如何获取菜单项的动作视图？

Question

这是我的代码

home.xml

<item
    android:id="@+id/action_shopping_cart"
    android:actionLayout="@layout/action_bar_cart_button"
    android:showAsAction="ifRoom"
    android:title="Shopping Cart" />
<item
    android:id="@+id/action_notifications"
    android:actionLayout="@layout/action_bar_notifications_button"
    android:showAsAction="ifRoom"
    android:title="Notifications" />
<item
    android:id="@+id/menu_overflow"
    android:orderInCategory="100"
    android:icon="@drawable/ic_action_overflow"
    android:showAsAction="always"
    android:title="OverFlow">

    <menu>
        <item
            android:id="@+id/action_my_account"
            android:orderInCategory="100"
            android:showAsAction="never"
            android:title="My Account" />
        <item
            android:id="@+id/action_current_orders"
            android:orderInCategory="100"
            android:showAsAction="never"
            android:title="My Orders" />
        <item
            android:id="@+id/action_wish_list"
            android:orderInCategory="100"
            android:showAsAction="never"
            android:title="My Wishlist" />
        <item
            android:id="@+id/action_contact_us"
            android:orderInCategory="100"
            android:showAsAction="never"
            android:title="Contact Us" />
        <item
            android:id="@+id/action_logout"
            android:orderInCategory="100"
            android:showAsAction="never"
            android:title="Logout" />
    </menu>
</item>

我想查看"menu_overflow"我怎么能得到它？

我试过以下方式:

Activity.java代码

public boolean onCreateOptionsMenu(Menu menu){

      final MenuItem item = menu.findItem(R.id.menu_overflow);
      View view = (View) findViewById(R.id.menu_overflow);
      new MaterialShowcaseView.Builder(this)
                        .setTarget(mOverFlowIcon)
                        .setRadius(10)
                        .setMaskColour(Color.argb(150, 0, 0, 0))
                        .setContentText("Find Your Wishlist Here") // optional but starting animations immediately in onCreate can make them choppy
                        .setDismissOnTouch(true)
                        .show();
    return super.onCreateOptionsMenu(menu);
}

但是返回视图是null.

请帮忙... thanx

Answer 1

你在onCreateOptionsMenu中夸大菜单吗？看来,当执行onCreateOptionsMenu时,xml通胀会被添加到事件队列中,而不是立即膨胀.这是执行findViewById()时导致空指针的原因.尝试将视图查找放在Handler中.Handler中的代码将添加到消息队列中,因此将在菜单膨胀后执行.这将解决您的空指针.它看起来像这样:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    new Handler().post(new Runnable() {
        @Override
        public void run() {
            View view = (View) findViewById(R.id.menu_overflow);
            new MaterialShowcaseView.Builder(this)
                    .setTarget(view)
                    .setRadius(10)
                    .setMaskColour(Color.argb(150, 0, 0, 0))
                    .setContentText("Find Your Wishlist Here") // optional but starting animations immediately in onCreate can make them choppy
                    .setDismissOnTouch(true)
                    .show();
        }
    });
    return true;
}

Answer 2

MenuItem您可以通过重写该方法来获取对 的引用onPrepareOptionsMenu(Menu)：

@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    MenuItem actionViewItem = menu.findItem(R.id.your_menu_item);
    return super.onPrepareOptionsMenu(menu);
}

如果您想要引用，ActionView可以使用以下方法执行此操作MenuItemCompat.getActionView(MenuItem)：

@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    MenuItem actionViewItem = menu.findItem(R.id.your_menu_item);
    View v = MenuItemCompat.getActionView(actionViewItem);
    return super.onPrepareOptionsMenu(menu);
}

Answer 3

你尝试过这个吗？

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.

        switch (item.getItemId()){
            case R.id.action_shopping_cart:
                Toast.makeText(this, "action_shopping_cart", Toast.LENGTH_SHORT).show();
                break;
            case R.id.action_notifications:
                Toast.makeText(this, "action_notifications", Toast.LENGTH_SHORT).show();
                break;
            case R.id.menu_overflow:
                Toast.makeText(this, "menu_overflow", Toast.LENGTH_SHORT).show();
                break;
            case R.id.action_my_account:
                Toast.makeText(this, "action_my_account", Toast.LENGTH_SHORT).show();
                break;
            case R.id.action_current_orders:
                Toast.makeText(this, "action_current_orders", Toast.LENGTH_SHORT).show();
                break;
            case R.id.action_wish_list:
                Toast.makeText(this, "action_wish_list", Toast.LENGTH_SHORT).show();
                break;
            case R.id.action_contact_us:
                Toast.makeText(this, "action_contact_us", Toast.LENGTH_SHORT).show();
                break;
            case R.id.action_logout:
                Toast.makeText(this, "action_logout", Toast.LENGTH_SHORT).show();
                break;



        }



        return super.onOptionsItemSelected(item);
    }

注意您的 xml 名称（即 home.xml）