I have question for receive value in smartwatch. Currently I follow this steps from this question
Actually,the person who ask it has the answer how to do that, but since my reputation for comment is not enough, so I can't ask question by comment in his/her question.
Right now, based on Mr. Eir,the person who answered the question. I have problem in what he answered:
You also want to pass some arguments to your Extension, i.e. the
String you mention. This can be a bit tricky; normally, you would pass
that String in the Intent itself, as an extra, but here, that is not
available. You need to save that information (the String) on a
location that your Extension can access as well. So, if your Activity
and your Extension are part of the same app, that location can be the
app preferences: the Activity saves the value in the preferences, and
the Extension reads it from the same preference and displays it on the
SmartWatch or whatever.
He said that I can save the value in preference and the Extension reads it from the same preference and displays it on the SmartWatch. Unfortunately, I don't know how the extension reads it. I have try to put the value in samplepreferenceactivity:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedPreferences settings = getSharedPreferences("SHARED_PREFS_FILE",0);
String message = settings.getString("send", "message");
}
I don't know how to put the value in controlextension class, If it possible to put, I want to you use for changing "Hello watch". Below you can find controlextension class:
public class HelloWatchExtension extends ControlExtension{
...
public HelloWatchExtension(Context context, String hostAppPackageName) {
super(context, hostAppPackageName);
width = getSupportedControlWidth(context);
height = getSupportedControlHeight(context);
layout = new RelativeLayout(context);
textView = new TextView(context);
textView.setText("Hello watch!");
textView.setTextSize(9);
textView.setGravity(Gravity.CENTER);
textView.setTextColor(Color.WHITE);
textView.layout(0, 0, width, height);
layout.addView(textView);
}
Since it is not activity, so it is n't possible to take by using getpreference. Anybody knows how?
"Since it is not activity, so it is n't possible to take by using getpreference. Anybody knows how?"
You can access the preferences through context:
context.getApplicationContext().getSharedPreferences(...);
A few pointers about using shared preferences:
SharedPreferences preferences = _context. getApplicationContext().getSharedPreferences("com.example.AppName", Context. MODE_MULTI_PROCESS);
Putting string in shared preferences:
_preferences.edit().putString(“OBJECT”, “object_name”).commit();
Retreaving string from shared preferences:
_preferences.getString(“OBJECT”, "default_name");
If you are just trying to pass a string between an Activity in your project and your ControlExtension you don't need to use SharedPreferences. The easiest way is to just register a dynamic BroadcastReceiver in your extension and broadcast an Intent from the Activity passing your string inside the Intent.
Related
This is a real noob question I'm sure, but I am finding it quite perplexing.
Why an earth would you want to ever use intent.putExtra method to share information between classes in Android?
Let me explain. I am making my first Android app following the instructions from the developers guide (I am already at a moderate level with Java) and I am using some code that looks like this:
//Class field
//key holds string????? not fully understanding this...
public static final String EXTRA_MESSAGE = "self.anon.myfirstapp.MESSAGE";
//this method is activated by a button being pressed
public void sendMessage(View view) {
Intent intent = new Intent(this,DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
//puts string message inside the string EXTRA_MESSAGE - why????
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
OK firstly I want to point out I see what is happening and for the most part how it works (am just confused by the field declaration = "myClassPath" why?)...
BUT....
Surely it would be easier just to have a static field called:
public static String message;
then my method would look like this:
public void sendMessage(View view) {
Intent intent = new Intent(this,DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
message = editText.getText().toString();
startActivity(intent);
}
Then when my class DisplayMessageActivity needs the string message he just calls for:
String message = myClass.message;
That seems so much more straight forward. What is with the creation of the new string EXTRA_MESSAGE which just seems to hold the string message and why send it with the intent when my other class can access this info directly anyway -- and what does the field declaration with the "self.anon.myfirstapp.MESSAGE" mean? I can find no such folder or path leading to anything.
As someone else stated there are often situations (such as a screen rotate) in which the android system destroys and restarts the app - so all variable data is lost. It would only work consistently the way you suggest if your data is hard coded as a final variable. That is not the only reason for using intents though.
The great thing with using an intent to pass information is that you can use the intent not just to communicate with sub-activities within your own application but to any activity installed on that android system. For example you may want to launch an intent which starts the phone application and include as an extra the number that you want to call.
Perhaps a better question than yours though is "why would you not use intents to pass information?" The intent.putExtra() method allows you a convenient flexible and straight forward method to pass as much information as you like in a safe and secure way to any other activity.
intent.putExtra(EXTRA_MESSAGE, message);
works like a key value pair, when you want to retrieve the information from the intent you can simply do intent.get<type>Extra and get said information, in this case, intent.getStringExtra("self.redway.myfirstapp.MESSAGE'). its simply the key to retrieve the information, it does not have to be your entire classpath.
it could just as easily be intent.putExtra("message",message).
They are helpful when passing information that you don't necessarily want to reveal to another class but you do want it to be able to get that information in another manner from what i have found.
message = myClass.message It is not always certain that this will retain its value especially when it extends Android framework classes like Activity. When your activity is recreated(change of screen orientation) then message can lose its current value and be assigned a default value. myClass.message would work if message was a static field or else you would need to provide getter and setter methods for object of the Activity Class. Well creating objects of activity class is unheard of in my experience.
I'm developing an app that has to share strings between activities. I'm trying to get the seperate activities to call a public class with set and get methods. The calling the methods part works and I manage to get a response although the set value has to be rememberd by the set and get class. Here's a link to my set and get class, it's pretty basic: http://pastebin.com/0WabNKz3
Now my question is this: How do I make the set and get class to remember my values between sessions? Feel free ask questions if there's anything you didn't understand.
Thanks!
You need to use SharedPreferences. That's the way to save data even after the app is closed and you can access it from anywhere:
public void savePrefrences(String key, String value)
{
SharedPreferences prefs = context.getSharedPreferences(context.getPackageName(), 0);
prefs.edit().putString(key, value).commit();
}
public String getPrefrences(String key)
{
SharedPreferences prefs = context.getSharedPreferences(context.getPackageName(), 0);
return prefs.getString(key, "");
}
Save the prefrence when and whereever you want and get it whenever and from wherver you want.
The value will not delete when you close the app.
I ended up creating invisible EditTextPreference that now hold the data that I want to keep because they can be shared easily.
When you say saving between sessions, do you mean between the app being paused, or closed completely?
A good resource for lifecycle and storing data across sessions is:
//developer.android.com/training/basics/activity-lifecycle/index.html
I’m a new developer, so my question maybe too much basic.
I look for example of defining preferences of sound. User can choose what kind of sound will start an application, for example. There can be such a RingtonPreference widjet, so user can choose a sound.
As I know, preferences support the primitive types: Boolean, string, float, long and integer. What way is the best to design preferences: store in entryValues the names if sounds (strings), the address of files from Resourse class (integer), or other way.
Please provide a short example of code.
Thanks in advance!
First of all thank you for the quick and detailed answer!
I want to arrange list of sounds: there must be one “None”, list of sounds that contains folder “raw”, option to add a new sound from different locations and two buttons: “set” and “cancel”. When user touches one item from the list – sound starts to play.
There is a little problem with standard widget that provide android library. “ListPreference” isn’t appropriate because on touch on one of the items – item is chosen and list closes, “there are not buttons set and cancel”.
“RingtonPreference” isn’t appropriate as well – I didn’t succeed to add something to list.
How is possible to build a custom preference layout and that is options that were chosen will be saved as well as on standard widgets. Please provide a short code example. Thanks in advance!
I think the best way to store the Resource are by integers. or you could do names.
I think integer is more reliable.
So to use SharedPreference with this you will need to get access to the apps SharedPreference
public class PreferencesDemo extends Activity {
SharedPreferences app_preferences;
private int resourceNumber;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Get the app's shared preferences
SharedPreferences app_preferences = PreferenceManager.getDefaultSharedPreferences(this);
resourceNumber = app_preferences.getInt("resourceNumber", 0);
if(resourceNumber == 0){
//This means the user hasnt selected a song and you must act accordingly. Or put a resource number where the 0 is do set it to a default song
}
You will probably want to create a method to put the songs in the SharedPreference such as;
private void createSongResouces(){
SharedPreferences.Editor editor = app_preferences.edit();
//Here you can put as many songs as you want just make sure you call editor.commit(); as i do.
editor.putInt("resourceNumber", resourceNumber);
editor.commit(); // Very important
}
In my app I have 5 String arrays that represent different fields of objects.
i.e.
String_A[1],
String_B[1],
String_C[1],
String_D[1],
String_E[1],
All are attributes of the same object (which is not really an object).
Now I want to store those in order to be able to use them in a new activity that I am creating. Since you are not able to pass objects around I thought that i should save them in Shared preferences.
My question is: Should I save them as separate strings or create a new class with all those fields and then serialize the objects?
Which is the best way in terms of memory usage? In fact is there any other way that you might achieve similar functionality?
Thanks in advance
Mike
If each of those String Arrays are big "enough" and it appears you do want to store them - have you considered Sqlite? SharedPreferences is most effective to store primitive data in key-value pairs. Check this link - it has neat comparison about the options you have - http://developer.android.com/guide/topics/data/data-storage.html
You can pass around objects via an intent. The extras function of an intent can store a bundle and send it to specified activities, however they cannot be called at any time (like from a later activity without being explicitly sent). If this is a one time pass to a different activity, the you'd probably want to use that.
http://developer.android.com/reference/android/content/Intent.html#putExtras%28android.content.Intent%29
Here is an example from a test app I made a while back:
public void onClick(View v) {
switch(v.getId()) { //this references the unique ID of the view that was clicked
case R.id.Button01: //this is what happens when the Button in the XML with android:id="#+id/Button01" is clicked
Intent nameGreet = new Intent(this, MainMenu.class);//creates Intent which will send the EditText input
String theName = firstName.getText().toString();// creates a new string named "theName" which is the text from an EditText called "firstName"
nameGreet.putExtra("helloName", theName);//puts the input from EditText into the Intent, this is a key/value pair
this.startActivity(nameGreet);//setting off the Intent
break;
Then you catch it like so:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main_menu);
String personsname = this.getIntent().getStringExtra("helloName");
welcome = (TextView)this.findViewById(R.id.TextView01);
welcome.setText(personsname);
Hope this helps.
You can pass a Serializable using an Intent.
Intent.putExtra(String name, Serializable value).
i have created a live wallpaper and in that there is a "setting" button which loads PreferenceActivity but without clicking on "settings" but i want to access the SharedPreferences within subclass of Engine or WallpaperService. As i just want to access the small single string so i don;t want user to go into settings and access that string.
So i want to execute this code inside Subclass of Engine or WallpaperSerivce
SharedPreferences mPrefs = getPreferenceManager().getSharedPreferences();
String option = mPrefs.getString(
this.getResources().getString(R.string.name),
this.getResources().getString(R.string.option));
It is not the best way to do it I'm sure but I use getters and setters to achieve this effect.
private int mySetting = defaultvalue
public int getMySetting() {
return mySetting;
}
public void setMySetting(int mySetting) {
this.mySetting = mySetting;
}
I obviously used some plain text in that code but hopefully it is pretty self explanitory
You set this variable while in Settings Class with...
Settings.this.setMySetting(value);
Remove "this" to call from other classes
You can retieve this information in any of your classes using the following
Settings.getMySetting();
You can use pretty much any variable type just make sure you define the mySetting variable as that type before trying to pass a value other than int as in this example. Hopefully this helps.