Sunday, February 3, 2019

android kotlin - WorkManager constraints example

MainActivity.kt

package com.cfsuman.jetpack

import android.content.Context
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import kotlinx.android.synthetic.main.activity_main.*
import android.graphics.BitmapFactory
import java.io.BufferedInputStream
import java.io.IOException
import java.net.HttpURLConnection
import android.graphics.Bitmap
import android.net.Uri
import androidx.lifecycle.Observer
import androidx.work.*


class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Download image
        btnDownload.setOnClickListener {
            // Create a Constraints object that defines when the task should run
            val downloadConstraints = Constraints.Builder()
                // Device need to charging for the WorkRequest to run.
                .setRequiresCharging(true)
                // Any working network connection is required for this work.
                .setRequiredNetworkType(NetworkType.CONNECTED)
                //.setRequiresBatteryNotLow(true)
                // Many other constraints are available, see the
                // Constraints.Builder reference
                .build()

            // Define the input data for work manager
            val data = Data.Builder()
            data.putString("imageUrl",
                "https://www.freeimageslive.com/galleries/buildings/structures/pics/canal100-0416.jpg")

            // Create an one time work request
            val downloadImageWork = OneTimeWorkRequest
                .Builder(DownloadImageWorker::class.java)
                .setInputData(data.build())
                .setConstraints(downloadConstraints)
                .build()

            // Enqueue the work
            WorkManager.getInstance().enqueue((downloadImageWork))

            // Get the work status using live data
            WorkManager.getInstance().getWorkInfoByIdLiveData(downloadImageWork.id)
                .observe(this, Observer { workInfo ->

                    // Toast the work state
                    toast(workInfo.state.name)

                    if (workInfo != null) {
                        if (workInfo.state == WorkInfo.State.ENQUEUED) {
                            // Show the work state in text view
                            textView.text = "Download enqueued."
                        } else if (workInfo.state == WorkInfo.State.BLOCKED) {
                            textView.text = "Download blocked."
                        } else if (workInfo.state == WorkInfo.State.RUNNING) {
                            textView.text = "Download running."
                        }
                    }

                    // When work finished
                    if (workInfo != null && workInfo.state.isFinished) {
                        if (workInfo.state == WorkInfo.State.SUCCEEDED) {
                            textView.text = "Download successful."

                            // Get the output data
                            val successOutputData = workInfo.outputData
                            val uriText = successOutputData.getString("uriString")

                            // If uri is not null then show it
                            uriText?.apply {
                                // If download finished successfully then show the downloaded image in image view
                                imageView.setImageURI(Uri.parse(uriText))
                                textView.text = uriText
                            }
                        } else if (workInfo.state == WorkInfo.State.FAILED) {
                            textView.text = "Failed to download."
                        } else if (workInfo.state == WorkInfo.State.CANCELLED) {
                            textView.text = "Work request cancelled."
                        }
                    }
                })
        }
    }
}


// Worker class to download image
class DownloadImageWorker(context:Context, params: WorkerParameters): Worker(context,params){
    override fun doWork(): Result {
        // Get the input data
        val urlString = inputData.getString("imageUrl")
        val url = stringToURL(urlString)

        // IMPORTANT - Put internet permission on manifest file
        var connection: HttpURLConnection? = null

        try {
            // Initialize a new http url connection
            connection = url?.openConnection() as HttpURLConnection

            // Connect the http url connection
            connection.connect()

            // Get the input stream from http url connection
            val inputStream = connection.getInputStream()

            // Initialize a new BufferedInputStream from InputStream
            val bufferedInputStream = BufferedInputStream(inputStream)

            // Convert BufferedInputStream to Bitmap object

            // Return the downloaded bitmap
            val bmp:Bitmap? = BitmapFactory.decodeStream(bufferedInputStream)
            val uri:Uri? = bmp?.saveToInternalStorage(applicationContext)

            Log.d("download","success")
            // Return the success with output data
            return Result.success(createOutputData(uri))

        } catch (e: IOException) {
            e.printStackTrace()
            Log.d("download",e.toString())

        } finally {
            // Disconnect the http url connection
            connection?.disconnect()
        }
        Log.d("download","failed")
        return Result.failure(createOutputData(null))
    }


    // Method to create output data
    private fun createOutputData(uri: Uri?): Data {
        return Data.Builder()
            .putString("uriString", uri.toString())
            .build()
    }
}
xBitmap.kt

package com.cfsuman.jetpack

import android.content.Context
import android.content.ContextWrapper
import android.graphics.Bitmap
import android.net.Uri
import android.widget.Toast
import java.io.File
import java.io.FileOutputStream
import java.io.IOException
import java.io.OutputStream
import java.net.MalformedURLException
import java.net.URL
import java.util.*


// Extension function to save bitmap in internal storage
fun Bitmap.saveToInternalStorage(context: Context): Uri {
    // Get the context wrapper instance
    val wrapper = ContextWrapper(context)

    // Initializing a new file
    // The bellow line return a directory in internal storage
    var file = wrapper.getDir("images", Context.MODE_PRIVATE)


    // Create a file to save the image
    file = File(file, "${UUID.randomUUID()}.png")

    try {
        // Get the file output stream
        val stream: OutputStream = FileOutputStream(file)

        // Compress bitmap
        this.compress(Bitmap.CompressFormat.PNG, 100, stream)

        // Flush the stream
        stream.flush()

        // Close stream
        stream.close()
    } catch (e: IOException){ // Catch the exception
        e.printStackTrace()
    }

    // Return the saved image uri
    return Uri.parse(file.absolutePath)
}


// Custom method to convert string to url
fun stringToURL(urlString: String?): URL? {
    urlString?.let {
        try {
            return URL(urlString)
        } catch (e: MalformedURLException) {
            e.printStackTrace()
        }
    }

    return null
}


fun Context.toast(message:String)=
    Toast.makeText(this,message, Toast.LENGTH_SHORT).show()
activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rootLayout"
        tools:context=".MainActivity"
        android:background="#fdfdfc">
    <Button
            android:text="Download Image"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btnDownload"
            android:layout_marginTop="8dp"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginStart="8dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            android:layout_marginEnd="8dp"/>
    <ImageView
            android:layout_width="0dp"
            android:layout_height="0dp"
            tools:srcCompat="@tools:sample/avatars"
            android:id="@+id/imageView"
            app:layout_constraintEnd_toEndOf="parent"
            android:layout_marginEnd="8dp"
            app:layout_constraintStart_toStartOf="parent"
            android:layout_marginStart="8dp"
            app:layout_constraintHorizontal_bias="0.0"
            android:layout_marginTop="8dp"
            app:layout_constraintTop_toBottomOf="@+id/textView"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"/>
    <TextView
            android:text=""
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/textView"
            app:layout_constraintEnd_toEndOf="parent"
            android:layout_marginEnd="16dp"
            app:layout_constraintStart_toStartOf="parent"
            android:layout_marginStart="16dp"
            android:layout_marginTop="16dp"
            app:layout_constraintTop_toBottomOf="@+id/btnDownload"
            android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium"
            android:textColor="#3F51B5"
            tools:text="Work Status"
            android:layout_marginBottom="16dp"
            app:layout_constraintBottom_toTopOf="@+id/imageView"/>
</androidx.constraintlayout.widget.ConstraintLayout>
gradle dependencies

// WorkManager
def work_version = "1.0.0-beta03"
implementation "android.arch.work:work-runtime:$work_version"
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