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Changing background in other activities with a button

I have a problem. I have 3 activities (MainActivity, DetailsActivity, SettingsActivity) and in SettingsActivity I have a Togglebutton "Nightmode". What I want is, when the button is changed, change background of all three activities on gray color.
public class SettingsActivity extends AppCompatActivity {
//This is SettingsActivity(not Main one)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_settings);
TextView SettingsTitle = (TextView) findViewById(R.id.SettingsTitle);
TextView NightText = (TextView) findViewById(R.id.NightmodeText);
ToggleButton toggleNightMode = (ToggleButton) findViewById(R.id.toggleNightmode);
final RelativeLayout NightBG = (RelativeLayout) findViewById(R.id.NightBG);
final LinearLayout DetailsBG = (LinearLayout) findViewById(R.id.mainBG);
final LinearLayout HomeBG = (LinearLayout) findViewById(R.id.HomeBG);
toggleNightMode.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
NightBG.setBackgroundColor(Color.parseColor("#545657"));
HomeBG.setBackgroundColor(Color.parseColor("#545657"));
DetailsBG.setBackgroundColor(Color.parseColor("#545657"));
}
});
NightBG is in the same activity as that java file (SettingsActivity). But HomeBG is in MainActivity and DetailsBG is in the DetailsActivity. Everytime I start the app, and press on that button, app craches. If I delete HomeBG and DetailsBG from this file, it works just fine with changing current layout's color to gray. Please help me.

One easy way to store little settings like this across multiple activities that may not be open/active at the time of the button click would be to use SharedPreferences.
It might be a little overkill for such a simple piece of code but you can always give it a try if you don't find anything else.
Your code could look something like this:
toggleNightMode.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Set the color of this activity
int color = Color.parseColor("#545657")
View view = SettingsActivity.this.getWindow().getDecorView();
view.setBackgroundColor(color);
// Save color preference
SharedPreferences sharedPref = SettingsActivity.this.getSharedPreferences("bgColorFile",Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putInt("color", color);
editor.apply();
}
});
And then when you open your activities you place something like this in the onStart() or onCreate() method of your activity:
// Get the color preference
SharedPreferences sharedPref = getSharedPreferences("bgColorFile",Context.MODE_PRIVATE);
int colorValue = sharedPref.getInt("color", 0);
View view = this.getWindow().getDecorView();
view.setBackgroundColor(colorValue);
So what you're actually doing is storing the background color as persistent data and fetching it once you reopen/open the activity that you want to have the color on. The benefit of this method is that whenever you close your app the preferred background color will be remembered. I hope this helps.

Change background for current activity in the same activity. Since DetailsActivity is not running, you can't do that, it gives you null pointer. Is kind of you are trying to eat 3 apples and you have just one. After current activity is started, change background.
Update:
You can do that in current activity and just in current activity:
findViewById(android.R.id.content).setBackground(getColor(R.color.your_color));
Don't try to call this in other activities that are not running.
setBackground()
or
setBackgroundColor()

If your other activities are open, you should send a message to the other activities by using an Intent.
How to send string from one activity to another?
When you receive the Intent you could then set the background of the activity.
If your other activities are not open yet, you will not be able to send an Intent to them. In this case you could have each Activity reference a static value in your main activity that could contain the current background color. You would want to reference that value on the other activities on create functions.
Here is an example on how to reference a variable from another activity.
How do I get a variable in another activity?
This might not be the most pretty way to handle it but it should work.

as Ay Rue said you have 2 options: use static variable for that button, and then in onResume of each activity, check the value of the static variable (true or false). or you can save a private variable nightMode and then pass this value in the intent when you need to move to the other two activities.
don't set the background color if you already set before and have an updated background color.

OnClickListener in custom dialog

This is what is working correctly
>>The user swipes on a part of the main activity ui we will call the MainTitleBar.
>>This creates a dialog with stuff in it
=----------------------------------------------------------------------------=
Now I need to make it so when someone clicks on the buttons or imageviews within that dialog STUFF happens. I cannot figure out for the life of me how to handle this.
Code I have currently inside the maintitlebar.java class (which extends view) and is the view they are swiping on to create the dialog box.
--- bunch of stuff like ui stuff and swipe calculations etc
public void onDownSwipe() {
// custom dialog object created
Dialog ntd = new Dialog(getContext(),R.style.lightbox_dialog);
ntd.setContentView(R.layout.create_task_dialog);
ntd.show();
ImageView cancelbutton = (ImageView) ntd.findViewById(R.id.cancelbutton);
cancelbutton.setOnClickListener(new OnclickListener(){
public void onClick(View v) {
ntd.dismiss();
}
}
);
In the xml for the dialog, the create_task_dialog is the overall xml for the dialog.
the cancelbutton (id) is the id for the cancel button (which is properly added with + sign into resource file).
Should I be putting the onclicklistener and clicky stuff somewhere else in my code?
So confused as to how to make my dialog buttons/imageviews clickable.
THANKS!

How to use a button to show a custom dialog in android application?

I am following a youtube tutorial and I've got most of the works done, but I still got some problems.
I have my custom layout for my custom dialog, all I wanted to do is to set the custom dialog on a button. Once we click the button ,the dialog shows, that's it. I've already set the onclicklistener on the button, here's my code.
Credit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Dialog credit = new Dialog(Main.this);
credit.setContentView(R.layout.creditdialog);
credit.setTitle(" ");
credit.show();
}
});
I followed all of this on a tutorial, but I don't know that the "MAIN" is about, I got an error there. Please tell me what to do. Sorry for my poor English.

new Dialog(Main.this);
The above line creates a new dialog object and associates it with the context of your Activity. SO you have to pass the context of your activity in the paranthesis..
Eg:
If you are calling the dialog from Activity "ActivityMain".. then use:
new Dialog(ActivityMain.this);

try this
Credit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Dialog credit = new Dialog(getApplicationContext());
credit.setContentView(R.layout.creditdialog);
credit.setTitle(" ");
credit.show();
}
});

it is common question! but you can extend dialog box and can set custom layout for your dialog than on button click just call dialog like this:
new CustomDialog(activity).show();
also you can follow this tutorial on custom dialog to understand how to customise dialog and how to use it on button click.
http://www.shaikhhamadali.blogspot.com/2013/09/types-of-dialogbox-part-two-custom.html

opening the same dialog from a list in android

I have a listActivity with many items.
For each item, I want to open the same popup while sending an item id\position\other
info object unique to that item.
But basically all the time I open the exact same popup.
Its buttons will send the extra unique data to the server.
I have read few tutorials, and saw a dialog is usually opened like this:
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.custom);
dialog.setTitle("Title...");
// set the custom dialog components - text, image and button
TextView text = (TextView) dialog.findViewById(R.id.text);
text.setText("Android custom dialog example!");
ImageView image = (ImageView) dialog.findViewById(R.id.image);
image.setImageResource(R.drawable.ic_launcher);
Button dialogButton = (Button) dialog.findViewById(R.id.dialogButtonOK);
// if button is clicked, close the custom dialog
dialogButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
}
});
dialog.show();
}
I think it's more readable to create a different file to the dialog.
like this:
public class SocialActionsDialog extends Dialog {
public SocialActionsDialog(Context context) {
super(context);
mContext = context;
}
Context mContext;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.social_actions);
setTitle("Title...");
}
but then I get a syntax error on the OnCreate.
Is it common and good practice to create new file? and if so- how to do it properly?
is it more efficient somehow - just showing the same dialog instead of initializing a new one each time? or is both ways the same?

For the syntax error, make sure you are importing the R class from your app and not the Android SDK class R resources.
For an experienced programmer your instinct is to move the dialog to a separate file, especially if it contains a lot of code. And that can be the right decision at times.
However, it is often convenient to have the dialog as an embedded class or to just create it inline (as in your example) because then it is within the scope of your activity and can access your state variables and protected methods on the Activity itself.
So you end up passing all this information to the dialog if you have it in a separate file, and at some point it just isn't worth it because the code becomes more complex and less maintainable.

Custom AlertDialog fails to initialize in onCreate()

I'm trying to build a custom AlertDialog by extending the AlertDialog class.
As usual, I'm setting up the dialog inside its onCreate() method. Or, I'm trying to do so:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setTitle("Some title");
this.setButton(BUTTON_POSITIVE, "Click me", (DialogInterface.OnClickListener)null);
final FrameLayout custom = (FrameLayout) this
.findViewById(android.R.id.custom);
custom.addView(this.getLayoutInflater().inflate(R.layout.mydlg, null),
LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
}
Now, when it comes to displaying an instance of this dialog, nothing is shown. The current Activity fades out and loses focus but not a single pixel of my dialog is displayed. Pressing Back brings the Activity back to the foreground, indicating to me that a dialog actually is shown, but just a completely empty one.
However, when I create an AlertDialog and use, for instance, dlg.setButton(BUTTON_POSITIVE, "Click me", (DialogInterface.OnClickListener)null);
the dialog is shown with the respective button.
Even when I set up my custom dialog in its constructor using the very same code as above everything seems to work ok.
Now, how can this be? Why can't I seem to initialize my dialog in its onCreate() method? Isn't this the way you're supposed to initialize any GUI element? What am I missing?
EDIT
Please note, that something is 'shown', fading out the Activity and taking focus from it. It's just that it seems to be completely empty/invisible.
Here another attempt:
this.setTitle("Some title");
this.setButton(BUTTON_POSITIVE, "Click me", (DialogInterface.OnClickListener)null);
final View v = this.getLayoutInflater().inflate(R.layout.mydlg, null);
this.setView(v);
These exact lines do work when put into my dialog's constructor.
These exact lines do not work when put into my dialog's onCreate().
What is going on here?!
Generally, am I not supposed to do it in onCreate()? - Am I facing trouble if I resort to doing the above initialization in the constructor instead? (This does not seem too clean to me, anyway.)

You need to call the show() method in order to see something.

You should consider using AlertDialog.Builder instead of subclassing AlertDialog itself. It allows you to do all the things you need in your example (in order: setTitle(),setPositiveButton() and setView() ). Don't forget to call create() at the end to actually get your dialog.
Also, check if your onCreateDialog() and onPrepareDialog() activity methods are implemented correctly. If you don't have them implemented at all (an unmanaged dialog), consider doing that anyway, especially if your app allows for orientation changes. You probably know about this, but here is a tutorial:
http://developer.android.com/guide/topics/ui/dialogs.html
also, DialogFragments are a bit easier way to implement this, but you need a newer API version or the Compatibility package:
http://developer.android.com/reference/android/app/DialogFragment.
One final issue - where are you calling show() in your activity? onResume() should be OK, onCreate() not as much.

Sorry I'm late to the party :)
You have to thing differently for the alert dialog.
The way I did it is to customize the view before creating the alert dialog:
// This is the activity that is the background of the AlertDialog
public class Main extends Activity {
public static final int DIALOG_CONFIG = 1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.emptybackground);
}
#Override
protected void onStart() {
super.onStart();
// Open the alert dialog on openning the Activity
showDialog(Main.DIALOG_CONFIG );
}
protected Dialog onCreateDialog(int id) {
LayoutInflater factory = LayoutInflater.from(this);
switch (id) {
case DIALOG_CONFIG:
// Here, we load the existing view R.layout.config
configView = factory.inflate(R.layout.config, null);
configDialog = new AlertDialog.Builder(this)
.setTitle("Configuration")
.setView(configView)
.create();
// Using configView, you can do whatever you want with the view. Here, we add value to a spinner.
Spinner spinner = (Spinner)configView.findViewById(R.id.config_select_conn);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
adapter.add("TCP");
adapter.add("Bluetooth");
spinner.setAdapter(adapter);
return configPrinter;
}
return null;
}
}

you should call custom_alertDialog.create(); before custom_alertDialog.show();