NativeScript - Modules

Application

Application contains platform specific implementation of mobile application. Simple core module is defined below −

const applicationModule = require("tns-core-modules/application");

Console

Console module is used to log message. It has the following methods −

console.log("My FirstApp project"); 
console.info("Native apps!"); 
console.warn("Warning message!"); 
console.error("Exception occurred");

application-settings

application-settings module contains method to manage application settings. To add this module, we need to add the following code −

const appSettings = require("tns-core-modules/application-settings");

Few methods available in the application-setting are as follows −

setBoolean(key: string, value: boolean) - set boolean object
setNumber(key: string, value: number) - set number object
setString(key: string, value: string) - sets string object
getAllKeys() - Contains all stored keys
hasKey(key: string) - check whether a key present or not
clear - clears stored values
remove - remove any entry based on key.

A simple example using application setting is as follows −

function onNavigatingTo(args) { 
   appSettings.setBoolean("isTurnedOff", false);
   appSettings.setString("name", "nativescript"); 
   appSettings.setNumber("locationX", 54.321); 
   const isTurnedOn = appSettings.getBoolean("isTurnedOn"); 
   const username = appSettings.getString("username"); 
   const locationX = appSettings.getNumber("locationX"); 
   // Will return "not present" if there is no value for "noKey" 
   const someKey = appSettings.getString("noKey", "not present"); 
}
exports.onNavigatingTo = onNavigatingTo; 
function onClear() {
   // Removing a single entry via its key name 
   appSettings.remove("isTurnedOff"); 
   // Clearing the whole settings 
   appSettings.clear(); 
}

http

This module is used for handling http request and response. To add this module in your application, add the following code −

const httpModule = require("tns-core-modules/http");

We can send data using the following methods −

getString − It is used to make request and downloads the data from URL as string. It is defined below −

httpModule.getString("https://.../get").then(
   (r) => { 
      viewModel.set("getStringResult", r); 
   }, (e) => 
   { 
   }
);

getJSON − It is used to access data from JSON. It is defined below −

httpModule.getJSON("https://.../get").then((r) => { 
}, (e) => { 
});

getImage − downloads the content from specified URL and return ImageSource object. It is defined below −

httpModule.getImage("https://.../image/jpeg").then((r) => { 
}, (e) => { 
});

getFile − It has two arguments URL and file path.

URL − downloads the data.
File path − save URL data into the file. It is defined below −

httpModule.getFile("https://").then((resultFile) => { 
}, (e) => { 
});

request − It has options argument. It is used to request options and return HttpResponse object. It is defined below −

httpModule.request({ 
   url: "https://.../get", 
   method: "GET" 
}).then((response) => { 
}, (e) => { 
});

Image-source

image-source module is used save image. We can add this module using the below statement −

const imageSourceModule = require("tns-core-modules/image-source");

If you want to load images from resource, use the below code −

const imgFromResources = imageSourceModule.fromResource("icon");

To add image from local file, use the below command −

const folder = fileSystemModule.knownFolders.currentApp(); 
const path = fileSystemModule.path.join(folder.path, "images/sample.png"); 
const imageFromLocalFile = imageSourceModule.fromFile(path);

To save image to the file path, use the below command −

const img = imageSourceModule.fromFile(imagePath); 
const folderDest = fileSystemModule.knownFolders.documents(); 
const pathDest = fileSystemModule.path.join(folderDest.path, "sample.png"); 
const saved = img.saveToFile(pathDest, "png"); if (saved) { 
   console.log(" sample image saved successfully!"); 
}

Timer

This module is used to execute code at specific time intervals. To add this, we need to use require −

const timerModule = require("tns-core-modules/timer");

It is based on two methods −

setTimeout − It is used to delay the execution. It is represented as milliseconds.

setInterval − It is used to apply recurring at specific intervals.

Trace

This module is useful for debugging. It gives the logging information. This module can be represented as −

const traceModule = require("tns-core-modules/trace");

If you want to enable in your application then use the below command −

traceModule.enable();

ui/image-cache

image-cache module is used to handle image download requests and caches downloaded images. This module can be represented as shown below −

const Cache = require("tns-core-modules/ui/image-cache").Cache;

connectivity

This module is used to receive the connection information of the connected network. It can be represented as −

const connectivityModule = require("tns-core-modules/connectivity");

Functionality Modules

Functionality modules include lot of system/platform specific modules. Some of the important modules are as follows −

platform − Used to display the information about your device. It can be defined as given below −

const platformModule = require("tns-core-modules/platform");

fps-meter − Used to capture frames per second. It can be defined as given below −

const fpsMeter = require("tns-core-modules/fps-meter");

file-system − Used to work with your device file system. It is defined below −

const fileSystemModule = require("tns-core-modules/file-system");

ui/gestures − Used to work with UI gestures.

UI module

UI module includes the UI component and its related functionality. Some of the important UI modules are as follows −

frame
page
color
text/formatted-string
xml
styling
animation

Previous Page Print Page