Develop Reference

Change ObjectBox LiveData Query

I have an ObjectBoxLiveData object with a query that is set at runtime:
private ObjectBoxLiveData<MyObject> myObjectLiveData;
public ObjectBoxLiveData<MyObject> getMyObjectLiveData(Box<MyObject> myObjectBox, String filterTerm)
{
if (myObjectLiveData == null)
myObjectLiveData = new ObjectBoxLiveData<>(myObjectBox.query().equal(MyObject_.filterProperty, filterTerm).build());
return myObjectLiveData;
}
But I also need to be able to change the filterTerm at runtime. My thinking is that I can make a private String currentFilterTerm; object in MyViewModel to see if I need to update the filter term in the LiveData object, but is there a correct way to update the filter term? I worry that setting myObjectLiveData = new ObjectBoxLiveData<> again will leave a memory leak for the previously defined myObjectLiveData or anything tied to it, but I don't see any graceful way to dispose of it or update the query once defined. Is there a way to redefine my query once defined?

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

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.

Save and read int - android

I'm making a settings screen using an int to set the background of my app. It works just fine... inside the current activity. But as soon as I leave the activity, the int value is lost and the background isn't changed.
what I want to do: I want to save the int from my settings activity, and then import it to my other activites and check if the int "bak" equals null, "bg", "bg1" or "bg2".
I've heard of sharedPreferences but never got it working. That is why I open a new thread.

OK, add these global variables
SharedPreferences data;
public static String filename = "whateveryou want";
initialize it in onCreate
data = getSharedPreferences(filename, 0);
then to add something to it, use this, with "key" being a unique descriptor and name being the variable name you want to store
SharedPreferences.Editor editor = data.edit();
editor.putInt("key", name);
editor.commit();
access it by this, where default is what you want the variable to be assigned if no preference exists.
intVariable = data.getInt("key", default);
EDIT:
I noticed you want to use letters, eg bg1 etc. To do that you need to use a String, or use an int with a switch case or multiple if statements. Here's a switch case example you can modify. Just make sure to put the switch case statement after you access the SharedPreference in the previous code block.
switch (integerVariable){
case 1: // if the intagerVariable = 1, notice the : not a ;
// set background to BG1
break;
case 2: // if the intagerVariable = 2, notice the : not a ;
// set background to BG2
break;
}
Just add as many case statements as needed.

How to use a single intent with multiple buttons

I have an android context menu with various selections and depending on the user selection I want to start an intent. The intent starts the same activity for all the buttons but will contain different String variables depending on the selection. I am currently using a switch, case methodology for my click listener but keep running into 'duplicate local variable' problems as I try to eliminate code repetition! If anyone could provide a-bit of pseudo-code that would be even better!

It's hard to tell without seeing some code, but "duplicate local variables" together with "switch case" makes me think you're declaring a variable in one of the cases with the same name as a variable from another case.
Code within different cases of the same switch is all in the same scope, unless you surround the code within a case with brackets, like this:
switch(VALUE) {
case A: {
String string = "";
}
case B: {
//Same variable name, possible since it's in a different scope now.
String string = "";
}
}
So either use brackets, or simply make sure you're using different variable names across the cases.

you can use intent.putExtra(String name, String value) and push it to the other activity.
Pseudo code:
Button1.value = "X" ;
Button2.value = "Y" ;
onClickListner(View v) {
Intent intent = new Intent() ;
intent.putExtra("ButtonValue",
v.value() ) ;
// extra code goes here...
}
Hope this is what you were looking for..
VInay

I like to use set/getTag(Object), as you can put any type you like into it (as long as you're careful about getting it out again):
button1.setTag(MyClass.STATIC_INT_1);
button2.setTag(MyClass.STATIC_INT_2);
button1.setOnClickListener(Click);
button2.setOnClickListener(Click);
private OnClickListener Click(View v) {
Intent intent = new Intent() ;
intent.putExtra("Value", Integer.parseInt(v.getTag().toString()) ) ;
···
}