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Unable to start activity ComponentInfo (LOGCAT)

I'm a new android programmer and recently, I'm getting this error in the logcat:
03-22 15:33:49.395 13639-13639/com.abaco.awser E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.abaco.awser, PID: 13639
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.abaco.awser/com.abaco.awser.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2429)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493)
at android.app.ActivityThread.access$800(ActivityThread.java:166)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5584)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.abaco.awser.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:5447)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2393)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493) 
at android.app.ActivityThread.access$800(ActivityThread.java:166) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:136) 
at android.app.ActivityThread.main(ActivityThread.java:5584) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084) 
at dalvik.system.NativeStart.main(Native Method) 
Here's my MainActivity.java:
package com.abaco.awser;
import android.content.pm.ActivityInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MainActivity extends AppCompatActivity {
#Override
public void onBackPressed() {
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
WebView myWebView = (WebView) findViewById(R.id.activity_main_webview);
myWebView.setWebViewClient(new WebViewClient());
myWebView.loadUrl("http://primopizza.com.br/eloja");
WebSettings webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
setContentView(R.layout.activity_main);
}
}
And here's my activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.abaco.abawser.MainActivity">
<WebView
android:id="#+id/activity_main_webview"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
Can you please help me solving this error? I already tried everything.

You are getting NPE because your myWebView is null
place this
WebView myWebView = (WebView)findViewById(R.id.activity_main_webview);
after
setContentView(R.layout.activity_main);
Because you can actually retrive your views only after setting content View

android.view.InflateException: Binary XML file line #16: Error inflating class <unknown> (ListView Maybe?) [duplicate]

This question already exists:
android.view.InflateException: Binary XML file line #16: Error inflating class fragment
Closed 6 years ago.
I made an app, it works well in virtual device and real device, but today my app is throwing exceptions, maybe it is the same with some old errors in here, but I can not find my own answer for this. So, please tell me how to solve it, thanks so much
here is my logcat
FATAL EXCEPTION: main
Process: com.gvc.tvschedule, PID: 1918
android.view.InflateException: Binary XML file line #16: Error inflating class <unknown>
at android.view.LayoutInflater.createView(LayoutInflater.java:620)
at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:669)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:694)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.widget.SimpleAdapter.createViewFromResource(SimpleAdapter.java:121)
at android.widget.SimpleAdapter.getView(SimpleAdapter.java:114)
at android.widget.AbsListView.obtainView(AbsListView.java:2255)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1263)
at android.widget.ListView.onMeasure(ListView.java:1175)
at android.view.View.measure(View.java:16497)
at android.widget.RelativeLayout.measureChild(RelativeLayout.java:689)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:473)
at android.view.View.measure(View.java:16497)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
at android.view.View.measure(View.java:16497)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:544)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at android.view.LayoutInflater.createView(LayoutInflater.java:594)
... 48 more
Caused by: android.content.res.Resources$NotFoundException: Resource is not a Drawable (color or path): TypedValue{t=0x12/d=0x0 a=2 r=0x7f0b0068}
at android.content.res.Resources.loadDrawable(Resources.java:2073)
at android.content.res.TypedArray.getDrawable(TypedArray.java:602)
at android.widget.TextView.<init>(TextView.java:806)
at android.widget.TextView.<init>(TextView.java:618)
... 51
here under is Layout XML: getprogram_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="#+id/relativeLayoutProgram"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_below="#+id/relativeLayoutProgram"
android:orientation="vertical"
android:layout_marginTop="40dp">
<ListView
android:id="#android:id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true">
</ListView>
<!-- #android:id/list or #id/android:list -->
</RelativeLayout>
</RelativeLayout>
and: view_program_entry.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="wrap_content"
android:orientation="horizontal" >
<TextView
android:id="#+id/programtime"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:paddingTop="15sp"
android:paddingLeft="6sp"
android:textStyle="bold"/>
<TextView
android:id="#+id/programtitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="25sp"
android:textStyle="bold"
android:drawableLeft="#+id/programtime" />
<!-- android:background="#color/blue2" -->
</LinearLayout>
and Java : ProgramPickerActivity.java
package com.gvc.tvschedule;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.gvc.service.DBController;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
public class ProgramPickerActivity extends Activity {
// DB Class to perform DB related operations
DBController controller = new DBController(this);
// Progress Dialog Object
ProgressDialog prgDialog;
HashMap<String, String> queryValues;
private static String titleTextFromView;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.getprogram_main);
ArrayList<HashMap<String, String>> programList = controller.generalProgram(MainActivity.getNameOfChannel(), DatePickerActivity.getDate());
if (programList.size() != 0) {
// Set the User Array list in ListView
ListAdapter adapter = new SimpleAdapter(getApplicationContext(), programList, R.layout.view_program_entry, new String[] {
"ptime", "ptitle" }, new int[] { R.id.programtime, R.id.programtitle });
ListView myList = (ListView) findViewById(android.R.id.list);
myList.setAdapter(adapter);
myList.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// TODO Auto-generated method stub
TextView titleVIew = (TextView) view.findViewById(R.id.programtitle);
titleTextFromView = titleVIew.getText().toString();
createPopupWindownForDescription(titleTextFromView);
}
});
}
prgDialog = new ProgressDialog(this);
prgDialog.setMessage("loading...");
prgDialog.setCancelable(false);
}
private void createPopupWindownForDescription(String pTitle){
String content = controller.getDescription(pTitle);
AlertDialog.Builder builder = new AlertDialog.Builder(ProgramPickerActivity.this);
builder.setTitle("Content");
builder.setMessage(content);
builder.show();
}
#Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
if(prgDialog!=null)
prgDialog.dismiss();
}
public static String getTitleTextFromView(){
return titleTextFromView;
}
}
I think the trouble is related with the listview, because, when no data put on listview, it is fine, but with data, it threw the errors.

I believe your current problem is
<TextView
android:id="#+id/programtitle"
...
android:drawableLeft="#+id/programtime" /> // HERE
You are referencing the other TextView but you should be referencing a Drawable. My guess is that you want to put it to the left of the other TextView?
If this is the case, the LinearLayout will lay them out from left to right by default so you just need to put them in the order that you want them to appear. Also, not a problem but since they are left to right by default, there's no need for
android:orientation="horizontal"
It's not showing when you don't have any items in your ListView because the layout is never inflated so the error is never caught.
Docs

android:id="#+id/list"
use that, you're welcome
PS: Change
ListView myList = (ListView) findViewById(android.R.id.list);
for:
ListView myList = (ListView) findViewById(R.id.list);

Unable to start activity: NullPointerException [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 8 years ago.
Hi I am encountering a null pointer error when I click on the activity Links. The purpose of my feature is to call a list of links in the form of list view. Below is the logcat and as far as I understand it is coming from my onItemClickListener, but I can't seem to point out the null error.:
sitesList.setOnItemClickListener(new OnItemClickListener()
Links.java
package com.example.sgrecipe;
import java.io.FileNotFoundException;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
public class Links extends Activity {
private SitesAdapter mAdapter;
private ListView sitesList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i("StackSites", "OnCreate()");
setContentView(R.layout.activity_main);
//Get reference to our ListView
sitesList = (ListView)findViewById(R.id.sitesList);
//Set the click listener to launch the browser when a row is clicked.
sitesList.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View v, int pos,long id) {
String url = mAdapter.getItem(pos).getLink();
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
startActivity(i);
}
});
/*
* If network is available download the xml from the Internet.
* If not then try to use the local file from last time.
*/
if(isNetworkAvailable()){
Log.i("StackSites", "starting download Task");
SitesDownloadTask download = new SitesDownloadTask();
download.execute();
}else{
mAdapter = new SitesAdapter(getApplicationContext(), -1, SitesXmlPullParser.getStackSitesFromFile(Links.this));
sitesList.setAdapter(mAdapter);
}
}
//Helper method to determine if Internet connection is available.
private boolean isNetworkAvailable() {
ConnectivityManager connectivityManager
= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}
/*
* AsyncTask that will download the xml file for us and store it locally.
* After the download is done we'll parse the local file.
*/
private class SitesDownloadTask extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... arg0) {
//Download the file
try {
Downloader.DownloadFromUrl("https://dl.dropboxusercontent.com/u/5724095/XmlParseExample/stacksites.xml", openFileOutput("StackSites.xml", Context.MODE_PRIVATE));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result){
//setup our Adapter and set it to the ListView.
mAdapter = new SitesAdapter(Links.this, -1, SitesXmlPullParser.getStackSitesFromFile(Links.this));
sitesList.setAdapter(mAdapter);
Log.i("StackSites", "adapter size = "+ mAdapter.getCount());
}
}
}
activity_links.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Links" >
<ListView
android:id="#+id/sitesList"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
row_site.xml (for the listview)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp" >
<ProgressBar
android:id="#+id/progress"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ImageView
android:id="#+id/iconImg"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_marginRight="8dp" />
<TextView
android:id="#+id/nameTxt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/iconImg"
android:textSize="16sp"
android:textStyle="bold" />
<TextView
android:id="#+id/aboutTxt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/iconImg"
android:textSize="12sp"
android:layout_below="#id/nameTxt"
/>
</RelativeLayout>
Here is the logcat:
02-23 15:13:10.856: E/AndroidRuntime(8201): FATAL EXCEPTION: main
02-23 15:13:10.856: E/AndroidRuntime(8201): Process: com.example.sgrecipe, PID: 8201
02-23 15:13:10.856: E/AndroidRuntime(8201): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sgrecipe/com.example.sgrecipe.Links}: java.lang.NullPointerException
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2350)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.ActivityThread.access$800(ActivityThread.java:163)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1257)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.os.Handler.dispatchMessage(Handler.java:102)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.os.Looper.loop(Looper.java:157)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.ActivityThread.main(ActivityThread.java:5335)
02-23 15:13:10.856: E/AndroidRuntime(8201): at java.lang.reflect.Method.invokeNative(Native Method)
02-23 15:13:10.856: E/AndroidRuntime(8201): at java.lang.reflect.Method.invoke(Method.java:515)
02-23 15:13:10.856: E/AndroidRuntime(8201): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
02-23 15:13:10.856: E/AndroidRuntime(8201): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
02-23 15:13:10.856: E/AndroidRuntime(8201): at dalvik.system.NativeStart.main(Native Method)
02-23 15:13:10.856: E/AndroidRuntime(8201): Caused by: java.lang.NullPointerException
02-23 15:13:10.856: E/AndroidRuntime(8201): at com.example.sgrecipe.Links.onCreate(Links.java:36)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.Activity.performCreate(Activity.java:5389)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
02-23 15:13:10.856: E/AndroidRuntime(8201): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2256)
Any help is really appreciate, thank you!

Change following line
setContentView(R.layout.activity_main);
to
setContentView(R.layout.activity_links);

Seems like your using different layouts:
setContentView(R.layout.activity_main);
vs
activity_links.xml

Could not find a method sendMessage(View) in the activity class

MainActivity.java
package com.example.myfirstapp;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.EditText;
import android.content.Intent;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#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;
}
/** Called when the user clicks the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
activitymain.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<EditText android:id="#+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="#string/edit_message"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_send"
android:onClick="sendMessage" />
</LinearLayout>
DisplayMessageActivity.java
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class DisplayMessageActivity extends ActionBarActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_display_message,
container, false);
return rootView;
}
}
}
Error Log
04-10 01:37:00.460: W/dalvikvm(1650): threadid=1: thread exiting with uncaught exception (group=0xb3aaeba8)
04-10 01:37:00.520: E/AndroidRuntime(1650): FATAL EXCEPTION: main
04-10 01:37:00.520: E/AndroidRuntime(1650): Process: com.example.myfirstapp, PID: 1650
04-10 01:37:00.520: E/AndroidRuntime(1650): java.lang.IllegalStateException: Could not find a method sendMessage(View) in the activity class com.example.myfirstapp.MainActivity for onClick handler on view class android.widget.Button
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View$1.onClick(View.java:3810)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View.performClick(View.java:4438)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View$PerformClick.run(View.java:18422)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.os.Handler.handleCallback(Handler.java:733)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.os.Handler.dispatchMessage(Handler.java:95)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.os.Looper.loop(Looper.java:136)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.reflect.Method.invokeNative(Native Method)
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.reflect.Method.invoke(Method.java:515)
04-10 01:37:00.520: E/AndroidRuntime(1650): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-10 01:37:00.520: E/AndroidRuntime(1650): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-10 01:37:00.520: E/AndroidRuntime(1650): at dalvik.system.NativeStart.main(Native Method)
04-10 01:37:00.520: E/AndroidRuntime(1650): Caused by: java.lang.NoSuchMethodException: sendMessage [class android.view.View]
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.Class.getConstructorOrMethod(Class.java:472)
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.Class.getMethod(Class.java:857)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View$1.onClick(View.java:3803)
04-10 01:37:00.520: E/AndroidRuntime(1650): ... 11 more
04-10 01:37:04.820: I/Process(1650): Sending signal. PID: 1650 SIG: 9
I've tried to look at other questions answered similar to mine, but I can't find an answer that seems to help my situation. Can anyone help?

I was struggling with a similar error following the android tutorial
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myfirstapp, PID: 18300
java.lang.IllegalStateException: Could not find method sendMessage (MainActivity)(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id '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:5197)
at android.view.View$PerformClick.run(View.java:20909)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5944)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
but in my case the WYSIWYG editor (IntelliJ w/Android Studio plugin) ended up populating the onClick property in activity_main.xml with some extra junk about MainActivity:
android:onClick="sendMessage (MainActivity)"
So I deleted " (MainActivity)" and it stopped crashing. I see this is different from your problem as your xml file already seems correct with android:onClick="sendMessage". But wanted to add it here for any others struggling with what I saw. This was the closest post to the issue I was seeing. I'm just getting started and this was killing me, so hope it helps someone else.

The problem is the onClick property in one of your Button tags:
android:onClick="sendMessage" />
Just make sure you have a method sendMessage(View) in your Activity.

It is because you need to implement implements android.view.View.OnClickListener in your class, therefore add the correct imports i.e. import android.view.View.

Going from Activity to ListActivity on Android

I am new to android development and I need help with going from an Acticity to a Listactivity.
I have a button in my mainActivity, here is the code:
package com.mz47.kazeroon;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button) findViewById(R.id.button1);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, DescriptionListActivity.class);
//intent.putExtra("thetext", edt.getText().toString());
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;
}
}
If I click that button, my intention it will go to:
package com.mz47.kazeroon;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.util.EventLogTags.Description;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class DescriptionListActivity extends ListActivity {
//Database Helper
MyDatabaseHelper db = new MyDatabaseHelper(getApplicationContext());;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.desc_list_layout);
setListAdapter(new DescriptionAdapter(this,
android.R.layout.simple_list_item_1,
R.id.textView1, db.getAllDescriptionNames()));
db.close();
}
private class DescriptionAdapter extends ArrayAdapter<String>{
public DescriptionAdapter(Context context, int resource,
int textViewResourceId, String[] objects) {
super(context, resource, textViewResourceId, objects);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row = inflater.inflate(R.layout.list_items, parent, false);
MyDescription[] descriptions = (MyDescription[])db.getAllDescriptions().toArray();
ImageView imgv = (ImageView) row.findViewById(R.id.imageView1);
TextView txtv = (TextView) row.findViewById(R.id.textView1);
txtv.setText(descriptions[position].getDescriptionName());
imgv.setImageBitmap(db.getImage(descriptions[position].getDescriptionID()).getImageData());
return row;
}
}
}
My question is why my application has stopped unexpectedly?
In manifest I register the DescriptionListActivity class as an Activity
Here is my manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mz47.kazeroon"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="10"
android:targetSdkVersion="10" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.mz47.kazeroon.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.mz47.kazeroon.DescriptionListActivity"></activity>
</application>
</manifest>
Logcat:
03-11 16:10:26.887: D/dalvikvm(3186): GC_EXPLICIT freed 5K, 58% free 2569K/6023K, external 716K/1228K, paused 61ms
03-11 16:10:53.627: D/dalvikvm(3186): Debugger has detached; object registry had 1 entries
03-11 16:18:32.777: D/AndroidRuntime(16464): Shutting down VM
03-11 16:18:32.777: W/dalvikvm(16464): threadid=1: thread exiting with uncaught exception (group=0x40015560)
03-11 16:18:32.797: E/AndroidRuntime(16464): FATAL EXCEPTION: main
03-11 16:18:32.797: E/AndroidRuntime(16464): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.mz47.kazeroon/com.mz47.kazeroon.DescriptionListActivity}: java.lang.NullPointerException
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.os.Handler.dispatchMessage(Handler.java:99)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.os.Looper.loop(Looper.java:123)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.ActivityThread.main(ActivityThread.java:3683)
03-11 16:18:32.797: E/AndroidRuntime(16464): at java.lang.reflect.Method.invokeNative(Native Method)
03-11 16:18:32.797: E/AndroidRuntime(16464): at java.lang.reflect.Method.invoke(Method.java:507)
03-11 16:18:32.797: E/AndroidRuntime(16464): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-11 16:18:32.797: E/AndroidRuntime(16464): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-11 16:18:32.797: E/AndroidRuntime(16464): at dalvik.system.NativeStart.main(Native Method)
03-11 16:18:32.797: E/AndroidRuntime(16464): Caused by: java.lang.NullPointerException
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:100)
03-11 16:18:32.797: E/AndroidRuntime(16464): at com.mz47.kazeroon.DescriptionListActivity.<init>(DescriptionListActivity.java:18)
03-11 16:18:32.797: E/AndroidRuntime(16464): at java.lang.Class.newInstanceImpl(Native Method)
03-11 16:18:32.797: E/AndroidRuntime(16464): at java.lang.Class.newInstance(Class.java:1409)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
03-11 16:18:32.797: E/AndroidRuntime(16464): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
03-11 16:18:32.797: E/AndroidRuntime(16464): ... 11 more
Other xml files:
desc_list_layout.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="#android:id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="16dp" >
</ListView>
</LinearLayout>
list_items.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:maxHeight="48dp"
android:maxWidth="48dp"
android:minHeight="48dp"
android:minWidth="48dp"
android:src="#drawable/ic_launcher" />
<TextView
android:id="#+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
</LinearLayout>

You have initialized your MyDatabaseHelper db to a context that is not yet existing
MyDatabaseHelper db = new MyDatabaseHelper(getApplicationContext());;
It should be done like this:
MyDatabaseHelper db;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.db = new MyDatabaseHelper(getApplicationContext());
setContentView(R.layout.desc_list_layout);
setListAdapter(new DescriptionAdapter(this,
android.R.layout.simple_list_item_1,
R.id.textView1, db.getAllDescriptionNames()));
db.close();
}

The problem is here:
MyDatabaseHelper db = new MyDatabaseHelper(getApplicationContext());
Method getApplicationContext() returns context after calling super.onCreate only. So try to change your activity like this:
MyDatabaseHelper db;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
db = new MyDatabaseHelper(getApplicationContext());
//rest of your code
}