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Null Pointer Exception while setting value of TextView in an Array Adapter class - Android

I'm getting a NullPointerException while trying to start an Activity which contains a ListView .
In the getView method of the adapter class, the exception happens when the setText function of a textView is being called .
The code bellow is my adapter class:
public class QuestionsListAdapter extends ArrayAdapter<Question> {
Context context;
List<Question> questions;
public QuestionsListAdapter(Context context, List<Question> questions){
super(context, R.layout.list_item_question, questions);
this.context = context;
this.questions = questions;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = vi.inflate(R.layout.list_item_question, null);
Question question = questions.get(position);
TextView tv = (TextView) view.findViewById(R.id.question_list_item_string);
Log.i(TableCreator.LOG_TAG, question.toString()); //this works fine and the string is not null .
tv.setText(question.toString()+""); //NULL POINTER EXCEPTION .
return view;
}
}
As you see, I've logged the string in the logcat and it works just fine, but the next line makes the mistake .
And this is the logcat output:
05-27 13:24:02.979 5325-5325/org.kabiri.operationcheklist I/Operation Checklist﹕ |-Question-> id:1 summary:mySummary comment:myComment solution:mySolution ownerList:dummyOwner
05-27 13:24:02.979 5325-5325/org.kabiri.operationcheklist D/AndroidRuntime﹕ Shutting down VM
05-27 13:24:02.979 5325-5325/org.kabiri.operationcheklist W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb0f5f648)
05-27 13:24:02.979 5325-5325/org.kabiri.operationcheklist E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at org.kabiri.operationchecklist.adapter.QuestionsListAdapter.getView(QuestionsListAdapter.java:43)
at android.widget.AbsListView.obtainView(AbsListView.java:2177)
at android.widget.ListView.makeAndAddView(ListView.java:1840)
at android.widget.ListView.fillDown(ListView.java:675)
at android.widget.ListView.fillFromTop(ListView.java:736)
at android.widget.ListView.layoutChildren(ListView.java:1655)
at android.widget.AbsListView.onLayout(AbsListView.java:2012)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.support.v7.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:502)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:14289)
at android.view.ViewGroup.layout(ViewGroup.java:4562)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1976)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1730)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
at android.view.Choreographer.doFrame(Choreographer.java:532)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
The logcat shows that the error happens on this line of my adapter class:
tv.setText(question.toString()+"");
I really appreciate your help .

You already know where the problem is!
tv.setText(question.toString()+"");
is causing the NPE that means the TextView tv is null. And that means that the line
TextView tv = (TextView) view.findViewById(R.id.question_list_item_string);
is not able to find the TextView. Check the question_list_item_string id and make sure it matches the id in your list_item_question.xml file

How to display message from Android to PHP? [duplicate]

This question already has answers here:
How can I fix 'android.os.NetworkOnMainThreadException'?
(66 answers)
Closed 8 years ago.
I am trying to create a function in an Android app that sends a message to a PHP file on a webserver (in my case, localhost) and have the PHP display the text. I am able to connect with the PHP file but only read JSON data from the file. I want to send data to the file and display it. Any ideas on how I can do this? I have tried a tutorial but my app is crashing.
Here is my code for this tutorial:
PHP code:
<?php
// get the "message" variable from the post request
// this is the data coming from the Android app
$message=$_POST["message"];
// specify the file where we will save the contents of the variable message
$filename="androidmessages.html";
// write (append) the data to the file
file_put_contents($filename,$message."<br />",FILE_APPEND);
// load the contents of the file to a variable
$androidmessages=file_get_contents($filename);
// display the contents of the variable (which has the contents of the file)
echo $androidmessages;
?>
Activity:
package com.yoursite.helloworld;
import java.io.IOException;
import org.apache.http.client.ClientProtocolException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.message.BasicNameValuePair;
// import everything you need
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class HelloWorldActivity extends Activity {
Button sendButton;
EditText msgTextField;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// load the layout
setContentView(R.layout.main);
// make message text field object
msgTextField = (EditText) findViewById(R.id.msgTextField);
// make send button object
sendButton = (Button) findViewById(R.id.sendButton);
}
// this is the function that gets called when you click the button
public void send(View v)
{
// get the message from the message text box
String msg = msgTextField.getText().toString();
// make sure the fields are not empty
if (msg.length()>0)
{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.0.9/testPHP.php");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("message", msg));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpclient.execute(httppost);
msgTextField.setText(""); // clear text box
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
else
{
// display message if text fields are empty
Toast.makeText(getBaseContext(),"All field are required",Toast.LENGTH_SHORT).show();
}
}
}
Logcat:
05-27 12:27:18.400: I/Process(9241): Sending signal. PID: 9241 SIG: 9
05-27 12:27:24.705: D/libEGL(9361): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so
05-27 12:27:24.705: D/libEGL(9361): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so
05-27 12:27:24.713: D/libEGL(9361): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
05-27 12:27:24.783: D/OpenGLRenderer(9361): Enabling debug mode 0
05-27 12:27:31.838: D/AndroidRuntime(9361): Shutting down VM
05-27 12:27:31.838: W/dalvikvm(9361): threadid=1: thread exiting with uncaught exception (group=0x416fe7c0)
05-27 12:27:31.845: E/AndroidRuntime(9361): FATAL EXCEPTION: main
05-27 12:27:31.845: E/AndroidRuntime(9361): java.lang.IllegalStateException: Could not execute method of the activity
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.view.View$1.onClick(View.java:3640)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.view.View.performClick(View.java:4247)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.view.View$PerformClick.run(View.java:17728)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.os.Handler.handleCallback(Handler.java:730)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.os.Handler.dispatchMessage(Handler.java:92)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.os.Looper.loop(Looper.java:137)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.app.ActivityThread.main(ActivityThread.java:5289)
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.lang.reflect.Method.invokeNative(Native Method)
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.lang.reflect.Method.invoke(Method.java:525)
05-27 12:27:31.845: E/AndroidRuntime(9361): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
05-27 12:27:31.845: E/AndroidRuntime(9361): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
05-27 12:27:31.845: E/AndroidRuntime(9361): at dalvik.system.NativeStart.main(Native Method)
05-27 12:27:31.845: E/AndroidRuntime(9361): Caused by: java.lang.reflect.InvocationTargetException
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.lang.reflect.Method.invokeNative(Native Method)
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.lang.reflect.Method.invoke(Method.java:525)
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.view.View$1.onClick(View.java:3635)
05-27 12:27:31.845: E/AndroidRuntime(9361): ... 11 more
05-27 12:27:31.845: E/AndroidRuntime(9361): Caused by: android.os.NetworkOnMainThreadException
05-27 12:27:31.845: E/AndroidRuntime(9361): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1133)
05-27 12:27:31.845: E/AndroidRuntime(9361): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
05-27 12:27:31.845: E/AndroidRuntime(9361): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
05-27 12:27:31.845: E/AndroidRuntime(9361): at libcore.io.IoBridge.connect(IoBridge.java:112)
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:460)
05-27 12:27:31.845: E/AndroidRuntime(9361): at java.net.Socket.connect(Socket.java:832)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
05-27 12:27:31.845: E/AndroidRuntime(9361): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
05-27 12:27:31.845: E/AndroidRuntime(9361): at com.example.testphp.MainActivity.send(MainActivity.java:63)
I have given permission to use the internet. Any ideas on why the app is crashing?

Make sure that you are running your Network stuff out of the mainUI. Example: Do it in a Thread or in an AsyncTask.
Example:
In your MainUI new MyAsyncTask().execute();
private class MyAsyncTask extends AsyncTask<String, Integer, Double>{
#Override
protected Double doInBackground(String... params) {
postData(params[0]);
return null;
}
protected void onPostExecute(Double result){}
protected void onProgressUpdate(Integer... progress){
pb.setProgress(progress[0]);
}
}
public void postData(String valueIWantToSend) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://somewebsite.com/receiver.php");
try {
List nameValuePairs = new ArrayList();
nameValuePairs.add(new BasicNameValuePair("myHttpData", valueIwantToSend));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
} catch (Exception e) {}
}

App using camera flash as a torch using Eclipse not working

I have been working on an app to use a phone's/tablet's camera flash as a flashlight. Everything seemed to be working fine but when I tested it on my Droid Bionic running Android 4.1.2, the app failed to turn on the flash even though it said it did. Here is the java code I used:
package com.example.flash;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.util.Log;
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 {
private boolean isFlashOn = false;
private Camera camera;
private Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.buttonFlashlight);
Context context = this;
PackageManager pm = context.getPackageManager();
if(!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
Log.e("err", "Device has no camera!");
Toast.makeText(getApplicationContext(),
"Your device doesn't have camera!",Toast.LENGTH_SHORT).show();
return;
}
camera = Camera.open();
final Parameters p = camera.getParameters();
button.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
if (isFlashOn) {
Log.i("info", "torch is turned off!");
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
isFlashOn = false;
button.setText("Tap to turn flashlight on.");
}
else {
Log.i("info", "torch is turned on!");
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
isFlashOn = true;
button.setText("Tap to turn flashlight off.");
}
}
});
}
#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;
}
#Override
protected void onStop() {
super.onStop();
if (camera != null) {
camera.release();
}
}}
Is this code correct or did I miss something?
Logcat:
07-03 18:48:29.064: E/Trace(773): error opening trace file: No such file or directory (2)
07-03 18:48:30.535: D/Camera(773): app passed NULL surface
07-03 18:48:31.023: D/libEGL(773): loaded /system/lib/egl/libEGL_emulation.so
07-03 18:48:31.073: D/(773): HostConnection::get() New Host Connection established 0x2a13c3c0, tid 773
07-03 18:48:31.123: D/libEGL(773): loaded /system/lib/egl/libGLESv1_CM_emulation.so
07-03 18:48:31.173: D/libEGL(773): loaded /system/lib/egl/libGLESv2_emulation.so
07-03 18:48:31.406: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:48:31.433: D/OpenGLRenderer(773): Enabling debug mode 0
07-03 18:48:31.723: I/Choreographer(773): Skipped 58 frames! The application may be doing too much work on its main thread.
07-03 18:49:05.923: D/dalvikvm(773): GC_CONCURRENT freed 202K, 12% free 2623K/2956K, paused 74ms+25ms, total 234ms
07-03 18:49:06.216: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:49:09.584: D/Camera(773): app passed NULL surface
07-03 18:49:09.853: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:49:11.813: I/info(773): torch is turned on!
07-03 18:49:13.467: I/info(773): torch is turned off!
07-03 18:49:16.263: W/EGL_emulation(773): eglSurfaceAttrib not implemented
07-03 18:49:16.713: D/AndroidRuntime(773): Shutting down VM
07-03 18:49:16.713: W/dalvikvm(773): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
07-03 18:49:16.936: E/AndroidRuntime(773): FATAL EXCEPTION: main
07-03 18:49:16.936: E/AndroidRuntime(773): java.lang.RuntimeException: Method called after release()
07-03 18:49:16.936: E/AndroidRuntime(773): at android.hardware.Camera._stopPreview(Native Method)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.hardware.Camera.stopPreview(Camera.java:543)
07-03 18:49:16.936: E/AndroidRuntime(773): at com.example.flash.MainActivity.surfaceDestroyed(MainActivity.java:140)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.SurfaceView.updateWindow(SurfaceView.java:553)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:231)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.View.dispatchWindowVisibilityChanged(View.java:7544)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:1039)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1211)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer.doFrame(Choreographer.java:532)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.os.Handler.handleCallback(Handler.java:725)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.os.Handler.dispatchMessage(Handler.java:92)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.os.Looper.loop(Looper.java:137)
07-03 18:49:16.936: E/AndroidRuntime(773): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-03 18:49:16.936: E/AndroidRuntime(773): at java.lang.reflect.Method.invokeNative(Native Method)
07-03 18:49:16.936: E/AndroidRuntime(773): at java.lang.reflect.Method.invoke(Method.java:511)
07-03 18:49:16.936: E/AndroidRuntime(773): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-03 18:49:16.936: E/AndroidRuntime(773): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-03 18:49:16.936: E/AndroidRuntime(773): at dalvik.system.NativeStart.main(Native Method)
07-03 18:49:24.854: E/Trace(811): error opening trace file: No such file or directory (2)
07-03 18:49:25.413: D/libEGL(811): loaded /system/lib/egl/libEGL_emulation.so
07-03 18:49:25.567: D/(811): HostConnection::get() New Host Connection established 0x2a15f570, tid 811
07-03 18:49:25.643: D/libEGL(811): loaded /system/lib/egl/libGLESv1_CM_emulation.so
07-03 18:49:25.663: D/libEGL(811): loaded /system/lib/egl/libGLESv2_emulation.so
07-03 18:49:25.934: W/EGL_emulation(811): eglSurfaceAttrib not implemented
07-03 18:49:25.963: D/OpenGLRenderer(811): Enabling debug mode 0
07-03 18:53:12.298: D/Camera(811): app passed NULL surface
07-03 18:53:12.723: D/dalvikvm(811): GC_CONCURRENT freed 172K, 11% free 2600K/2904K, paused 9ms+165ms, total 421ms
07-03 18:53:12.934: E/EGL_emulation(811): rcCreateWindowSurface returned 0
07-03 18:53:12.934: E/EGL_emulation(811): tid 811: eglCreateWindowSurface(631): error 0x3003 (EGL_BAD_ALLOC)
07-03 18:53:12.943: D/AndroidRuntime(811): Shutting down VM
07-03 18:53:12.943: W/dalvikvm(811): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
07-03 18:53:13.033: E/AndroidRuntime(811): FATAL EXCEPTION: main
07-03 18:53:13.033: E/AndroidRuntime(811): java.lang.RuntimeException: createWindowSurface failed EGL_BAD_ALLOC
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.HardwareRenderer$GlRenderer.createSurface(HardwareRenderer.java:1064)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.HardwareRenderer$GlRenderer.createEglSurface(HardwareRenderer.java:961)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.HardwareRenderer$GlRenderer.initialize(HardwareRenderer.java:787)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1502)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer.doFrame(Choreographer.java:532)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.os.Handler.handleCallback(Handler.java:725)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.os.Handler.dispatchMessage(Handler.java:92)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.os.Looper.loop(Looper.java:137)
07-03 18:53:13.033: E/AndroidRuntime(811): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-03 18:53:13.033: E/AndroidRuntime(811): at java.lang.reflect.Method.invokeNative(Native Method)
07-03 18:53:13.033: E/AndroidRuntime(811): at java.lang.reflect.Method.invoke(Method.java:511)
07-03 18:53:13.033: E/AndroidRuntime(811): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-03 18:53:13.033: E/AndroidRuntime(811): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-03 18:53:13.033: E/AndroidRuntime(811): at dalvik.system.NativeStart.main(Native Method)

UPDATE
I think the key is you are running Android 4.1.2. Since Android 4.0, if you want to use the Camera Device, even if you only want to use the flash, you are forced to use a SurfaceView.
In the previous answer (below), I gave you a link to a Torch app which uses SurfaceView. Try it or adapt it to your code.
PREVIOUS ANSWER:
As stated in many other cases (like this one), you may be facing a Device-Specific issue that is quite common in the Android world.
Although getSupportedFlashModes() may return FLASH_MODE_TORCH on nearly every device, many of them don't actually support it.
Anyway, you could try these:
Use camera.startPreview(); after camera = Camera.open();
Try setting FLASH_MODE_OFF initially (before camera.startPreview();).
Check if this Torch app works in your device. In case it does, you have the source code to compare it to yours.
Download a Torch app from the Play Store to test if it's a device issue or not.
Post the issue in a Droid Bionic support forum.
UPDATE: I would say the final keyword is a problem in your code. Try changing it to:
//camera = Camera.open();
//final Parameters p = camera.getParameters();
button.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
if (isFlashOn) {
Log.i("info", "torch is turned off!");
cam.stopPreview();
cam.release();
isFlashOn = false;
button.setText("Tap to turn flashlight on.");
}
else {
Log.i("info", "torch is turned on!");
camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.startPreview();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
isFlashOn = true;
button.setText("Tap to turn flashlight off.");
}
}
});

user the permission "android.permission.FLASHLIGHT" in the manifest
<uses-permission android:name="android.permission.FLASHLIGHT" />
<uses-permission android:name="android.permission.CAMERA" />

Unfortunately app has stopped working

I am new to android application development. I was doing this tutorial app.It's a very simple one. It adds one and subtracts one from the counter.When I run it in the emulator ,it says "Unfortunately tutorial has stopped working." There are no errors in the code. The API level is 17. Please help me out.
Code for java:
public class Startingpoint extends Activity {
int counter=0;
Button add,subtract;
TextView display;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.startingpoint);
add = (Button) findViewById(R.id.bAdd);
subtract= (Button) findViewById(R.id.bSubtract);
display= (Button) findViewById(R.id.text);
add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
counter++;
display.setText("The total is " + counter);
}
});
subtract.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
counter--;
display.setText("The total is " + counter);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.startingpoint, menu);
return true;
}
}
Layout code in xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Your total is 0"
android:textSize="35dp"
android:layout_gravity="center"
android:gravity="center"/>
<Button android:layout_width="250dp"
android:layout_height="wrap_content"
android:text="Add One"
android:layout_gravity="center"
android:textSize="25dp"
android:id="#+id/bAdd"/>
<Button android:layout_width="250dp"
android:layout_height="wrap_content"
android:text="Subtract One"
android:layout_gravity="center"
android:textSize="25dp"
android:id="#+id/bSubtract"/>
</LinearLayout>
Here is the logcat :
03-02 02:45:10.730: D/AndroidRuntime(780): Shutting down VM
03-02 02:45:10.730: W/dalvikvm(780): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
03-02 02:45:10.750: E/AndroidRuntime(780): FATAL EXCEPTION: main
03-02 02:45:10.750: E/AndroidRuntime(780): java.lang.RuntimeException: Unable to start activity ComponentInfo{tutorial.example.tutorial/tutorial.example.tutorial.Startingpoint}: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.os.Handler.dispatchMessage(Handler.java:99)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.os.Looper.loop(Looper.java:137)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.ActivityThread.main(ActivityThread.java:5041)
03-02 02:45:10.750: E/AndroidRuntime(780): at java.lang.reflect.Method.invokeNative(Native Method)
03-02 02:45:10.750: E/AndroidRuntime(780): at java.lang.reflect.Method.invoke(Method.java:511)
03-02 02:45:10.750: E/AndroidRuntime(780): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-02 02:45:10.750: E/AndroidRuntime(780): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-02 02:45:10.750: E/AndroidRuntime(780): at dalvik.system.NativeStart.main(Native Method)
03-02 02:45:10.750: E/AndroidRuntime(780): Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button
03-02 02:45:10.750: E/AndroidRuntime(780): at tutorial.example.tutorial.Startingpoint.onCreate(Startingpoint.java:22)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.Activity.performCreate(Activity.java:5104)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-02 02:45:10.750: E/AndroidRuntime(780): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
03-02 02:45:10.750: E/AndroidRuntime(780): ... 11 more

display= (Button) findViewById(R.id.text);
should be
display= (TextView) findViewById(R.id.text);
Since display is supposed to reference a TextView instance, but you're explictly casting into a Button, and these are not compatible types.

As you got the answer from A-C this time, but for next time in android application development a important suggestion:
Always see the logcat for error, and see the "Caused by:" tag, It specifies what was the cause of the problem with sufficient detail, Also see the line no that caused that error.
And try to find what can be wrong with that line of code.
For example: in your logcat it is showing-
Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button
at tutorial.example.tutorial.Startingpoint.onCreate(Startingpoint.java:22)
So you can try to read the log, and you will understand that in your file Startingpoint.java at line 22 which is located in onCreate method the error is android.widget.TextView cannot be cast to android.widget.Button. So you can easily remove your errors without any help.
Hope that helps not only you current problem but prevented your future time and efforts.

FATAL EXCEPTION: main on Android 4.x but not Android 2.X

I am getting some errors when trying to run my android app on an emulator that is running any version of Android 4.x but it works fine on any version of Android 2.X.
package com.EXCLUDED_FOR_PRIVACY.EXCLUDED_FOR_PRIVACY;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.TabHost;
import android.widget.TabHost.OnTabChangeListener;
import android.widget.TabHost.TabSpec;
import android.widget.ImageView;
import android.graphics.Color;
public class EXCLUDED_FOR_PRIVACY extends Activity {
public int WebView1Bool=0;
public int WebView2Bool=0;
public int WebView3Bool=0;
public int WebView4Bool=0;
private TabHost tabs;
private void setupTabHost() {
tabs = (TabHost) findViewById(R.id.my_tabhost);
tabs.setup();
}
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setupTabHost();
tabs.getTabWidget().setDividerDrawable(R.drawable.tab_divider);
setupTab(new ImageView(this), 1);
setupTab(new ImageView(this), 2);
setupTab(new ImageView(this), 3);
setupTab(new ImageView(this), 4);
WebView mWebView1;
mWebView1 = (WebView) findViewById(R.id.webview1);
mWebView1.setBackgroundColor(Color.parseColor("#a3a3a3"));
mWebView1.setBackgroundColor(0);
mWebView1.getSettings().setJavaScriptEnabled(true);
mWebView1.setWebViewClient(new MobileClient());
mWebView1.loadUrl("EXCLUDED_FOR_PRIVACY");
WebView1Bool=1;
tabs.getTabWidget().getChildAt(0).setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
tabs.setCurrentTab(0);
if(WebView1Bool==0){
WebView mWebView1;
mWebView1 = (WebView) findViewById(R.id.webview1);
mWebView1.setBackgroundColor(Color.parseColor("#a3a3a3"));
mWebView1.setBackgroundColor(0);
mWebView1.getSettings().setJavaScriptEnabled(true);
mWebView1.setWebViewClient(new MobileClient());
mWebView1.loadUrl("EXCLUDED_FOR_PRIVACY");
WebView1Bool=1;
}
}
});
tabs.getTabWidget().getChildAt(2).setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
tabs.setCurrentTab(1);
if(WebView2Bool==0){
WebView mWebView2;
mWebView2 = (WebView) findViewById(R.id.webview2);
mWebView2.setBackgroundColor(Color.parseColor("#a3a3a3"));
mWebView2.setBackgroundColor(0);
mWebView2.getSettings().setJavaScriptEnabled(true);
mWebView2.setWebViewClient(new MobileClient());
mWebView2.loadUrl("EXCLUDED_FOR_PRIVACY");
WebView2Bool=1;
}
}
});
tabs.getTabWidget().getChildAt(4).setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
tabs.setCurrentTab(2);
if(WebView3Bool==0){
WebView mWebView3 = (WebView) findViewById(R.id.webview3);
mWebView3.setBackgroundColor(Color.parseColor("#a3a3a3"));
mWebView3.setBackgroundColor(0);
mWebView3.getSettings().setJavaScriptEnabled(true);
mWebView3.setWebViewClient(new MobileClient());
mWebView3.loadUrl("EXCLUDED_FOR_PRIVACY");
WebView3Bool=1;
}
}
});
tabs.getTabWidget().getChildAt(6).setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
tabs.setCurrentTab(3);
if(WebView4Bool==0){
WebView mWebView4;
mWebView4 = (WebView) findViewById(R.id.webview4);
mWebView4.setBackgroundColor(Color.parseColor("#a3a3a3"));
mWebView4.setBackgroundColor(0);
mWebView4.getSettings().setJavaScriptEnabled(true);
mWebView4.setWebViewClient(new MobileClient());
mWebView4.loadUrl("EXCLUDED_FOR_PRIVACY");
WebView4Bool=1;
}
}
});
}
private class MobileClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
private void setupTab(final View view, final int i) {
View createTabView_view = LayoutInflater.from(tabs.getContext()).inflate(R.layout.tabs_bg, null);
ImageView createTabView_tv = (ImageView) createTabView_view.findViewById(R.id.tabsImage);
if(i==1){
TabSpec tabSpec = tabs.newTabSpec("EXCLUDED_FOR_PRIVACY");
createTabView_tv.setImageResource(R.drawable.ic_discounts);
tabSpec.setIndicator(createTabView_view);
tabSpec.setContent(R.id.webview1);
tabs.addTab(tabSpec);
} else if(i==2){
TabSpec tabSpec = tabs.newTabSpec("EXCLUDED_FOR_PRIVACY");
createTabView_tv.setImageResource(R.drawable.ic_specials);
tabSpec.setIndicator(createTabView_view);
tabSpec.setContent(R.id.webview2);
tabs.addTab(tabSpec);
} else if(i==3){
TabSpec tabSpec = tabs.newTabSpec("EXCLUDED_FOR_PRIVACY");
createTabView_tv.setImageResource(R.drawable.ic_directory);
tabSpec.setIndicator(createTabView_view);
tabSpec.setContent(R.id.webview3);
tabs.addTab(tabSpec);
} else if(i==4){
TabSpec tabSpec = tabs.newTabSpec("EXCLUDED_FOR_PRIVACY");
createTabView_tv.setImageResource(R.drawable.ic_membership);
tabSpec.setIndicator(createTabView_view);
tabSpec.setContent(R.id.webview4);
tabs.addTab(tabSpec);
}
}
}
Here are the errors I am seeing
09-24 13:11:25.329: E/Trace(1151): error opening trace file: No such file or directory (2)
09-24 13:11:25.539: D/dalvikvm(1151): GC_FOR_ALLOC freed 43K, 4% free 8316K/8583K, paused 42ms, total 45ms
09-24 13:11:25.549: I/dalvikvm-heap(1151): Grow heap (frag case) to 8.829MB for 691216-byte allocation
09-24 13:11:25.669: D/dalvikvm(1151): GC_CONCURRENT freed <1K, 4% free 8990K/9287K, paused 75ms+6ms, total 124ms
09-24 13:11:25.829: D/gralloc_goldfish(1151): Emulator without GPU emulation detected.
09-24 13:11:26.209: I/Choreographer(1151): Skipped 42 frames! The application may be doing too much work on its main thread.
09-24 13:11:26.379: I/Choreographer(1151): Skipped 44 frames! The application may be doing too much work on its main thread.
09-24 13:11:27.509: I/Choreographer(1151): Skipped 54 frames! The application may be doing too much work on its main thread.
09-24 13:11:28.319: D/AndroidRuntime(1151): Shutting down VM
09-24 13:11:28.319: W/dalvikvm(1151): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-24 13:11:28.379: E/AndroidRuntime(1151): FATAL EXCEPTION: main
09-24 13:11:28.379: E/AndroidRuntime(1151): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.EXCLUDED.EXCLUDED/com.EXCLUDED.EXCLUDED.EXCLUDED}: java.lang.NullPointerException
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.ActivityThread.access$600(ActivityThread.java:130)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.os.Handler.dispatchMessage(Handler.java:99)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.os.Looper.loop(Looper.java:137)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.ActivityThread.main(ActivityThread.java:4745)
09-24 13:11:28.379: E/AndroidRuntime(1151): at java.lang.reflect.Method.invokeNative(Native Method)
09-24 13:11:28.379: E/AndroidRuntime(1151): at java.lang.reflect.Method.invoke(Method.java:511)
09-24 13:11:28.379: E/AndroidRuntime(1151): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-24 13:11:28.379: E/AndroidRuntime(1151): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-24 13:11:28.379: E/AndroidRuntime(1151): at dalvik.system.NativeStart.main(Native Method)
09-24 13:11:28.379: E/AndroidRuntime(1151): Caused by: java.lang.NullPointerException
09-24 13:11:28.379: E/AndroidRuntime(1151): at com.EXCLUDED.EXCLUDED.EXCLUDED.onCreate(EXCLUDED.java:85)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.Activity.performCreate(Activity.java:5008)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
09-24 13:11:28.379: E/AndroidRuntime(1151): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
09-24 13:11:28.379: E/AndroidRuntime(1151): ... 11 more
09-24 13:11:30.289: I/Process(1151): Sending signal. PID: 1151 SIG: 9
I apologize if this is something really simple that any java developer would know, I have to admit I barely know what I am doing in Java but am under the gun to get this built. Thank you very much for any help.

Get rid of all the tabs.getTabWidget().getChildAt(...).setOnClickListener() crap, replacing it with a single TabHost.OnTabChangeListener that you register with your TabHost, to find out when the user changes tabs. Your existing code assumes a particular internal structure of a TabWidget, and that assumption is unreliable, as you are discovering.