I'm trying to write a simple calculator. I have a SimpleActivity class which looks like this:\[code\]package org.muzzy.calc;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.webkit.WebChromeClient;import android.webkit.WebView;import android.widget.Button;public class SimpleActivity extends Activity implements OnClickListener {/** Called when the activity is first created. */private WebView numer;private Button guzik;private StringBuilder wys;@Overridepublic void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); numer = (WebView) findViewById(R.id.webview); numer.getSettings().setJavaScriptEnabled(true); numer.setWebChromeClient(new WebChromeClient()); guzik = (Button) findViewById(R.id.button0); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button1); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button2); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button3); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button4); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button5); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button6); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button7); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button8); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.button9); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.plus); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.minus); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.multi); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.divide); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.leftP); guzik.setOnClickListener(this); guzik = (Button) findViewById(R.id.rightP); guzik.setOnClickListener(this);}@Overridepublic void onClick(View v) { // TODO Auto-generated method stub StringBuilder wyr = new StringBuilder(); switch (v.getId()) { case R.id.bs: if (wyr.length() > 0) wyr.deleteCharAt(wyr.length() - 1); break; case R.id.ac: if (wyr.length() > 0) wyr.delete(0, wyr.length()); break; default: wyr.append(((Button) v).getText()); } wys.append("<html><body>"); wys.append("<script type=\"text/javascript\">document.write('"); wys.append(wyr.toString()); wys.append("');"); wys.append("document.write('<br />=' + eval(\""); wys.append(wyr.toString()); wys.append("\"));</script>"); wys.append("</body></html>"); numer.loadData(wys.toString(), "application/xhtml", "UTF-8");}}\[/code\]I'm starting that class from another Activity class like this:\[code\]Intent simpleIntent = new Intent(this, SimpleActivity.class); startActivity(simpleIntent);\[/code\]When I'm trying to run the project on VM Android 2.3.3 I get this errors:\[code\]03-07 21:52:36.624: D/AndroidRuntime(411): Shutting down VM03-07 21:52:36.624: W/dalvikvm(411): threadid=1: thread exiting with uncaught exception (group=0x40015560)03-07 21:52:36.634: E/AndroidRuntime(411): FATAL EXCEPTION: main03-07 21:52:36.634: E/AndroidRuntime(411): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.muzzy.calc/org.muzzy.calc.SimpleActivity}: java.lang.NullPointerException03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.ActivityThread.access$1500(ActivityThread.java:117)03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)03-07 21:52:36.634: E/AndroidRuntime(411): at android.os.Handler.dispatchMessage(Handler.java:99)03-07 21:52:36.634: E/AndroidRuntime(411): at android.os.Looper.loop(Looper.java:123)03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.ActivityThread.main(ActivityThread.java:3683)03-07 21:52:36.634: E/AndroidRuntime(411): at java.lang.reflect.Method.invokeNative(Native Method)03-07 21:52:36.634: E/AndroidRuntime(411): at java.lang.reflect.Method.invoke(Method.java:507)03-07 21:52:36.634: E/AndroidRuntime(411): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)03-07 21:52:36.634: E/AndroidRuntime(411): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)03-07 21:52:36.634: E/AndroidRuntime(411): at dalvik.system.NativeStart.main(Native Method)03-07 21:52:36.634: E/AndroidRuntime(411): Caused by: java.lang.NullPointerException03-07 21:52:36.634: E/AndroidRuntime(411): at org.muzzy.calc.SimpleActivity.onCreate(SimpleActivity.java:25)03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)03-07 21:52:36.634: E/AndroidRuntime(411): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)03-07 21:52:36.634: E/AndroidRuntime(411): ... 11 more\[/code\]My xml file for simpleActivity looks like this:\[code\]<?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
rientation="vertical" ><WebView android:id="@+id/webview" android:layout_width="fill_parent" android:layout_height="50dip" android:visibility="visible" /><TableLayout android:id="@+id/tableLayout1" android:layout_width="match_parent" android:layout_height="wrap_content" android:stretchColumns="0,1,2,3" > <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content" > <Button android:id="@+id/button1" android:text="@string/b1" /> <Button android:id="@+id/button2" android:text="@string/b2" /> <Button android:id="@+id/button3" android:text="@string/b3" /> <Button android:id="@+id/plus" android:text="@string/plus" /> </TableRow> <TableRow android:id="@+id/tableRow2" android:layout_width="wrap_content" android:layout_height="wrap_content" > <Button android:id="@+id/button4" android:text="@string/b4" /> <Button android:id="@+id/button5" android:text="@string/b5" /> <Button android:id="@+id/button6" android:text="@string/b6" /> <Button android:id="@+id/minus" android:text="@string/minus" /> </TableRow> <TableRow android:id="@+id/tableRow3" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/button7" android:text="@string/b7" /> <Button android:id="@+id/button8" android:text="@string/b8" /> <Button android:id="@+id/button9" android:text="@string/b9" /> <Button android:id="@+id/multi" android:text="@string/multi" /> </TableRow> <TableRow android:id="@+id/tableRow4" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/leftP" android:text="@string/leftParen" /> <Button android:id="@+id/button0" android:text="@string/b0" /> <Button android:id="@+id/rightP" android:text="@string/rightParen" /> <Button android:id="@+id/divide" android:text="@string/divide" /> </TableRow> <TableRow android:id="@+id/tableRow5" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/bs" android:text="@string/backspace" /> <Button android:id="@+id/dot" android:text="@string/dot" /> <Button android:id="@+id/ac" android:text="@string/allclear" /> <Button android:id="@+id/equals" android:text="@string/equals" /> </TableRow></TableLayout></LinearLayout>\[/code\]I read a bunch of tutorials and threads at lot of forums and still nothing. What am I doing wrong??
rientation="vertical" ><WebView android:id="@+id/webview" android:layout_width="fill_parent" android:layout_height="50dip" android:visibility="visible" /><TableLayout android:id="@+id/tableLayout1" android:layout_width="match_parent" android:layout_height="wrap_content" android:stretchColumns="0,1,2,3" > <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content" > <Button android:id="@+id/button1" android:text="@string/b1" /> <Button android:id="@+id/button2" android:text="@string/b2" /> <Button android:id="@+id/button3" android:text="@string/b3" /> <Button android:id="@+id/plus" android:text="@string/plus" /> </TableRow> <TableRow android:id="@+id/tableRow2" android:layout_width="wrap_content" android:layout_height="wrap_content" > <Button android:id="@+id/button4" android:text="@string/b4" /> <Button android:id="@+id/button5" android:text="@string/b5" /> <Button android:id="@+id/button6" android:text="@string/b6" /> <Button android:id="@+id/minus" android:text="@string/minus" /> </TableRow> <TableRow android:id="@+id/tableRow3" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/button7" android:text="@string/b7" /> <Button android:id="@+id/button8" android:text="@string/b8" /> <Button android:id="@+id/button9" android:text="@string/b9" /> <Button android:id="@+id/multi" android:text="@string/multi" /> </TableRow> <TableRow android:id="@+id/tableRow4" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/leftP" android:text="@string/leftParen" /> <Button android:id="@+id/button0" android:text="@string/b0" /> <Button android:id="@+id/rightP" android:text="@string/rightParen" /> <Button android:id="@+id/divide" android:text="@string/divide" /> </TableRow> <TableRow android:id="@+id/tableRow5" android:layout_width="match_parent" android:layout_height="wrap_content" > <Button android:id="@+id/bs" android:text="@string/backspace" /> <Button android:id="@+id/dot" android:text="@string/dot" /> <Button android:id="@+id/ac" android:text="@string/allclear" /> <Button android:id="@+id/equals" android:text="@string/equals" /> </TableRow></TableLayout></LinearLayout>\[/code\]I read a bunch of tutorials and threads at lot of forums and still nothing. What am I doing wrong??