Thursday, December 24, 2009

Android Basics - Dialogs and Floating Activities

original link:

As we know android provide Activity class for developing application screens. But many a time application needs to show Dialog boxes or floating screen to do simple tasks likes taking input from user or ask for confirmation etc.

In android Dialogs can be created in following 2 ways:

1. Creating a dialog with the help of android Dialog class or its subclass like AlertDialog.
2. Using dialog theme for the activity.

Using android Dialog class:
Let see how we can create a dialog with the help of Dialog class. To define a dialog the dialog class has to extend the android Dialog class.

class MyDialog extends Dialog {
* @param context
public MyDialog(Context context) {

Define a layout for our dialog. Here is the xml file for of the layout that asks for user’s name.

xmlns:android =””
android:text=”Enter Name:”




Use the above layout for our dialog

class MyDialog extends Dialog {

* @see
protected void onCreate(Bundle savedInstanceState) {
Log.d(”TestApp”, “Dialog created”);

Now the dialog can be shown by calling the show method like this

MyDialog dialog = new MyDialog(context);;

Event handling for the Dialog controls are same as in case of the activity. Modify the dialog code to handle the onclick event on the ok and cancel button.

class MyDialog extends Dialog implements OnClickListener {

private Button okButton;

private Button cancelButton;

private EditText nameEditText;

protected void onCreate(Bundle savedInstanceState) {
okButton = (Button) findViewById(;
cancelButton = (Button) findViewById(;

nameEditText = (EditText) findViewById(;


public void onClick(View view) {
switch (view.getId()) {

To close the dialog the dismiss() method can be called. The dialog can call the dismiss method itself or some other code can also close the dialog by calling dismiss().

The dialog also supports cancel. Canceling means the dialog action is canceled and does not need to perform any operation. Dialog can be canceled by calling cancel() method. Canceling the dialog also dismisses the dialog.

When user clicks the phones BACK button the dialog gets canceled. If you do not want to cancel the dialog on BACK button you can set cancelable to false as


Note that the cancel() method call till be able to cancel the dialog (which is the desirable functionality in most cases). The dialog’s cancel and dismiss events can be listened with the help of OnCancelListener and OnDismissListener.

Returning information from dialog:
Now our dialog can take the name from the user. We need to pass that name to the calling activity. Dialog class does not provide any direct method for returning values. But our own Listener can be created as follows:

public interface MyDialogListener {

public void onOkClick(String name); // User name is provided here.

public void onCancelClick();

The dialog’s constructor has to be modified to take the object of the listener:

public MyDialog(Context context, MyDialogListener listener) {
this.listener = listener;

Now the calling activity needs to provide the object of the class that implements the MyDialogListener which will gets called on ok or cancel button clicks.

Now we need update the onclick method to return the user name.

public void onClick(View view) {
switch (view.getId()) {
listener.onOkClick(nameEditText.getText().toString()); // returning the user’s name.

Using AlertDialog:

AlertDialog is the subclass of the Dialog. It by default provide 3 buttons and text message. The buttons can be made visible as required. Following code creates an AlertDialog that ask user a question and provide Yes, No option.

AlertDialog dialog = new AlertDialog.Builder(context).create();

dialog.setMessage(”Do you play cricket?”);
dialog.setButton(”Yes”, myOnClickListener);
dialog.setButton2(”No”, myOnClickListener);;

The onClick method code for the button listener myOnClickListener will be like this:

public void onClick(DialogInterface dialog, int i) {
switch (i) {
case AlertDialog.BUTTON1:
/* Button1 is clicked. Do something */
case AlertDialog.BUTTON2:
/* Button2 is clicked. Do something */

AlertDialog has a nested class called ‘Builder’. Builder class provides facility to add multichoice or single choice lists. The class also provides methods to set the appropriate Adaptors for the lists, set event handlers for the list events etc. The Builder button calls the Button1, Button2, Button3 as PositiveButton, NeutralButton, NegativeButton.

Here is an example of dialog box with Multichoice list

new AlertDialog.Builder(context)
new boolean[]{false, true, false, true, false},
new DialogInterface.OnMultiChoiceClickListener() {
public void onClick(DialogInterface dialog, int whichButton, boolean isChecked) {
/* Something on click of the check box */
.setPositiveButton(R.string.alert_dialog_ok, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {

/* User clicked Yes so do some stuff */
.setNegativeButton(R.string.alert_dialog_cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {

/* User clicked No so do some stuff */

Activity Managed Dialog:

Android also provide facility to create dialogs. Activity created dialog can be managed by Activity methods like showDialog(), onCreateDialog(), onPrepareDialog(), dismissDialog(), removeDialog().
The onCreateDialog create the dialog that needs to be shown, for example

* @see
protected Dialog onCreateDialog(int id) {
return new AlertDialog.Builder(this).setMessage(”How are you?”).setPositiveButton(”Fine”, new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {
/* Do something here */
}).setNegativeButton(”Not so good”, new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {
/* Do something here */

You can create multiple dialog boxes and differentiate them with the id parameter. The dialog can be shown with the help of showDialog(id) method. The onCreateDialog method gets called for the first time when showDialog method is called. For subsequent calls to the showDialog() the dialog is not created but shown directly.
If you need to update the dialog before it is getting shown then you can do that in onPrepareDialog() method. The methods get called just before the dialog is shown to the user.
To close the dialog you can call dismissDialog() method. Generally you will dismiss the dialogs in the click handles of the dialog buttons.
The removeDialog() method will remove the dialog from the activity management and if showDialog is again called for that dialog, the dialog needs to be created.

Using android Dialog theme for activity:
Another simple way to show the dialog is to make the Activity to work as a Dialog (floating activity). This can be done by applying dialog Theme while defining the activity entry in the AndroidManifest.xml

The activity will be shown as a dialog as the activity is using ‘Theme.Dialog’ as theme.

Tuesday, December 22, 2009

iphone: tips collection

iPhone: Make your Default.png

A UIPickerView with labels

how to send SMS/Email from an application

You can do this with a short code by way of a SMS/MMS aggregator like OpenMarket or as another person has posted you can use the SMS Gateway but this requires the knowledge of the end users carrier name. If your replying to a SMS on the iPhone I believe you can use the API which in turn would give you the carrier id of the incoming SMS message you would like to reply to.

Launch SMS with New Message Window Open:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"sms:"]]

"sms" - brings up general Text Messages screen

"sms: " - brings up the New Message screen, but with a little blue circle in the To field that it a little confusing and probably needs to be deleted.

"sms:?" - brings up the New Message screen, but with a question mark in a blue circle in the To field

"sms://" - brings up general Text Messages screen

"sms:&" - brings up the New Message screen, but with a ampersand in a blue circle in the To field

"sms:." - brings up the New Message screen, but with a period in a blue circle in the To field

how to invite friends from facebook conenct in iphone app:

You can find info about using FBC on the iPhone here(

there are two modes you can use it in. One where your developer secret is in the phone app, if that makes you nervous you can proxy the authentication through your own server. FB developer site has the info along with programmer supported wikis

Facebook Connect 能做什么? 这个是个老外做的,想像了一些商业场景:如果 Amazon/iTunes/iPhone 这些网站//设备实现了Facebook Connect……

how to debug EXC_BAD_ACCESS on iPhone

Instruments on Leopard: How to debug those random crashes in your Cocoa app

google geocoding UK postcode issue:

oogle Maps API provides a geocoding feature, for finding the latitude and longitude of places or addresses; but it does not work for UK postcodes. This is thanks to Royal Mail who have a copyright on the data, and are very restrictive with their (expensive) licenses for it.


if use restFul ajax local search, use this:


memory leaks detecting:

un the tools within XCode over menu -> run -> start with performance tool ->......

Introduction to Instruments User Guide

Finding iPhone Memory Leaks: A “Leaks” Tool Tutorial

Instruments on Leopard: How to debug those random crashes in your Cocoa app

how to handle & in xml file:

answer: Put the data in a section and you should get what you want.


How to view contents of NSDictionary variable in Xcode debugger?

In the gdb window you can use po to inspect the object.

The difference between initWithString and stringWithString is that stringWithString returns an auto-released pointer. This means that you don't need to release it specifically, since that will be taken care of next time that the auto-release pool cleans up any auto-released pointers. initWithString, on the other hand, returns a pointer with a retain count of 1 - you do need to call release on that pointer, or else it would result in a memory leak.

code for plucking useful bits out of the addressBook:

- (BOOL)peoplePickerNavigationController:(ABPeoplePickerNavigationController *)peoplePicker

shouldContinueAfterSelectingPerson:(ABRecordRef)person {

customer.firstName = (NSString *)ABRecordCopyValue(person, kABPersonFirstNameProperty);

customer.lastName = (NSString *)ABRecordCopyValue(person, kABPersonLastNameProperty);

customer.companyName = (NSString *)ABRecordCopyValue(person, kABPersonOrganizationProperty);

if (!customer.firstName.length) {

customer.firstName = @"*";


if (!customer.lastName.length) {

customer.lastName = @"*";


if (!customer.companyName.length) {

customer.companyName = @"";


CFStringRef email, emailLabel, phone, phoneLabel;

ABMutableMultiValueRef phoneMulti = ABRecordCopyValue(person, kABPersonPhoneProperty);

NSMutableDictionary *myPhoneDict = [NSMutableDictionary dictionaryWithCapacity:ABMultiValueGetCount(phoneMulti)];

for (CFIndex i = 0; i <>

phoneLabel = ABAddressBookCopyLocalizedLabel(ABMultiValueCopyLabelAtIndex(phoneMulti, i));

phone = ABMultiValueCopyValueAtIndex(phoneMulti, i);

[myPhoneDict setObject:(NSString*)phone forKey:(NSString*)phoneLabel];




if ( [myPhoneDict objectForKey:@"mobile"] != nil) { = [myPhoneDict objectForKey:@"mobile"];

} else if ( [myPhoneDict objectForKey:@"home"] != nil) { = [myPhoneDict objectForKey:@"home"];

} else if ( [myPhoneDict objectForKey:@"work"] != nil) { = [myPhoneDict objectForKey:@"work"];


ABMutableMultiValueRef multi = ABRecordCopyValue(person, kABPersonEmailProperty);

NSMutableDictionary *myEmailDict = [NSMutableDictionary dictionaryWithCapacity:ABMultiValueGetCount(multi)];

for (CFIndex i = 0; i <>

emailLabel = ABAddressBookCopyLocalizedLabel(ABMultiValueCopyLabelAtIndex(multi, i));

email = ABMultiValueCopyValueAtIndex(multi, i);

[myEmailDict setObject:(NSString*)email forKey:(NSString*)emailLabel];




if ([myEmailDict objectForKey:@"home"] != nil) { = [myEmailDict objectForKey:@"home"];

} else if ([myEmailDict objectForKey:@"work"] != nil) { = [myEmailDict objectForKey:@"work"];

} else if ([myEmailDict objectForKey:@"other"] != nil) { = [myEmailDict objectForKey:@"other"];


// get the address stuff

ABMultiValueRef streets = ABRecordCopyValue(person, kABPersonAddressProperty);

NSMutableDictionary *myAddressDict = [NSMutableDictionary dictionaryWithCapacity:ABMultiValueGetCount(streets)];

for (CFIndex j = 0; j <>

NSMutableDictionary *myLabelDict = [[NSMutableDictionary alloc] init];

CFDictionaryRef dict = ABMultiValueCopyValueAtIndex(streets, j);

CFStringRef typeTmp = ABMultiValueCopyLabelAtIndex(streets, j);

CFStringRef type = ABAddressBookCopyLocalizedLabel(typeTmp);

NSString *street = [(NSString *)CFDictionaryGetValue(dict, kABPersonAddressStreetKey) copy];

NSString *city = [(NSString *)CFDictionaryGetValue(dict, kABPersonAddressCityKey) copy];

NSString *state = [(NSString *)CFDictionaryGetValue(dict, kABPersonAddressStateKey) copy];

NSString *zip = [(NSString *)CFDictionaryGetValue(dict, kABPersonAddressZIPKey) copy];

NSString *country = [(NSString *)CFDictionaryGetValue(dict, kABPersonAddressCountryKey) copy];

if ((street != nil) && (street.length > 0))

[myLabelDict setObject:street forKey:@"street"];

if ((city != nil) && (city.length > 0))

[myLabelDict setObject:city forKey:@"city"];

if ((state != nil) && (state.length > 0))

[myLabelDict setObject:state forKey:@"state"];

if ((zip != nil) && (zip.length > 0))

[myLabelDict setObject:zip forKey:@"zip"];

if ((country != nil) && (country.length > 0))

[myLabelDict setObject:country forKey:@"country"];

[myAddressDict setObject:myLabelDict forKey:(NSString *)type];

[myLabelDict release];

[street release];

[city release];

[state release];

[zip release];

[country release];





NSString *theKey;

if ([myAddressDict objectForKey:@"home"] != nil) {

theKey = @"home";

} else if ([myAddressDict objectForKey:@"work"] != nil) {

theKey = @"work";

} else if ([myAddressDict objectForKey:@"other"] != nil) {

theKey = @"other";


if ([[[myAddressDict objectForKey:theKey] objectForKey:@"street"] length] > 0) {

customer.street = [[myAddressDict objectForKey:theKey] objectForKey:@"street"];

} else {

customer.street = @"";


if ([[[myAddressDict objectForKey:theKey] objectForKey:@"city"] length] > 0) { = [[myAddressDict objectForKey:theKey] objectForKey:@"city"];

} else { = @"";


if ([[[myAddressDict objectForKey:theKey] objectForKey:@"state"] length] > 0) {

customer.state = [[myAddressDict objectForKey:theKey] objectForKey:@"state"];

} else {

customer.state = @"";


if ([[[myAddressDict objectForKey:theKey] objectForKey:@"zip"] length] > 0) {

customer.postalCode = [[myAddressDict objectForKey:theKey] objectForKey:@"zip"];

} else {

customer.postalCode = @"";


if ([[[myAddressDict objectForKey:theKey] objectForKey:@"country"] length] > 0) { = [[myAddressDict objectForKey:theKey] objectForKey:@"country"];

} else { = @"";





[customer dehydrate];

[self dismissModalViewControllerAnimated:YES];

return NO;


Friday, December 18, 2009

How to add photos to iPhone Simulator from Mac OS X?

Open the Window in mac where your images are stored.

Open your simulator another side.

Now drag your image from mac window to simulator,

simulator will open safari, and in a safari tab your image will be shown.

press left button of mouse and hold for a while on image in simulator,

There will be message to "save image",

save image.

It will be added to your iPhone simulator.

Saturday, December 12, 2009

Debug Java by JVM diagnostics tools

sometimes I need to debug program with multiple threads and complex codes. Or I work on analyzing and interpreting the JVM performance monitoring and diagnostics statistics. I need a sharp tool to do it. So I find most powerful kits to help.

1. An Introduction to Java Stack Traces
2. JDB Example: Generating a Thread Dump
3. How to debug a multithreaded java program
4. Schedule your own Java thread dumps
5. JDK Debugging Tools
6. JDK Tools and Utilities
7. Exercise basic command line debugging tools
8. Debug your Java code with ease using JPDA
9. IBM and SAP Open Source their JVM Diagnostics Tools
10. IBM Thread and Monitor Dump Analyzer for Java
11. Sun VisualVM is a visual tool integrating several commandline JDK tools and lightweight profiling capabilities.
12. Eclipse Test & Performance Tools Platform Project
13. Eclipse Tips: Debugging your multi thread application