组菜单项有效但不显示复选标记 [英] Group menu items work but don't display checkmark
问题描述
我有一个带有溢出菜单的工作应用程序.菜单中的所有代码都有效，但在我单击可单击的分组菜单项后，没有显示复选标记.
I have a working app with an overflow menu. All the code in the menu works, but no checkmarks are being shown after I click on a single-clickable, grouped menu item.
我做错了什么吗?我认为此复选标记的显示对 Android 来说是自动的，并且系统会为我执行此操作.Android 知道它在一个组中，它知道只能选择一个，并且它知道我选择了哪一个！所以..... Android 应该知道如何显示复选标记.
Am I doing something fundamentally wrong? I thought that this displaying of the checkmark was automatic to Android and that the system would do this for me. Android knows it is in a group, it knows that only one can be selected, and it knows which one I selected! So..... Android should know how to display the checkmarks.
<menu
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".Calculator">
<group
android:checkableBehavior="single"
android:visible="true">
<item
android:id="@+id/ui_simple"
android:orderInCategory="100"
app:showAsAction="ifRoom|withText"
android:title="Regular"
android:checkable="true"/>
<item
android:id="@+id/ui_doge"
android:orderInCategory="100"
app:showAsAction="ifRoom|withText"
android:title="Doge"
android:checkable="true"/>
<item
android:id="@+id/ui_static"
android:orderInCategory="100"
app:showAsAction="ifRoom|withText"
android:title="Static"
android:checkable="true"/>
</group>
<item android:title="Display Mode"
android:orderInCategory="101" >
<menu>
<group android:checkableBehavior="single" android:visible="true" >
<item
android:id="@+id/mode_sign"
android:orderInCategory="100"
app:showAsAction="collapseActionView"
android:title="Sign Form"
android:checkable="true"/>
<item
android:id="@+id/mode_noun"
android:orderInCategory="100"
app:showAsAction="collapseActionView"
android:title="Noun Form"
android:checkable="true"/>
<item
android:id="@+id/mode_verb"
android:orderInCategory="100"
app:showAsAction="collapseActionView"
android:title="Verb Form"
android:checkable="true"/>
</group>
</menu>
</item>
</menu>
界面
注意:我已经尝试将所有 break 切换为 return true，但没有任何反应.
UI
Note: I have tried switching all the breaks to return true, but nothing happens.
@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.ui_simple :
startActivity(new Intent(this, Calculator.class));
break;
case R.id.ui_doge :
startActivity(new Intent(this, CalculatorDoge.class));
break;
case R.id.ui_static :
startActivity(new Intent(this, CalculatorStatic.class));
break;
case R.id.mode_sign : display = BinaryOperation.Display.SIGN; break;
case R.id.mode_verb : display = BinaryOperation.Display.VERB; break;
case R.id.mode_noun : display = BinaryOperation.Display.NOUN; break;
}
return super.onOptionsItemSelected(item);
}
推荐答案
虽然@Elltz 为代码中的一个问题提供了一个有价值的解决方案，但代码中总共有 2 个问题.
While @Elltz provides a valuable solution to a problem in the code, there are a total of 2 issues in the code.
不要在菜单组和单个MenuItem的中设置可检查的XML属性.
Do not set a checkable XML attribute in both the Menu Group and the individual MenuItems.
因为在 XML 中有 <group android:checkableBehavior="single" 它表明 radio buttons 是需要的；因此，group 中的item 不应该有 android:checkable="true"
since in the XML there is <group android:checkableBehavior="single" it shows that radio buttons are desired; therefore, no item within the group should have android:checkable="true"
<group
android:checkableBehavior="single" <!-- ONLY HERE -->
android:visible="true" >
<item
android:id="@+id/mode_sign"
android:orderInCategory="100"
app:showAsAction="collapseActionView"
android:title="Sign Form" />
<item
android:id="@+id/mode_noun"
android:orderInCategory="100"
app:showAsAction="collapseActionView"
android:title="Noun Form"/>
<item
android:id="@+id/mode_verb"
android:orderInCategory="100"
app:showAsAction="collapseActionView"
android:title="Verb Form"/>
</group>
问题 2
同样，@Elltz 提供了一个很好的解决方案；然而，它比实际需要的要复杂一些.
Problem 2
Again, @Elltz provides a good solution; however, it is slightly more complex than what it needs to be.
仅限单选
switch (item.getItemId()) {
case R.id.ui_simple : startActivity(new Intent(this, Calculator.class)); return true;
case R.id.ui_doge : startActivity(new Intent(this, CalculatorDoge.class)); return true;
case R.id.ui_static : startActivity(new Intent(this, CalculatorStatic.class)); return true;
// Single Selection - Radio Buttons
case R.id.mode_sign :
item.setChecked(true); // ONLY THIS....HERE
display = BinaryOperation.Display.SIGN;
return true;
case R.id.mode_verb :
item.setChecked(true); // HERE
display = BinaryOperation.Display.VERB;
return true;
case R.id.mode_noun :
item.setChecked(true); // AND HERE
display = BinaryOperation.Display.NOUN;
return true;
default : return super.onOptionsItemSelected(item);
}
单选或多选
// Single OR Multi Select - Radio Buttons or CheckBoxes
switch (item.getItemId()) {
case R.id.ui_simple : startActivity(new Intent(this, Calculator.class)); return true;
case R.id.ui_doge : startActivity(new Intent(this, CalculatorDoge.class)); return true;
case R.id.ui_static : startActivity(new Intent(this, CalculatorStatic.class)); return true;
case R.id.mode_sign :
item.setChecked(!item.isChecked()); // LIKE THIS...HERE
display = BinaryOperation.Display.SIGN;
return true;
case R.id.mode_verb :
item.setChecked(!item.isChecked()); // HERE
display = BinaryOperation.Display.VERB;
return true;
case R.id.mode_noun :
item.setChecked(!item.isChecked()); // AND HERE
display = BinaryOperation.Display.NOUN;
return true;
default : return super.onOptionsItemSelected(item);
}
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