When i press on button app force closes? Android

Question

When i run my app, and i press on a button it force closes. I fixed my Android manifest and i cannot find the problem. Here is the Logcat:

   03-09 17:46:17.301: D/dalvikvm(2133): Debugger has detached; object registry had 1 entries
03-09 17:46:17.438: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed 43K, 49% free 2794K/5379K, external 1596K/2108K, paused 95ms
03-09 17:46:17.587: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed 1K, 49% free 2793K/5379K, external 3471K/4335K, paused 42ms
03-09 17:46:17.825: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed <1K, 49% free 2795K/5379K, external 5048K/5580K, paused 76ms
03-09 17:46:18.001: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed <1K, 49% free 2796K/5379K, external 8143K/8403K, paused 44ms
03-09 17:46:49.407: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed 15K, 48% free 2825K/5379K, external 11785K/11958K, paused 19ms
03-09 17:46:49.544: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed 1K, 48% free 2826K/5379K, external 13363K/14068K, paused 19ms
03-09 17:46:49.622: D/dalvikvm(2133): GC_EXTERNAL_ALLOC freed <1K, 48% free 2827K/5379K, external 16457K/17091K, paused 19ms
03-09 17:46:49.704: D/AndroidRuntime(2133): Shutting down VM
03-09 17:46:49.704: W/dalvikvm(2133): threadid=1: thread exiting with uncaught exception (group=0x40015578)
03-09 17:46:49.708: E/AndroidRuntime(2133): FATAL EXCEPTION: main
03-09 17:46:49.708: E/AndroidRuntime(2133): java.lang.RuntimeException: Unable to start activity ComponentInfo{izzy.n/izzy.n.main1}: java.lang.NullPointerException
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.os.Looper.loop(Looper.java:130)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.ActivityThread.main(ActivityThread.java:3687)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at java.lang.reflect.Method.invokeNative(Native Method)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at java.lang.reflect.Method.invoke(Method.java:507)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at dalvik.system.NativeStart.main(Native Method)
03-09 17:46:49.708: E/AndroidRuntime(2133): Caused by: java.lang.NullPointerException
03-09 17:46:49.708: E/AndroidRuntime(2133):     at izzy.n.main1.populateCalendarSpinner(main1.java:69)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at izzy.n.main1.onCreate(main1.java:52)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-09 17:46:49.708: E/AndroidRuntime(2133):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
03-09 17:46:49.708: E/AndroidRuntime(2133):     ... 11 more

Here is the code for Android Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="izzy.n"
    android:versionCode="1"
    android:versionName="1.0" >

     <uses-sdk android:minSdkVersion="10" />


     <uses-permission android:name="android.permission.READ_CALENDAR"></uses-permission>
    <uses-permission android:name="android.permission.WRITE_CALENDAR"></uses-permission>

    <application



        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name="izzy.n.IzzynActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="izzy.n.notes"
            android:label="@string/notes"></activity>


        <activity 
            android:name="izzy.n.calculator"
            android:label="@string/calculator"></activity>


        <activity android:name="izzy.n.main1"
                  android:label="@string/app_name"></activity>

    </application>








</manifest>

and finally here is the main1.java:

class MyCalendar {
    public String name;
    public String id;
    public MyCalendar(String _name, String _id) {
        name = _name;
        id = _id;
    }
    @Override
    public String toString() {
        return name;
    }
}

public class main1 extends Activity {
    /*********************************************************************
     * UI part*/
    private Spinner m_spinner_calender;
    private Button m_button_add;
    private Button m_button_add2;
    private Button m_button_getEvents;
    private TextView m_text_event;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        /*get calendar list and populate the view*/
        getCalendars();
        populateCalendarSpinner();
        populateAddBtn();
        populateAddBtn2();
        populateTextEvent();
        populateGetEventsBtn();
    }
    private void populateCalendarSpinner() {
        m_spinner_calender = (Spinner)this.findViewById(R.id.spinner_calendar);
        ArrayAdapter l_arrayAdapter = new ArrayAdapter(this.getApplicationContext(), android.R.layout.simple_spinner_item, m_calendars);
        l_arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        m_spinner_calender.setAdapter(l_arrayAdapter);
        m_spinner_calender.setSelection(0);
        m_spinner_calender.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> p_parent, View p_view,
                    int p_pos, long p_id) {
                m_selectedCalendarId = m_calendars[(int)p_id].id;
            }
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {}
        });
    }
    private void populateAddBtn() {
        m_button_add = (Button) this.findViewById(R.id.button_add);
        m_button_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addEvent();
            }
        });
    }
    private void populateAddBtn2() {
        m_button_add2 = (Button) this.findViewById(R.id.button_add2);
        m_button_add2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addEvent2();
            }
        });
    }
    private void populateGetEventsBtn() {
        m_button_getEvents = (Button) findViewById(R.id.button_get_events);
        m_button_getEvents.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getLastThreeEvents();
            }
        });
    }
    private void populateTextEvent() {
        m_text_event = (TextView) findViewById(R.id.text_event);
        String l_str = "title: roman10 calendar tutorial test\n" +
            "description: This is a simple test for calendar api\n" + 
            "eventLocation: @home\n" + 
            "start time:" + getDateTimeStr(0) + "\n" + 
            "end time: " + getDateTimeStr(30) + "\n" + 
            "event status: confirmed\n" + 
            "all day: no\n" + 
            "has alarm: yes\n";
        m_text_event.setText(l_str);
    }
    /****************************************************************
     * Data part
     */
    /*retrieve a list of available calendars*/
    private MyCalendar m_calendars[];
    private String m_selectedCalendarId = "0";
    private void getCalendars() {
        String[] l_projection = new String[]{"_id", "displayName"};
        Uri l_calendars;
        if (Build.VERSION.SDK_INT >= 8) {
            l_calendars = Uri.parse("content://com.android.calendar/calendars");
        } else {
            l_calendars = Uri.parse("content://calendar/calendars");
        }
        Cursor l_managedCursor = this.managedQuery(l_calendars, l_projection, null, null, null);    //all calendars
        //Cursor l_managedCursor = this.managedQuery(l_calendars, l_projection, "selected=1", null, null);   //active calendars
        if (l_managedCursor.moveToFirst()) {
            m_calendars = new MyCalendar[l_managedCursor.getCount()];
            String l_calName;
            String l_calId;
            int l_cnt = 0;
            int l_nameCol = l_managedCursor.getColumnIndex(l_projection[1]);
            int l_idCol = l_managedCursor.getColumnIndex(l_projection[0]);
            do {
                l_calName = l_managedCursor.getString(l_nameCol);
                l_calId = l_managedCursor.getString(l_idCol);
                m_calendars[l_cnt] = new MyCalendar(l_calName, l_calId);
                ++l_cnt;
            } while (l_managedCursor.moveToNext());
        }
    }
    /*add an event to calendar*/
    private void addEvent() {
        ContentValues l_event = new ContentValues();
        l_event.put("calendar_id", m_selectedCalendarId);
        l_event.put("title", "roman10 calendar tutorial test");
        l_event.put("description", "This is a simple test for calendar api");
        l_event.put("eventLocation", "@home");
        l_event.put("dtstart", System.currentTimeMillis());
        l_event.put("dtend", System.currentTimeMillis() + 1800*1000);
        l_event.put("allDay", 0);
        //status: 0~ tentative; 1~ confirmed; 2~ canceled
        l_event.put("eventStatus", 1);
        //0~ default; 1~ confidential; 2~ private; 3~ public
        l_event.put("visibility", 0);
        //0~ opaque, no timing conflict is allowed; 1~ transparency, allow overlap of scheduling
        l_event.put("transparency", 0);
        //0~ false; 1~ true
        l_event.put("hasAlarm", 1);
        Uri l_eventUri;
        if (Build.VERSION.SDK_INT >= 8) {
            l_eventUri = Uri.parse("content://com.android.calendar/events");
        } else {
            l_eventUri = Uri.parse("content://calendar/events");
        }
        Uri l_uri = this.getContentResolver().insert(l_eventUri, l_event);
        Log.v("++++++test", l_uri.toString());
    }
    /*add an event through intent, this doesn't require any permission
     * just send intent to android calendar
     * http://www.openintents.org/en/uris*/
    private void addEvent2() {
        Intent l_intent = new Intent(Intent.ACTION_EDIT);
        l_intent.setType("vnd.android.cursor.item/event");
        //l_intent.putExtra("calendar_id", m_selectedCalendarId);  //this doesn't work
        l_intent.putExtra("title", "roman10 calendar tutorial test");
        l_intent.putExtra("description", "This is a simple test for calendar api");
        l_intent.putExtra("eventLocation", "@home");
        l_intent.putExtra("beginTime", System.currentTimeMillis());
        l_intent.putExtra("endTime", System.currentTimeMillis() + 1800*1000);
        l_intent.putExtra("allDay", 0);
        //status: 0~ tentative; 1~ confirmed; 2~ canceled
        l_intent.putExtra("eventStatus", 1);
        //0~ default; 1~ confidential; 2~ private; 3~ public
        l_intent.putExtra("visibility", 0);
        //0~ opaque, no timing conflict is allowed; 1~ transparency, allow overlap of scheduling
        l_intent.putExtra("transparency", 0);
        //0~ false; 1~ true
        l_intent.putExtra("hasAlarm", 1);
        try {
            startActivity(l_intent);
        } catch (Exception e) {
            Toast.makeText(this.getApplicationContext(), "Sorry, no compatible calendar is found!", Toast.LENGTH_LONG).show();
        }
    }
    /*get a list of events
     * http://jimblackler.net/blog/?p=151*/
    private void getLastThreeEvents() {
        Uri l_eventUri;
        if (Build.VERSION.SDK_INT >= 8) {
            l_eventUri = Uri.parse("content://com.android.calendar/events");
        } else {
            l_eventUri = Uri.parse("content://calendar/events");
        }
        String[] l_projection = new String[]{"title", "dtstart", "dtend"};
        Cursor l_managedCursor = this.managedQuery(l_eventUri, l_projection, "calendar_id=" + m_selectedCalendarId, null, "dtstart DESC, dtend DESC");
        //Cursor l_managedCursor = this.managedQuery(l_eventUri, l_projection, null, null, null);
        if (l_managedCursor.moveToFirst()) {
            int l_cnt = 0;
            String l_title;
            String l_begin;
            String l_end;
            StringBuilder l_displayText = new StringBuilder();
            int l_colTitle = l_managedCursor.getColumnIndex(l_projection[0]);
            int l_colBegin = l_managedCursor.getColumnIndex(l_projection[1]);
            int l_colEnd = l_managedCursor.getColumnIndex(l_projection[1]);
            do {
                l_title = l_managedCursor.getString(l_colTitle);
                l_begin = getDateTimeStr(l_managedCursor.getString(l_colBegin));
                l_end = getDateTimeStr(l_managedCursor.getString(l_colEnd));
                l_displayText.append(l_title + "\n" + l_begin + "\n" + l_end + "\n----------------\n");
                ++l_cnt;
            } while (l_managedCursor.moveToNext() && l_cnt < 3);
            m_text_event.setText(l_displayText.toString());
        }
    }
    /************************************************
     * utility part
     */
    private static final String DATE_TIME_FORMAT = "yyyy MMM dd, HH:mm:ss";
    public static String getDateTimeStr(int p_delay_min) {
        Calendar cal = Calendar.getInstance();
        SimpleDateFormat sdf = new SimpleDateFormat(DATE_TIME_FORMAT);
        if (p_delay_min == 0) {
            return sdf.format(cal.getTime());
        } else {
            Date l_time = cal.getTime();
            l_time.setMinutes(l_time.getMinutes() + p_delay_min);
            return sdf.format(l_time);
        }
    }
    public static String getDateTimeStr(String p_time_in_millis) {
        SimpleDateFormat sdf = new SimpleDateFormat(DATE_TIME_FORMAT);
        Date l_time = new Date(Long.parseLong(p_time_in_millis));
        return sdf.format(l_time);
    }
}

Answer 1

If you look at your stack trace, you'll see that the problem is a NullPointerException from here:

at izzy.n.main1.populateCalendarSpinner(main1.java:69)

Something at line 69 in main1 is null, but you are trying to use it. I can't tell which line that is from what you've provided above, so its tough to provide a more specific answer.

Here is my guess. If the cause is from this line:

  m_selectedCalendarId = m_calendars[(int)p_id].id;

Then there might not be an element at m_calendars[(int)p_id] . What you might really need is:

  m_selectedCalendarId = m_calendars[p_pos].id;

For future reference, the Eclipse Debugger is a great help in situations like this. Here is a tutorial to help you get started with it: http://www.ibm.com/developerworks/library/os-ecbug/

Answer 2

Have you checked if m_calendars is being initialized correctly. Ensure that the l_arrayAdapter is not null.