The basic APP page is composed of bar and content view, and bar is composed of status bar, navigation bar and TAB bar, as shown in the figure below
Status bar: Located at the top of the page, it is 40 pixels high and is used to display general information such as notifications, time, signals, and power. On both iOS and Android, the status bar is usually transparent, with ICONS and text changing to white or black depending on the color of the current page, as shown in the figure below.
Navigation bar: Located below the status bar and 88 pixels high, it is used to manage on-screen information and navigation between page-level structures. The back button is displayed on the left of the navigation bar. The title of the current page is displayed in the middle of the navigation bar. The operation button of the current page is displayed on the right. The buttons in the bar can be text or ICONS.
The navigation bar adds buttons, which can be replaced by plus signs or other ICONS that indicate expansion
TAB bar: it is the global navigation of the APP. Users can click the function icon in this bar to switch pages quickly. The TAB bar is usually located at the bottom of the page with a height of 98 pixels. The ICONS in the bar can be selected or unselected. They are usually represented by a silhouette icon and a text description. It is advisable to have 3 to 5 ICONS in the column, and the text should be easy to understand and concise, and the width should not exceed 4 Chinese characters as far as possible, as shown in the following figure.
