注释代码

DateTimePickerDialog.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */           /*版权和许可证声明，说明了该文件的版权信息以及遵循的许可协议*/ 
+
+package net.micode.notes.ui;
+
+import java.util.Calendar;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.DateTimePicker;
+import net.micode.notes.ui.DateTimePicker.OnDateTimeChangedListener;
+
+import android.app.AlertDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.DialogInterface.OnClickListener;
+import android.text.format.DateFormat;
+import android.text.format.DateUtils;       /*设置了代码的包名，并导入了所需的类和接口*/
+
+public class DateTimePickerDialog extends AlertDialog implements OnClickListener {   /*定义了一个名为 DateTimePickerDialog 的公共类，它扩展了 AlertDialog 并实现了 OnClickListener 接口。*/
+
+    private Calendar mDate = Calendar.getInstance();
+    private boolean mIs24HourView;
+    private OnDateTimeSetListener mOnDateTimeSetListener;
+    private DateTimePicker mDateTimePicker;  /*声明了一些私有变量，用于存储日期时间信息、24小时格式标志、监听器和日期时间选择器。 */
+
+    public interface OnDateTimeSetListener {
+        void OnDateTimeSet(AlertDialog dialog, long date);
+    }     /*定义了一个内部接口 OnDateTimeSetListener，用于接收日期时间设置事件的回调。 */
+
+    public DateTimePickerDialog(Context context, long date) {
+        super(context);   /*构造函数初始化父类 AlertDialog */
+        mDateTimePicker = new DateTimePicker(context);
+        setView(mDateTimePicker);/*创建一个 DateTimePicker 实例并设置为对话框的内容视图*/
+        mDateTimePicker.setOnDateTimeChangedListener(new OnDateTimeChangedListener() {
+            public void onDateTimeChanged(DateTimePicker view, int year, int month,
+                    int dayOfMonth, int hourOfDay, int minute) {
+                mDate.set(Calendar.YEAR, year);
+                mDate.set(Calendar.MONTH, month);
+                mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
+                mDate.set(Calendar.HOUR_OF_DAY, hourOfDay);
+                mDate.set(Calendar.MINUTE, minute);
+                updateTitle(mDate.getTimeInMillis());
+            }
+        });/*为 DateTimePicker 设置监听器，在日期时间改变时更新内部的日历对象，并调用 updateTitle 方法更新对话框标题 */
+        mDate.setTimeInMillis(date);
+        mDate.set(Calendar.SECOND, 0);
+        mDateTimePicker.setCurrentDate(mDate.getTimeInMillis());
+        setButton(context.getString(R.string.datetime_dialog_ok), this);
+        setButton2(context.getString(R.string.datetime_dialog_cancel), (OnClickListener)null);
+        set24HourView(DateFormat.is24HourFormat(this.getContext()));
+        updateTitle(mDate.getTimeInMillis());
+    }   /*初始化日期时间对象，并设置到 DateTimePicker 中。设置对话框的确认和取消按钮，并根据系统设置决定是否使用24小时制显示时间。最后更新对话框标题。 */
+
+    public void set24HourView(boolean is24HourView) {
+        mIs24HourView = is24HourView;
+    }    /*设置是否使用24小时制显示时间的方法*/
+
+    public void setOnDateTimeSetListener(OnDateTimeSetListener callBack) {
+        mOnDateTimeSetListener = callBack;
+    }    /*设置监听器的方法*/
+
+    private void updateTitle(long date) {
+        int flag =
+            DateUtils.FORMAT_SHOW_YEAR |
+            DateUtils.FORMAT_SHOW_DATE |
+            DateUtils.FORMAT_SHOW_TIME;
+        flag |= mIs24HourView ? DateUtils.FORMAT_24HOUR : DateUtils.FORMAT_24HOUR;
+        setTitle(DateUtils.formatDateTime(this.getContext(), date, flag));
+    }   /*更新对话框标题的方法，根据当前日期时间和格式化标志来显示日期时间。*/
+
+    public void onClick(DialogInterface arg0, int arg1) {
+        if (mOnDateTimeSetListener != null) {
+            mOnDateTimeSetListener.OnDateTimeSet(this, mDate.getTimeInMillis());
+        }
+    }/*实现 OnClickListener 接口的 onClick 方法，当点击对话框上的按钮时，如果设置了监听器，则调用其 OnDateTimeSet 方法*/
+
+}/*类定义结束*/

DropdownMenu.java

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+
+
+/*这段代码展示了如何在 Android 应用程序中实现一个带有弹出菜单的下拉按钮。
+这个 DropdownMenu 类封装了创建一个带有菜单的按钮所需的所有步骤。 */
+
+
+
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.ui;
+
+import android.content.Context;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.widget.Button;
+import android.widget.PopupMenu;
+import android.widget.PopupMenu.OnMenuItemClickListener;
+
+import net.micode.notes.R;
+
+public class DropdownMenu {  /*定义了一个名为 DropdownMenu 的公共类*/
+    private Button mButton;
+    private PopupMenu mPopupMenu;
+    private Menu mMenu;   /*声明了一些私有变量，分别代表按钮、弹出菜单和菜单对象。*/
+
+    public DropdownMenu(Context context, Button button, int menuId) {
+        mButton = button;
+        mButton.setBackgroundResource(R.drawable.dropdown_icon);  /*构造函数初始化成员变量，设置按钮的背景图片*/
+        mPopupMenu = new PopupMenu(context, mButton);
+        mMenu = mPopupMenu.getMenu();
+        mPopupMenu.getMenuInflater().inflate(menuId, mMenu);/*创建 PopupMenu 实例，获取菜单对象，并通过提供的菜单资源 ID 充气菜单*/
+        mButton.setOnClickListener(new OnClickListener() {
+            public void onClick(View v) {
+                mPopupMenu.show();
+            }
+        });
+    }    /*为按钮设置点击监听器，点击时显示弹出菜单*/
+
+    public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {
+        if (mPopupMenu != null) {
+            mPopupMenu.setOnMenuItemClickListener(listener);
+        }
+    }   /*设置弹出菜单项点击监听器的方法，允许外部设置监听器以便处理菜单项点击事件*/
+
+    public MenuItem findItem(int id) {
+        return mMenu.findItem(id);
+    }   /*提供一个方法用于根据资源 ID 查找菜单项*/
+
+    public void setTitle(CharSequence title) {
+        mButton.setText(title);
+    }/*设置按钮文本的方法*/
+}
+  
+  /*这个 DropdownMenu 类使得在应用程序中添加带有弹出菜单的按钮变得更加容易，通过构造函数传入上下文、按钮和菜单资源 ID，就可以轻松地创建和使用带有菜单的按钮。*/