# Part A Questions With Solutions
**2.Create an Android Application to demonstrate change of background color using Radio
Buttons.**
```package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RadioGroup;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
RadioGroup b;
LinearLayout l;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b=findViewById(R.id.r);
l=findViewById(R.id.main);
b.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
if (checkedId==R.id.blue){
l.setBackgroundColor(Color.BLUE);
} else if (checkedId==R.id.red) {
l.setBackgroundColor(Color.RED);
}else{
l.setBackgroundColor(Color.GREEN);
}
}
});
}
}
```
#
**3.Create an Android Application to demonstrate choosing of food items and cost
computation using Check Box.**
```package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.LinearLayout;
import android.widget.RadioGroup;
import android.widget.Toast;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Button t;
CheckBox b,p,s;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
t=findViewById(R.id.btn);
b=findViewById(R.id.b);
p = findViewById(R.id.p);
s=findViewById(R.id.s);
t.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String li="";
int amt=0;
if(b.isChecked()){
li=li+b.getText().toString()+"\n";
amt+=100;
}
if (p.isChecked()) {
li=li+p.getText().toString()+"\n";
amt+=100;
}
if (s.isChecked()){
li=li+s.getText().toString()+"\n";
amt+=100;
}
Toast.makeText(MainActivity.this ,li+amt,Toast.LENGTH_LONG).show();
}
});
}
}
```
#
**4.Create an Android Application to add and delete items from ListView dynamically.**
- An ArrayAdapter in Android is a type of adapter used to bind data from an ArrayList (or other data sources) to a UI component such as a ListView or Spinner. It acts as a bridge between the data source and the UI, allowing the data to be displayed and managed easily.
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Button t;
ListView l;
EditText e;
ArrayList<String>arr= new ArrayList<String>();
ArrayAdapter<String>adp;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
t=findViewById(R.id.b);
e=findViewById(R.id.e);
l = findViewById(R.id.l);
arr.add("mango");
arr.add("Orange");
adp=new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1,arr);
l.setAdapter(adp);
t.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String s=e.getText().toString();
arr.add(s);
adp.notifyDataSetChanged();
}
});
l.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
arr.remove(position);
adp.notifyDataSetChanged();
return false;
}
});
}
}
```
#
**5.Simple Calulater**
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Button a,m,d,s ;
TextView r;
EditText e1 ,e2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
e1=findViewById(R.id.etNumber1);
e2=findViewById(R.id.etNumber2);
a = findViewById(R.id.btnAdd);
m = findViewById(R.id.btnMultiply);
d = findViewById(R.id.btnDivide);
s = findViewById(R.id.btnSubtract);
r=findViewById(R.id.tvResult);
a.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int num1= Integer.parseInt(e1.getText().toString());
int num2 = Integer.parseInt(e2.getText().toString());
int result = num1 + num2;
r.setText(String.valueOf(result));
}
});
//add all other buttons Listener
}
}
```
```<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="16dp"
android:paddingTop="50dp">
<!-- Input Fields -->
<EditText
android:id="@+id/etNumber1"
android:layout_width="match_parent"
android:layout_height="50dp"
android:hint="Enter first number"
android:inputType="numberDecimal" />
<EditText
android:id="@+id/etNumber2"
android:layout_width="match_parent"
android:layout_height="50dp"
android:hint="Enter second number"
android:inputType="numberDecimal" />
<!-- Buttons for Operations -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center">
<Button
android:id="@+id/btnAdd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add" />
<Button
android:id="@+id/btnSubtract"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Subtract"
android:layout_marginStart="8dp" />
<Button
android:id="@+id/btnMultiply"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Multiply"
android:layout_marginStart="8dp" />
<Button
android:id="@+id/btnDivide"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Divide"
android:layout_marginStart="8dp" />
</LinearLayout>
<!-- Result Display -->
<TextView
android:id="@+id/tvResult"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Result: "
android:textSize="18sp"
android:paddingTop="16dp"
android:gravity="center" />
</LinearLayout>
```
#
**6.Create an Android Application to send SMS.**
==Settings->apps->permisions->sms->allow==
```<uses-feature
android:name="android.hardware.telephony"
android:required="false" />
<uses-permission android:name="android.permission.SEND_SMS"/>
```
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Color;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Button s;
EditText m ,p;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
m=findViewById(R.id.msg);
p=findViewById(R.id.phn);
s = findViewById(R.id.send);
s.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String ph=p.getText().toString();
String msg=m.getText().toString();
SmsManager smsManager =SmsManager.getDefault();
smsManager.sendTextMessage(ph,null,msg,null,null);
Toast.makeText(MainActivity.this,"SMS Sent",Toast.LENGTH_LONG).show();
}
});
}
}
```
#
**7.Create an Android Application to read the battery percentage from cellphone and
change background color based on level using Broadcast Receiver.**
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Color;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
LinearLayout c1;
TextView t;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
c1=findViewById(R.id.main);
t=findViewById(R.id.t);
bat_b b = new bat_b();
registerReceiver(b,new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
}
class bat_b extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
int per=intent.getIntExtra("level",0);
if (per > 60) {
c1.setBackgroundColor(Color.GREEN);
} else if (per >= 0 && per <= 20) {
c1.setBackgroundColor(Color.RED);
} else {
c1.setBackgroundColor(Color.YELLOW);
}
}
}
}
```
Q: What is BroadcastReceiver in Android?
A: It is a component that listens for system-wide or application-specific broadcast messages.
Q: What does Intent.ACTION_BATTERY_CHANGED do?
A: It is a system broadcast that provides information about the current battery state.
Q: How do you register a BroadcastReceiver in your app?
A: By using registerReceiver method with an IntentFilter for the desired action.
Q: What does getIntExtra("level", 0) in onReceive do?
A: It retrieves the battery level from the Intent.
Q: Why do we use registerReceiver instead of declaring the receiver in the manifest?
A: ACTION_BATTERY_CHANGED is a sticky broadcast and is only available when registered programmatically.
Q: What is the role of EdgeToEdge.enable(this) in this code?
A: It enables edge-to-edge display for the activity, providing a modern UI look.
Q: What is the default value provided in getIntExtra and why?
A: 0 is the default value to avoid null or incorrect data when the level key is not present.
Q: What happens if the BroadcastReceiver is not unregistered?
A: It can cause memory leaks as the system will still try to send broadcasts to the receiver.
Q: Can BroadcastReceiver run on the main thread?
A: Yes, onReceive runs on the main thread, so heavy operations should be avoided.
Q: Why use Color.GREEN, Color.RED, and Color.YELLOW?
A: To visually indicate different battery levels.
Q: What is the purpose of setContentView in onCreate?
A: It sets the layout resource for the activity.
Q: Can BroadcastReceiver be used for custom broadcasts?
A: Yes, using sendBroadcast to send custom intents.
- What is an Intent in Android?:
Definition:
An Intent is a messaging object used in Android to request an action from another app component. It facilitates communication between components such as activities, services, and broadcast receivers.
#
**8.Create an Android Application to change image in Image View on Button Click**
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.os.Bundle;
import android.provider.MediaStore;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
ImageView i;
Button b;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
i=findViewById(R.id.imageView);
b=findViewById(R.id.button4);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i =new Intent(MediaStore.ACTION_IMAGE_CAPTURE_SECURE);
startActivityForResult(i,1);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == 1){
Bitmap t=(Bitmap)data.getExtras().get("data");
i.setImageBitmap(t);
}
}
}
```
- Bitmap: Represents an image in memory that you can manipulate or display in your app.
- Intent: A messaging object used to request actions from other components (like capturing an image using the camera in this case).
- startActivityForResult(): Starts an activity (camera app here) and expects a result to be returned later.
- getExtras(): Retrieves additional data passed with the Intent, which in this case contains the captured image.
#
**9.Create an Android Application to capture video using Camera and illustrate
playback.**
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.VideoView;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
VideoView v;
Button b;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
v=findViewById(R.id.videoView);
b=findViewById(R.id.button4);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i =new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
startActivityForResult(i,1);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == 1){
Uri u = data.getData();
v.setVideoURI(u);
v.start();
}
}
}
```
```Uri u = data.getData();```
- data.getData() is used to retrieve the Uri of the video file selected by the user. This
- Uri: A URI (Uniform Resource Identifier) is used to identify and access a resource, like a video file, on the system.
- VideoView: A UI element in Android used to display and play videos.
#
**10.Create an Android Application to demonstrate the following Android Animations. i)
Rotate ii) Fade**
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.telephony.SmsManager;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.VideoView;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
ImageView i ;
Button r , f;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
i=findViewById(R.id.imageView3);
r=findViewById(R.id.button4);
f=findViewById(R.id.button5);
r.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Animation a = AnimationUtils.loadAnimation(MainActivity.this,R.anim.rotate);
i.startAnimation(a);
}
});
f.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Animation a = AnimationUtils.loadAnimation(MainActivity.this,R.anim.fade);
i.startAnimation(a);
}
});
}
}
```
==rotate.xml==
```<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<rotate android:fromDegrees="0" android:toDegrees="360" android:pivotX="50%"
android:pivotY="50%" android:duration="1000"/>
</set>
```
==fade.xml==
```<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<alpha android:toAlpha="0" android:fromAlpha="1"
android:duration="1000"/>
</set>
```
#
**11.Gyroscope and accelerometer**
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.telephony.SmsManager;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.VideoView;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
TextView x,y,z ;
Sensor s;
SensorManager sm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
x=findViewById(R.id.textView);
y=findViewById(R.id.textView1);
z=findViewById(R.id.textView2);
sm=(SensorManager)getSystemService(SENSOR_SERVICE) ;
s=sm.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
if(s==null){
Toast.makeText(this,"Suported",Toast.LENGTH_LONG).show();
finish();
}
sm.registerListener(new SensorEventListener() {
@Override
public void onSensorChanged(SensorEvent event) {
float xval=event.values[0];
float yval=event.values[1];
float zval=event.values[2];
x.setText(xval+"");
y.setText(yval+"");
z.setText(zval+"");
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
},s,SensorManager.SENSOR_DELAY_NORMAL);
}
}
```
```<?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"
android:orientation="vertical"
android:padding="16dp"
android:paddingTop="50dp"
android:id="@+id/main">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="TextView" />
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="TextView" />
<TextView
android:id="@+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="TextView" />
</LinearLayout>
```
#
# PART-B QUESTIONS
**Sql**
```package com.example.myapplication;
public class MainActivity extends AppCompatActivity {
EditText name,usn,age ;
Button insert,select;
Dbhelper db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
db=new Dbhelper(this);
name=findViewById(R.id.name);
age=findViewById(R.id.age);
usn=findViewById(R.id.usn);
insert=findViewById(R.id.i);
select=findViewById(R.id.s);
insert.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nm =name.getText().toString();
String us = usn.getText().toString();
int a = Integer.parseInt(age.getText().toString()) ;
boolean res=db.InserData(nm,us,a);
if(res){
Toast.makeText(MainActivity.this,"Inserted",Toast.LENGTH_LONG).show();
}else{
Toast.makeText(MainActivity.this,"Not Inserted",Toast.LENGTH_LONG).show();
}
}
});
select.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String uss = usn.getText().toString();
Cursor c = db.SelectData(uss);
if(c.getCount()==0){
Toast.makeText(MainActivity.this,"No Data",Toast.LENGTH_LONG).show();
}else{
c.moveToFirst();
String n1=c.getString(0);
String n2=c.getString(1);
int a=c.getInt(2);
String data = "Name:"+n1+"\nUsn:"+n2+"\nage"+a;
Toast.makeText(MainActivity.this,data,Toast.LENGTH_LONG).show();
}
}
});
}
}
```
```package com.example.myapplication;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class Dbhelper extends SQLiteOpenHelper {
public Dbhelper( Context context) {
super(context, "User1.db",null,1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE Student(name TEXT,usn TEXT primary key,age INTEGER)");
}
public boolean InserData(String name ,String usn,int age){
SQLiteDatabase db=getWritableDatabase();
ContentValues cv =new ContentValues();
cv.put("name",name);
cv.put("usn",usn);
cv.put("age",age);
long res = db.insert("Student",null,cv);
db.close();
return res!=1;
}
public Cursor SelectData(String u){
SQLiteDatabase db = getWritableDatabase();
Cursor c=db.rawQuery("select * from Student where usn=?",new String[]{u});
return c;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS Student");
onCreate(db);
}
}
```
#
**Create an Android Application to demonstrate communication between two
activities using Explicit Intents.**
==main==
```public class MainActivity extends AppCompatActivity {
EditText m ;
Button s;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
m=findViewById(R.id.m);
s=findViewById(R.id.s);
s.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String s = m.getText().toString();
Intent i = new Intent(MainActivity.this ,MainActivity2.class);
i.putExtra("Msg",s);
startActivityForResult(i,1);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode==RESULT_OK){
String s = data.getStringExtra("Ack");
Toast.makeText(MainActivity.this,s,Toast.LENGTH_LONG).show(); }
}
}
```
==main2==
```package com.example.myapplication;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity2 extends AppCompatActivity {
TextView t;
Button b;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main2);
t=findViewById(R.id.textView);
b=findViewById(R.id.btn);
Intent i = getIntent();
String s = i.getStringExtra("Msg");
t.setText(s);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent();
i.putExtra("Ack","Recived");
setResult(RESULT_OK,i);
finish();
}
});
}
}
```
#
**Create an Android Application to demonstrate implicit intents for Call, Maps and
browser activity.**
```package com.example.myapplication;
public class MainActivity extends AppCompatActivity {
EditText e1, e2, e3;
Button b1, b2, b3, b4;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
e1 = findViewById(R.id.pe);
e2 = findViewById(R.id.me);
e3 = findViewById(R.id.be);
b1 = findViewById(R.id.pb);
b2 = findViewById(R.id.mb);
b3 = findViewById(R.id.bb);
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String s = e1.getText().toString();
Intent call = new Intent(Intent.ACTION_VIEW,Uri.parse("tel:"+s));
startActivity(call);
}
});
b2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String m= e2.getText().toString();
Intent map = new Intent(Intent.ACTION_VIEW,Uri.parse("google.navigation:q="+m));
startActivity(map);
}
});
b3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String url =e3.getText().toString();
url="http://"+url;
Intent brw = new Intent(Intent.ACTION_VIEW,Uri.parse(url));
startActivity(brw);
}
});
}
}
```
# h1
**option/contextMenu**
```public class MainActivity extends AppCompatActivity {
EditText e1, e2 ;
TextView t;
Button b1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
e1 = findViewById(R.id.e1);
e2 = findViewById(R.id.e2);
t=findViewById(R.id.t);
b1 = findViewById(R.id.b1);
registerForContextMenu(b1);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(1,101,1,"ADD");
menu.add(1,102,2,"SUB");
menu.add(1,103,3,"ADD");
menu.add(1,104,4,"ADD");
return super.onCreateOptionsMenu(menu);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.add(1,101,1,"ADD");
menu.add(1,102,2,"SUB");
menu.add(1,103,3,"ADD");
menu.add(1,104,4,"ADD");
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
double f = Double.parseDouble(e1.getText().toString());
double s =Double.parseDouble(e2.getText().toString());
switch(item.getItemId()){
case 101:t.setText(String.valueOf(f+s));
return true;
case 102:t.setText(String.valueOf(f-s));
return true;
case 103:t.setText(String.valueOf(f*s));
return true;
case 104:
if (s != 0)
t.setText(String.valueOf(f / s));
else
Toast.makeText(MainActivity.this, "Divide by zer0",
Toast.LENGTH_LONG).show();
return true;
default:
return super.onContextItemSelected(item);
}
}
@Override
public boolean onContextItemSelected(@NonNull MenuItem item) {
double f = Double.parseDouble(e1.getText().toString());
double s =Double.parseDouble(e2.getText().toString());
switch(item.getItemId()){
case 101:t.setText(String.valueOf(f+s));
return true;
case 102:t.setText(String.valueOf(f-s));
return true;
case 103:t.setText(String.valueOf(f*s));
return true;
case 104:
if (s != 0)
t.setText(String.valueOf(f / s));
else
Toast.makeText(MainActivity.this, "Divide by zer0",
Toast.LENGTH_LONG).show();
return true;
default:
return super.onContextItemSelected(item);
}
}
}
```
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