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Change background color of another activity with button

I have two activities main and settings. I want to change the background color of the main using a button that's on settings. I tried using RelativeLayout and get the layout of the main using the id and changing the color when touching the button but it doesn't work. I also tried doing with Intent but I don't know how to do it. Got the code for the settings activity below
public class Settings extends AppCompatActivity {
private Button changeColorButton;
private RelativeLayout layout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_settings);
changeColorButton = findViewById(R.id.changeColorButton);
layout = findViewById(R.id.mainLayout);
/** Called when the user taps the Settings button */
changeColorButton.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View V){
Intent intent = new Intent(Settings.this, Main.class);
startActivity(intent);
layout.setBackgroundColor(Color.BLUE);
}
});
}
}
Any help please?

You cannot change views of another activity like that.
You can send an 'extra' parameter with your Intent and read it on Settings activity. You can change the color based on the value you receive via the intent.
Or if its a more permanent setting, you can save it on SharedPreferences and read it on Main.

Causing an exception when setting 2 onClickListener() on buttons located on 2 different layout

I have a problem and I can't seem to set 2 onClickListener for 2 separate buttons located on 2 different layout, when running the program, it cause an exception to occur.
btnClickToSecondPage button is located in activity_main.xml layout and btnObjClickToGoToFirstPage button is located at second_activity.xml layout.
The java code for my program is located below here
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(getWindow().FEATURE_NO_TITLE);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
Button btnObjClickToGoToSecondPage = (Button) findViewById(R.id.btnClickToSecondPage);
Button btnObjClickToGoToFirstPage = (Button) findViewById(R.id.btnChangetoFirstPage);
btnObjClickToGoToFirstPage.setOnClickListener(
new Button.OnClickListener(){
#Override
public void onClick (View v)
{
setContentView(R.layout.second_activity);
}
}
);
btnObjClickToGoToSecondPage.setOnClickListener(
new Button.OnClickListener(){
#Override
public void onClick (View v)
{
setContentView(R.layout.activity_main);
}
}
);
} }
Please help me rectified the problem thanks.

Please implement the View.Onclick listener not Button.onclick listener
btnObjClickToGoToFirstPage.setOnClickListener(
new View.OnClickListener(){
#Override
public void onClick (View v)
{
setContentView(R.layout.second_activity);
}
}
);

It is not a proper way switching pages in Android. Use two activities for switching pages with intents.
Intent newPage = new Intent (this, YourActivityNameForNewPage.class);
startActivity(newPage);
Put above code in your button's onClick().

If you want to show a new page you either start a new activity or start a new fragment.
Changing the contentView is not the correct way to approach this and should not be done.
You refer to the documentation on activities here.
Assuming you have another Activity called SecondActivity here is how you would start it:
btnObjClickToGoToSecondPage.setOnClickListener(
new Button.OnClickListener(){
#Override
public void onClick (View v)
{
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
startActivity(intent);
}
}
);
And then you define the layout in the XML of the new activity, that is second_activity.xml
If they all have similar layouts using a fragment is also a good option.
Basically you start a new activity or fragment to show anything new or change the data dynamically say on your button's onClick().
This question may further clear your doubts:
What is setContentView(R.layout.main)?

Multiple buttons in single page navigating each button to different page in android studio

Please solve this problem in android studio, I am new to app development.
I want to create 3 buttons in a single page and navigate each button to each different page.
I need code for java i.e "Mainactivity.java"
I have declared 3 button id's
I have set everything in app manifest.
I am able to navigate only single button at once but how can I arrange all three buttons for navigation?
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button buttonWRGL = (Button)findViewById(R.id.buttonWRGL);
Button buttonHNK = (Button)findViewById(R.id.buttonHNK);
Button buttonKZP = (Button)findViewById(R.id.buttonKZP);
buttonWRGL.setOnClickListener(this);
buttonHNK.setOnClickListener(this);
buttonKZP.setOnClickListener(this);
}
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.buttonWRGL:
break;
case R.id.buttonHNK:
break;
case R.id.buttonKZP:
break;
}
}
}

Your question seems unclear, but I suppose that you are asking how to load another layout/activity/fragment by clicking on a button.
Well, it depends on which of the three actions you want to do:
1) in order to load another layout, you need to inflate the new layout in your view; in order to do that you need to clear the actual layout and inflate the new one.
Here's some sample code:
//you may change it to whichever layout you used
LinearLayout ll = (LinearLayout) findViewById(R.id.mainLayout);
//remove previous view
ll.removeAllViews();
//set the new view
setContentView(R.layout.new_layout);
2) in case you want to start a new activity, you need to use a Intent and load it.
Sample code:
//create the new intent; it will refer to the new activity
Intent intent = new Intent(this, NewActivity.class);
//pass any data to the new activity; cancel this line if you don't need it
intent.putExtra(extra_title, extra)
//start the new activity
startActivity(intent);
3) in case you want to change fragment, you need to perform a transaction.
Sample code:
//create the new fragment
Fragment newFragment = new MyFragment();
//start a fragment transaction
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
//replace the old fragment with the new
transaction.replace(R.id.frame, newFragment).commit();
Hope this helps; if not, try to edit your question in order to clarify what you mean.
EDIT:
You should add a new OnClickListener to each button, but I would do it differently than you are doing right now.
I would do something like this sample code:
buttonWRGL.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(this, NewActivity1.class);
startActivity(intent);
}
});
For each button. In this code, I directly attach a specific OnClickListener to the button; it will contain the intent that you need.
You can copy this in every button, even 10k buttons, you just need to change the activity name inside the intent declaration with the activity that you want to launch.

Simple tab activity in android

What i am trying to do::
BreakfastLunchDinnerIndividualListOfItems.java
public class BreakfastLunchDinnerIndividualListOfItems extends TabActivity implements OnTabChangeListener{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.breakfast_lunch_dinner_individual_list_of_items);
Resources res = getResources(); // Resource object to get Drawables
TabHost tabHost = getTabHost(); // The activity TabHost
TabHost.TabSpec spec; // Reusable TabSpec for each tab
Intent intent; // Reusable Intent for each tab
String REST = getTabHost().toString();
// Create an Intent to launch an Activity for the tab (to be reused)
intent = new Intent().setClass(this, BLD_IndividualListOfItems_Starters.class);
//intent.putExtra("Starters", REST);
spec = tabHost.newTabSpec("Starters").setIndicator("Starters").setContent(intent);
tabHost.addTab(spec);
// Do the same for the other tabs
intent = new Intent().setClass(this, BLD_IndividualListOfItems_MainCourse.class);
//intent.putExtra("MainCourse", REST);
spec = tabHost.newTabSpec("MAIN_COURSE").setIndicator("Main Course").setContent(intent);
tabHost.addTab(spec);
}
public void onTabChanged(String arg0)
{
// TODO Auto-generated method stub
//Toast.makeText(getApplicationContext(),arg0, Toast.LENGTH_LONG).show();
}
}
I tried with String REST = getTabHost().toString(); problem is that
on click of tab i am not able to send perticular tabtext to the
activity that the tab launches
I know tab activity is depricated, i am just learning
How to resolve this, hope i am clear

spec = tabHost.newTabSpec("Starters").setIndicator("Starters").setContent(intent);
spec = tabHost.newTabSpec("MAIN_COURSE").setIndicator("Main Course").setContent(intent);
here Starters and Main Course are the titles of tabs. The easiest way to send this strings to bounded activities is to send them throught intents which are bounded to corresponding
tabSpecs.
String TAB_TITLE="Starters";
Intent intent = new Intent().setClass(this, BLD_IndividualListOfItems_Starters.class);
Bundle bundle =new Bundle();
bundle.putString("key_title", TAB_TITLE);
intent.putExtras(bundle);
spec = tabHost.newTabSpec("Starters").setIndicator(TAB_TITLE).setContent(intent);
tabHost.addTab(spec);
And here is how you can get this string in BLD_IndividualListOfItems_Starters activity :
protected void onCreate(Bundle savedInstanceState) {
...
String title=getIntent().getExtras().getString("key_title");
}
But as Raghunandan says, it's better to use fragments instead of depracated TabActivity.
EDITED:
if you want to send text to corresponding activity dinamically, i mean exactly after tab is changed - you can:
create and broadcast custom intent with your string. (CUSTOM_INTENT_EXAMPLE)
in BLD_IndividualListOfItems_Starters activity register BroadcastReciever which will catch your custom intent and take text from it. (BROADCAST_RECIEVER_FROM_ACTIVITY_EXAMPLE)
You can't directly access tab text from BLD_IndividualListOfItems_Starters, because TabActivity and BLD_IndividualListOfItems_Starters are two different activities.
But you can send data between activities via bundles, static fields, singletons etc. Here is link to docs
http://developer.android.com/guide/faq/framework.html#3

How to initialize tab content when app is initialized

I have an app that has 2 tabs. Each tab loads an xml file (fairly large, maybe 400 item rss file).
By default the tab doesn't get the xml until it's clicked on. I simply wanted a way to load it all when the app is first opened.
Here is the main view:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Resources res = getResources(); // Resource object to get Drawables
TabHost tabHost = getTabHost(); // The activity TabHost
TabHost.TabSpec spec; // Resusable TabSpec for each tab
Intent intent; // Reusable Intent for each tab
// Audio Feed
intent = new Intent().setClass(this, AudioFeed.class);
spec = tabHost.newTabSpec("audio").setIndicator("",
res.getDrawable(R.drawable.ic_tab_audio))
.setContent(intent);
tabHost.addTab(spec);
// Video Feed
intent = new Intent().setClass(this, VideoFeed.class);
spec = tabHost.newTabSpec("video").setIndicator("",
res.getDrawable(R.drawable.ic_tab_video))
.setContent(intent);
tabHost.addTab(spec);
tabHost.setCurrentTab(0); //todo: remember what tab user was last on
}

I use TabHost.setCurrentTab(x) or TabHost.setCurrentTabByTag(x).
mTabHost.setCurrentTab(1);
mTabHost.setCurrentTab(0);
For Initialization I use TabHost.OnTabChangeListener.
private OnTabChangeListener mOnTabChangeListener = new OnTabChangeListener() {
#Override
public void onTabChanged(String tag) {
if (FBIntent.EXTRA_XX.equals(tag)) {
// Current tab is xx.
... if xx not init -> ...
} else if (FBIntent.EXTRA_YY.equals(tag)) {
// Current tab is yy.
...
}
}
};

In this same method do whats the other tabs do. I mean what the other do when you click them. So you have the same thing for all tabs. Don't forget to include this same tab in the OnTabChanged() method and do the same operations again, otherwise you'll get nothing when this tab is clicked again.