i’ve got a little problem.
I’m working on a little TicTacToe-Game.
I’ve got a Start-Screen where you can enter Player-names and it gives that Strings to the Game-Activity by putExtra. It works so far, Playernames are displayed in the Game-Activity.
My problem now: if one player wins the game a “NewGame”-Button becomes visible.
On click it should restart the Game-Activity with the same Names given in StartScreen.
This is the point where it crashes.
Here my code and logcat:
StartScreen:
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.EditText;
import android.widget.ImageButton;
public class TicTacToeMenu extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tic_tac_toe_menu);
final ImageButton createGame = (ImageButton)findViewById(R.id.newGameButton);
final EditText spieler1 = (EditText)findViewById(R.id.addsp1);
final EditText spieler2 = (EditText)findViewById(R.id.addsp2);
final Intent newGame = new Intent(TicTacToeMenu.this, NewGame.class);
createGame.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
newGame.putExtra("Name1", spieler1.getText().toString());
newGame.putExtra("Name2", spieler2.getText().toString());
startActivity(newGame);
}
});
}
}
Game-Activity:
package de.android.pali;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
public class NewGame extends TicTacToeMenu{
int turn = 1;
int[] felder = new int[9];
boolean gotWinner = false;
ImageButton feld1;
ImageButton feld2;
ImageButton feld3;
ImageButton feld4;
ImageButton feld5;
ImageButton feld6;
ImageButton feld7;
ImageButton feld8;
ImageButton feld9;
Button anotherGame;
TextView spieler1;
TextView spieler2;
TextView ergebnis;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.game);
setupUI();
setOnClickListeners(feld1, feld2, feld3, feld4, feld5, feld6, feld7,
feld8, feld9);
}
public void setupUI() {
feld1 = (ImageButton)findViewById(R.id.feld1);
feld2 = (ImageButton)findViewById(R.id.feld2);
feld3 = (ImageButton)findViewById(R.id.feld3);
feld4 = (ImageButton)findViewById(R.id.feld4);
feld5 = (ImageButton)findViewById(R.id.feld5);
feld6 = (ImageButton)findViewById(R.id.feld6);
feld7 = (ImageButton)findViewById(R.id.feld7);
feld8 = (ImageButton)findViewById(R.id.feld8);
feld9 = (ImageButton)findViewById(R.id.feld9);
final TextView spieler1 = (TextView)findViewById(R.id.sp1name);
final TextView spieler2 = (TextView)findViewById(R.id.sp2name);
spieler1.setText(getIntent().getStringExtra("Name1").toString());
spieler2.setText(getIntent().getStringExtra("Name2").toString());
for(int x=0; x<9; x++){felder[x]=2;};
}
public void setOnClickListeners(final ImageButton feld1,
final ImageButton feld2, final ImageButton feld3,
final ImageButton feld4, final ImageButton feld5,
final ImageButton feld6, final ImageButton feld7,
final ImageButton feld8, final ImageButton feld9) {
feld1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld1.setEnabled(false);
feld1.setAlpha(1);
if(turn==1){
feld1.setBackgroundResource(R.drawable.o);
turn = 0;
felder[0] = 1;
checkWinner();
}
else{
feld1.setBackgroundResource(R.drawable.x);
turn = 1;
felder[0] = 0;
checkWinner();
}
}
});
feld2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld2.setEnabled(false);
if(turn==1){
feld2.setBackgroundResource(R.drawable.o);
turn = 0;
felder[1] = 1;
checkWinner();
}
else{
feld2.setBackgroundResource(R.drawable.x);
felder[1] = 0;
turn = 1;
checkWinner();
}
}
});
feld3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld3.setEnabled(false);
if(turn==1){
feld3.setBackgroundResource(R.drawable.o);
turn = 0;
felder[2] = 1;
checkWinner();
}
else{
feld3.setBackgroundResource(R.drawable.x);
turn = 1;
felder[2] = 0;
checkWinner();
};
}
});
feld4.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld4.setEnabled(false);
if(turn==1){
feld4.setBackgroundResource(R.drawable.o);
turn = 0;
felder[3] = 1;
checkWinner();
}
else{
feld4.setBackgroundResource(R.drawable.x);
felder[3] = 0;
turn = 1;
checkWinner();
}
}
});
feld5.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld5.setEnabled(false);
if(turn==1){
feld5.setBackgroundResource(R.drawable.o);
turn = 0;
felder[4] = 1;
checkWinner();
}
else{
feld5.setBackgroundResource(R.drawable.x);
turn = 1;
felder[4] = 0;
checkWinner();
}
}
});
feld6.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld6.setEnabled(false);
if(turn==1){
feld6.setBackgroundResource(R.drawable.o);
turn = 0;
felder[5] = 1;
checkWinner();
}
else{
feld6.setBackgroundResource(R.drawable.x);
turn = 1;
felder[5] = 0;
checkWinner();
}
}
});
feld7.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld7.setEnabled(false);
if(turn==1){
feld7.setBackgroundResource(R.drawable.o);
turn = 0;
felder[6] = 1;
checkWinner();
}
else{
feld7.setBackgroundResource(R.drawable.x);
turn = 1;
felder[6] = 0;
checkWinner();
}
}
});
feld8.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld8.setEnabled(false);
if(turn==1){
feld8.setBackgroundResource(R.drawable.o);
turn = 0;
felder[7] = 1;
checkWinner();
}
else{
feld8.setBackgroundResource(R.drawable.x);
turn = 1;
felder[7] = 0;
checkWinner();
}
}
});
feld9.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
feld9.setEnabled(false);
if(turn==1){
feld9.setBackgroundResource(R.drawable.o);
turn = 0;
felder[8] = 1;
checkWinner();
}
else{
feld9.setBackgroundResource(R.drawable.x);
turn = 1;
felder[8] = 0;
checkWinner();
}
}
});
}
public int getTurn() {
int whois = turn;
return whois;
}
public void checkWinner(){
ergebnis = (TextView)findViewById(R.id.winners);
if( (felder[0]==1 & felder[1]==1 & felder[2]==1) ||
(felder[3]==1 & felder[4]==1 & felder[5]==1) ||
(felder[6]==1 & felder[7]==1 & felder[8]==1) ||
(felder[0]==1 & felder[4]==1 & felder[8]==1) ||
(felder[6]==1 & felder[4]==1 & felder[2]==1) ||
(felder[0]==1 & felder[3]==1 & felder[6]==1) ||
(felder[1]==1 & felder[4]==1 & felder[7]==1) ||
(felder[2]==1 & felder[5]==1 & felder[8]==1) ){
ergebnis.setText((getIntent().getStringExtra("Name1").toString()) + " " + getString((R.string.gewinnt)));
gotWinner = true;
}else
{ }
if( (felder[0]==1 & felder[1]==1 & felder[2]==1) ||
(felder[3]==0 & felder[4]==0 & felder[5]==0) ||
(felder[6]==0 & felder[7]==0 & felder[8]==0) ||
(felder[0]==0 & felder[4]==0 & felder[8]==0) ||
(felder[6]==0 & felder[4]==0 & felder[2]==0) ||
(felder[0]==0 & felder[3]==0 & felder[6]==0) ||
(felder[1]==0 & felder[4]==0 & felder[7]==0) ||
(felder[2]==0 & felder[5]==0 & felder[8]==0) ){
ergebnis.setText((getIntent().getStringExtra("Name2").toString()) + " " + (getString(R.string.gewinnt)));
gotWinner = true;
}else
{ }
checkIfGotWinner();
}
public void checkIfGotWinner() {
anotherGame = (Button)findViewById(R.id.anotherGame);
if(gotWinner == true){
anotherGame.setVisibility(1);
final Intent anotGame = new Intent(NewGame.this,NewGame.class);
anotGame.putExtra("Name1", spieler1.getText().toString());
anotGame.putExtra("Name2", spieler2.getText().toString());
feld1.setEnabled(false);
feld2.setEnabled(false);
feld3.setEnabled(false);
feld4.setEnabled(false);
feld5.setEnabled(false);
feld6.setEnabled(false);
feld7.setEnabled(false);
feld8.setEnabled(false);
feld9.setEnabled(false);
final TextView spieler1 = (TextView)findViewById(R.id.sp1name);
final TextView spieler2 = (TextView)findViewById(R.id.sp2name);
final ImageView sp1Icon = (ImageView)findViewById(R.id.sp1icon);
final ImageView sp2Icon = (ImageView)findViewById(R.id.sp2icon);
final View trenn = (View)findViewById(R.id.trennlinie);
ergebnis = (TextView)findViewById(R.id.winners);
spieler1.setAlpha(0);
spieler2.setAlpha(0);
sp1Icon.setAlpha(0);
sp2Icon.setAlpha(0);
trenn.setAlpha(0);
ergebnis.setVisibility(1);
anotherGame.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
startActivity(anotGame);
}
});
};
if(feld1.isEnabled()==false & feld2.isEnabled()==false & feld3.isEnabled()==false & feld4.isEnabled()==false & feld5.isEnabled()==false & feld6.isEnabled()==false &
feld7.isEnabled()==false & feld8.isEnabled()==false & feld9.isEnabled()==false & gotWinner == false){ergebnis.setText(R.string.draw);
anotherGame.setVisibility(1);
final Intent anotGame = new Intent(NewGame.this,NewGame.class);
anotherGame.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
startActivity(anotGame);
}
});
}
else{}
}
}
logCat:
11-29 15:59:30.681: E/AndroidRuntime(2683): FATAL EXCEPTION: main
11-29 15:59:30.681: E/AndroidRuntime(2683): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.android.pali/de.android.pali.NewGame}: java.lang.NullPointerException
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.ActivityThread.access$600(ActivityThread.java:123)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.os.Handler.dispatchMessage(Handler.java:99)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.os.Looper.loop(Looper.java:137)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.ActivityThread.main(ActivityThread.java:4424)
11-29 15:59:30.681: E/AndroidRuntime(2683): at java.lang.reflect.Method.invokeNative(Native Method)
11-29 15:59:30.681: E/AndroidRuntime(2683): at java.lang.reflect.Method.invoke(Method.java:511)
11-29 15:59:30.681: E/AndroidRuntime(2683): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
11-29 15:59:30.681: E/AndroidRuntime(2683): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
11-29 15:59:30.681: E/AndroidRuntime(2683): at dalvik.system.NativeStart.main(Native Method)
11-29 15:59:30.681: E/AndroidRuntime(2683): Caused by: java.lang.NullPointerException
11-29 15:59:30.681: E/AndroidRuntime(2683): at de.android.pali.NewGame.setupUI(NewGame.java:65)
11-29 15:59:30.681: E/AndroidRuntime(2683): at de.android.pali.NewGame.onCreate(NewGame.java:40)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.Activity.performCreate(Activity.java:4465)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
11-29 15:59:30.681: E/AndroidRuntime(2683): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
11-29 15:59:30.681: E/AndroidRuntime(2683): ... 11 more
Hope anyone can help.
First of all starting the same activity within it’s own is not good practice. it’s like Snake is swallowing own tail. so you need to write some logic which can directly reset the game. and look like user had started first time
Tips:Remove values of all the variable by setting it empty, Keep only user’s name(Make one function which will do this for you)