Changing android nav bar title in xamarin.forms project

问题

I try to change android nav bar title of my xamarin forms project

I can't do that im app.xaml because when i change the color in pcl it changes ios back button too, And I don't wanna it...then I have already tried:

<resources>
 <style name="MyTheme" parent="@android:style/Theme.Holo.Light">
<item name="android:actionBarStyle">@style/MyTheme.ActionBarStyle</item>
</style>

 <style name="MyTheme.ActionBarStyle" 
 parent="@android:style/Widget.Holo.Light.ActionBar">
  <item 
name="android:titleTextStyle">@style/MyTheme.ActionBar.TitleTextStyle</item>
  </style>

  <style name="MyTheme.ActionBar.TitleTextStyle" 
parent="@android:style/TextAppearance.Holo.Widget.ActionBar.Title">
    <item name="android:textColor">#f08080</item>
 </style>

I read that I need to put something in the manifest but I Didn't found how to do that...

no error and nothing change...

My 'MainActivity':

namespace neoFly_Montana.Droid
{

[Activity(Label = "neoFly_Montana", Icon = "@drawable/icon", Theme = "@style/MainTheme", MainLauncher = false, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
    public static Context AppContext;
    protected override void OnCreate(Bundle bundle)
    {
        TabLayoutResource = Resource.Layout.Tabbar;
        ToolbarResource = Resource.Layout.Toolbar;

        base.OnCreate(bundle);

        global::Xamarin.Forms.Forms.Init(this, bundle);

        //qrcode inicializa
        ZXing.Net.Mobile.Forms.Android.Platform.Init();

        //inicializa imageCircle
        ImageCircleRenderer.Init();

        //inicializa o mapa
        global::Xamarin.FormsMaps.Init(this, bundle);

        //shared Preferences
        App.Init(new AndroidUserPreferences());

        //Gerenciador de memória
        CachedImageRenderer.Init();

        //AndroidUserPreferences sharedPref = new AndroidUserPreferences();
        //var token = FirebaseInstanceId.Instance.Token;
        //sharedPref.SetString("token", token); joyce descomentar

        LoadApplication(new App());
    }

    // Field, property, and method for Picture Picker
    public static readonly int PickImageId = 1000;

    public TaskCompletionSource<Stream> PickImageTaskCompletionSource { set; get; 
 }

    protected override void OnActivityResult(int requestCode, Result resultCode, Intent intent)
    {
        base.OnActivityResult(requestCode, resultCode, intent);

        if (requestCode == PickImageId)
        {
            if ((resultCode == Result.Ok) && (intent != null))
            {
                Android.Net.Uri uri = intent.Data;
                Stream stream = ContentResolver.OpenInputStream(uri);

                // Set the Stream as the completion of the Task
                PickImageTaskCompletionSource.SetResult(stream);
            }
            else
            {
                PickImageTaskCompletionSource.SetResult(null);
            }
        }
    }

    //qrcode permission
    public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
    {
        global::ZXing.Net.Mobile.Forms.Android.PermissionsHandler.OnRequestPermissionsResult(requestCode, permissions, grantResults);
    }    

}
}

If I change the theme to MyTheme this exception ocures:

Unhandled Exception: Java.Lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

回答1:

I try to change android nav bar title of my xamarin forms project

As Rendy Del Rosario said, setting a theme to MainActivity defined in a Styles.xml inside Android Resources/valuesinstead of put this style in the manifest.

Defined in a Styles.xml inside Android Resources/values

Your Styles.xml :

<resources>
     <style name="MyTheme" parent="@android:style/Theme.Holo.Light">
         <item name="android:actionBarStyle">@style/MyTheme.ActionBarStyle</item>
     </style>

     <style name="MyTheme.ActionBarStyle" parent="@android:style/Widget.Holo.Light.ActionBar">
         <item name="android:titleTextStyle">@style/MyTheme.ActionBar.TitleTextStyle</item>
     </style>

     <style name="MyTheme.ActionBar.TitleTextStyle" parent="@android:style/TextAppearance.Holo.Widget.ActionBar.Title">
         <item name="android:textColor">#f08080</item>
     </style>
</resources>

Set activity theme

Add your custom style :

[Activity (Label = "WorkingWithNavigation.Droid", Theme = "@style/MyTheme",
    Icon = "@drawable/icon", 
    MainLauncher = true, 
    ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsApplicationActivity
{
    ...
}

Effect :

Use theme, No theme.

EDIT :

Unhandled Exception: Java.Lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

I read your MainActivity code, this error occurs because the activity you are trying to apply the dialog theme to is extending AppCompatActivity which requires the AppCompat theme to be applied. To solve this problem and implement your feature I found another solution and it works fine on my side.

Since you are using toolbar in your MainActivity :

ToolbarResource = Resource.Layout.Toolbar;

The nav bar title in Android is Toolbar, so you just need to change the toolbar title color.

1.Using the default theme when you create a Xamarin.Android project :

Resources/values/Styles.xml :

<?xml version="1.0" encoding="utf-8" ?>
<resources>

  <style name="ToolbarTheme" parent="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:textColorPrimary">#ff0000</item>
  </style>

  <style name="MainTheme" parent="MainTheme.Base">
  </style>

  <style name="MainTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar">
    <item name="windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
    <item name="colorPrimary">#2196F3</item>
    <item name="colorPrimaryDark">#1976D2</item>
    <item name="colorAccent">#FF4081</item>
    <item name="windowActionModeOverlay">true</item>
    <item name="android:datePickerDialogTheme">@style/AppCompatDialogStyle</item>
  </style>

  <style name="AppCompatDialogStyle" parent="Theme.AppCompat.Light.Dialog">
    <item name="colorAccent">#FF4081</item>
  </style>
</resources>

2.Add a ToolbarTheme to your Toolbar :

Define a ToolbarTheme, place it in Resources/values/Styles.xml file, you could see it in the above code, I write here again :

 <style name="ToolbarTheme" parent="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:textColorPrimary">#ff0000</item>
 </style>

The android:textColorPrimary is the nav bar title color, replace it with the color you want to change.

Find your Toolbar.axml file :

Modify your Toolbar theme to :

android:theme="@style/ToolbarTheme"

Complete Toolbar.axml code :

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?attr/colorPrimary"
    android:theme="@style/ToolbarTheme"
    android:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

Effect :

When I change the toolbar title color to red ：

<item name="android:textColorPrimary">#ff0000</item>

来源：https://stackoverflow.com/questions/46637596/changing-android-nav-bar-title-in-xamarin-forms-project

标签

android

xaml

Xamarin

mobile