Develop Reference

How to access value of an extra

I want to access the extras contained in the BluetoothDevice.ACTION_FOUND, for example if i want to access the value containd in BluetoothDevice.EXTRA_CLASS, I should use it as shown below in the code, but when I display the value of the variable "state", it was something like -245175
Are there other values contined inside BluetoothDevice.EXTRA_CLASS? how should i know them? and how should i access them?
update:
intent i am registered to is : BluetoothDevice.ACTION_FOUND
code:
switch (action) {
case BluetoothDevice.ACTION_FOUND:
Log.d(TAG, LogAnd.i("onReceive", "BluetoothDevice.ACTION_FOUND"));
final int state = intent.getIntExtra(BluetoothDevice.EXTRA_CLASS, BluetoothAdapter.ERROR);
Log.d(TAG, LogAnd.i("onReceive", "state: "+state));
break;

You're using getIntExtra(), but the extra value isn't an integer. It still "works", but the content is interpreted in the wrong way, so you get a meaningless value.
The docs for EXTRA_CLASS say:
Used as a Parcelable BluetoothClass extra field in ACTION_FOUND and ACTION_CLASS_CHANGED intents.
You should use getParcelableExtra() instead. That should give you an instance of the correct class out. Like so:
BluetoothClass bclass = (BluetoothClass)intent.getParcelableExtra(BluetoothDevice.EXTRA_CLASS);

SharedPreferences - Android (different data types)

I have a problem with with sharing data between two different activities. I have data like :
int number
String name
int number_2
int time
int total
I'm trying to make something like order list with this set of data . So it will take one set of data , then back to previous activity , move forward and again add data to it .
I have an idea of making it in array of object - but data inside was cleared after changing activity.
How can I make it ?
I don't know if and how to add Array of object to SharedPreferences , and get value of one element from there.

You should have a look at the documentation of the Intent(s) if you want to do that on the fly associating a key to the value(s) that you want to pass to your second activity.
Anyway, you can think any(sharedpref, database,...) way to pass your parameters but for those kind of things it's a convention and a good practice to follow that.

Don't used share preferences for this...Use the singleton pattern, extend Application, or just make a class with static variables and update them...
You can use .putExtra but since you are communicating with more than one activity the above suggestions are probably the best.
public class ShareData {
private String s;
private int s;
private static ShareData shareData = new ShareData();
private ShareData(){}
public static ShareData getInstance(){ return shareData}
//create getters and setters;
}

Why not to use Intents
Intent intent = new Intent(FirstActivity.this, (destination activity)SecondActivity.class);
intent.putExtra("some_key", value);
intent.putExtra("some_other_key", "a value");
startActivity(intent);
in the second activity
Bundle bundle = getIntent().getExtras();
int value = bundle.getInt("some_key");
String value2 = bundle.getString("some_other_key");
EDIT if you want to read more about adding array to shared preferences check this
Is it possible to add an array or object to SharedPreferences on Android
also this
http://www.sherif.mobi/2012/05/string-arrays-and-object-arrays-in.html

Basics ---> Checking strings using if else to set value of an int, possible wrong use of onResume

So I'm still working on my first little app here, new to Android and Java, so I'm stuck on a basic little problem here. Answers to my first questions were really helpful, so after researching and not coming up with anything, I thought I'd ask for some more help!
The idea is that on another screen the user makes a choice A, B, C, or D, and that choices is passed as a string through the intent. OnResume checks if the choice is not null and sets an integer that corresponds to that string. Later when the user pushes another button, some if else logic checks that int and performs and action based on which was chosen. The problem is that the App crashed at onResume.
I learned that I have to use equals(string) to compare string reference, but maybe the problem is that I am trying to compare a string in reference to a literal string? Any help would be greatly appreciated.
Thanks!
protected void onResume() {
super.onResume();
// Get the message from the intent
Intent intent = getIntent();
String choice = intent
.getStringExtra(ExtensionSetupSlector.TORQUE_SETUP);
// Create the text view
TextView displayChoice = (TextView) findViewById(R.id.displayChoice);
if (!choice.equals("")){
displayChoice.setText(choice);
if (choice.equals("A")) {
myChoice = 1;
}
if (choice.equals("B")) {
myChoice = 2;
}
if (choice.equals("C")) {
myChoice = 3;
}
if (choice.equals("D")) {
myChoice = 4;
}
}
}
myChoice is declare right after ...extends Activity{ Also I'm not quite sure If this should really be in onResume, but it was working before I started try to set myChoice in the onResume (when I was just displaying the choice). Thanks again!

Change if (!choice.equals("")) to check for null instead. Otherwise your app attempts to access an empty reference and crashes.

Passing multiple data to an Activity?

I'm trying to pass multiple data items in one Intent:
if (strActStat == "Sedentary") {
// passactStat.putString("keySedentary", strActStat);
// passSeden.putString("keyMale", gender);
i = new Intent(CalorieTrackerTargetWeight.this, TargetWeightResults.class);
i.putExtra("keyGender", gender);
i.putExtra("keyAct", strActStat);
//i.putExtra("keyAct", strActStat);
startActivity(i);
}
Why doesn't this work? Why can't I pass multiple items in one Intent?

You can't compare strings with ==.
if (strActStat.equals("Sedentary")) { // should work
Edit:
#Hesam has written a pretty detailed answer but his solution is not really usable. Instead of using an ArrayList<String> you should stick with the putExtra(key, value). Why? Well there are some advantages over the ArrayList solution:
you are not limited to the type of the ArrayList
you are not forced to keep a static order in you list. As you can only work with index values to get a list you need to make sure that the put() was in the same order as get(). Think of the following case: You you often send 3 values, but in some cases you don't want to send the second value. When you use the ArrayList solution, you end up sending null as the second value to ensure that the third value will stay in his place. This is highly confusing coding! Instead you should just send two values and when the receiving activity tries to receive the second value, it can handle the returning null like it want... for example replace it with a default value.
Naming of the key will grant you the knowledge of always knowing what should be inside...
Your key should be declared in the receiving Activity as a constant. So you always know by looking at this constants what intent data the activity can handle. This is good programming!
Hope this helps in clarifying the intent usage a bit.

I think this is not the only problem, first, if (strActStat == "Sedentary") this is wrong. you can't compare to string in this way. Because in this way objects are comparing not the string. Correct way is if (strActStat.equalIgnoreCase("Sedentary")).
If you use Parcelable then you can pass multiple data in just 1 intent.
Also you can use ArrayList<String>.
Here is a skeleton of the code you need:
Declare List
private List<String> test;
Init List at appropriate place
test = new ArrayList<String>();
and add data as appropriate to test.
Pass to intent as follows:
Intent intent = getIntent();
intent.putStringArrayListExtra("test", (ArrayList<String>) test);
Retrieve data as follows:
ArrayList<String> test = data.getStringArrayListExtra("test");
Hope that helps.

Try this:
done.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
namevalue=name.getText().toString();
overvalue=over.getText().toString();
audiostatus=audio.getText().toString();
Intent intent=new Intent(Settings.this,home.class);
Bundle bundle = new Bundle();
bundle.putString( "namevalue",namevalue);
bundle.putString("overvalue",overvaluse);
bundle.putInt("value",variablename);
intent.putExtras(bundle);
startActivity(intent);
}
});

I faced the same problem.
My mistake was that one of the variable I was transferring was not initialized.
Like gender or strActStat in your case.

programming style with modal dialog

in my android application at some event in an activity I want to ask the user for a name (string). I know how to do this: call showDialog, create the dialog in the Activity.onCreateDialog method (I need to supply a string for the label) and handle the result in the onClick of the dialog. This works fine and to my satisfaction.
BUT this way I have three different places, where this simple task spreads throughout the code of my activity. I would much more prefer to keep this code together, to write some code like this:
string result;
if (showSimpleEditDialog(idForLabelString, result)==DIALOG_OK)
{
// do something with the result
}
or maybe with a class instance
SimpleEditDialog dlg = new SimpleEditDialog(idForLabelString);
if (dlg.showModal()==DIALOG_OK)
{
string result = dgl.getResult();
// do something with the result
}
(The "idForLabelString" would be some resource id for the label to use, DIALOG_OK would be some constant returned when the user clicks OK)
I know, I would have to write this methodes or this class. But for better readibility of my code I would do it. Any suggestions?
Thank you,
Gerhard

"BUT this way I have three different places, where this simple task spreads throughout the code"
So why don't you create a Method for this task? What you are talking about sounds like some sort of 'ActionListener' to me. This can be done in Java/Swing, but not in Android.
But, if you have three Dialogs, which all need to do the same when "YES" e.g. "NO" is pressed, you could define the 'DialogInterface.OnClickListener()' as a global inner-Class (or in a second class which extends the 'onClickListener') and then use it for all the Dialogs.

Now actually the problem with modal dialogs is mostly a problem with programm flow. You want to keep things together that belong together. You want to display a dialog that returns "ok" or "cancel" and additionaly e.g. a string that the user entered into one of the dialog widgets.
I do not want to write half of the code up to the line where I need the result of the dialog on one place and the rest of the code on another place namely the onClickListener of the dialog.
In some scenarios the first dialog might invoke a second dialog e.g. to specify a color which is not in the list of the first dialog's ListView.
Your code will be scattered all over the place (in each dialog's button onClickListener) and will be hard to read or to maintain.
Now after having written some unclear code like that I came up with the following solution which certainly respects the android design guides.
Instead of directly showing a dialog I create a Handler derived class which handles messages.
I send it a first message which creates and shows a dialog. It also forwards the handler to the dialog and the diaolg in it's onStop method sends another message to the handler, indicating the end of the dialog. There you can examine the dialogs properties, the contents of the edit fields or whether it was stopped with OK or CANCEL.
Now in the message handler all the logic of the task sits in different cases of the messages arg1 value.
Some cases might be skipped (e.g. the user selected a standard color and did not need a special color dialog).
The dialogs are independant of the scenario from which they are called and in their code only reflect their simple task (selecting from a list, some checkboxes etc.). They may be reused from other scenarios.
Following a kind of a template how to use this approach:
public class DoSomethingWithDialogs extends Handler
{
Context context; // from which it was called
final static int stepBegin = 0;
final static int stepNext = 1;
final static int stepSomethingElse = 2;
final static int stepLast = 3;
protected DoSomethingWithDialogs(Context context)
{
this.context = context;
}
public static void start(Context context)
{ // this is the main (only) entry point from outside
DoSomethingWithDialogs st = new DoSomethingWithDialogs(context);
st.sendMessage(st.obtainMessage(0, stepBegin, 0));
}
#Override
public void handleMessage(Message msg)
{
// step by step handling the task
switch (msg.arg1)
{
case stepBegin:
{
SomeDlg somedlg = new SomeDlg(context, this, stepNext);
// when the dialog closes, it sends a message to this with stepNext as arg1
somedlg.show();
}
break;
case stepNext:
{ // this message was send by the dialog when it finished
SomeDlg somedlg = (SomeDlg) msg.obj;
if (msg.arg2 == Dialog.BUTTON_NEGATIVE)
{
// has been canceled, nothing to do
} else
{
if (somedlg.someProperty)
{
} else
{
sendMessage(obtainMessage(0, stepSomethingElse, 0));
}
}
}
break;
case stepSomethingElse:
break;
}
}
}