android - MenuItem.setIcon() 方法不起作用

Question

我已经尝试了所有可能的解决方案。这是我的代码:

private Menu mMenu;

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.fragment_article_detail_menu, menu);
    mMenu = menu;
}

void changeStar(boolean added) {
    if (mMenu != null) {
        MenuItem item = mMenu.findItem(R.id.favourites_item);
        if (added) {
            Log.d(LOG_TAG, "Set full icon");
            item.setIcon(getResources().getDrawable(R.drawable.star_full));
        } else {
            Log.d(LOG_TAG, "Set empty icon");
            item.setIcon(getResources().getDrawable(R.drawable.star_empty));
        }
    }
}

这是我的菜单 xml 文件:

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context="ssidit.pp.ua.payspacereader.ArticleDetailActivity">
    <item
        android:id="@+id/refresh_item"
        android:title="@string/refresh"
        app:showAsAction="never"></item>

    <item
        android:id="@+id/favourites_item"
        android:icon="@drawable/star_empty"
        android:title="@string/add_to_favourite"
        app:showAsAction="ifRoom"></item>

    <item
        android:id="@+id/share_item"
        android:icon="@drawable/ic_share"
        android:title="@string/share"
        app:actionProviderClass="android.support.v7.widget.ShareActionProvider"
        app:showAsAction="ifRoom"></item>
</menu>

invalidateMenu() 方法没有帮助。当我调用 setIcon 方法时，我的 Android 设备上没有任何变化。

这是我的代码:

private boolean isFavourite;

 private void setValues(Cursor cursor) {

    Log.d(LOG_TAG, "Setting values");

    setData(titleTextView, CursorUtility.getTitle(cursor));
    setData(dateTextView, CursorUtility.getDateText(cursor));
    setData(timeTextView, CursorUtility.getTimeText(cursor));
    isFavourite = CursorUtility.isFavourite(cursor);
    getActivity().invalidateOptionsMenu();
}


@Override
public void onPrepareOptionsMenu(Menu menu) {
    super.onPrepareOptionsMenu(menu);
    Log.d(LOG_TAG, "OnPrepareOptionsMenu");
    MenuItem item = menu.findItem(R.id.favourites_item);
    if (isFavourite) {
        Log.d(LOG_TAG, "Set full icon");
        item.setIcon(R.drawable.star_full);
    } else {
        Log.d(LOG_TAG, "Set empty icon");
        item.setIcon(R.drawable.star_empty);
    }
}

如您所见，所有内容均已记录。所以如果某些方法没有调用就不会出错。我还通过获取标题来检查项目。是正确的项目。只是某种黑魔法。

Answer 1

尝试使用 invalidateOptionsMenu 并将您的 changeStar 逻辑移动到 onPrepareOptionsMenu。来自 Android documentation :

public boolean onPrepareOptionsMenu (Menu menu)

Added in API level 1 Prepare the Screen's standard options menu to be displayed. This is called right before the menu is shown, every time it is shown. You can use this method to efficiently enable/disable items or otherwise dynamically modify the contents.

The default implementation updates the system menu items based on the activity's state. Deriving classes should always call through to the base class implementation.