禁用菜单项？

Question

善良的人们！告诉我如何制作具有适当外观的禁用菜单项这样的基本事物，如 material 设计中的示例？以编程方式。提前谢谢你

编辑：以下示例将禁用点击，但不会根据 material 设计更改外观：

代码示例：

@Override
public void onPrepareOptionsMenu(@NonNull Menu menu) {
    super.onPrepareOptionsMenu(menu);
        MenuItem menuItem = menu.findItem(R.id.someItem);
        menuItem.setEnable(false);
}

Xml 示例：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/someItem"
        android:enabled="false"
        android:title="Some title" />
</menu>

Answer 1

您可以添加、删除或禁用菜单项，并在运行时更改菜单项的文本颜色，就像这样::

If you want to modify the options menu based on events that occur during the activity lifecycle, you can do so in the onPrepareOptionsMenu() method. This method passes you the Menu object as it currently exists so you can modify it, such as add, remove, or disable items. (Fragments also provide an onPrepareOptionsMenu() callback.)

On Android 2.3.x and lower, the system calls onPrepareOptionsMenu() each time the user opens the options menu (presses the Menu button).

On Android 3.0 and higher, the options menu is considered to always be open when menu items are presented in the app bar. When an event occurs and you want to perform a menu update, you must call invalidateOptionsMenu() to request that the system call onPrepareOptionsMenu().

可以看到the Documentation

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item
    android:id="@+id/someItem"
    android:enabled="false"
    android:title="Some title"
    app:actionViewClass="android.support.v7.widget.TextView" 
    // if using androidX
    //app:actionViewClass="androidx.appcompat.widget.AppCompatTextView"/>
 </menu>

并在 java 代码中

 //sample code
 @Override
 public boolean onPrepareOptionsMenu (Menu menu) {
   //disable menu item and change text color
   MenuItem menu1 = menu.findItem(R.id.yourmenuid);
   menu1.setEnabled(false);
   TextView textView = (TextView) menu1.getActionView();
   textView.setTextColor(Color.BLACK);
   return true;
  }

必须调用invalidateOptionsMenu()请求系统调用onPrepareOptionsMenu()。

Answer 2

我找到了关于如何更改菜单项中的文本颜色的解决方法。非常可悲的是，没有开箱即用的这种基本的东西。也许有人有更好的解决方案，我会很高兴看到！

MenuItem  menuItem = menu.findItem(R.id.some_item);
menuItem.setEnabled(false);
SpannableString s = new SpannableString(menuItem.getTitle());
s.setSpan(new ForegroundColorSpan(Color.GRAY), 0, s.length(), 0);
menuItem.setTitle(s);

结果：

禁用菜单项？

Disabled menuItem?

java

android

menu

material-design