JSON es una notación de objetos de JavaScript que es un formato para intercambiar los datos del servidor. JSON almacena los datos en un formato ligero. Con la ayuda de JSON, podemos acceder a los datos en forma de JsonArray, JsonObject y JsonStringer. En este artículo, veremos específicamente la implementación de JsonObject usando Volley en Android usando Jetpack Compose. Crearemos una aplicación simple en la que analizaremos los datos de una URL usando la biblioteca Volley en Android usando Jetpack Compose .
Implementación paso a paso
Paso 1: crea un nuevo proyecto en Android Studio
Para crear un nuevo proyecto en Android Studio, consulte Cómo crear/iniciar un nuevo proyecto en Android Studio . Al elegir la plantilla, seleccione Actividad de composición vacía . Si no encuentra esta plantilla, intente actualizar Android Studio a la última versión. Demostramos la aplicación en Kotlin, así que asegúrese de seleccionar Kotlin como idioma principal al crear un nuevo proyecto.
Paso 2: Agregar dependencia para usar Volley
Vaya a aplicación > Gradle Scripts > archivo build.gradle y agréguele la siguiente dependencia. Los comentarios se agregan al código.
// dependency for volley
implementation 'com.android.volley:volley:1.2.0'
// dependency for loading image from url
implementation("io.coil-kt:coil-compose:2.0.0-rc01")
Ahora sincronice su proyecto para instalar la dependencia.
Paso 3: Agregar un nuevo color en el archivo Color.kt
Vaya a aplicación > java > nombre del paquete de su aplicación > ui.theme > archivo Color.kt y agréguele el siguiente código.
Kotlin
package com.example.newcanaryproject.ui.theme import androidx.compose.ui.graphics.Color val Purple200 = Color(0xFF0F9D58) val Purple500 = Color(0xFF0F9D58) val Purple700 = Color(0xFF3700B3) val Teal200 = Color(0xFF03DAC5) // on below line we are adding different colors. val greenColor = Color(0xFF0F9D58)
Paso 4: agregar permisos a Internet en el archivo AndroidManifest.xml
Vaya a la aplicación > AndroidManifest.xml y agréguele el siguiente código.
XML
<!--permissions for INTERNET--> <uses-permission android:name="android.permission.INTERNET"/>
Paso 5: trabajar con el archivo MainActivity.kt
Vaya al archivo MainActivity.kt y consulte el siguiente código. A continuación se muestra el código del archivo MainActivity.kt. Se agregan comentarios dentro del código para comprender el código con más detalle.
Kotlin
package com.example.newcanaryproject
import android.content.Context
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.*
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.res.colorResource
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.*
import coil.compose.rememberAsyncImagePainter
import com.android.volley.Request
import com.android.volley.RequestQueue
import com.android.volley.toolbox.JsonObjectRequest
import com.android.volley.toolbox.Volley
import com.example.newcanaryproject.ui.theme.*
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
NewCanaryProjectTheme {
// on below line we are specifying background color for our application
Surface(
// on below line we are specifying modifier and color for our app
modifier = Modifier.fillMaxSize(), color = MaterialTheme.colors.background
) {
// on below line we are specifying theme as scaffold.
Scaffold(
// in scaffold we are specifying top bar.
topBar = {
// inside top bar we are specifying background color.
TopAppBar(backgroundColor = greenColor,
// along with that we are
// specifying title for our top bar.
title = {
// in the top bar we are specifying tile as a text
Text(
// on below line we are specifying
// text to display in top app bar.
text = "JSON Parsing in Android",
// on below line we are specifying
// modifier to fill max width.
modifier = Modifier.fillMaxWidth(),
// on below line we are specifying
// text alignment.
textAlign = TextAlign.Center,
// on below line we are
// specifying color for our text.
color = Color.White
)
})
}) {
// on below line
// we are calling pop window
// dialog method to display ui.
volleyJSONParsing()
}
}
}
}
}
}
// on below line we are creating
// a pop up window dialog method
@Composable
fun volleyJSONParsing() {
val ctx = LocalContext.current
// on below line we are creating variables.
val courseName = remember {
mutableStateOf("")
}
val courseRequisites = remember {
mutableStateOf("")
}
val courseImg = remember {
mutableStateOf("")
}
val courseDesc = remember {
mutableStateOf("")
}
val courseLink = remember {
mutableStateOf("")
}
val progress = remember {
mutableStateOf(true)
}
jsonParsing(ctx, courseName, courseRequisites, courseImg, courseDesc, courseLink, progress)
// on the below line we are creating a column.
Column(
// in this column we are specifying
// modifier to add padding and fill
// max size
modifier = Modifier
.fillMaxSize()
.padding(horizontal = 20.dp),
// on below line we are adding horizontal alignment
// and vertical arrangement
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Top
) {
// on below line we are creating a column.
if (progress.value) {
Column(
// in this column we are specifying
// modifier to add padding and fill
// max size
modifier = Modifier
.fillMaxSize()
.padding(horizontal = 20.dp),
// on below line we are adding horizontal alignment
// and vertical arrangement
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center
) {
// below line is use to display a circular progress bar.
CircularProgressIndicator(
// below line is use to add padding
// to our progress bar.
modifier = Modifier.padding(16.dp),
// below line is use to add color to our progress bar.
color = colorResource(id = R.color.purple_200),
// below line is use to add stroke
// width to our progress bar.
strokeWidth = Dp(value = 4F)
)
}
}
// on the below line we are adding a spacer.
Spacer(modifier = Modifier.height(4.dp))
// on below line we are adding image for our image view.
Image(
// on below line we are adding the image url
// from which we will be loading our image.
painter = rememberAsyncImagePainter(courseImg.value),
// on below line we are adding content
// description for our image.
contentDescription = "gfg image",
// on below line we are adding modifier for our
// image as wrap content for height and width.
modifier = Modifier
.wrapContentSize()
.wrapContentHeight()
.fillMaxWidth()
.padding(4.dp),
alignment = Alignment.Center
)
// on the below line we are adding a spacer.
Spacer(modifier = Modifier.height(10.dp))
// on below line we are creating
// text for course name.
Text(
text = courseName.value,
modifier = Modifier.fillMaxWidth(),
color = Color.Black,
fontSize = 20.sp,
fontFamily = FontFamily.Default,
fontWeight = FontWeight.Bold, textAlign = TextAlign.Center
)
// on below line we are adding spacer
Spacer(modifier = Modifier.height(20.dp))
// on below line we are adding
// text for course prerequisites
Text(
text = courseRequisites.value,
modifier = Modifier.fillMaxWidth(),
color = Color.Black,
fontSize = 16.sp,
fontFamily = FontFamily.Default,
fontWeight = FontWeight.Normal, textAlign = TextAlign.Center
)
// on below line we are adding spacer
Spacer(modifier = Modifier.height(30.dp))
// on below line we are creating a
// text for our description.
Text(
text = courseDesc.value,
modifier = Modifier.fillMaxWidth(),
color = Color.Black,
fontSize = 15.sp,
fontFamily = FontFamily.Default,
fontWeight = FontWeight.Normal, textAlign = TextAlign.Start
)
// on the below line we are creating a column.
Column(
// in this column we are specifying
// modifier to add padding and fill
// max size
modifier = Modifier.fillMaxSize(),
// on below line we are adding horizontal alignment
// and vertical arrangement
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Bottom
) {
// on below line we are creating a button
Button(
onClick = {
// on below line we are opening
// a intent to view the url.
val i = Intent(Intent.ACTION_VIEW)
i.setData(Uri.parse(courseLink.value))
ctx.startActivity(i)
},
// on below line we are
// adding modifier for our button.
modifier = Modifier
.fillMaxWidth()
.padding(3.dp)
.align(Alignment.CenterHorizontally)
.fillMaxWidth()
) {
// on below line we are setting text as visit course
Text(text = "Visit Course", color = Color.White)
}
}
}
}
fun jsonParsing(
ctx: Context,
name: MutableState<String>,
requisites: MutableState<String>,
Img: MutableState<String>,
Desc: MutableState<String>,
Link: MutableState<String>,
progress: MutableState<Boolean>,
) {
// on below line we are creating
// a variable for our url.
var url = "https://jsonkeeper.com/b/8RFY"
// on below line we are creating a variable for
// our request queue and initializing it.
val queue: RequestQueue = Volley.newRequestQueue(ctx)
// on below line we are creating a variable for request
// and initializing it with json object request
val request = JsonObjectRequest(Request.Method.GET, url, null, { response ->
// this method is called when we get a successful response from API.
// on below line we are adding a try catch block.
try {
// on below line we are getting data from our response
// and setting it in variables.
val courseName: String = response.getString("courseName")
val courseLink: String = response.getString("courseLink")
val courseImg: String = response.getString("courseimg")
val courseDesc: String = response.getString("courseDesc")
val coursePreq: String = response.getString("Prerequisites")
// on below line we are setting
// data to our variables which we have passed.
name.value = courseName
Link.value = courseLink
requisites.value = coursePreq
Img.value = courseImg
Desc.value = courseDesc
progress.value = false
} catch (e: Exception) {
// on below line we are
// handling our exception.
e.printStackTrace()
}
}, { error ->
// this method is called when we get any error while
// fetching data from our API
// in this case we are simply displaying a toast message.
Toast.makeText(ctx, "Fail to get response", Toast.LENGTH_SHORT)
.show()
})
// at last we are adding
// our request to our queue.
queue.add(request)
}
Ahora ejecute su aplicación para ver el resultado.
Producción:
Publicación traducida automáticamente
Artículo escrito por chaitanyamunje y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA