[Snackbar] Add support for changing text & background tint color at r…

…untime

Resolves #360

GIT_ORIGIN_REV_ID=ced4885fd03d6117d5ee460253184d1605895e55
PiperOrigin-RevId: 248537604

lib/java/com/google/android/material/snackbar/Snackbar.java

@@ -23,6 +23,9 @@
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.TypedArray;
+import android.graphics.PorterDuff;
+import android.graphics.drawable.Drawable;
+import android.os.Build;
 import androidx.annotation.ColorInt;
 import androidx.annotation.IntDef;
 import androidx.annotation.IntRange;
@@ -31,6 +34,7 @@
 import androidx.annotation.RestrictTo;
 import androidx.annotation.StringRes;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
+import androidx.core.graphics.drawable.DrawableCompat;
 import android.text.TextUtils;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
@@ -331,6 +335,30 @@ public int getDuration() {
         : super.getDuration();
   }
 
+  /**
+   * Sets the text color of the message specified in {@link #setText(CharSequence)} and {@link
+   * #setText(int)}.
+   */
+  @NonNull
+  public Snackbar setTextColor(ColorStateList colors) {
+    final SnackbarContentLayout contentLayout = (SnackbarContentLayout) view.getChildAt(0);
+    final TextView tv = contentLayout.getMessageView();
+    tv.setTextColor(colors);
+    return this;
+  }
+
+  /**
+   * Sets the text color of the message specified in {@link #setText(CharSequence)} and {@link
+   * #setText(int)}.
+   */
+  @NonNull
+  public Snackbar setTextColor(@ColorInt int color) {
+    final SnackbarContentLayout contentLayout = (SnackbarContentLayout) view.getChildAt(0);
+    final TextView tv = contentLayout.getMessageView();
+    tv.setTextColor(color);
+    return this;
+  }
+
   /**
    * Sets the text color of the action specified in {@link #setAction(CharSequence,
    * View.OnClickListener)}.
@@ -355,6 +383,22 @@ public Snackbar setActionTextColor(@ColorInt int color) {
     return this;
   }
 
+  /** Sets the tint color of the background Drawable. */
+  @NonNull
+  public Snackbar setBackgroundTint(@ColorInt int color) {
+    Drawable background = view.getBackground();
+    if (background != null) {
+      // Drawable doesn't implement setTint in API 21 and Snackbar does not yet use
+      // MaterialShapeDrawable as its background (i.e. TintAwareDrawable)
+      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
+        DrawableCompat.setTint(background, color);
+      } else {
+        background.setColorFilter(color, PorterDuff.Mode.SRC_IN);
+      }
+    }
+    return this;
+  }
+
   /**
    * Set a callback to be called when this the visibility of this {@link Snackbar} changes. Note
    * that this method is deprecated and you should use {@link #addCallback(BaseCallback)} to add a