Develop Reference

I keep getting "default activity not found" in my android application

I have created an android application with a simple login page, when i try run the app though i keep getting the same error. Can someone please tell me what I am missing here? Below are my android manifest and my two activities java classes.
Main Activity (Login) -
package com.example.squashsademo;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
EditText mTextUsername;
EditText mTextPassword;
Button mButtonLogin;
TextView mTextViewRegister;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
mTextUsername = (EditText)findViewById(R.id.edittext_username);
mTextPassword = (EditText)findViewById(R.id.edittext_password);
mButtonLogin = (Button)findViewById(R.id.button_login);
mTextViewRegister.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
Intent RegisterIntent = new Intent(MainActivity.this,Register_Activity.class);
startActivity(RegisterIntent);
}
});
mButtonLogin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, PlayerInfo.class));
}
});
}
}
Register Activity -
package com.example.squashsademo;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Register_Activity extends AppCompatActivity {
EditText mTextEmail;
EditText mTextUsername;
EditText mTextPassword;
EditText mTextCnfPassword;
Button mButtonRegister;
TextView mTextViewLogin;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register_);
mTextUsername = (EditText)findViewById(R.id.edittext_username);
mTextPassword = (EditText)findViewById(R.id.edittext_password);
mTextCnfPassword = (EditText) findViewById(R.id.edittext_cnf_password);
mButtonRegister = (Button)findViewById(R.id.button_register);
mTextViewLogin = (TextView)findViewById(R.id.txtViewLogin);
mTextViewLogin.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
Intent LoginIntent = new Intent(Register_Activity.this,MainActivity.class);
startActivity(LoginIntent);
}
});
}
}
Android Manifest -
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.squashsademo">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.SquashSADemo">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<action android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=".Register_Activity" />
<activity android:name=".PlayerInfo" />
</application>
</manifest>

You have to replace
<action android:name="android.intent.category.LAUNCHER" />
with
<category android:name="android.intent.category.LAUNCHER" />
in your AndroidManifest.xml file.

Android app crashes on Bluetooth connect?

I'm trying to connect to other Android devices using Bluetooth via my app. The app works fine while discovering nearby Bluetooth devices. However, upon connecting, the app crashes.
I have two JAVA files other than MainActivity.java that are responsible for discovering & connecting to other Bluetooth devices. Their codes are posted below:
SearchBTDevice.java (for discovering nearby devices)
package vertex2016.mvjce.edu.bluealert;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGattDescriptor;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.bluetooth.BluetoothAdapter;
import android.provider.Settings;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.Set;
public class SearchBTDevice extends AppCompatActivity {
public BluetoothAdapter BlueAdapter = BluetoothAdapter.getDefaultAdapter();
public ArrayAdapter PairedArrayAdapter;
public ArrayAdapter BTArrayAdapter;
BluetoothDevice btd;
public ListView devicesFound;
private final BroadcastReceiver BTReceiver= new BroadcastReceiver(){
public void onReceive(Context context, Intent intent)
{
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
btd = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
BTArrayAdapter.add(btd.getName() + "\t" + btd.getAddress() + "\n");
}
}
};
IntentFilter filter1 = new IntentFilter(BluetoothDevice.ACTION_FOUND);
#Override
protected void onResume() {
super.onResume();
this.registerReceiver(BTReceiver,filter1);
}
#Override
protected void onPause() {
super.onPause();
BlueAdapter.cancelDiscovery();
this.unregisterReceiver(BTReceiver);
Toast.makeText(SearchBTDevice.this, "Discovery Stopped!!", Toast.LENGTH_SHORT).show();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search_btdevice);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);
searchBTDevices();
}
public void searchBTDevices()
{
if(!BlueAdapter.startDiscovery())
Toast.makeText(SearchBTDevice.this, "Failed to Start Discovery", Toast.LENGTH_SHORT).show();
else
Toast.makeText(SearchBTDevice.this, "Discovery Startred", Toast.LENGTH_SHORT).show();
BTArrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1);
devicesFound = (ListView)findViewById(R.id.searchpagelistView);
devicesFound.setAdapter(BTArrayAdapter);
devicesFound.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent connectedBTintent = new Intent(SearchBTDevice.this, ConnectedBTDevice.class);
connectedBTintent.putExtra("BluetoothDevice", btd);
startActivity(connectedBTintent);
}
});
}
}
This is updated ConnectedBTDevice.java, responsible for connecting devices
package vertex2016.mvjce.edu.bluealert;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.io.IOException;
import java.util.UUID;
public class ConnectedBTDevice extends AppCompatActivity {
public BluetoothDevice btd;
public BluetoothSocket btSocket, tempSocket;
private UUID myUUID;
ArrayAdapter arr;
ListView lv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_connected_btdevice);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);
arr = new ArrayAdapter(this, android.R.layout.simple_list_item_2);
btd = getIntent().getParcelableExtra("BluetoothDevice");
connectBT();
displayStuff();
}
public void connectBT() {
Thread myThread = new Thread() {
public void run() {
tempSocket = null;
try {
tempSocket = btd.createRfcommSocketToServiceRecord(myUUID);
} catch (IOException e) {
e.printStackTrace();
}
BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
try {
tempSocket.connect();
arr.add("CONNECTED TO-->" + btd.getName());
} catch (IOException e) {
e.printStackTrace();
try {
tempSocket.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
};
myThread.start();
}
public void displayStuff()
{
lv = (ListView)findViewById(R.id.connectedBTlistView);
lv.setAdapter(arr);
}
}
This is activity_connected_btdevice.xml for ConnectedBTDevice.java activity
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:fitsSystemWindows="true"
tools:context="vertex2016.mvjce.edu.bluealert.SearchBTDevice">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/AppTheme.NoActionBar.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/AppTheme.NoActionBar.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/content_connected_btdevice" />
</android.support.design.widget.CoordinatorLayout>
This is content_connected_btdevice.xml for ConnectedBTDevice.java
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="vertex2016.mvjce.edu.bluealert.ConnectedBTDevice"
tools:showIn="#layout/activity_connected_btdevice">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/connectedBTimageView"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:src="#drawable/bluealert_bg"
android:scaleType="centerCrop"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Connected Bluetooth Device"
android:id="#+id/connectedBTtextextView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="105dp"
android:textSize="25dp"
android:textAlignment="center"/>
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/connectedBTlistView"
android:layout_below="#+id/connectedBTtextextView"
android:layout_centerHorizontal="true"
android:layout_marginTop="65dp" />
</RelativeLayout>
This is AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="vertex2016.mvjce.edu.bluealert">
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<application
android:allowBackup="true"
android:icon="#mipmap/bluealerticon"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme.NoActionBar">
<activity
android:name=".SplashScreen"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity" />
<activity
android:name=".SearchBTDevice"
android:label="#string/title_activity_search_btdevice"
android:parentActivityName=".MainActivity"
android:theme="#style/AppTheme.NoActionBar">
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="vertex2016.mvjce.edu.bluealert.MainActivity" />
</activity>
<activity
android:name=".ConnectedBTDevice"
android:label="#string/title_activity_connected_btdevice"
android:parentActivityName=".SearchBTDevice"
android:theme="#style/AppTheme.NoActionBar">
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="vertex2016.mvjce.edu.bluealert.SearchBTDevice" />
</activity>
</application>
</manifest>
Here's the exception that my updated logcat shows
03-24 00:19:40.541 7205-9703/vertex2016.mvjce.edu.bluealert E/AndroidRuntime: FATAL EXCEPTION: Thread-35890
Process: vertex2016.mvjce.edu.bluealert, PID: 7205
java.lang.NullPointerException: Attempt to invoke virtual method 'long java.util.UUID.getMostSignificantBits()' on a null object reference
at android.os.ParcelUuid.writeToParcel(ParcelUuid.java:129)
at android.bluetooth.IBluetooth$Stub$Proxy.connectSocket(IBluetooth.java:1767)
at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:309)
at vertex2016.mvjce.edu.bluealert.ConnectedBTDevice$1.run(ConnectedBTDevice.java:63)
I don't understand what the problem is. I have tried several online tutorials, but nothing seemed to work. I know the problem is in my ConnectedBTDevice.java, but can't figure out the point at which it's throwing the exception.
Thank you for your time.

You are assigning BluetoothSocket to tempSocket, and then you try to invoke connect() method on btSocket which is null.

simple navigation from 2nd activity to 3rd activity in android without passing any values

From first activity to second activity navigation is working but second activity to third activity navigation is not working in android can any1 please help me.
This is my MainActivity.java
package com.exampl.test;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.app.Activity;
import android.view.View;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void activity2(View view){
Intent intent = new Intent(this,com.exampl.test.MainActivity2.class);
startActivity(intent);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
This is my MainActivity2.java
package com.exampl.test;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MainActivity2 extends Activity {
#SuppressLint("NewApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity2);
getActionBar().setDisplayHomeAsUpEnabled(true);
}
public void activity3(View view){
Intent intent = new Intent(this,com.exampl.test.MainActivity3.class);
startActivity(intent);
}
#Override
public void onBackPressed() {
super.onBackPressed();
}
}
This is my MainActivity3.java
package com.exampl.test;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity3 extends Activity {
#SuppressLint("NewApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity3);
getActionBar().setDisplayHomeAsUpEnabled(true);
}
#Override
public void onBackPressed() {
super.onBackPressed();
}
}
This is my appmanifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.exampl.test"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.exampl.test.MainActivity2"
android:label="#string/title_activity_main_activity2"
android:parentActivityName="com.exampl.test.MainActivity" >
</activity>
<activity
android:name="com.exampl.test.MainActivity3"
android:label="#string/title_activity_main_activity3"
android:parentActivityName="com.exampl.test.MainActivity2" >
</activity>
</application>
</manifest>
please help me wt to modify in above coding
Thanks in advance

Try This!
MainActivity
package com.example.acct;
import com.example.acct.R;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button =(Button) findViewById(R.id.button1);
Toast.makeText(this, "Activity1", Toast.LENGTH_SHORT).show();
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
activity2();
}
});
}
public void activity2() {
Intent intent = new Intent(this, com.example.acct.MainActivity2.class);
startActivity(intent);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
MainActivity2
package com.example.acct;
import com.example.acct.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity2 extends Activity {
Button button;
#SuppressLint("NewApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getActionBar().setDisplayHomeAsUpEnabled(true);
button = (Button) findViewById(R.id.button1);
Toast.makeText(this, "Activity2", Toast.LENGTH_SHORT).show();
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
activity3();
}
});
}
public void activity3() {
Intent intent = new Intent(this, com.example.acct.MainActivity3.class);
startActivity(intent);
}
#Override
public void onBackPressed() {
super.onBackPressed();
}
}
MainActivity3
package com.example.acct;
import com.example.acct.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity3 extends Activity {
Button button;
#SuppressLint("NewApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.button1);
Toast.makeText(this, "Activity3", Toast.LENGTH_SHORT).show();
getActionBar().setDisplayHomeAsUpEnabled(true);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
activity3();
}
});
}
public void activity3() {
Intent intent = new Intent(this, com.example.acct.MainActivity3.class);
startActivity(intent);
}
#Override
public void onBackPressed() {
super.onBackPressed();
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.acct"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.acct.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MainActivity2"
android:parentActivityName=".MainActivity" >
</activity>
<activity
android:name=".MainActivity3"
android:parentActivityName=".MainActivity2" >
</activity>
</application>
</manifest>

onClickListener crashes program wont link to another activity android

My Main Activity class is as follows
package com.example.barnight2;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView date;
private Button taxiButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
dateAndTime();
}
public void addListenerOnButton() {
taxiButton = (Button) findViewById(R.id.btnTaxi);
taxiButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent taxiIntent = new Intent(MainActivity.this, TaxiActivity.class);
startActivity(taxiIntent);
}
});
}
public void dateAndTime() {
date = (TextView) findViewById(R.id.lblDate);
SimpleDateFormat sdf = new SimpleDateFormat("EEEE");
Date day = new Date();
String dayOfTheWeek = sdf.format(day);
date.setText(dayOfTheWeek);
}
}
then i have my second activity called the Taxi Activity
package com.example.barnight2;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class TaxiActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_taxi);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.taxi, menu);
return true;
}
}
Here is my Manifest.xml i thought i had done everything perfectly but it seems to always crash upon start up of the app
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.barnight2"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.barnight2.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.barnight2.TaxiActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
</activity>
</application>
</manifest>
![image]http://i62.tinypic.com/16rma8.png

ClassCastException
you're casting an object that it's not the same type you're trying to cast, so that's why it throw a RunTimeException with ClassCastException.
It should be:
taxiButton = (ImageButton) findViewById(R.id.btnTaxi);
Since you declared it as ImageButton in xml.

Please remove :
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
from your activity com.example.barnight2.TaxiActivity in the AndroidManifest.xml

android application crashes as I pass string to another activity

so here is another basic problem i'm having...my application crashes as i try to pass a string to another activity. i have tried a few ways but in vain. here's the code
Main Activity named Main.java
package com.ammad.test;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Main extends Activity {
TextView tv;
Button b1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.tvShow);
b1 = (Button) findViewById(R.id.bt1);
b1.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
Bundle basket = new Bundle();
String myScore = "testing";
basket.putString("key", myScore);
Intent intent = new Intent(Main.this, Second.class);
intent.putExtras(basket);
startActivity(intent);
}
});
}
}
Second class to which the data is passes named Second.java
package com.ammad.test;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class Second extends Activity{
TextView tv;
String getScore;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
tv= (TextView) findViewById(R.id.tvRes);
Bundle gotBasket = getIntent().getExtras();
getScore = gotBasket.getString("key");
tv.setText(getScore);
}
}
and finally the manifest file:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ammad.test"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".Main"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Sec"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="com.ammad.test.SECS" />
</intent-filter>
</activity>
</application>
</manifest>

Seems to me your second activity is declared wrong in the manifest, as .Sec not .Second as would be expected - the log is probably showing a exception because the intent was invalid.