在android中创建菜单/子菜单

Question

我几乎没有任何开发android应用程序的经验。我的朋友问我为他的应用程序创建一个小功能。我坚持的是为选项创建一个子菜单，也就是说，我点击了一个按钮后，会弹出一个菜单并带有一些选项，当点击某个特定选项时我需要它打开第二个菜单。我会在下面发布我的代码（XML和Java），希望有人能帮助我。目前，我的菜单通过Java代码显示，而不是XML代码。我不确定这是否是不好的练习，但我会让任何能够帮助我的人告诉我是否是这样。提前致谢。

XML代码：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout 
    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" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:showIn="@layout/activity_main" 
    tools:context="com.example.android.postvu.MainActivity"> 

<ImageView 
    android:id="@+id/imageView2" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:contentDescription="@string/background" 
    android:scaleType="centerCrop" 
    android:src="@drawable/grid" /> 

<TextView 
    android:id="@+id/textView" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginLeft="8dp" 
    android:layout_marginRight="8dp" 
    android:layout_marginTop="8dp" 
    android:text="@string/image_text_editor" 
    android:textColor="@android:color/black" 
    android:textSize="28sp" 
    android:textStyle="bold" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintTop_toTopOf="parent" 
    tools:text="Image Text Editor" /> 


<Button 
    android:layout_width="50dp" 
    android:layout_height="50dp" 
    android:layout_marginBottom="8dp" 
    android:layout_marginLeft="8dp" 
    android:layout_marginRight="8dp" 
    android:layout_marginTop="8dp" 
    android:background="@mipmap/ic_launcher" 
    android:scaleType="centerCrop" 
    android:onClick="myOnClickMethod" 
    app:layout_constraintBottom_toBottomOf="parent" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintTop_toBottomOf="@+id/textView" 
    app:layout_constraintVertical_bias="0.98" /> 

的Java代码（与该按钮被点击，菜单显示出来）：

public void myOnClickMethod(View v) { 
    registerForContextMenu(v); 
    openContextMenu(v); 
} 

final int CONTEXT_MENU_VIEW = 1; 
final int CONTEXT_MENU_EDIT = 2; 
final int CONTEXT_MENU_ARCHIVE = 3; 


@Override 
public void onCreateContextMenu (ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) { 
    menu.setHeaderTitle("Options"); 
    menu.add(Menu.NONE, CONTEXT_MENU_VIEW, Menu.NONE, "Take Photo"); 
    menu.add(Menu.NONE, CONTEXT_MENU_EDIT, Menu.NONE, "Photo Album"); 
    menu.add(Menu.NONE, CONTEXT_MENU_ARCHIVE, Menu.NONE, "Plain Image"); 
} 

@Override 
public boolean onContextItemSelected (MenuItem item) { 
    switch (item.getItemId()) { 
     case CONTEXT_MENU_VIEW: { 
     } 
     break; 
     case CONTEXT_MENU_EDIT: { 
     } 
     break; 
     case CONTEXT_MENU_ARCHIVE: { 
     } 
     break; 
    } 

    return super.onContextItemSelected(item); 
} 

Answer 1

您可以在下面显示的子菜单办法。我修改了你的代码并使用了硬编码的常量。我希望这能帮到您。

public class MainActivity extends AppCompatActivity { 
    private View menuAnchorView; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     menuAnchorView = findViewById(R.id.imageView2); 
     menuAnchorView.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       myOnClickMethod(menuAnchorView); 
      } 
     }); 
    } 

    public void myOnClickMethod(View v) { 
     registerForContextMenu(v); 
     openContextMenu(v); 
    } 

    final int CONTEXT_MENU_VIEW = 1; 
    final int CONTEXT_MENU_EDIT = 2; 
    final int CONTEXT_MENU_ARCHIVE = 3; 


    @Override 
    public void onCreateContextMenu (ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) { 
     if(v.getTag() == null || !v.getTag().equals("menu_item")) { 
      menu.setHeaderTitle("Options"); 
      menu.add(Menu.NONE, CONTEXT_MENU_VIEW, Menu.NONE, "Take Photo"); 
      menu.add(Menu.NONE, CONTEXT_MENU_EDIT, Menu.NONE, "Photo Album"); 
      menu.add(Menu.NONE, CONTEXT_MENU_ARCHIVE, Menu.NONE, "Plain Image"); 
     } 
     else { 
      menu.setHeaderTitle("Sub menu"); 
      menu.add(Menu.NONE, 4, Menu.NONE, "Sub-view"); 
      menu.add(Menu.NONE, 5, Menu.NONE, "Sub-view-2"); 
     } 
    } 

    @Override 
    public boolean onContextItemSelected (MenuItem item) { 
     closeContextMenu(); 
     switch (item.getItemId()) { 
      case CONTEXT_MENU_VIEW: { 
       menuAnchorView.setTag("menu_item"); 
       openContextMenu(menuAnchorView); 
      } 
      break; 
      case CONTEXT_MENU_EDIT: { 
      } 
      break; 
      case CONTEXT_MENU_ARCHIVE: { 
      } 
      break; 
      case 4: 
      case 5: menuAnchorView.setTag(null); 
       break; 
     } 

     return super.onContextItemSelected(item); 
    } 

}