Theme/Style is not applied when inflater used with ApplicationContext

I have theme that specifies textColor for TextView as red.

I am using LayoutInflater to instantiate TextView. The problem is that styles are not applied to TextView when inflater created using ApplicationContext - the color is not red. All works fine when LayoutInflater created using activity.

Why this happens, and how can be fixed?

/res/values/styles.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="MyTheme">
        <item name="android:textViewStyle">@style/MyTextView</item>
    </style>
    
    <style name="MyTextView" parent="@android:style/Widget.TextView">
        <item name="android:textColor">#f00</item>
    </style>
</resources>

AndroidManifest.xml:

<application 
    android:icon="@drawable/icon" 
    android:label="@string/app_name"
    android:theme="@style/MyTheme"
    >

Code:

public class A extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test_a);
        
        final LayoutInflater goodInflater = getInflater((Activity)this); 
        final LayoutInflater badInflater = getInflater(getApplicationContext());
        final LinearLayout container = (LinearLayout)findViewById(R.id.container);
        
        findViewById(R.id.add_with_appContext).setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                add(container, badInflater); // Creates gray TextView
            }            
        });

        findViewById(R.id.add_with_activity).setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                add(container, goodInflater); // Creates red TextView
            }            
        });
    }
    
    private LayoutInflater getInflater(Context context) {
        return (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    
    private void add(LinearLayout container, LayoutInflater inflater) {
        inflater.inflate(R.layout.my_template, container, true);
    }
}

/res/layout/test_a.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">
      
    <Button 
        android:text="Add with AppContext" 
        android:id="@+id/add_with_appContext" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        />
        
    <Button 
        android:text="Add with Activity" 
        android:id="@+id/add_with_activity" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        />
    
    <LinearLayout
        android:id="@+id/container"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"  
        />
          
</LinearLayout>

/res/layout/my_template.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    >
    
    <TextView
        android:id="@+id/text"
        android:text="Some text..."
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content"
    />
    
</LinearLayout>

Solution # 1

The inflate method accepts optional 'ViewGroup root' argument:

public View inflate (int resource, ViewGroup root, boolean attachToRoot)

If we have value to pass as 'root' parameter, than hence we can use it to get 'activity context' from where we can get correct LayoutInflater:

ViewGroup root > activity context > LayoutInflater

So my code could be:

private void add(LinearLayout container) {
    LayoutInflater inflater = getInflater(container.getContext());
    inflater.inflate(R.layout.my_template, container, true);
}

Solution # 2

Just tried to set Application Context theme programmatically, and it works:

getApplicationContext().setTheme(R.style.MyTheme);

I think it was logical to expect this markup:

<application 
    android:icon="@drawable/icon" 
    android:label="@string/app_name"
    android:theme="@style/MyTheme"
    >

to set it automatically, but it does not.

Never use an Application Context to inflate views, because styling doesn't work with this context. Always use an Activity's context when playing with views. The only exception is when you need to create RemoteViews from a Service.

More info about the different types of Contexts and their capabilities can be found in this excellent article.

You probably use a context that isn't one that has a theme.

To solve it, use something as such:

val inflater= LayoutInflater.from(context).cloneInContext(ContextThemeWrapper(context, R.style.some_activity_theme))

You can read more about this here

I usually come across this issue on inflating a custom view. Here is what I personally do to keep the same theme of the activity in the CustomView

public class CustomView extends ViewGroup{

public CustomView (Context context) {
    super(context);
    init(context);
}

public CustomView (Context context, AttributeSet attrs) {
    super(context, attrs);
    init(context);
}

public CustomView (Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init(context);
}

@TargetApi(21)
public CustomView (Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
    init(context);
}

private void init(Context context) {
    LayoutInflater  mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View v = mInflater.inflate(R.layout.review_list_item, this, true);
    //rest of view initialization       
}   
}