Question

I’m new to Android and trying to learn how to pass some variables from activity to another activity by Intents. The problem is when I run the app after finishing answering my questions it will take me to the Summary activity which has the result of the AskQusetions activity (the count of yes and no)

Here is my AskQuestion Activity:

    package com.example.quizapp;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.widget.TextView;


public class AskQuestions extends Activity {

    private String[] messages;
    private int yesCount;
    private int noCount;
    private int messageNum;
    public final static String EXTRA_MESSAGE = "com.example.quizapp.MESSAGE";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.ask_questions);

    }

    @Override
    public void onStart() {
        super.onStart();
        messages = getResources().getStringArray(R.array.lblask_questions);
        messageNum = 0;
        setYesCount(0);
        setNoCount(0);

        TextView lblQuestion = (TextView)findViewById(R.id.lblask_questions);
        lblQuestion.setText(messages[messageNum]);
    }

    public void onYes(View view) {
        Log.i("Quiz App", "viewing next question");

        setYesCount(getYesCount() + 1); // count yes
        messageNum++;
        if (messageNum >= messages.length) { // if the questions finished got to summary
            // go to summary
            Intent summaryIntent = new Intent(this, Summary.class);
            //int messageYes = getYesCount();
            summaryIntent.putExtra("value", getYesCount());
            startActivity(summaryIntent);
        }

        TextView lblQuestion = (TextView)findViewById(R.id.lblask_questions);
        lblQuestion.setText(messages[messageNum]);
    }

    public void onNo(View view) {
        Log.i("Quiz App", "viewing next question");

        setNoCount(getNoCount() + 1); // count not
        messageNum++;
        if (messageNum >= messages.length) { // if the questions finished got to summary
            // go to summary
            Intent summaryIntent = new Intent(this, Summary.class);
            summaryIntent.putExtra("value", getNoCount()); 
            startActivity(summaryIntent);
        }



        TextView lblQuestion = (TextView)findViewById(R.id.lblask_questions);
        lblQuestion.setText(messages[messageNum]);
    }

    public int getYesCount() {
        return yesCount;
    }

    public void setYesCount(int yesCount) {
        this.yesCount = yesCount;
    }

    public int getNoCount() {
        return noCount;
    }

    public void setNoCount(int noCount) {
        this.noCount = noCount;
    }

}

Here is my Summary Activity:

package com.example.quizapp;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.widget.TextView;


/**
 * @author ***
 *
 */
public class Summary extends Activity {


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //Bundle extras = getIntent().getExtras();
        //String value = extras.getString(AskQuestions.EXTRA_MESSAGE);


        setContentView(R.layout.summary);

    }
    @Override
    public void onStart() {
        super.onStart();

        //String value = "HELLO";

        TextView lblYes = (TextView)findViewById(R.id.yes_result);
        lblYes.setText(getIntent().getExtras().getString("value"));

        TextView lblNo = (TextView)findViewById(R.id.no_result);
        lblNo.setText(getIntent().getExtras().getString("value"));


    }


}

The error (app crashes):

The consol output:

[2012-10-16 01:28:04 – QuizApp] Android Launch!
[2012-10-16 01:28:04 – QuizApp] adb is running normally.
[2012-10-16 01:28:04 – QuizApp] Performing com.example.quizapp.MainActivity activity launch
[2012-10-16 01:28:04 – QuizApp] Automatic Target Mode: using existing emulator ’emulator-5554′ running compatible AVD ‘firstDevice’
[2012-10-16 01:28:05 – QuizApp] Attempting to connect debugger to ‘com.example.quizapp’ on port 8621
[2012-10-16 01:28:07 – QuizApp] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.example.quizapp/.MainActivity }
[2012-10-16 01:28:08 – QuizApp] Application already deployed. No need to reinstall.
[2012-10-16 01:28:08 – QuizApp] Starting activity com.example.quizapp.MainActivity on device emulator-5554
[2012-10-16 01:28:10 – QuizApp] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.example.quizapp/.MainActivity }
[2012-10-16 01:28:10 – QuizApp] Attempting to connect debugger to ‘com.example.quizapp’ on port 8621
[2012-10-16 01:28:12 – QuizApp] Attempting to connect debugger to ‘com.example.quizapp’ on port 8621

Logcat error (after restarting the eclipse):

10-16 02:17:34.469: D/AndroidRuntime(1496): Shutting down VM
10-16 02:17:34.469: W/dalvikvm(1496): threadid=1: thread exiting with uncaught exception (group=0xb3f68288)
10-16 02:17:34.479: E/AndroidRuntime(1496): FATAL EXCEPTION: main
10-16 02:17:34.479: E/AndroidRuntime(1496): java.lang.IllegalStateException: Could not execute method of the activity
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.view.View$1.onClick(View.java:3591)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.view.View.performClick(View.java:4084)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.view.View$PerformClick.run(View.java:16966)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.os.Handler.handleCallback(Handler.java:615)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.os.Handler.dispatchMessage(Handler.java:92)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.os.Looper.loop(Looper.java:137)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.app.ActivityThread.main(ActivityThread.java:4745)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at java.lang.reflect.Method.invokeNative(Native Method)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at java.lang.reflect.Method.invoke(Method.java:511)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at dalvik.system.NativeStart.main(Native Method)
10-16 02:17:34.479: E/AndroidRuntime(1496): Caused by: java.lang.reflect.InvocationTargetException
10-16 02:17:34.479: E/AndroidRuntime(1496):     at java.lang.reflect.Method.invokeNative(Native Method)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at java.lang.reflect.Method.invoke(Method.java:511)
10-16 02:17:34.479: E/AndroidRuntime(1496):     at android.view.View$1.onClick(View.java:3586)
10-16 02:17:34.479: E/AndroidRuntime(1496):     ... 11 more
10-16 02:17:34.479: E/AndroidRuntime(1496): Caused by: java.lang.ArrayIndexOutOfBoundsException: length=5; index=5
10-16 02:17:34.479: E/AndroidRuntime(1496):     at com.example.quizapp.AskQuestions.onYes(AskQuestions.java:56)
10-16 02:17:34.479: E/AndroidRuntime(1496):     ... 14 more
10-16 02:17:38.499: E/Trace(1604): error opening trace file: No such file or directory (2)
10-16 02:17:39.020: D/gralloc_goldfish(1604): Emulator without GPU emulation detected.

Answer 1

The first paramater to putExtra() is a String with the package name of the application AND the name of the value, for instance “com.example.quizapp.yesValues” or “com.example.quizapp.noValues”

You then retrieve the values via

getIntent().getExtras().getInt("com.example.quizapp.yesValues", -1);
getIntent.getExtras().getInt("com.example.quizapp.noValues", -1);

note the second parameter in getInt() is the default value

Your second error is due to IndexOutOfBoundsException. You are trying to access an index that does not exist in your array at the line:

lblQuestion.setText(messages[messageNum]);

In your onYes() and onNo() methods. Notice right above it you check that messageNum >= messages.length, then immediately after you address the array by it. Do that inside of a check

if(messageNum < messages.length)

good luck and happy coding!