We Keep Coding

Why Design(activity_main.xml) and actual app look different?

i am new in Android development in java
my activity_main.xml file is look like this
But when i run this application in my pixel 3 phone than it's look's like
why this design are different ?

As seen in background, you ignore missing constraints. When working with ConstraintLayout you must provide at least one horizontal and one vertical constraint, otherwise views could jump, and I believe IDE gave u that error.

check your style file.
By default is with Dialog.
u can change it with No Dialog
Sorry i mean
the line
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
u can change the theme with no actionbar
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
there are many variants

if you want to have a full screen theme like Design(activity_main.xml):
solution 1: go into the manifest and use a full screen theme.
<activity
.
.
android:theme="#android:style/Theme.NoTitleBar.Fullscreen">
solution 2:
Just add the following attribute to your current theme:
<item name="android:windowFullscreen">true</item>
for example :
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">#color/orange</item>
<item name="colorPrimaryDark">#android:color/holo_orange_dark</item>
<item name="android:windowNoTitle">true</item>
<item name="android:windowFullscreen">true</item>
solution 3 :
public class MainActivity extends AppCompatActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
}
}
and for manage your buttons, read Dorian's answer to Design and actual app look same.

Remove dim duration of AlertDialog

The AlertDialog's dim effect can be disabled with:
alertDialog.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
Also, the dim amount can be changed by using:
alertDialog.getWindow().setDimAmount(0.0f);
However, whenever I call these functions, the change seems to be animated for a short duration (a long value between 100-200). Is there a way to make the change instant?
When trying to replace the standard dim with a mimicking View, the screen seems to flash due to the animation of the dim change.
Edit: Here's the base application theme:
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<item name="colorPrimary">#color/colorPrimary</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="colorAccent">#color/colorAccent</item>
</style>
The AlertDialog was created from an AlertDialog.Builder (click listeners have been added later):
dialogBuilder=new AlertDialog.Builder(this);
dialogBuilder.setTitle("Title").setIcon(null).setMessage("Description")
.setNeutralButton("Neutral",null).setNegativeButton("Cancel",null).setPositiveButton("Ok",null);
alertDialog=dialogBuilder.create();

add this to your theme:
<item name="android:backgroundDimEnabled">false</item>
And control the theme strictly from code
If you don't want to control the theme of the dialog by the main theme
create a subclass for the dialog only and use it the following way
<style name="DialogTheme" parent="Theme.MaterialComponents.Light.NoActionBar.Bridge">
<item name="android:backgroundDimEnabled">false</item>
</style>
dialogBuilder = new AlertDialog.Builder(this, R.style.DialogTheme);

If you want all the dialogs to have disabled dim then you can do something like this:
Go to styles.xml, then in your main theme add:
<item name="alertDialogTheme">#style/MyAlertDialogTheme</item>
Then in below that add another theme (the one we are referencing above)
<style name="MyAlertDialogTheme" parent="Theme.AppCompat.Light.Dialog.Alert">
<item name="android:backgroundDimEnabled">false</item>
</style>
Also, if you want a very low dim you can change it to:
<item name="android:backgroundDimAmount">0.05</item>

As the other answers here suggest, I figured that it's better to just disable the dim effect altogether. I didn't want to override all the AlertDialogs, so it seems to work well enough with just using a background View and fading it in/out with the AlertDialog's setOnShowListener and setOnDismissListener.
alertDialog=dialogBuilder.create();
alertDialog.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
alertDialog.setOnShowListener(new DialogInterface.OnShowListener(){
#Override public void onShow(DialogInterface dialog) {
background.setAlpha(0f);background.setVisibility(View.VISIBLE);background.animate().alpha(1f).setDuration(dur);
}
});
alertDialog.setOnDismissListener(new DialogInterface.OnDismissListener(){
#Override public void onDismiss(DialogInterface dialog){
background.animate().alpha(0f).withEndAction(runnable_background_gone);
}
});

Can I change my android application style at runtime?

I want to change the manifest style when the user chooses a setting in the preferences file or settings. I have a setting in my apk which includes a list of preferences with three entries {Style_1, Style_2, Style_3}. I want to change the style color, like primaryColor, when the user clicks a style. How can I do this?

Yes you can do this easily, I do it all the time.
Just call this method before setContentView like this:
setTheme(R.style.Theme);
setContentView(R.layout.activity_layout);
Now what I do is that i take a static int variable in the app constants and change it according to my theme. Then i do something like this
//This is in my constants file
public static int CURRENT_THEME = R.style.AppTheme;
//This is in my onCreate of every Activity.
setTheme(Constants.CURRENT_THEME);
setContentView(R.layout.activity_layout);
Hope this helps.

Yes you can set Theme like this:
activity.setTheme(R.style.theme_large);
activity.setTheme(R.style.theme_small);
<style name="theme_large">
<item name="main_background">#drawable/background_red</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="button_light">#color/button_light</item>
</style>
<style name="theme_small">
<item name="main_background">#drawable/background_red</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="button_light">#color/button_light</item>
</style>

Create Two Style
setTheme(darkTheme ? R.style.AppThemeDark : R.style.AppThemeLight);
<style name="AppThemeDark">
<item name="main_background">#drawable/background_dark</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="button_light">#color/button_dark</item>
</style>
<style name="AppThemeLight">
<item name="main_background">#drawable/background_light</item>
<item name="colorPrimaryDark">#color/colorPrimaryLight</item>
<item name="button_light">#color/button_light</item>
</style>

I think, setting theme after a button click or option choosen could be harsh for an Activity to handle.
What I am suggesting you is to reload your activity on button click but before that simply save the style_name , the user want to apply in internal memory or Shared Preferences. You can apply shared preference simply looking at here.
At the start of onCreate of your activity, apply that fetching part of shared preferences and apply the theme as user has indicated. This would help you to preserve the theme for that user until s/he uninstall that application or clears the app data.
If s/he is using the application for first time, the stored style_name string would be null so load your application with default theme.
You can simply reload your activity on button click by using the below code:
public void onClick (View v){
Intent intent = getIntent();
finish();
startActivity(intent);
}
Hope it helps !!

Style applied to an AlertDialog not working correctly

I've been asked to match the look of an Alert Dialog in our app to the one used by the app's theme.
I managed to apply a style to all Alert Dialogs in the app using it as part of the app's theme, but there are situations where the style is not applying correctly.
It happens for example when the Alert Dialog contains a 'Single Choice List' as its' message.
The title looks fine, so is the background and the button bar, but the list itself is problematic.
At first, the radio buttons as well as their textual description were black colored, as if android is using the default color.
I somehow managed to color the radio buttons as I wish, by using these attributes:
<item name="android:colorControlNormal">#color/text_secondary</item>
<item name="android:colorControlActivated">#color/text_secondary</item>
But the text color still remains black, and I've tried EVERY possible text color attribute exposed by android.
It looks like this:
Now this is the full style defined for the Alert Dialogs:
<style name="GenericAlertDialog.Alter" parent="Theme.AppCompat.Light.Dialog.Alert">
<item name="android:windowContentOverlay">#null</item>
<item name="android:windowIsFloating">true</item>
<item name="android:windowAnimationStyle">#android:style/Animation.Dialog</item>
<item name="android:windowMinWidthMajor">#android:dimen/dialog_min_width_major</item>
<item name="android:windowMinWidthMinor">#android:dimen/dialog_min_width_minor</item>
<item name="android:windowTitleStyle">#style/DialogTitle</item>
<item name="android:textColor">#color/text_secondary</item>
<item name="android:textColorPrimary">#color/primary</item>
<item name="android:background">#color/window_background</item>
<item name="android:colorAccent">#color/accent</item>
<item name="android:textColorAlertDialogListItem">#color/text_secondary</item>
<!--<item name="android:textColorSecondary">#color/text_secondary</item>-->
<item name="android:colorControlNormal">#color/text_secondary</item>
<item name="android:colorControlActivated">#color/text_secondary</item>
</style>
This is my Theme definition:
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<item name="android:windowBackground">#color/window_background</item>
<item name="android:colorPrimary">#color/primary</item>
<item name="android:colorAccent">#color/accent</item>
<item name="android:textColorPrimary">#color/text_primary</item>
<item name="android:textColorSecondary">#color/text_secondary</item>
<item name="android:textColorHint">#color/text_hint</item>
<item name="android:buttonStyle">#style/GenericButton</item>
<item name="android:checkboxStyle">#style/GenericCheckBox</item>
<item name="android:alertDialogTheme">#style/GenericAlertDialog</item>
<item name="alertDialogTheme">#style/GenericAlertDialog</item>
</style>
This is the code I'm using to create a custom Alert Dialog:
AlertDialog.Builder dialogBuilder = null;
try
{
dialogBuilder = new AlertDialog.Builder(i_OwnerActivity, R.style.GenericAlertDialog_Alter);
LayoutInflater layoutInflater = i_OwnerActivity.getLayoutInflater();
// Inflate the dialog's custom title view and set it's text to the matching one to this class
View customTitleView = layoutInflater.inflate(R.layout.dialog_title, null);
TextView customTitleTextView = (TextView) customTitleView.findViewById(R.id.DialogTitleText);
// Set text of customTitleView
dialogBuilder.setCustomTitle(customTitleView);
// Create an event handler for clicking on the negative button
dialogBuilder.setNegativeButton(R.string.action_dialog_negative_cancel, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface i_Dialog, int i_Which)
{
// Do Something
}
});
} catch (Exception e)
{
LogUtils.logException(AlterDialogUtils.class, e);
}
return dialogBuilder;
And finally, here's the code I'm using to create an Alert Dialog with a 'Single Choice List':
dialogBuilder.setSingleChoiceItems(R.array.squelch_modes, m_InitialState, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
// Do Something
}
});
What am I doing wrong? How can I change the color of the text?
It is also worth saying that I'm using AppCompat's AlertDialog.

Just found this old post with Google, but since there is no answer I will add what did the trick in my case:
remove the android: prefix from the textColorAlertDialogListItem in your alertdialog style
<item name="textColorAlertDialogListItem">#color/text_secondary</item>
I guess that's because of the parent being an AppCompat theme, but I am not sure about this. I still added both (with and without prefix) in my style...

I know it's probably late... but here's your answer: android.support.v7.app.AlertDialog in AppCompat support library use this layout by default (unless you provide your own adapter) for singleChoiceDialog:
<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/text1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?attr/listPreferredItemHeightSmall"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="?attr/textColorAlertDialogListItem"
android:gravity="center_vertical"
android:paddingLeft="#dimen/abc_select_dialog_padding_start_material"
android:paddingRight="?attr/dialogPreferredPadding"
android:paddingStart="#dimen/abc_select_dialog_padding_start_material"
android:paddingEnd="?attr/dialogPreferredPadding"
android:drawableLeft="?android:attr/listChoiceIndicatorSingle"
android:drawableStart="?android:attr/listChoiceIndicatorSingle"
android:drawablePadding="20dp"
android:ellipsize="marquee" />
The attribute used to set this up in the theme is singleChoiceItemLayout so you can override it with your own layout to get whatever UI you want.
If you just want to change the text color just define the attribute textColorAlertDialogListItem as you can see from the layout it's the one used for android:textColor.
In general when I need something like this i go and look at the source code since it is available. The support libraries source code can be found here, while most of the framework source code can be find here.

Android action bar overlay & hidden by default in xml

I need to have the action bar hidden on application start. Then, after some user action, it has to show up again overlaying the content. Currently I turn it off in a custom style by setting <item name="android:windowActionBar">false</item>, and then call
getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
getActionBar().hide();
in onCreate() of the activity.
That seems a little awkward though. Can I do all of it in xml configs?

I don't know about the hiding part, but you cna style the ActionBar as an overlay in your apps theme like this:
<style name="AppTheme" parent="#style/Theme.AppCompat">
<item name="android:windowNoTitle">false</item>
<item name="android:windowFullscreen">true</item>
<item name="android:windowActionBarOverlay">true</item>
</style>