Android Lab file 12 to 22

Q13. Write a program to demonstrate Context Menu in android.

activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout 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=".ContextMenuBar">

<ListView

android:layout_width="match_parent"

android:layout_height="match_parent"

android:id="@+id/fileslist"

</LinearLayout>

MainActivity.java:

package com.example.menubar; import

androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.View;

import android.widget.ArrayAdapter;

import android.widget.ListView;

public class ContextMenuBar extends AppCompatActivity {

ListView file_list;

String[] files={"PDF","DOCS","HTML","PPT","ZIP"};

@Override protected void onCreate(Bundle

savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_context_menu_bar);

file_list=(ListView) findViewById(R.id.fileslist);

ArrayAdapter<String> adapter=new ArrayAdapter<>(this,

android.R.layout.simple_list_item_1,files);

file_list.setAdapter(adapter);

registerForContextMenu(file_list);

}

@Override

public void onCreateContextMenu(ContextMenu menu, View v,

ContextMenu.ContextMenuInfo menuInfo) {

super.onCreateContextMenu(menu, v, menuInfo);

getMenuInflater().inflate(R.menu.context_menu,menu);

}

Output-

==========================================================================

Q14 . Design android application for login activity. Write android code to check login credentials with username = "mca" and password = "android". Display appropriate toast message to the user.

activity_main.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    android:gravity="center">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Login Action"
        android:textSize="40dp"
        android:textStyle="bold"
        android:layout_marginBottom="40dp"
        />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10px"
            android:text="Username : "
            android:textSize="20dp" />

        <EditText
            android:id="@+id/username"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:layout_margin="10px"
            android:hint="Enter Username"
            android:textSize="20dp"
            tools:ignore="TouchTargetSizeCheck" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Password : "
            android:textSize="20dp"
            android:layout_margin="10px"/>

        <EditText
            android:id="@+id/password"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:textSize="20dp"
            android:layout_margin="10px"
            android:hint="Enter Password"
            tools:ignore="TouchTargetSizeCheck" />
    </LinearLayout>
    <Button
        android:id="@+id/submit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Submit"
        android:layout_marginTop="20dp"/>
</LinearLayout>

MainActivity.java :

package com.example.labq14;

import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText ed1, ed2;
    Button b;
    String u,p;
    Context context;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ed1 = (EditText) findViewById(R.id.username);
        ed2 = (EditText) findViewById(R.id.password);

        b = (Button) findViewById(R.id.submit);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                u = ed1.getText().toString();
                p = ed2.getText().toString();
                if (u.equals("mca") && p.equals("android")){
                    Toast.makeText(MainActivity.this,"Login Successful",Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this,"Invalid username & password",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }}

Output :

==========================================================================

Q15. Write a program to demonstrate Popup Menu in android for cut, copy and paste options in it and display appropriate information related to operation.

activity_main.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">

<Button

android:id="@+id/clickBtn"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:background="#0F9D58"

android:text="Click Me"

android:textColor="#ffffff"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintLeft_toLeftOf="parent"

app:layout_constraintRight_toRightOf="parent"

app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

popup_menu.xml

<?xml version="1.0" encoding="utf-8"?>

<item

android:id="@+id/java"

android:title="Java" />

<item

android:id="@+id/kotlin"

android:title="Kotlin" />

<item

android:id="@+id/android"

android:title="Android" />

<item

android:id="@+id/react_native"

android:title="React Native" />

</menu>

MainActivity.xml

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;

import android.widget.PopupMenu;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

Button button;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

button = (Button) findViewById(R.id.clickBtn);

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

PopupMenu popupMenu = new PopupMenu(MainActivity.this, button);

popupMenu.getMenuInflater().inflate(R.menu.popup_menu, popupMenu.getMenu());

popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {

@Override

public boolean onMenuItemClick(MenuItem menuItem) {

Toast.makeText(MainActivity.this,"YouClicked"+menuItem.getTitle(), Toast.LENGTH_SHORT).show();

return true;

}

});

popupMenu.show();

}

});

} }

Output :

==========================================================================

Q16. Write an application to display image button.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingLeft="16dp"

android:paddingTop="16dp"

android:paddingRight="16dp"

android:paddingBottom="16dp"

tools:context=".MainActivity">

<ImageButton

android:id="@+id/imageButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:src="@drawable/ic_launcher_foreground"

android:layout_centerInParent="true"/>

</RelativeLayout>

MainActivity.java

package com.example.imagebuttonexample;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.ImageButton;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

ImageButton imageButton = findViewById(R.id.imageButton);

imageButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

// Display a toast message when the image button is clicked

Toast.makeText(getApplicationContext(), "You clicked image button", Toast.LENGTH_SHORT).show();

}

});

}

Output :

==========================================================================

Q17. Demonstrate an application to implement web view in android.

<uses-permission android:name="android.permission.INTERNET" />

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingLeft="16dp"

android:paddingTop="16dp"

android:paddingRight="16dp"

android:paddingBottom="16dp"

tools:context=".MainActivity">

<WebView

android:id="@+id/webView"

android:layout_width="match_parent"

android:layout_height="match_parent"/>

</RelativeLayout>

MainActivity.java

package com.example.webviewexample;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.webkit.WebSettings;

import android.webkit.WebView;

import android.webkit.WebViewClient;

public class MainActivity extends AppCompatActivity {

private WebView webView;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

webView = findViewById(R.id.webView);

WebSettings webSettings = webView.getSettings();

webSettings.setJavaScriptEnabled(true);

webView.setWebViewClient(new WebViewClient());

webView.loadUrl("https://www.google.com/");

}

// Override the onBackPressed method to handle navigation within the WebView

@Override

public void onBackPressed() {

if (webView.canGoBack()) {

webView.goBack();

} else {

super.onBackPressed();

}

Output :

==========================================================================

Q.18.Write an android code to turn ON/OFF Bluetooth

XML : -

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context=".MainActivity">

<Button

android:id="@+id/BtBtn"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

android:text="Click" />

<TextView

android:id="@+id/BtTv"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_above="@id/BtBtn"

android:layout_centerHorizontal="true"

android:hint="Bluetooth Status"

android:textSize="30sp" />

</RelativeLayout>

Java Code

import android.bluetooth.BluetoothAdapter;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

private BluetoothAdapter bluetoothAdapter;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

Button toggleButton = findViewById(R.id.toggleButton);

toggleButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

toggleBluetooth();

}

});

}

private void toggleBluetooth() {

if (bluetoothAdapter == null) {

// Device does not support Bluetooth

return;

}

if (bluetoothAdapter.isEnabled()) {

// Bluetooth is currently enabled, turn it off

bluetoothAdapter.disable();

} else {

// Bluetooth is currently disabled, turn it on

Intent enableBluetoothIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);

startActivityForResult(enableBluetoothIntent, 1);

}

Output :

==========================================================================

Q19. Write an android application using SQLite to create table and perform CRUD operations (Example. COURSE table (ID, Name, Duration, Description), perform ADD, UPDATE, DELETE and READ operations)

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">

    
    <EditText
        android:id="@+id/editTextName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Name"/>

    
    <EditText
        android:id="@+id/editTextDuration"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editTextName"
        android:layout_marginTop="16dp"
        android:hint="Duration"/>

    
    <EditText
        android:id="@+id/editTextDescription"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editTextDuration"
        android:layout_marginTop="16dp"
        android:hint="Description"/>

    
    <Button
        android:id="@+id/buttonAdd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editTextDescription"
        android:layout_marginTop="16dp"
        android:text="Add"/>

    
    <Button
        android:id="@+id/buttonRead"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/buttonAdd"
        android:layout_marginTop="16dp"
        android:text="Read"/>

    
    <Button
        android:id="@+id/buttonUpdate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/buttonRead"
        android:layout_marginTop="16dp"
        android:text="Update"/>

    
    <Button
        android:id="@+id/buttonDelete"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/buttonUpdate"
        android:layout_marginTop="16dp"
        android:text="Delete"/>

</RelativeLayout>

MainActivity.java

package com.example.a19;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private EditText etName, etDuration, etDescription;
    private Button btnAdd, btnRead, btnUpdate, btnDelete;
    private DatabaseHelper dbHelper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        etName = findViewById(R.id.editTextName);
        etDuration = findViewById(R.id.editTextDuration);
        etDescription = findViewById(R.id.editTextDescription);

        btnAdd = findViewById(R.id.buttonAdd);
        btnRead = findViewById(R.id.buttonRead);
        btnUpdate = findViewById(R.id.buttonUpdate);
        btnDelete = findViewById(R.id.buttonDelete);

        dbHelper = new DatabaseHelper(this);

        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                addCourse();
            }
        });

        btnRead.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                readCourses();
            }
        });

        btnUpdate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                updateCourse();
            }
        });

        btnDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                deleteCourse();
            }
        });
    }

    private void addCourse() {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();

        values.put(DatabaseHelper.COLUMN_NAME, etName.getText().toString());
        values.put(DatabaseHelper.COLUMN_DURATION, etDuration.getText().toString());
        values.put(DatabaseHelper.COLUMN_DESCRIPTION, etDescription.getText().toString());

        long newRowId = db.insert(DatabaseHelper.TABLE_NAME, null, values);

        showToast(newRowId != -1 ? "Course added successfully!" : "Error adding course.");

        db.close();
    }

    private void readCourses() {
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        String[] projection = {
                DatabaseHelper.COLUMN_ID,
                DatabaseHelper.COLUMN_NAME,
                DatabaseHelper.COLUMN_DURATION,
                DatabaseHelper.COLUMN_DESCRIPTION
        };

        Cursor cursor = db.query(
                DatabaseHelper.TABLE_NAME,
                projection,
                null,
                null,
                null,
                null,
                null
        );

        StringBuilder result = new StringBuilder("Courses:\n");

        while (cursor.moveToNext()) {
            long id = cursor.getLong(cursor.getColumnIndexOrThrow(DatabaseHelper.COLUMN_ID));
            String name = cursor.getString(cursor.getColumnIndexOrThrow(DatabaseHelper.COLUMN_NAME));
            String duration = cursor.getString(cursor.getColumnIndexOrThrow(DatabaseHelper.COLUMN_DURATION));
            String description = cursor.getString(cursor.getColumnIndexOrThrow(DatabaseHelper.COLUMN_DESCRIPTION));

            result.append("ID: ").append(id).append(", Name: ").append(name)
                    .append(", Duration: ").append(duration).append(", Description: ").append(description).append("\n");
      }

        showToast(result.toString());

        cursor.close();
        db.close();
    }

    private void updateCourse() {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ContentValues values = new ContentValues();

        values.put(DatabaseHelper.COLUMN_NAME, etName.getText().toString());
        values.put(DatabaseHelper.COLUMN_DURATION, etDuration.getText().toString());
        values.put(DatabaseHelper.COLUMN_DESCRIPTION, etDescription.getText().toString());

        String selection = DatabaseHelper.COLUMN_ID + " = ?";
        String[] selectionArgs = {String.valueOf(1)}; // You need to provide the course ID for update

        int count = db.update(
                DatabaseHelper.TABLE_NAME,
                values,
                selection,
                selectionArgs
        );

        showToast(count > 0 ? "Course updated successfully!" : "Error updating course.");

        db.close();
    }

    private void deleteCourse() {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        String selection = DatabaseHelper.COLUMN_ID + " = ?";
        String[] selectionArgs = {String.valueOf(1)}; // You need to provide the course ID for delete

        int count = db.delete(
                DatabaseHelper.TABLE_NAME,
                selection,
                selectionArgs
        );

        showToast(count > 0 ? "Course deleted successfully!" : "Error deleting course.");

        db.close();
    }

    private void showToast(String message) {
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
    }
}

DatabaseHelper.java

package com.example.a19;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

    private static final String DATABASE_NAME = "courses.db";
    private static final int DATABASE_VERSION = 1;

    public static final String TABLE_NAME = "COURSE";
    public static final String COLUMN_ID = "ID";
    public static final String COLUMN_NAME = "Name";
    public static final String COLUMN_DURATION = "Duration";
    public static final String COLUMN_DESCRIPTION = "Description";

    private static final String SQL_CREATE_TABLE =
            "CREATE TABLE " + TABLE_NAME + " (" +
                    COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
                    COLUMN_NAME + " TEXT," +
                    COLUMN_DURATION + " TEXT," +
                    COLUMN_DESCRIPTION + " TEXT)";

    private static final String SQL_DELETE_TABLE =
            "DROP TABLE IF EXISTS " + TABLE_NAME;

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(SQL_CREATE_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL(SQL_DELETE_TABLE);
        onCreate(db);
    }
}

Output:-

==========================================================================

Q20. Create an Android app, powered by Firebase Realtime database that supports: Adding Data to Firebase Realtime database, Retrieving Data from Firebase and Deleting data from firebase data.

Activity_main.xml

<LinearLayout

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:padding="16dp"

tools:context=".MainActivity">

<EditText

android:id="@+id/editTextData"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:hint="Enter data"/>

<Button

android:id="@+id/btnAdd"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Add Data"/>

<Button

android:id="@+id/btnRetrieve"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Retrieve Data"/>

<Button

android:id="@+id/btnDelete"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Delete Data"/>

<TextView

android:id="@+id/textViewData"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="16dp"/>

</LinearLayout>

MainActivity.java

package com.example.a20;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

import androidx.annotation.NonNull;

import androidx.appcompat.app.AppCompatActivity;

import com.google.firebase.database.*;

public class MainActivity extends AppCompatActivity {

private EditText editTextData;

private TextView textViewData;

private DatabaseReference database;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

editTextData = findViewById(R.id.editTextData);

textViewData = findViewById(R.id.textViewData);

// Get the Firebase reference

database = FirebaseDatabase.getInstance().getReference();

Button btnAdd = findViewById(R.id.btnAdd);

Button btnRetrieve = findViewById(R.id.btnRetrieve);

Button btnDelete = findViewById(R.id.btnDelete);

btnAdd.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

addData();

}

});

btnRetrieve.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

retrieveData();

}

});

btnDelete.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

deleteData();

}

});

}

private void addData() {

String data = editTextData.getText().toString().trim();

if (!data.isEmpty()) {

String key = database.child("data").push().getKey();

if (key != null) {

database.child("data").child(key).setValue(data);

editTextData.getText().clear();

}

private void retrieveData() {

database.child("data").addListenerForSingleValueEvent(new ValueEventListener() {

@Override

public void onDataChange(@NonNull DataSnapshot snapshot) {

StringBuilder dataStringBuilder = new StringBuilder();

for (DataSnapshot childSnapshot : snapshot.getChildren()) {

String data = childSnapshot.getValue(String.class);

if (data != null) {

dataStringBuilder.append(data).append("\n");

}

textViewData.setText(dataStringBuilder.toString());

}

@Override

public void onCancelled(@NonNull DatabaseError error) {

// Handle error

}

});

}

private void deleteData() {

// Delete all data in the "data" node

database.child("data").removeValue();

textViewData.setText("");

}

Output:-

==========================================================================

Q21. Write an android app to write JSON data into a file and read JSON data from created file

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/buttonWrite"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Write JSON to File"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="16dp"/>

    <Button
        android:id="@+id/buttonRead"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Read JSON from File"
        android:layout_below="@id/buttonWrite"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="16dp"
        android:layout_marginBottom="16dp"/>

    <TextView
        android:id="@+id/textViewOutput"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:layout_below="@id/buttonRead"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="16dp"/>

</RelativeLayout>

MainActivity.java

package com.example.a21;

import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class MainActivity extends AppCompatActivity {

    private static final String FILE_NAME = "json_data.json";
    private TextView textViewOutput;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button buttonWrite = findViewById(R.id.buttonWrite);
        Button buttonRead = findViewById(R.id.buttonRead);
        textViewOutput = findViewById(R.id.textViewOutput);

        buttonWrite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                writeJsonToFile();
            }
        });

        buttonRead.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                readJsonFromFile();
            }
        });
    }

    private void writeJsonToFile() {
        try {
            // Create a JSON object
            JSONObject jsonObject = new JSONObject();
            jsonObject.put("name", "Bhupendra Jogi");
            jsonObject.put("age", 29);
            jsonObject.put("city", "New York");

            // Convert the JSON object to a string
            String jsonString = jsonObject.toString();

            // Write the JSON string to a file
            FileOutputStream fileOutputStream = openFileOutput(FILE_NAME, Context.MODE_PRIVATE);
            fileOutputStream.write(jsonString.getBytes());
            fileOutputStream.close();

            Log.d("WriteJsonToFile", "JSON data written to file successfully");
        } catch (JSONException | IOException e) {
            e.printStackTrace();
        }
    }

    private void readJsonFromFile() {
        try {
            // Read the JSON string from the file
            InputStream inputStream = openFileInput(FILE_NAME);
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            StringBuilder stringBuilder = new StringBuilder();
            String line;

            while ((line = bufferedReader.readLine()) != null) {
                stringBuilder.append(line);
            }

            inputStream.close();

            // Convert the JSON string to a JSON object
            JSONObject jsonObject = new JSONObject(stringBuilder.toString());

            // Display the JSON data in the TextView
            String output = "Name: " + jsonObject.getString("name") +
                    "\nAge: " + jsonObject.getInt("age") +
                    "\nCity: " + jsonObject.getString("city");

            textViewOutput.setText(output);

            Log.d("ReadJsonFromFile", "JSON data read from file successfully");
        } catch (JSONException | IOException e) {
            e.printStackTrace();
        }
    }
}

AndroidManifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Output:-

==========================================================================

Q22.Demonstrate flutter application using android.

import 'package:flutter/material.dart';

void main() {

runApp(MyApp());

}

class MyApp extends StatelessWidget {

@override

Widget build(BuildContext context) {

return MaterialApp(

title: 'Flutter Counter App',

theme: ThemeData(

primarySwatch: Colors.blue,

home: MyHomePage(),

);

}

class MyHomePage extends StatefulWidget {

@override

_MyHomePageState createState() => _MyHomePageState();

}

class _MyHomePageState extends State<MyHomePage> {

int _counter = 0;

@override

Widget build(BuildContext context) {

return Scaffold(

appBar: AppBar(

title: Text('Counter App'),

body: Center(

child: Column(

mainAxisAlignment: MainAxisAlignment.center,

children: <Widget>[

Text(

'Counter:',

style: TextStyle(fontSize: 20),

Text(

'$_counter',

style: TextStyle(fontSize: 40, fontWeight: FontWeight.bold),

floatingActionButton: FloatingActionButton(

onPressed: _incrementCounter,

tooltip: 'Increment',

child: Icon(Icons.add),

);

}

void _incrementCounter() {

setState(() {

_counter++;

});

}}

Ticker

Android Lab file 12 to 22

Post a Comment

0 Comments

Subscribe Us

Most Popular

Facebook

Search This Blog

Report Abuse

About Me

Popular Posts

Footer Menu Widget

Ad Code

Ticker

Android Lab file 12 to 22

Post a Comment

0 Comments

Social Plugin

Subscribe Us

Most Popular

Facebook

Search This Blog

Report Abuse

About Me

Ad Code

Popular Posts

Footer Menu Widget