React Native -- StyleSheet

React Native -- StyleSheet

StyleSheet style sheet to render component styles. The source code is as follows:

 

 /* Code quality: * *  - By moving styles away from the render function, you're making the code *  easier to understand. *  - Naming the styles is a good way to add meaning to the low level components *  in the render function. * * Performance: * *  - Making a stylesheet from a style object makes it possible to refer to it * by ID instead of creating a new style object every time. *  - It also allows to send the style only once through the bridge. All * subsequent uses are going to refer an id (not implemented yet). */class StyleSheet {  static create(obj: {[key: string]: any}): {[key: string]: number} {    var result = {};    for (var key in obj) {      StyleSheetValidation.validateStyle(key, obj);      result[key] = StyleSheetRegistry.registerStyle(obj[key]);    }    return result;  }}

Create StyleSheet

 

 

var styles = StyleSheet.create({      container: {        borderRadius: 4,        borderWidth: 0.5,        borderColor: '#d6d7da',      },      title: {        fontSize: 19,        fontWeight: 'bold',      },      activeTitle: {        color: 'red',      },    });

StyleSheetRegistry. registerStyle (obj [key]); returns a uniqueID, StyleSheet. the uniqueID, styles storage key, and uniqueID corresponding to each key returned by create. When setting component attributes, uniqueID is obtained based on the key and the corresponding style is obtained based on uniqueID.

 

 

var styles = {};var uniqueID = 1;var emptyStyle = {};class StyleSheetRegistry {  static registerStyle(style: Object): number {    var id = ++uniqueID;    if (__DEV__) {      Object.freeze(style);    }    styles[id] = style;    return id;  }  static getStyleByID(id: number): Object {    if (!id) {      // Used in the style={[condition && id]} pattern,      // we want it to be a no-op when the value is false or null      return emptyStyle;    }    var style = styles[id];    if (!style) {      console.warn('Invalid style with id `' + id + '`. Skipping ...');      return emptyStyle;    }    return style;  }}

 

Use StyleSheet

 

Set a style to use style = {styles. container}

 

Set multiple styles to use style = {[styles. title, this. props. isActive & styles. activeTitle]}. However, the subsequent style will overwrite the previous style.