I’m trying to code a little tictactoe game. Now I came to a point where it throws a nullPointerException which I can’t explain. Can anyone help?
code main activity:
package de.android.pali;
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;
public class TicTacToeMenu extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tic_tac_toe_menu);
final Button createGame = (Button)findViewById(R.id.newGameButton);
final Intent newGame = new Intent(TicTacToeMenu.this, newGame.class);
createGame.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
startActivity(newGame);
}
});
}
}
Code of second Activity:
package de.android.pali;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.TextView;
public class newGame extends TicTacToeMenu{
int turn = 1;
int[] felder = new int[9];
TextView ergebnis = (TextView)findViewById(R.id.winners);
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.game);
final ImageButton feld1 = (ImageButton)findViewById(R.id.feld1);
final ImageButton feld2 = (ImageButton)findViewById(R.id.feld2);
final ImageButton feld3 = (ImageButton)findViewById(R.id.feld3);
final ImageButton feld4 = (ImageButton)findViewById(R.id.feld4);
final ImageButton feld5 = (ImageButton)findViewById(R.id.feld5);
final ImageButton feld6 = (ImageButton)findViewById(R.id.feld6);
final ImageButton feld7 = (ImageButton)findViewById(R.id.feld7);
final ImageButton feld8 = (ImageButton)findViewById(R.id.feld8);
final ImageButton feld9 = (ImageButton)findViewById(R.id.feld9);
feld1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld1.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[0] = 1;
}
else{
feld1.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[0] = 0;
}
}
});
feld2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld2.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[1] = 1;
}
else{
feld2.setBackgroundResource(R.drawable.kreuz);
felder[1] = 0;
}
}
});
feld3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld3.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[2] = 1;
}
else{
feld3.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[2] = 0;
};
}
});
feld4.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld4.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[3] = 1;
}
else{
feld4.setBackgroundResource(R.drawable.kreuz);
felder[3] = 0;
}
}
});
feld5.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld5.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[4] = 1;
}
else{
feld5.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[4] = 0;
}
}
});
feld6.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld6.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[5] = 1;
}
else{
feld6.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[5] = 0;
}
}
});
feld7.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld7.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[6] = 1;
}
else{
feld7.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[6] = 0;
}
}
});
feld8.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld8.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[7] = 1;
}
else{
feld8.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[7] = 0;
}
}
});
feld9.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(turn==1){
feld9.setBackgroundResource(R.drawable.kreis);
turn = 0;
felder[8] = 1;
}
else{
feld9.setBackgroundResource(R.drawable.kreuz);
turn = 1;
felder[8] = 0;
}
}
});
}
public int getTurn() {
int whois = turn;
return whois;
}
public void checkWinner(){
if(felder[0]==1 & felder[1]==1 & felder[2]==1){
ergebnis.setText(R.string.kreuz);
}else
{ }
}
}
Logcat:
11-13 12:26:55.579: I/ActivityManager(88): START {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=de.android.pali/.TicTacToeMenu} from pid 772
11-13 12:26:55.589: W/WindowManager(88): Failure taking screenshot for (180x300) to layer 21005
11-13 12:26:55.629: D/AndroidRuntime(772): Shutting down VM
11-13 12:26:55.639: D/dalvikvm(772): GC_CONCURRENT freed 101K, 77% free 485K/2048K, paused 1ms+1ms
11-13 12:26:55.649: D/dalvikvm(772): Debugger has detached; object registry had 1 entries
11-13 12:26:55.659: D/dalvikvm(782): Not late-enabling CheckJNI (already on)
11-13 12:26:55.669: I/AndroidRuntime(772): NOTE: attach of thread 'Binder Thread #3' failed
11-13 12:26:55.719: I/ActivityManager(88): Start proc de.android.pali for activity de.android.pali/.TicTacToeMenu: pid=782 uid=10045 gids={}
11-13 12:26:55.948: W/NetworkManagementSocketTagger(88): setKernelCountSet(10045, 1) failed with errno -2
11-13 12:26:56.449: I/Process(88): Sending signal. PID: 782 SIG: 3
11-13 12:26:56.449: I/dalvikvm(782): threadid=3: reacting to signal 3
11-13 12:26:56.569: I/dalvikvm(782): Wrote stack traces to '/data/anr/traces.txt'
11-13 12:26:56.819: D/gralloc_goldfish(782): Emulator without GPU emulation detected.
11-13 12:26:56.868: I/ActivityManager(88): Displayed de.android.pali/.TicTacToeMenu: +1s263ms (total +37s914ms)
11-13 12:26:57.088: W/NetworkManagementSocketTagger(88): setKernelCountSet(10009, 0) failed with errno -2
11-13 12:27:00.828: I/ActivityManager(88): START {cmp=de.android.pali/.newGame} from pid 782
11-13 12:27:00.838: W/WindowManager(88): Failure taking screenshot for (180x300) to layer 21010
11-13 12:27:00.868: D/AndroidRuntime(782): Shutting down VM
11-13 12:27:00.868: W/dalvikvm(782): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
11-13 12:27:00.889: E/AndroidRuntime(782): FATAL EXCEPTION: main
11-13 12:27:00.889: E/AndroidRuntime(782): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{de.android.pali/de.android.pali.newGame}: java.lang.NullPointerException
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.ActivityThread.access$600(ActivityThread.java:123)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.os.Handler.dispatchMessage(Handler.java:99)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.os.Looper.loop(Looper.java:137)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.ActivityThread.main(ActivityThread.java:4424)
11-13 12:27:00.889: E/AndroidRuntime(782): at java.lang.reflect.Method.invokeNative(Native Method)
11-13 12:27:00.889: E/AndroidRuntime(782): at java.lang.reflect.Method.invoke(Method.java:511)
11-13 12:27:00.889: E/AndroidRuntime(782): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
11-13 12:27:00.889: E/AndroidRuntime(782): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
11-13 12:27:00.889: E/AndroidRuntime(782): at dalvik.system.NativeStart.main(Native Method)
11-13 12:27:00.889: E/AndroidRuntime(782): Caused by: java.lang.NullPointerException
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.Activity.findViewById(Activity.java:1794)
11-13 12:27:00.889: E/AndroidRuntime(782): at de.android.pali.newGame.<init>(newGame.java:13)
11-13 12:27:00.889: E/AndroidRuntime(782): at java.lang.Class.newInstanceImpl(Native Method)
11-13 12:27:00.889: E/AndroidRuntime(782): at java.lang.Class.newInstance(Class.java:1319)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
11-13 12:27:00.889: E/AndroidRuntime(782): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871)
11-13 12:27:00.889: E/AndroidRuntime(782): ... 11 more
11-13 12:27:00.929: W/ActivityManager(88): Force finishing activity de.android.pali/.newGame
11-13 12:27:00.929: W/ActivityManager(88): Force finishing activity de.android.pali/.TicTacToeMenu
11-13 12:27:01.359: I/Process(88): Sending signal. PID: 782 SIG: 3
11-13 12:27:01.359: I/dalvikvm(782): threadid=3: reacting to signal 3
11-13 12:27:01.379: I/dalvikvm(782): Wrote stack traces to '/data/anr/traces.txt'
11-13 12:27:01.439: W/ActivityManager(88): Activity pause timeout for ActivityRecord{415b08b0 de.android.pali/.newGame}
11-13 12:27:01.439: I/Process(88): Sending signal. PID: 782 SIG: 3
11-13 12:27:01.439: I/dalvikvm(782): threadid=3: reacting to signal 3
11-13 12:27:01.459: I/dalvikvm(782): Wrote stack traces to '/data/anr/traces.txt'
11-13 12:27:01.488: W/NetworkManagementSocketTagger(88): setKernelCountSet(10009, 1) failed with errno -2
11-13 12:27:01.748: W/NetworkManagementSocketTagger(88): setKernelCountSet(10045, 0) failed with errno -2
11-13 12:27:02.169: I/Process(782): Sending signal. PID: 782 SIG: 9
11-13 12:27:02.178: I/ActivityManager(88): Process de.android.pali (pid 782) has died.
11-13 12:27:02.178: W/InputDispatcher(88): channel '415c53c8 de.android.pali/de.android.pali.TicTacToeMenu (server)' ~ Consumer closed input channel or an error occurred. events=0x8
11-13 12:27:02.178: E/InputDispatcher(88): channel '415c53c8 de.android.pali/de.android.pali.TicTacToeMenu (server)' ~ Channel is unrecoverably broken and will be disposed!
11-13 12:27:02.189: I/WindowManager(88): WIN DEATH: Window{415c53c8 de.android.pali/de.android.pali.TicTacToeMenu paused=true}
11-13 12:27:02.189: W/InputDispatcher(88): Attempted to unregister already unregistered input channel '415c53c8 de.android.pali/de.android.pali.TicTacToeMenu (server)'
11-13 12:27:02.199: I/WindowManager(88): WINDOW DIED Window{415c53c8 de.android.pali/de.android.pali.TicTacToeMenu paused=true}
11-13 12:27:02.359: W/InputManagerService(88): Got RemoteException sending setActive(false) notification to pid 782 uid 10045
11-13 12:27:11.749: W/ActivityManager(88): Activity destroy timeout for ActivityRecord{415a28b8 de.android.pali/.TicTacToeMenu}
11-13 12:27:11.749: W/ActivityManager(88): Activity destroy timeout for ActivityRecord{415b08b0 de.android.pali/.newGame}
I hope anyone can help 🙂
This line of your logcat is showing where in your code the error is:
This appears to relate to this:
For some reason, it isn’t finding
feld1when you callfinal ImageButton feld1 = (ImageButton)findViewById(R.id.feld1);. Are you sure this is the right ID for the ImageButton on that layout file (game)?