Develop Reference

Why pass textInput content to string into ArrayList

I want pass values from a form making with TextInputLayout but Android Studio detects my content as INT.
I put the complete class of my activity as well as the view in .xml to determine the problem
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.design.widget.TextInputEditText;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import com.prosegma.rso.R;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
public class AccionActivity extends AppCompatActivity {
ImageView imageView;
private Context activity;
private String[]header={"Campo","Respuesta"};
private String shortText="RSO PROSEGMA";
private String longText="Eliminamos Riesgos Sumamos Valor";
private AccionPdf accionPdf;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_accion);
Button btnCamera1 = (Button)findViewById(R.id.BtnCamera1);
imageView = (ImageView)findViewById(R.id.reporte1);
btnCamera1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent,0);
}
});
Date date = new Date();
String timeStamp = new SimpleDateFormat("dd/MM/yyyy").format(date);
accionPdf=new AccionPdf(getApplicationContext());
accionPdf.openDocument();
accionPdf.addMetaData("Reporte","Acción Insegura","www.prosegma.com");
accionPdf.addTitle("Reporte Acción Insegura","RSO Prosegma"," " +timeStamp);
accionPdf.addParagraph(shortText);
accionPdf.addParagraph(longText);
accionPdf.createTable(header,getClients());
accionPdf.closeDocument();
}
TextInputEditText Nreport = (TextInputEditText) findViewById(R.id.nReporta);
private ArrayList<String[]>getClients(){
ArrayList<String[]>rows=new ArrayList<>();
rows.add(new String[]{"Nombre de quien reporta", Nreport });
rows.add(new String[]{"Nombre del trabajador","No"});
rows.add(new String[]{"Empresa contratista","ju"});
rows.add(new String[]{"Medidas Necesarias","hu"});
return rows;
}
public void pdfAccion(View view)
{
accionPdf.verReporteAccion();
}
public void enviarA(View view) {
Intent email = new Intent(Intent.ACTION_SEND);
email.putExtra(Intent.EXTRA_EMAIL, "receiver_email_address");
email.putExtra(Intent.EXTRA_SUBJECT, "subject");
email.putExtra(Intent.EXTRA_TEXT, "email body");
Uri uri = Uri.fromFile(new File(android.os.Environment.getExternalStorageDirectory(), "pdfFileName"));
email.putExtra(Intent.EXTRA_STREAM, uri);
email.setType("application/pdf");
email.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getActivity().startActivity(email);
}
public Context getActivity() {
return activity;
}
}
I update the publication with the activity, I have tried to change the InputTextLayout by EditText but the situation is the same, it throws me an incompatibility error.
<?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">
<include layout="#layout/actionbar_toolbar"/>
<ScrollView
android:id="#+id/reportes0"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
>
<LinearLayout
android:id="#+id/reportes1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="#dimen/activity_vertical_margin"
android:orientation="vertical"
android:weightSum="10"
>
<View
android:layout_width="match_parent"
android:layout_height="7dp"
/>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#android:color/darker_gray"
/>
<View
android:layout_width="match_parent"
android:layout_height="7dp"
/>
<ImageView
android:id="#+id/reporte1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="#+id/BtnCamera1"
android:layout_weight="1"
android:layout_height="64sp"
android:layout_width="64sp"
android:background="#drawable/camera"
android:gravity="center"
/>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/EditTextBlack"
android:layout_marginTop="4dp"
>
<android.support.design.widget.TextInputEditText
android:id="#+id/nReporta"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="text"
android:hint="NOMBRE DE QUIEN REPORTA"
/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/EditTextBlack"
android:layout_marginTop="4dp"
>
<android.support.design.widget.TextInputEditText
android:id="#+id/nTrabajador"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="NOMBRE DEL TRABAJADOR"
/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/EditTextBlack"
android:layout_marginTop="4dp"
>
<android.support.design.widget.TextInputEditText
android:id="#+id/eContratista"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="EMPRESA CONTRATISTA"
/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/EditTextBlack"
android:layout_marginTop="4dp"
>
<android.support.design.widget.TextInputEditText
android:id="#+id/aMedidas"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="14sp"
android:hint="ACCIÓN, MEDIDAS CORRECTIVAS INMEDIATAS"
android:inputType="textShortMessage"
/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/EditTextBlack"
android:layout_marginTop="4dp"
>
</android.support.design.widget.TextInputLayout>
<CheckBox
android:id="#+id/checkAccidente"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ACCIDENTE" />
<CheckBox
android:id="#+id/checkImpacto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="IMPACTO AMBIENTAL" />
<CheckBox
android:id="#+id/checkEnfermedad"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ENFERMEDAR PROFESIONAL" />
<CheckBox
android:id="#+id/checkReincidente"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="REINCIDENTE" />
<CheckBox
android:id="#+id/checkSancion"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold"
android:text="¿APLICA SANCIÓN?"
/>
<Button
android:id="#+id/guardarAccion"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="GUARDAR REPORTE"
android:theme="#style/RaisedButtonDark"
android:onClick="pdfAccion"
/>
</LinearLayout>
</ScrollView>
</android.support.design.widget.CoordinatorLayout>

TextInputEditText Nreport = (TextInputEditText) findViewById(R.id.nReporta);
this line is outside OnCreate(Bundle savedInstanceState) method. Thats why it throws null. It should be like this
public class MainActivity extends AppCompatActivity {
TextInputEditText Nreport;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Button btnCamera1 = (Button)findViewById(R.id.BtnCamera1);
// imageView = (ImageView)findViewById(R.id.reporte1);
Date date = new Date();
String timeStamp = new SimpleDateFormat("dd/MM/yyyy").format(date);
Nreport = (TextInputEditText) findViewById(R.id.nReporta);
getClients();
}
private ArrayList<String[]> getClients(){
ArrayList<String[]>rows=new ArrayList<>();
rows.add(new String[]{"Nombre de quien reporta", Nreport.getText().toString() }); // get text like this
rows.add(new String[]{"Nombre del trabajador","No"});
rows.add(new String[]{"Empresa contratista","ju"});
rows.add(new String[]{"Medidas Necesarias","hu"});
return rows;
}

my app crashes whenever i click the button

whenever i click the increment button while running the app on my device my app forces unexpectedly
this is my activity_main.xml code
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_height="match_parent"
android:layout_width="match_parent"
tools:context=".MainActivity"
>
<RelativeLayout
android:padding="20dp"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
android:gravity="center_vertical"
>
<EditText
android:id="#+id/name_text_field"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name"
android:inputType="textCapWords"
></EditText>
<TextView
android:layout_centerVertical="true"
android:id="#+id/heading1"
style="#style/HeaderTextStyle"
android:text="Toppings"
android:layout_below="#id/name_text_field"
/>
<CheckBox
android:layout_below="#id/heading1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/whipped_cream"
android:textSize="16sp"
android:paddingLeft="24dp"
android:layout_marginTop="20dp"
android:text="Whipped Cream"
/>
<CheckBox
android:layout_marginTop="20dp"
android:layout_below="#id/whipped_cream"
android:id="#+id/chocolate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="chocolate"
android:textSize="16sp"
android:paddingLeft="24dp"
/>
<TextView
android:layout_below="#id/chocolate"
android:id="#+id/quantity_text_view"
style="#style/HeaderTextStyle"
android:text="Quantity"
android:layout_marginBottom="20dp"
/>
<Button
android:layout_below="#id/quantity_text_view"
android:id="#+id/decrement_button"
android:layout_width="48dp"
android:layout_height="48dp"
android:onClick="decrement"
android:text="-"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="48dp"
android:paddingLeft="10dp"
android:layout_below="#id/quantity_text_view"
android:paddingRight="10dp"
android:textSize="15sp"
android:layout_toRightOf="#id/decrement_button"
android:id="#+id/initial_qty"
android:gravity="center_vertical"
android:text="1"
/>
<Button
android:layout_toRightOf="#id/initial_qty"
android:layout_below="#id/quantity_text_view"
android:id="#+id/increment_button"
android:onClick="increment"
android:layout_width="48dp"
android:layout_height="48dp"
android:text="+"
/>
<Button
android:id="#+id/submit_button"
android:layout_marginTop="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="order"
android:onClick="submitOrder"
android:gravity="center_vertical"
android:layout_below="#id/decrement_button"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:gravity="center_vertical"
android:id="#+id/order_summary_text_view"
android:textAllCaps="true"
android:textStyle="bold"
android:textSize="16sp"
android:layout_below="#id/submit_button"
/>
</RelativeLayout>
</ScrollView>
and this is my MainActivity.java file
package com.orton.birthdaycard;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.util.Log;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import java.text.NumberFormat;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
int quantity=1;
private void increment(View view)
{
if(quantity==100)
return;
else
quantity++;
displayQuantity(quantity);
}
private void decrement(View view)
{
if(quantity==1)
return;
else
quantity--;
displayQuantity(quantity);
}
private void displayQuantity(int qty)
{
TextView quantityTextView=(TextView) findViewById(R.id.initial_qty);
quantityTextView.setText(String.valueOf(quantity));
Log.v("MainActivity","the quantity is " + quantity);
}
int basePrice;
private int calculatePrice(boolean hasWhippedCream,boolean hasChocolate)
{
basePrice = 5;
if(hasWhippedCream==true)
basePrice += 1;
if(hasChocolate==true)
basePrice +=2 ;
return basePrice=basePrice*quantity;
}
String priceMessage="";
private void submitOrder(View view)
{
EditText nameField = (EditText) findViewById(R.id.name_text_field);
String name = nameField.getText().toString();
CheckBox whippedCream = (CheckBox) findViewById(R.id.whipped_cream);
boolean hasWhippedCream = whippedCream.isChecked();
CheckBox chocolate = (CheckBox) findViewById(R.id.chocolate);
boolean hasChocolate = chocolate.isChecked();
int price=calculatePrice(hasWhippedCream,hasChocolate);
String orderSummary=createOrderSummary(name,price,hasWhippedCream,hasChocolate);
displayMessage(orderSummary);
}
private void displayMessage(String orderSummary)
{
TextView summary= (TextView) findViewById(R.id.order_summary_text_view);
summary.setText(""+orderSummary);
}
private String createOrderSummary(String name, int price, boolean hasWhippedCream, boolean hasChocolate)
{
String priceMessage = "Name :" + name;
if(hasWhippedCream)
priceMessage += "\nWhipped Cream Added" ;
if(hasChocolate)
priceMessage += "\nChocolate Added" ;
priceMessage+="\nQuantity : "+quantity;
priceMessage+="\nTotal : $"+price;
priceMessage+="Thank You!" ;
return priceMessage;
}
}
this is debugging report
05-23 22:14:45.695 29736-29736/com.orton.birthdaycard E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.orton.birthdaycard, PID: 29736
java.lang.IllegalStateException: Could not find method increment(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'increment_button'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:5612)
at android.view.View$PerformClick.run(View.java:22285)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)

Your method must use the public modifier:
public void increment(View view)
{
if(quantity==100)
return;
else
quantity++;
displayQuantity(quantity);
}

Do this
increment_button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
}
});
instead of android:onClick="increment"

Add checkboxes on click

I have an image file on which if clicked anywhere I would like X'd checkboxes to show up. (Right now its set up as check marks). The code that I have is just for connecting page 1 to page 2 with a button click. Here it is
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;
public class MainActivity extends AppCompatActivity {
public static Button button1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
OnclickButtonListener();
}
public void OnclickButtonListener() {
button1 = (Button) findViewById(R.id.nextpage);
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
EditText userTextEntry = (EditText)findViewById(R.id.BRinfo);
String userdata = userTextEntry.getText().toString();
int userNumber = Integer.parseInt(userdata);
Intent intent = new Intent(MainActivity.this,Page2.class);
intent.putExtra("para name",userNumber);
startActivity(intent);
}
});
}}
Part of the XML code is
<?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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="vt.tacticalcombat.MainActivity"
android:clickable="true">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/imageView2"
android:src="#mipmap/combat2"
android:layout_alignBottom="#+id/editText17"
android:layout_alignLeft="#+id/last4"
android:layout_alignStart="#+id/last4"
android:layout_alignRight="#+id/tableLayout"
android:layout_alignEnd="#+id/tableLayout"
android:layout_alignTop="#+id/imageView" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="NEXT"
android:id="#+id/nextpage"
android:layout_alignBottom="#+id/tableLayout"
android:layout_alignRight="#+id/otherinfo"
android:layout_alignEnd="#+id/otherinfo"
tools:ignore="HardcodedText,RtlHardcoded"
android:nestedScrollingEnabled="true" />
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/checkBox28"
android:checked="false"
android:visibility="visible"
android:layout_alignBottom="#+id/rarmtypeinfo"
android:layout_toRightOf="#+id/mvc"
android:clickable="true"
android:layout_toEndOf="#+id/mvc" />
<Button
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/button"
android:layout_alignBottom="#+id/checkBox28"
android:layout_alignRight="#+id/injury"
android:layout_alignEnd="#+id/injury"
android:layout_alignTop="#+id/larmtype"
android:layout_alignLeft="#+id/checkBox28"
android:layout_alignStart="#+id/checkBox28" />
</RelativeLayout>
I tried using this link! but it did not work. How can I do this? Any help is appreciated

how to display value of textbox on same screen in android application just like whatsaap

This is my main file where i am calling the click event on button to pass the value.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view);
getActionBar().setHomeButtonEnabled(true);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setTitle("aakash");
SetContentView(R.id.lst);
Button b = (Button) findViewById(R.id.sendbtn);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(android.view.View v) {
startActivity(new Intent(View.this,View.class));
}
});
}
**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:orientation="vertical"
android:background="#ffffff"
>
<TextView
android:id="#+id/username"
android:layout_width="match_parent"
android:layout_height="50dp"
android:gravity="center_vertical"
android:layout_alignParentTop="true"
android:textColor="#000000"
android:text="aakash"
android:background="#c0c0c0"
/>
<ScrollView
android:id="#+id/lst"
android:background="#fefefe"
android:layout_below="#+id/username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/bottom_holder"
>
</ScrollView>
<EditText
android:id="#+id/chattxt"
android:layout_width="230dp"
android:layout_height="45dp"
android:hint="type here"
android:inputType="textMultiLine" />
<Button
android:id="#+id/sendbtn"
android:layout_width="75dp"
android:layout_height="45dp"
android:text="Send" />
</LinearLayout>
I want the value of textbox to display on the same screen(scrollview)box and also i want to pass a httppost request to pass a value..plz help me out
Thnks in advance

I think, you can use a ListView insted of scroll view. and add list items from the chat text value dynamically.
call notifydatasetchanged() every time when you add a new item to it.
<TextView
android:id="#+id/username"
android:layout_width="match_parent"
android:layout_height="50dp"
android:gravity="center_vertical"
android:layout_alignParentTop="true"
android:textColor="#000000"
android:text="aakash"
android:background="#c0c0c0"
/>
<ListView
android:id="#+id/listView_chats"
android:layout_width="match_parent"
android:layout_height="100dp"
>
</ListView>
<EditText
android:id="#+id/chattxt"
android:layout_width="230dp"
android:layout_height="45dp"
android:hint="type here"
android:inputType="textMultiLine" />
<Button
android:id="#+id/sendbtn"
android:layout_width="75dp"
android:layout_height="45dp"
android:text="Send" />
</LinearLayout>
Write a custom adapter for the listView and add the code to manage the list data.

i got the answer to my question
import android.R;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class ButtonActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_button);
}
public void setText(){
Button myButton = (Button)findViewById(R.id.button1);
final TextView myText = (TextView)findViewById(R.id.text1);
final EditText myInput = (EditText)findViewById(R.id.edit);
myButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
myText.setText(myInput.getText());
}
});
}
}

"Source not found" error in Eclipse

Developing my first app for android. Works OK on emulator, but on phone I get a "Source not found error" ViewRoot.handleMessage(Message)line:1757. I get the error when I press button number 4 on the application and try to display my media images on phone.
Code:
package com.example.famiily_connect_v1;
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.EditText;
import android.widget.TextView;
public class family_connect extends Activity implements OnClickListener {
/** Called when the activity is first created. */
Button incrementButton, decrementButton, makecallButton,
media_cameraButton;
TextView numberdisplayTextView;
EditText inputEditText;
int A = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
incrementButton = (Button) findViewById(R.id.Button01);
decrementButton = (Button) findViewById(R.id.Button02);
makecallButton = (Button) findViewById(R.id.Button03);
media_cameraButton = (Button) findViewById(R.id.Button04);
numberdisplayTextView = (TextView) findViewById(R.id.TextView01);
inputEditText = (EditText) findViewById(R.id.EditText01);
incrementButton.setOnClickListener(this);
decrementButton.setOnClickListener(this);
makecallButton.setOnClickListener(this);
media_cameraButton.setOnClickListener(this);
numberdisplayTextView.setOnClickListener(this);
inputEditText.setOnClickListener(this);
}
#Override
public void onClick(View arg0) {
switch (arg0.getId()) {
case R.id.Button01:
A++;
numberdisplayTextView.setText(String.valueOf(A));
break;
case R.id.Button02:
A--;
numberdisplayTextView.setText(String.valueOf(A));
break;
case R.id.Button03:
break;
case R.id.Button04:
Intent myIntent = new Intent();
myIntent.setAction(Intent.ACTION_VIEW);
myIntent.setData(android.provider.MediaStore.Images.Media.INTERNAL_CONTENT_URI);
startActivity(myIntent);
break;
default:
break;
}
}
}
XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:background="#00AAAA">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="#string/hello" />
<LinearLayout android:id="#+id/LinearLayout01"
android:layout_width="wrap_content" android:layout_height="wrap_content"></LinearLayout>
<Button android:id="#+id/Button01" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="increment"></Button>
<Button android:id="#+id/Button02" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="decrement"></Button>
<Button android:id="#+id/Button03" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="make call"></Button>
<Button android:id="#+id/Button04" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="media_camera"></Button>
<TextView android:id="#+id/TextView01" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:textSize="24sp"
android:text="0" android:textStyle="bold" android:textColor="#000000"></TextView>
<EditText android:id="#+id/EditText01" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="enter new button text"></EditText>
<RadioButton android:id="#+id/RadioButton01"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:text="camera"></RadioButton>
</LinearLayout>

Enable in your Eclipse the LogCat
Window > Show View > Other > Android >
LogCat
then you can find what is the real description of your Exception.