow child elements to specify their positions relative to other elements or parent elements by ID ). Therefore, you can arrange two elements in the right-aligned, up/down, or in the center of the screen. Elements are arranged in order. Therefore, if the first element is in the center of the screen, other elements relative to the element are arranged in the relative position in the center of the screen.

If you use XML to specify this layout, the associated elements must be defined before you define it. This is an example of an Android application, which has visible and invisible elements. The basic screen layout object is a RelativeLayout object.

This view displays the Class Name of the screen element. The attribute list of each element is shown below. One part of these attributes is provided directly by the element, and the other part is provided by the subclass of the LayoutParams member RelativeLayout of the container. The RelativeLayout parameters include width, height, below, alignTop, toLeft, padding, and marginLeft.

Note: A portion of these parameters. Its value is relative to other child elements, so it is RelativeLayout. These parameters include toLeft, alignTop, and below. They are used to specify the left, top, and bottom positions relative to other elements, and process user operations. Android sets AdapterView of the class. onItemClickListener members are directed to a listener and capture user operation events to process user operations.