Android Home key press behavior | Activity stack confused when launching app

Hello Droid Guys

I found an strange issue with the behavior of Home key press in android.Please

check below link if you want more details about this issue.

https://code.google.com/p/android/issues/detail?id=26658

Actually, I think this is an android bug. If an app is installed via market, market 

update, or download from browser and the user launches the app directly from the

installer (ie: when the installer completes it offers the user the options to launch(open)

and done and when use select open the app now) it is launched in such a way that 

the OS gets confused.

If, after the app is launched, the user presses the HOME key to return to the home 

screen and then tries to return to the app by selecting it from the list of applications 

(or by putting a shortcut on the home screen and then selecting the shortcut), the OS

launches the root activity of the app AGAIN, bringing the existing task to the foreground

and placing ANOTHER instance of the root activity on top of the existing activity stack.

This behavior is extremely difficult to debug and has certainly caused countless hours 

of head-scratching by developers.

Note: I too found the same issue when I install an app from my mail and directly launch

the app.Go to Activity "A" then goes to Activity "B" and then I pressed "Home button".

Then ,When I open the same app pressing the app launcher on home screen,Instead of 

taking me directly to Activity "B" where I left it last time , It loads the app from the start.

It takes lots of my time to fixed this issue but finally I did that. I found the

way to resolve this problme :) .
I Added following code in the onCreate() method of my launcher activity and then Its

works fine for me.

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash_screen);

if (!isTaskRoot()) {
           Intent intent = getIntent();
           String action = intent.getAction();
           if (intent.hasCategory(Intent.CATEGORY_LAUNCHER) && action != null &&                           action.equals(Intent.ACTION_MAIN)) {
               finish();
               return;
           }
    }
}

Hope, my above code will save some one time.
Enjoy Coding :)

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Android ListView Background Color Changes on Scrolling

Hello Friends,
This is very common issue I saw in android with Listview. In one of my app I am using a
listview for displaying the list of Items.I set the background of Listview as blue. Below is 
the Listview code which I am using.

 <ListView
        android:id="@+id/left_drawer"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:choiceMode="singleChoice"
        android:background="#0000FF"/>


But, some times when I scroll the Listview the background color will be automatically change
to black or white. Then, I found a solution I added below line in my Listview(in xml file).

android:cacheColorHint="#00000000"
        OR
android:cacheColorHint="@android:color/transparent"

And Finally my Listview code contains following code.....

<ListView
        android:id="@+id/left_drawer"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:cacheColorHint="#00000000"
        android:choiceMode="singleChoice"
        android:background="#2A323D"/>

OR at java code,use below line of code

listview.setCacheColorHint(Color.TRANSPARENT);


After adding the above one line in my xml or java file , the Listview background color 
change on scrolling issue will be gone.

Hope , the above code helps some one.
Enjoy coding......

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android listview adapter getview() called multiple times

Hello Droid Guys,
Today , I found a strange issue in android custom listView adapter. I found that
the adapter getview() method called multiple times.

On my listview I am showing following Item:
1. User facebook image
2. His|Her Name
3. Some description

As, I told you that getview() method calls multiple time, due to this behavior the Image on
list item some times remain unchanged or same profile picture will be attach on different
user , in listview.
First of all I think that this was an issue of lazy image loader library But I was wronged.
After spent few times on google for searching this issue , I found this link

http://stackoverflow.com/questions/2618272/custom-listview-adapter-getview-method-being-called-multiple-times-and-in-no-co

Then After I checked my xml file and I found I am using height = wrap_content in listview.

<ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="3dp"
        android:layout_marginRight="3dp"
        android:padding="5dp"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="5dp"
         android:layout_below="@+id/facebook_friend_list_header" >
    </ListView>

And when I changed this to fill_parent

        android:layout_height="fill_parent"

then all problem is resolved and now the getview() method will be called only once.
Also the user profile picture issue will be resolved.

Android Guys , still I was not cleared about the above tricks. Please let me know why
getview() method called multiple times when I am using
android:layout_height="wrap_content" . If some one know the reason then
please let me know.

Thanks in advance.
Enjoy Coding :)

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ActionBarSherlock with custom View | Changing sherlock action bar menu item background

Hello Friends,
Today , I am going to share my another android tutorial which is based on the
Sherlock Action Bar. ABS(Action Bar Sherlock) is an support library which helps
to use action bar design pattern over all android devices.

Initially , Action bar is supportable over android version 3.0. But if you want to
provide the interactive user interface on lower version of device too, then
ABS comes in a role.

 

       

1. MainActivity.java

package com.example.actionbar;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.MenuItem;
import android.widget.Toast;

import com.actionbarsherlock.app.ActionBar;
import com.actionbarsherlock.app.SherlockActivity;
import com.actionbarsherlock.view.SubMenu;

public class MainActivity extends SherlockActivity {

 private SubMenu mGoItem;

 private static final int GO_ITEM_ID = 1;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  ActionBar ab = getSupportActionBar();
  ab.setBackgroundDrawable(getApplicationContext().getResources()
    .getDrawable(R.drawable.bg_titlebar_tile));
  ab.setLogo(getResources().getDrawable(R.drawable.logo));
  ab.setDisplayShowTitleEnabled(false);
 }

 @SuppressLint("InlinedApi")
 @Override
 public boolean onCreateOptionsMenu(com.actionbarsherlock.view.Menu menu) {

  mGoItem = menu.addSubMenu(0, GO_ITEM_ID, 0, null);
  mGoItem.setIcon(R.drawable.setting_icon);
  // SubMenu sub = menu.addSubMenu("Theme");
  mGoItem.add(0, R.style.Theme_Sherlock, 0, "View Profile");
  mGoItem.add(0, R.style.Theme_Sherlock_Light, 0, "Account Privacy");
  mGoItem.add(0, R.style.Theme_Sherlock_Light_DarkActionBar, 0,
    "Logout");
  mGoItem.getItem().setShowAsAction(
    MenuItem.SHOW_AS_ACTION_ALWAYS
      | MenuItem.SHOW_AS_ACTION_WITH_TEXT);

  return true;
 }

 @SuppressLint("InlinedApi")
 @Override
 public boolean onOptionsItemSelected(
   com.actionbarsherlock.view.MenuItem item) {

  switch (item.getItemId()) {
  case GO_ITEM_ID:
   Toast.makeText(MainActivity.this,
     "You have Pressed 'Setting' Menu Button", Toast.LENGTH_LONG)
     .show();
   return true;
  }

  return false;
 }

}

2.activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:textColor="@android:color/black"
        android:textStyle="bold"
        android:text="@string/hello_action_bar" />

</RelativeLayout>

Download the complete source code: Here

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Asserting Toast message using Robolectric | Testing Toast message Android

Hello Friends,
Today , I am sharing my another android tutorial. In this tutorial I am going to show
how to write the test case for android Toast message using Roboelectric and Junit.

 @Test
 public void testToastMesaage() throws Exception{
    Helper.showBadServerNotification(activity);
     assertThat( ShadowToast.getTextOfLatestToast(),equalTo(
              shadowActivity.getString(R.string.bad_server_response)));

 }

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Activity Life Cycle | Android Activity Life Cycle

Hello Droid Guys,

1. If an activity in the foreground of the screen (at the top of the stack), it is active or running.
2. If an activity has lost focus but is still visible (that is, a new non-full-sized or transparent
    activity has focus on top of your activity), it is paused. A
    paused activity is completely alive (it maintains all state and member information and
    remains attached to the window manager), but can be killed by the system in extreme
    low memory situations.
3. If an activity is completely obscured by another activity, it is stopped. It still retains all
    state and member information, however, it is no longer visible to
    the user so its window is hidden and it will often be killed by the system when memory
    is needed elsewhere.
4. If an activity is paused or stopped, the system can drop the activity from memory by
    either asking it to finish, or simply killing its process. When it is displayed again to the
    user, it must be completely restarted and restored to its previous state.

1. onCreate() : Called when the activity is first created. This is where you should do all of
    your normal static set up: create views, bind data to lists,etc.  This method also provides
    you with a Bundle containing the activity's previously frozen state, if there was one.
    Always followed by onStart()

 2. onRestart() : Called after your activity has been stopped, prior to it being started again.
     Always followed by onStart()

 3. onStart() : Called when the activity is becoming visible to the user.
                     Followed by onResume() if the activity comes to the foreground, or onStop()
                      if it becomes hidden.                

 4. onResume() :  Called when the activity will start interacting with the user. At this point
                           your activity is at the top of the activity stack, with user input going to it.
     Always followed by onPause().      

 5. onPause() : Called when the system is about to start resuming a previous activity.
     This is typically used to commit unsaved changes to persistent data,stop animations
     and other things that may be consuming CPU, etc. Implementations of this method
     must be very quick because the next activity will not be resumed until this method
     returns.Followed by either onResume() if the activity returns back to the front, or
     onStop() if it becomes invisible to the user.  

 6. onStop() : Called when the activity is no longer visible to the user, because another
     activity has been resumed and is covering this one. This may happen either because a new activity is being started, an existing one is being brought in front of this one, or this one is being destroyed.Followed by either onRestart() if this activity is coming back to interact with the user, or onDestroy() if this activity is going away.

 7. onDestroy() : The final call you receive before your activity is destroyed. This can
     happen either because the activity is finishing (someone called finish() on it, or
     because the system is temporarily destroying this instance of the activity to save space.
    You can distinguish between these two scenarios with the isFinishing() method.  

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Android Calendar Sync | Android Custom Calendar | Android Calendar event!Android Custom Calendar View

    Hello Friends,

   Have you Searching for Android calender syncing in your android app.Displaying
   all the events, birthday, reminder and meeting In your android app. Today I am sharing my
   another android tutorial for android custom calendar view and listing all the calendar
   event in my own android app. It is a small sample application for syncing of android
   calender events.

android calander syncing

 
 1. CalendarView.java

package com.examples.android.calendar;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.GregorianCalendar;
import java.util.Locale;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

public class CalendarView extends Activity {

 public GregorianCalendar month, itemmonth;// calendar instances.

 public CalendarAdapter adapter;// adapter instance
 public Handler handler;// for grabbing some event values for showing the dot
       // marker.
 public ArrayList items; // container to store calendar items which
         // needs showing the event marker
 ArrayList event;
 LinearLayout rLayout;
 ArrayList date;
 ArrayList desc;

 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.calendar);
  Locale.setDefault(Locale.US);

  rLayout = (LinearLayout) findViewById(R.id.text);
  month = (GregorianCalendar) GregorianCalendar.getInstance();
  itemmonth = (GregorianCalendar) month.clone();

  items = new ArrayList();

  adapter = new CalendarAdapter(this, month);

  GridView gridview = (GridView) findViewById(R.id.gridview);
  gridview.setAdapter(adapter);

  handler = new Handler();
  handler.post(calendarUpdater);

  TextView title = (TextView) findViewById(R.id.title);
  title.setText(android.text.format.DateFormat.format("MMMM yyyy", month));

  RelativeLayout previous = (RelativeLayout) findViewById(R.id.previous);

  previous.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    setPreviousMonth();
    refreshCalendar();
   }
  });

  RelativeLayout next = (RelativeLayout) findViewById(R.id.next);
  next.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    setNextMonth();
    refreshCalendar();

   }
  });

  gridview.setOnItemClickListener(new OnItemClickListener() {
   public void onItemClick(AdapterView parent, View v,
     int position, long id) {
    // removing the previous view if added
    if (((LinearLayout) rLayout).getChildCount() > 0) {
     ((LinearLayout) rLayout).removeAllViews();
    }
    desc = new ArrayList();
    date = new ArrayList();
    ((CalendarAdapter) parent.getAdapter()).setSelected(v);
    String selectedGridDate = CalendarAdapter.dayString
      .get(position);
    String[] separatedTime = selectedGridDate.split("-");
    String gridvalueString = separatedTime[2].replaceFirst("^0*",
      "");// taking last part of date. ie; 2 from 2012-12-02.
    int gridvalue = Integer.parseInt(gridvalueString);
    // navigate to next or previous month on clicking offdays.
    if ((gridvalue > 10) && (position < 8)) {
     setPreviousMonth();
     refreshCalendar();
    } else if ((gridvalue < 7) && (position > 28)) {
     setNextMonth();
     refreshCalendar();
    }
    ((CalendarAdapter) parent.getAdapter()).setSelected(v);

    for (int i = 0; i < Utility.startDates.size(); i++) {
     if (Utility.startDates.get(i).equals(selectedGridDate)) {
      desc.add(Utility.nameOfEvent.get(i));
     }
    }

    if (desc.size() > 0) {
     for (int i = 0; i < desc.size(); i++) {
      TextView rowTextView = new TextView(CalendarView.this);

      // set some properties of rowTextView or something
      rowTextView.setText("Event:" + desc.get(i));
      rowTextView.setTextColor(Color.BLACK);

      // add the textview to the linearlayout
      rLayout.addView(rowTextView);

     }

    }

    desc = null;

   }

  });
 }

 protected void setNextMonth() {
  if (month.get(GregorianCalendar.MONTH) == month
    .getActualMaximum(GregorianCalendar.MONTH)) {
   month.set((month.get(GregorianCalendar.YEAR) + 1),
     month.getActualMinimum(GregorianCalendar.MONTH), 1);
  } else {
   month.set(GregorianCalendar.MONTH,
     month.get(GregorianCalendar.MONTH) + 1);
  }

 }

 protected void setPreviousMonth() {
  if (month.get(GregorianCalendar.MONTH) == month
    .getActualMinimum(GregorianCalendar.MONTH)) {
   month.set((month.get(GregorianCalendar.YEAR) - 1),
     month.getActualMaximum(GregorianCalendar.MONTH), 1);
  } else {
   month.set(GregorianCalendar.MONTH,
     month.get(GregorianCalendar.MONTH) - 1);
  }

 }

 protected void showToast(String string) {
  Toast.makeText(this, string, Toast.LENGTH_SHORT).show();

 }

 public void refreshCalendar() {
  TextView title = (TextView) findViewById(R.id.title);

  adapter.refreshDays();
  adapter.notifyDataSetChanged();
  handler.post(calendarUpdater); // generate some calendar items

  title.setText(android.text.format.DateFormat.format("MMMM yyyy", month));
 }

 public Runnable calendarUpdater = new Runnable() {

  @Override
  public void run() {
   items.clear();

   // Print dates of the current week
   DateFormat df = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
   String itemvalue;
   event = Utility.readCalendarEvent(CalendarView.this);
   Log.d("=====Event====", event.toString());
   Log.d("=====Date ARRAY====", Utility.startDates.toString());

   for (int i = 0; i < Utility.startDates.size(); i++) {
    itemvalue = df.format(itemmonth.getTime());
    itemmonth.add(GregorianCalendar.DATE, 1);
    items.add(Utility.startDates.get(i).toString());
   }
   adapter.setItems(items);
   adapter.notifyDataSetChanged();
  }
 };
}

2. CalendarAdapter.java

package com.examples.android.calendar;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.GregorianCalendar;
import java.util.List;
import java.util.Locale;

import android.content.Context;
import android.graphics.Color;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class CalendarAdapter extends BaseAdapter {
 private Context mContext;

 private java.util.Calendar month;
 public GregorianCalendar pmonth; // calendar instance for previous month
 /**
  * calendar instance for previous month for getting complete view
  */
 public GregorianCalendar pmonthmaxset;
 private GregorianCalendar selectedDate;
 int firstDay;
 int maxWeeknumber;
 int maxP;
 int calMaxP;
 int lastWeekDay;
 int leftDays;
 int mnthlength;
 String itemvalue, curentDateString;
 DateFormat df;

 private ArrayList items;
 public static List dayString;
 private View previousView;

 public CalendarAdapter(Context c, GregorianCalendar monthCalendar) {
  CalendarAdapter.dayString = new ArrayList();
  Locale.setDefault(Locale.US);
  month = monthCalendar;
  selectedDate = (GregorianCalendar) monthCalendar.clone();
  mContext = c;
  month.set(GregorianCalendar.DAY_OF_MONTH, 1);
  this.items = new ArrayList();
  df = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
  curentDateString = df.format(selectedDate.getTime());
  refreshDays();
 }

 public void setItems(ArrayList items) {
  for (int i = 0; i != items.size(); i++) {
   if (items.get(i).length() == 1) {
    items.set(i, "0" + items.get(i));
   }
  }
  this.items = items;
 }

 public int getCount() {
  return dayString.size();
 }

 public Object getItem(int position) {
  return dayString.get(position);
 }

 public long getItemId(int position) {
  return 0;
 }

 // create a new view for each item referenced by the Adapter
 public View getView(int position, View convertView, ViewGroup parent) {
  View v = convertView;
  TextView dayView;
  if (convertView == null) { // if it's not recycled, initialize some
         // attributes
   LayoutInflater vi = (LayoutInflater) mContext
     .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   v = vi.inflate(R.layout.calendar_item, null);

  }
  dayView = (TextView) v.findViewById(R.id.date);
  // separates daystring into parts.
  String[] separatedTime = dayString.get(position).split("-");
  // taking last part of date. ie; 2 from 2012-12-02
  String gridvalue = separatedTime[2].replaceFirst("^0*", "");
  // checking whether the day is in current month or not.
  if ((Integer.parseInt(gridvalue) > 1) && (position < firstDay)) {
   // setting offdays to white color.
   dayView.setTextColor(Color.WHITE);
   dayView.setClickable(false);
   dayView.setFocusable(false);
  } else if ((Integer.parseInt(gridvalue) < 7) && (position > 28)) {
   dayView.setTextColor(Color.WHITE);
   dayView.setClickable(false);
   dayView.setFocusable(false);
  } else {
   // setting curent month's days in blue color.
   dayView.setTextColor(Color.BLUE);
  }

  if (dayString.get(position).equals(curentDateString)) {
   setSelected(v);
   previousView = v;
  } else {
   v.setBackgroundResource(R.drawable.list_item_background);
  }
  dayView.setText(gridvalue);

  // create date string for comparison
  String date = dayString.get(position);

  if (date.length() == 1) {
   date = "0" + date;
  }
  String monthStr = "" + (month.get(GregorianCalendar.MONTH) + 1);
  if (monthStr.length() == 1) {
   monthStr = "0" + monthStr;
  }

  // show icon if date is not empty and it exists in the items array
  ImageView iw = (ImageView) v.findViewById(R.id.date_icon);
  if (date.length() > 0 && items != null && items.contains(date)) {
   iw.setVisibility(View.VISIBLE);
  } else {
   iw.setVisibility(View.INVISIBLE);
  }
  return v;
 }

 public View setSelected(View view) {
  if (previousView != null) {
   previousView.setBackgroundResource(R.drawable.list_item_background);
  }
  previousView = view;
  view.setBackgroundResource(R.drawable.calendar_cel_selectl);
  return view;
 }

 public void refreshDays() {
  // clear items
  items.clear();
  dayString.clear();
  Locale.setDefault(Locale.US);
  pmonth = (GregorianCalendar) month.clone();
  // month start day. ie; sun, mon, etc
  firstDay = month.get(GregorianCalendar.DAY_OF_WEEK);
  // finding number of weeks in current month.
  maxWeeknumber = month.getActualMaximum(GregorianCalendar.WEEK_OF_MONTH);
  // allocating maximum row number for the gridview.
  mnthlength = maxWeeknumber * 7;
  maxP = getMaxP(); // previous month maximum day 31,30....
  calMaxP = maxP - (firstDay - 1);// calendar offday starting 24,25 ...
  /**
   * Calendar instance for getting a complete gridview including the three
   * month's (previous,current,next) dates.
   */
  pmonthmaxset = (GregorianCalendar) pmonth.clone();
  /**
   * setting the start date as previous month's required date.
   */
  pmonthmaxset.set(GregorianCalendar.DAY_OF_MONTH, calMaxP + 1);

  /**
   * filling calendar gridview.
   */
  for (int n = 0; n < mnthlength; n++) {

   itemvalue = df.format(pmonthmaxset.getTime());
   pmonthmaxset.add(GregorianCalendar.DATE, 1);
   dayString.add(itemvalue);

  }
 }

 private int getMaxP() {
  int maxP;
  if (month.get(GregorianCalendar.MONTH) == month
    .getActualMinimum(GregorianCalendar.MONTH)) {
   pmonth.set((month.get(GregorianCalendar.YEAR) - 1),
     month.getActualMaximum(GregorianCalendar.MONTH), 1);
  } else {
   pmonth.set(GregorianCalendar.MONTH,
     month.get(GregorianCalendar.MONTH) - 1);
  }
  maxP = pmonth.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);

  return maxP;
 }

}

3. Utility.java

package com.examples.android.calendar;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;

import android.content.Context;
import android.database.Cursor;
import android.net.Uri;

public class Utility {
 public static ArrayList nameOfEvent = new ArrayList();
 public static ArrayList startDates = new ArrayList();
 public static ArrayList endDates = new ArrayList();
 public static ArrayList descriptions = new ArrayList();

 public static ArrayList readCalendarEvent(Context context) {
  Cursor cursor = context.getContentResolver()
    .query(Uri.parse("content://com.android.calendar/events"),
      new String[] { "calendar_id", "title", "description",
        "dtstart", "dtend", "eventLocation" }, null,
      null, null);
  cursor.moveToFirst();
  // fetching calendars name
  String CNames[] = new String[cursor.getCount()];

  // fetching calendars id
  nameOfEvent.clear();
  startDates.clear();
  endDates.clear();
  descriptions.clear();
  for (int i = 0; i < CNames.length; i++) {

   nameOfEvent.add(cursor.getString(1));
   startDates.add(getDate(Long.parseLong(cursor.getString(3))));
   endDates.add(getDate(Long.parseLong(cursor.getString(4))));
   descriptions.add(cursor.getString(2));
   CNames[i] = cursor.getString(1);
   cursor.moveToNext();

  }
  return nameOfEvent;
 }

 public static String getDate(long milliSeconds) {
  SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
  Calendar calendar = Calendar.getInstance();
  calendar.setTimeInMillis(milliSeconds);
  return formatter.format(calendar.getTime());
 }
}

   Download the complete Source code 
   Calenderview.zip

   Enjoy coding :)

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