How to Create Custom Model For Android Using TensorFlow?

Last Updated : 05 Oct, 2021

Tensorflow is an open-source library for machine learning. In android, we have limited computing power as well as resources. So we are using TensorFlow light which is specifically designed to operate on devices with limited power. In this post, we going to see a classification example called the iris dataset. The dataset contains 3 classes of 50 instances each, where each class refers to the type of iris plant.

Attribute information:

sepal length in cm
sepal width in cm
petal length in cm
petal width in cm

Based on the information given in the input, we will predict whether the plant is Iris Setosa, Iris Versicolour, or Iris Virginica. You can refer to this link for more information.

Step by step Implementation

Step 1:

Download the iris data set (file name: iris.data) from this (https://archive.ics.uci.edu/ml/machine-learning-databases/iris/) link.

Step 2:

Create a new python file with a name iris in the Jupyter notebook. Put the iris.data file in the same directory where iris.ipynb resides. Copy the following code in the Jupyter notebook file.

iris.ipynb

Python

import pandas as pd
import numpy as np
import tensorflow as tf
from sklearn.preprocessing import LabelEncoder
from keras.utils import to_categorical

# reading the csb into data frame
df = pd.read_csv('iris.data')

# specifying the columns values into x and y variable
# iloc range based selecting 0 to 4 (4) values
X = df.iloc[:, :4].values
y = df.iloc[:, 4].values

# normalizing labels
le = LabelEncoder()

# performing fit and transform data on y
y = le.fit_transform(y)

y = to_categorical(y)

from tensorflow.keras.layers import Dense
from tensorflow.keras.models import Sequential

model = Sequential()

# input layer
# passing number neurons =64
# relu activation
# shape of neuron 4
model.add(Dense(64, activation='relu', input_shape=[4]))

# processing layer
# adding another denser layer of size 64
model.add(Dense(64))

# creating 3 output neuron
model.add(Dense(3, activation='softmax'))


# compiling model
model.compile(optimizer='sgd', loss='categorical_crossentropy',
              metrics=['acc'])

# training the model for fixed number of iterations (epoches)
model.fit(X, y, epochs=200)

from tensorflow import lite
converter = lite.TFLiteConverter.from_keras_model(model)

tfmodel = converter.convert()

open('iris.tflite', 'wb').write(tfmodel)

Step 3:

After executing the line open('iris.tflite','wb').write(tfmodel) a new file named iris.tflite will get created in the same directory where iris.data resides.

A) Open Android Studio. Create a new kotlin-android project. (You can refer here for creating a project).

B) Right-click on app > New > Other >TensorFlow Lite Model

C) Click on the folder icon.

D) Navigate to iris.tflite file

E) Click on OK

F) Your model will look like this after clicking on the finish. (It may take some time to load).

Copy the code and paste it in the click listener of a button in MainActivity.kt.(It is shown below).

Step 5: Create XML layout for prediction

Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file.

XML

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="50dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">
          
            <!-- creating  edittexts for input-->
            <EditText
                android:id="@+id/tf1"
                android:layout_width="175dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_marginTop="70dp"
                android:ems="10"
                android:inputType="numberDecimal" />

            <EditText
                android:id="@+id/tf2"
                android:layout_width="175dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_marginTop="20dp"
                android:ems="10"
                android:inputType="numberDecimal" />

            <EditText
                android:id="@+id/tf3"
                android:layout_width="175dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_marginTop="20dp"
                android:ems="10"
                android:inputType="numberDecimal" />

            <EditText
                android:id="@+id/tf4"
                android:layout_width="175dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_marginTop="20dp"
                android:ems="10"
                android:inputType="numberDecimal" />

            <!-- creating  Button for input-->
            <!-- after clicking on button we will see prediction-->
            <Button
                android:id="@+id/button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_marginTop="100dp"
                android:text="Button"
                app:layout_constraintBottom_toTopOf="@+id/textView"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintHorizontal_bias="0.0"
                app:layout_constraintStart_toStartOf="parent" />

            <!-- creating  textview on which we will see prediction-->
            <TextView
                android:id="@+id/textView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_marginTop="50dp"
                android:text="TextView"
                android:textSize="20dp"
                app:layout_constraintEnd_toEndOf="parent" />
        </LinearLayout>
    </ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>

Step 6: Working with the MainActivity.kt file

Go to the MainActivity.kt file and refer to the following code. Below is the code for the MainActivity.kt file. Comments are added inside the code to understand the code in more detail.

Kotlin

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import com.example.gfgtfdemo.ml.Iris
import org.tensorflow.lite.DataType
import org.tensorflow.lite.support.tensorbuffer.TensorBuffer
import java.nio.ByteBuffer

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

        // getting the object edit texts
        var ed1: EditText = findViewById(R.id.tf1);
        var ed2: EditText = findViewById(R.id.tf2);
        var ed3: EditText = findViewById(R.id.tf3);
        var ed4: EditText = findViewById(R.id.tf4);
      
        // getting the object of result textview
        var txtView: TextView = findViewById(R.id.textView);
        var b: Button = findViewById<Button>(R.id.button);

        // registering listener
        b.setOnClickListener(View.OnClickListener {
          
            val model = Iris.newInstance(this)

            // getting values from edit text and converting to float
            var v1: Float = ed1.text.toString().toFloat();
            var v2: Float = ed2.text.toString().toFloat();
            var v3: Float = ed3.text.toString().toFloat();
            var v4: Float = ed4.text.toString().toFloat();

            /*************************ML MODEL CODE STARTS HERE******************/
            
              // creating byte buffer which will act as input for model 
            var byte_buffer: ByteBuffer = ByteBuffer.allocateDirect(4 * 4)
            byte_buffer.putFloat(v1)
            byte_buffer.putFloat(v2)
            byte_buffer.putFloat(v3)
            byte_buffer.putFloat(v4)

            // Creates inputs for reference.
            val inputFeature0 = TensorBuffer.createFixedSize(intArrayOf(1, 4), DataType.FLOAT32)
            inputFeature0.loadBuffer(byte_buffer)

            // Runs model inference and gets result.
            val outputs = model.process(inputFeature0)
            val outputFeature0 = outputs.outputFeature0AsTensorBuffer.floatArray

            
            // setting the result to the output textview
            txtView.setText(
                "Iris-setosa : =" + outputFeature0[0].toString() + "\n" +
                "Iris-versicolor : =" + outputFeature0[1].toString() + "\n" +
                "Iris-virginica: =" +  outputFeature0[2].toString()
            )

            // Releases model resources if no longer used.
            model.close()
        })
    }
}