test

src/Notesmaster/app/src/main/java/net/micode/notes/ui/DropdownMenu.java

@@ -27,35 +27,36 @@ import android.widget.PopupMenu.OnMenuItemClickListener;
 
 import net.micode.notes.R;
 
-public class DropdownMenu {
-    private Button mButton;
-    private PopupMenu mPopupMenu;
-    private Menu mMenu;
-
-    public DropdownMenu(Context context, Button button, int menuId) {
-        mButton = button;
-        mButton.setBackgroundResource(R.drawable.dropdown_icon);
-        mPopupMenu = new PopupMenu(context, mButton);
-        mMenu = mPopupMenu.getMenu();
-        mPopupMenu.getMenuInflater().inflate(menuId, mMenu);
+public class DropdownMenu {// 按钮，用于触发下拉菜单的显示
+    private Button mButton;; // 弹出菜单，包含下拉菜单项
+    private PopupMenu mPopupMenu;// 菜单，用于管理下拉菜单项
+    private Menu mMenu;//构造方法，初始化下拉菜单
+
+    public DropdownMenu(Context context, Button button, int menuId) {// 上下文，用于创建弹出菜单; 按钮，用于触发下拉菜单的显示 ;菜单资源ID，定义下拉菜单项的布局
+        mButton = button;// 设置按钮的背景为下拉菜单图标
+        mButton.setBackgroundResource(R.drawable.dropdown_icon);// 创建弹出菜单
+        mPopupMenu = new PopupMenu(context, mButton); // 获取弹出菜单的菜单对象
+        mMenu = mPopupMenu.getMenu();// 从资源文件中 inflate 菜单项到弹出菜单
+        mPopupMenu.getMenuInflater().inflate(menuId, mMenu);// 设置按钮点击监听器，当按钮被点击时显示下拉菜单
         mButton.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
-                mPopupMenu.show();
+                mPopupMenu.show();// 设置下拉菜单项点击监听器 * * @param listener 下拉菜单项点击监听器，当菜单项被点击时回调 */
             }
         });
     }
 
-    public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {
-        if (mPopupMenu != null) {
-            mPopupMenu.setOnMenuItemClickListener(listener);
+    public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {//确保弹出菜单不为空
+        if (mPopupMenu != null) {// 设置弹出菜单的菜单项点击监听器
+            mPopupMenu.setOnMenuItemClickListener(listener);//查找菜单项 * * @param id 菜单项的ID * @return 找到的菜单项，如果没有找到则返回null */
         }
     }
 
-    public MenuItem findItem(int id) {
+    public MenuItem findItem(int id) {// 在菜单中查找指定ID的菜单项 return mMenu.findItem(id); } /** * 设置按钮的标题 * * @param title 按钮的标题
+    public MenuItem findItem(int id) {// 在菜单中查找指定ID的菜单项 return mMenu.findItem(id); } /** * 设置按钮的标题 * * @param title 按钮的标题
         return mMenu.findItem(id);
     }
 
-    public void setTitle(CharSequence title) {
+    public void setTitle(CharSequence title) {// 设置按钮的文本内容
         mButton.setText(title);
     }
 }