I am building my first app and I am running into an issue with passing on extras in an intent for onActivityResult. I tried looking for the answer but I cant find one that seems to fit. As far as I can tell i follow the "normal" structure of using intents to pass data making sure to use the intent passed by the setResult() and not the intent of the activity. But my knowledge is very limited so probably I am just overlooking something obvious.
The idea of the app is score tracking during a card game.
My apps consists for now out of 3 activities.
I tried passing a bundle in the extras of the intent that is passed in the setResult(). And I tried putting the score as direct extras of the intent. With both ways I get the same error. So it looks like the returned extras do not exist in the returned intent. But I do not understand why not as with the setResult() the intent has the extras.
Error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.wiezen, PID: 7924
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { (has extras) }} to activity {com.example.wiezen/com.example.wiezen.StartToWiez}: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference
at android.app.ActivityThread.deliverResults(ActivityThread.java:4976)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:5017)
at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2123)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7710)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference
at com.example.wiezen.StartToWiez.onActivityResult(StartToWiez.java:65)
at android.app.Activity.dispatchActivityResult(Activity.java:8140)
at android.app.ActivityThread.deliverResults(ActivityThread.java:4969)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:5017)
at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:51)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2123)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7710)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
Activity: MainActivity.java
package com.example.wiezen;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
//create a Bundle object
Bundle extras = new Bundle();
SharedPreferences sharedpreferences;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sharedpreferences = getSharedPreferences("Settings", Context.MODE_PRIVATE);
}
/** Called when the user taps the Send button */
public void startToWiez(View view) {
Intent intent = new Intent(this, StartToWiez.class);
EditText player1Name = (EditText) findViewById(R.id.Player1Name);
String player1NameText = player1Name.getText().toString();
EditText player2Name = (EditText) findViewById(R.id.Player2Name);
String player2NameText = player2Name.getText().toString();
EditText player3Name = (EditText) findViewById(R.id.Player3Name);
String player3NameText = player3Name.getText().toString();
EditText player4Name = (EditText) findViewById(R.id.Player4Name);
String player4NameText = player4Name.getText().toString();
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putString("PLAYER1_NAME", player1NameText);
editor.putString("PLAYER2_NAME", player2NameText);
editor.putString("PLAYER3_NAME", player3NameText);
editor.putString("PLAYER4_NAME", player4NameText);
editor.apply();
startActivity(intent);
}}
Activity StartToWiez.java
package com.example.wiezen;
import androidx.appcompat.app.AppCompatActivity;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
public class StartToWiez extends AppCompatActivity {
Bundle extras;
SharedPreferences sharedpreferences;
Integer player1Score;
Integer player2Score;
Integer player3Score;
Integer player4Score;
Integer aantalRondes = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_start_to_wiez);
// Get the Intent that started this activity and extract the string
Intent intent = getIntent();
sharedpreferences = getSharedPreferences("Settings", Context.MODE_PRIVATE);
extras = intent.getExtras();
// Capture the layout's TextView and set the string as its text
TextView header1 = findViewById(R.id.Player1Header);
TextView header2 = findViewById(R.id.Player2Header);
TextView header3 = findViewById(R.id.Player3Header);
TextView header4 = findViewById(R.id.Player4Header);
header1.setText(sharedpreferences.getString("PLAYER1_NAME", "Player 1"));
header2.setText(sharedpreferences.getString("PLAYER2_NAME", "Player 2"));
header3.setText(sharedpreferences.getString("PLAYER3_NAME", "Player 3"));
header4.setText(sharedpreferences.getString("PLAYER4_NAME", "Player 4"));
}
public void startRound(View view) {
Intent intent = new Intent(this, StartRound.class);
startActivityForResult(intent, 1);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK) {
aantalRondes++;
TableLayout table = (TableLayout) StartToWiez.this.findViewById(R.id.tableLayout);
// Inflate your row "template" and fill out the fields.
TableRow row = (TableRow) LayoutInflater.from(StartToWiez.this).inflate(R.layout.tablerow, null);
player1Score += data.getIntExtra("Player1Score", 0);
player2Score += data.getIntExtra("Player2Score", 0);
player3Score += data.getIntExtra("Player3Score", 0);
player4Score += data.getIntExtra("Player4Score", 0);
((TextView) row.findViewById(R.id.player1Score)).setText(String.valueOf(player1Score));
((TextView) row.findViewById(R.id.player2Score)).setText(String.valueOf(player2Score));
((TextView) row.findViewById(R.id.player3Score)).setText(String.valueOf(player3Score));
((TextView) row.findViewById(R.id.player4Score)).setText(String.valueOf(player4Score));
table.addView(row);
if(aantalRondes == 4){
TableRow row2 = (TableRow) LayoutInflater.from(StartToWiez.this).inflate(R.layout.line_after_4_rounds, null);
table.addView(row2);
aantalRondes = 0;
}
}
}
}
Activity: StartRound.java
package com.example.wiezen;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CheckedTextView;
import android.widget.Spinner;
import android.widget.TextView;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
public class StartRound extends AppCompatActivity {
SharedPreferences sharedpreferences;
Spinner gameType;
Spinner troef;
Spinner aantalSlagen;
ArrayAdapter<String> adapter;
ArrayAdapter<String> adapterTroef;
ArrayAdapter<String> adapterAantalSlagen;
CheckBox player1;
CheckBox player2;
CheckBox player3;
CheckBox player4;
CheckBox player1Win;
CheckBox player2Win;
CheckBox player3Win;
CheckBox player4Win;
Boolean[] winners = new Boolean[4];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_start_round);
// Get the Intent that started this activity and extract the string
Intent intent = getIntent();
//get the shared prefs that store player names
sharedpreferences = getSharedPreferences("Settings", Context.MODE_PRIVATE);
//set player names for the checkboxes
player1 = findViewById(R.id.player1Checkbox);
player2 = findViewById(R.id.player2Checkbox);
player3 = findViewById(R.id.player3Checkbox);
player4 = findViewById(R.id.player4Checkbox);
player1.setText(sharedpreferences.getString("PLAYER1_NAME", "defaultValue"));
player2.setText(sharedpreferences.getString("PLAYER2_NAME", "defaultValue"));
player3.setText(sharedpreferences.getString("PLAYER3_NAME", "defaultValue"));
player4.setText(sharedpreferences.getString("PLAYER4_NAME", "defaultValue"));
player1Win = findViewById(R.id.player1Win);
player2Win = findViewById(R.id.player2Win);
player3Win = findViewById(R.id.player3Win);
player4Win = findViewById(R.id.player4Win);
//set the game type dropdown values for the spinner
gameType = (Spinner) findViewById(R.id.gameType);
adapter = new ArrayAdapter<String>(StartRound.this,android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.typeSpel));
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
gameType.setAdapter(adapter);
//set the game type dropdown values for the spinner
troef = (Spinner) findViewById(R.id.troef);
adapterTroef = new ArrayAdapter<String>(StartRound.this,android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.troef));
adapterTroef.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
troef.setAdapter(adapterTroef);
//set the game type dropdown values for the spinner
aantalSlagen = (Spinner) findViewById(R.id.aantalSlagen);
adapterAantalSlagen = new ArrayAdapter<String>(StartRound.this,android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.aantalSlagen));
adapterAantalSlagen.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
aantalSlagen.setAdapter(adapterAantalSlagen);
//on change of game type spinner do something
gameType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// your code here
}
});
// using finsih()
Button closeButton = (Button) findViewById(R.id.calculateScore);
closeButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
winners[0] = player1Win.isChecked();
winners[1] = player2Win.isChecked();
winners[2] = player3Win.isChecked();
winners[3] = player4Win.isChecked();
Boolean[] players = new Boolean[4];
players[0] = player1.isChecked();
players[1] = player2.isChecked();
players[2] = player3.isChecked();
players[3] = player4.isChecked();
int[] score = new int[4];
Integer behaaldAantalSlagen = (Integer) Integer.parseInt(aantalSlagen.getSelectedItem().toString());
String gametypetest = gameType.getSelectedItem().toString();
switch(gametypetest) {
//algorithm to define the score based on the gametype. score is added to the array score
}
Intent returnIntent = getIntent();
returnIntent.putExtra("Player1Score", score[0]);
returnIntent.putExtra("Player2Score", score[1]);
returnIntent.putExtra("Player3Score", score[2]);
returnIntent.putExtra("Player4Score", score[3]);
setResult(RESULT_OK, returnIntent);
StartRound.this.finish();
}
});
}
}
I think I have figured this out now. I am trying to use =+ on an unitialized integer. So on top when I define my integer it is not set to 0. Which is the starting point of the game. All players should have score 0.
So when using += on the integer it is complaining not about the intent or data, but about the fact that you cannot add to a null value integer.