zhangcongyu

src/net/micode/notes/ui/DateTimePicker.java

@@ -1,19 +1,3 @@
-/*
- * 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 java.text.DateFormatSymbols;
@@ -21,7 +5,6 @@ import java.util.Calendar;
 
 import net.micode.notes.R;
 
-
 import android.content.Context;
 import android.text.format.DateFormat;
 import android.view.View;
@@ -30,6 +13,7 @@ import android.widget.NumberPicker;
 
 public class DateTimePicker extends FrameLayout {
 
+    // 默认启用状态
     private static final boolean DEFAULT_ENABLE_STATE = true;
 
     private static final int HOURS_IN_HALF_DAY = 12;
@@ -46,39 +30,44 @@ public class DateTimePicker extends FrameLayout {
     private static final int AMPM_SPINNER_MIN_VAL = 0;
     private static final int AMPM_SPINNER_MAX_VAL = 1;
 
+    // 日期选择器、小时选择器、分钟选择器和上午/下午选择器
     private final NumberPicker mDateSpinner;
     private final NumberPicker mHourSpinner;
     private final NumberPicker mMinuteSpinner;
     private final NumberPicker mAmPmSpinner;
-    private Calendar mDate;
+    private Calendar mDate;  // 日历对象
 
     private String[] mDateDisplayValues = new String[DAYS_IN_ALL_WEEK];
 
-    private boolean mIsAm;
+    private boolean mIsAm;  // 是否是上午
 
-    private boolean mIs24HourView;
+    private boolean mIs24HourView;  // 是否是24小时制
 
-    private boolean mIsEnabled = DEFAULT_ENABLE_STATE;
+    private boolean mIsEnabled = DEFAULT_ENABLE_STATE;  // 是否启用标志
 
-    private boolean mInitialising;
+    private boolean mInitialising;  // 初始化标志
 
-    private OnDateTimeChangedListener mOnDateTimeChangedListener;
+    private OnDateTimeChangedListener mOnDateTimeChangedListener;  // 日期时间改变监听器
 
+    // 日期改变监听器
     private NumberPicker.OnValueChangeListener mOnDateChangedListener = new NumberPicker.OnValueChangeListener() {
         @Override
         public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
-            mDate.add(Calendar.DAY_OF_YEAR, newVal - oldVal);
-            updateDateControl();
-            onDateTimeChanged();
+            mDate.add(Calendar.DAY_OF_YEAR, newVal - oldVal);  // 改变日期
+            updateDateControl();  // 更新日期控件
+            onDateTimeChanged();  // 日期时间改变回调
         }
     };
 
+    // 小时改变监听器
     private NumberPicker.OnValueChangeListener mOnHourChangedListener = new NumberPicker.OnValueChangeListener() {
         @Override
         public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
+            // 判断日期是否改变
             boolean isDateChanged = false;
             Calendar cal = Calendar.getInstance();
             if (!mIs24HourView) {
+                // 非24小时制
                 if (!mIsAm && oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY) {
                     cal.setTimeInMillis(mDate.getTimeInMillis());
                     cal.add(Calendar.DAY_OF_YEAR, 1);
@@ -90,10 +79,11 @@ public class DateTimePicker extends FrameLayout {
                 }
                 if (oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY ||
                         oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {
-                    mIsAm = !mIsAm;
-                    updateAmPmControl();
+                    mIsAm = !mIsAm;  // 上午/下午切换
+                    updateAmPmControl();  // 更新上午/下午控件
                 }
             } else {
+                // 24小时制
                 if (oldVal == HOURS_IN_ALL_DAY - 1 && newVal == 0) {
                     cal.setTimeInMillis(mDate.getTimeInMillis());
                     cal.add(Calendar.DAY_OF_YEAR, 1);
@@ -106,7 +96,7 @@ public class DateTimePicker extends FrameLayout {
             }
             int newHour = mHourSpinner.getValue() % HOURS_IN_HALF_DAY + (mIsAm ? 0 : HOURS_IN_HALF_DAY);
             mDate.set(Calendar.HOUR_OF_DAY, newHour);
-            onDateTimeChanged();
+            onDateTimeChanged();  // 日期时间改变回调
             if (isDateChanged) {
                 setCurrentYear(cal.get(Calendar.YEAR));
                 setCurrentMonth(cal.get(Calendar.MONTH));
@@ -115,6 +105,7 @@ public class DateTimePicker extends FrameLayout {
         }
     };
 
+    // 分钟改变监听器
     private NumberPicker.OnValueChangeListener mOnMinuteChangedListener = new NumberPicker.OnValueChangeListener() {
         @Override
         public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
@@ -140,51 +131,60 @@ public class DateTimePicker extends FrameLayout {
                 }
             }
             mDate.set(Calendar.MINUTE, newVal);
-            onDateTimeChanged();
+            onDateTimeChanged();  // 日期时间改变回调
         }
     };
 
+    // 上午/下午改变监听器
     private NumberPicker.OnValueChangeListener mOnAmPmChangedListener = new NumberPicker.OnValueChangeListener() {
         @Override
         public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
-            mIsAm = !mIsAm;
+            mIsAm = !mIsAm;  // 切换上午/下午
             if (mIsAm) {
                 mDate.add(Calendar.HOUR_OF_DAY, -HOURS_IN_HALF_DAY);
             } else {
                 mDate.add(Calendar.HOUR_OF_DAY, HOURS_IN_HALF_DAY);
             }
-            updateAmPmControl();
-            onDateTimeChanged();
+            updateAmPmControl();  // 更新上午/下午控件
+            onDateTimeChanged();  // 日期时间改变回调
         }
     };
 
+    // 日期时间改变监听器接口
     public interface OnDateTimeChangedListener {
         void onDateTimeChanged(DateTimePicker view, int year, int month,
                                int dayOfMonth, int hourOfDay, int minute);
     }
 
+    // 构造函数
     public DateTimePicker(Context context) {
         this(context, System.currentTimeMillis());
     }
 
+    // 带参数的构造函数
     public DateTimePicker(Context context, long date) {
         this(context, date, DateFormat.is24HourFormat(context));
     }
 
+    // 带参数的构造函数
     public DateTimePicker(Context context, long date, boolean is24HourView) {
         super(context);
-        mDate = Calendar.getInstance();
+        mDate = Calendar.getInstance();  // 初始化日历对象
         mInitialising = true;
         mIsAm = getCurrentHourOfDay() >= HOURS_IN_HALF_DAY;
-        inflate(context, R.layout.datetime_picker, this);
+        inflate(context, R.layout.datetime_picker, this);  // 填充布局
 
+        // 初始化日期选择器
         mDateSpinner = (NumberPicker) findViewById(R.id.date);
         mDateSpinner.setMinValue(DATE_SPINNER_MIN_VAL);
         mDateSpinner.setMaxValue(DATE_SPINNER_MAX_VAL);
         mDateSpinner.setOnValueChangedListener(mOnDateChangedListener);
 
+        // 初始化小时选择器
         mHourSpinner = (NumberPicker) findViewById(R.id.hour);
         mHourSpinner.setOnValueChangedListener(mOnHourChangedListener);
+
+        // 初始化分钟选择器
         mMinuteSpinner =  (NumberPicker) findViewById(R.id.minute);
         mMinuteSpinner.setMinValue(MINUT_SPINNER_MIN_VAL);
         mMinuteSpinner.setMaxValue(MINUT_SPINNER_MAX_VAL);
@@ -192,28 +192,30 @@ public class DateTimePicker extends FrameLayout {
         mMinuteSpinner.setOnValueChangedListener(mOnMinuteChangedListener);
 
         String[] stringsForAmPm = new DateFormatSymbols().getAmPmStrings();
+
+        // 初始化上午/下午选择器
         mAmPmSpinner = (NumberPicker) findViewById(R.id.amPm);
         mAmPmSpinner.setMinValue(AMPM_SPINNER_MIN_VAL);
         mAmPmSpinner.setMaxValue(AMPM_SPINNER_MAX_VAL);
         mAmPmSpinner.setDisplayedValues(stringsForAmPm);
         mAmPmSpinner.setOnValueChangedListener(mOnAmPmChangedListener);
 
-        // update controls to initial state
+        // 更新控件到初始状态
         updateDateControl();
         updateHourControl();
         updateAmPmControl();
 
         set24HourView(is24HourView);
 
-        // set to current time
+        // 设置为当前时间
         setCurrentDate(date);
 
         setEnabled(isEnabled());
 
-        // set the content descriptions
-        mInitialising = false;
+        mInitialising = false;  // 初始化完成
     }
 
+    // 设置是否启用
     @Override
     public void setEnabled(boolean enabled) {
         if (mIsEnabled == enabled) {
@@ -227,24 +229,25 @@ public class DateTimePicker extends FrameLayout {
         mIsEnabled = enabled;
     }
 
+    // 获取是否启用
     @Override
     public boolean isEnabled() {
         return mIsEnabled;
     }
 
     /**
-     * Get the current date in millis
+     * 获取当前日期的毫秒表示
      *
-     * @return the current date in millis
+     * @return 当前日期的毫秒表示
      */
     public long getCurrentDateInTimeMillis() {
         return mDate.getTimeInMillis();
     }
 
     /**
-     * Set the current date
+     * 设置当前日期
      *
-     * @param date The current date in millis
+     * @param date 当前日期的毫秒表示
      */
     public void setCurrentDate(long date) {
         Calendar cal = Calendar.getInstance();
@@ -254,13 +257,13 @@ public class DateTimePicker extends FrameLayout {
     }
 
     /**
-     * Set the current date
+     * 设置当前日期
      *
-     * @param year The current year
-     * @param month The current month
-     * @param dayOfMonth The current dayOfMonth
-     * @param hourOfDay The current hourOfDay
-     * @param minute The current minute
+     * @param year 年
+     * @param month 月
+     * @param dayOfMonth 日
+     * @param hourOfDay 时
+     * @param minute 分
      */
     public void setCurrentDate(int year, int month,
                                int dayOfMonth, int hourOfDay, int minute) {
@@ -271,20 +274,12 @@ public class DateTimePicker extends FrameLayout {
         setCurrentMinute(minute);
     }
 
-    /**
-     * Get current year
-     *
-     * @return The current year
-     */
+    // 获取当前年份
     public int getCurrentYear() {
         return mDate.get(Calendar.YEAR);
     }
 
-    /**
-     * Set current year
-     *
-     * @param year The current year
-     */
+    // 设置当前年份
     public void setCurrentYear(int year) {
         if (!mInitialising && year == getCurrentYear()) {
             return;
@@ -294,20 +289,12 @@ public class DateTimePicker extends FrameLayout {
         onDateTimeChanged();
     }
 
-    /**
-     * Get current month in the year
-     *
-     * @return The current month in the year
-     */
+    // 获取当前月份
     public int getCurrentMonth() {
         return mDate.get(Calendar.MONTH);
     }
 
-    /**
-     * Set current month in the year
-     *
-     * @param month The month in the year
-     */
+    // 设置当前月份
     public void setCurrentMonth(int month) {
         if (!mInitialising && month == getCurrentMonth()) {
             return;
@@ -317,20 +304,12 @@ public class DateTimePicker extends FrameLayout {
         onDateTimeChanged();
     }
 
-    /**
-     * Get current day of the month
-     *
-     * @return The day of the month
-     */
+    // 获取当前日期
     public int getCurrentDay() {
         return mDate.get(Calendar.DAY_OF_MONTH);
     }
 
-    /**
-     * Set current day of the month
-     *
-     * @param dayOfMonth The day of the month
-     */
+    // 设置当前日期
     public void setCurrentDay(int dayOfMonth) {
         if (!mInitialising && dayOfMonth == getCurrentDay()) {
             return;
@@ -340,14 +319,12 @@ public class DateTimePicker extends FrameLayout {
         onDateTimeChanged();
     }
 
-    /**
-     * Get current hour in 24 hour mode, in the range (0~23)
-     * @return The current hour in 24 hour mode
-     */
+    // 获取24小时模式下的当前小时
     public int getCurrentHourOfDay() {
         return mDate.get(Calendar.HOUR_OF_DAY);
     }
 
+    // 获取当前小时
     private int getCurrentHour() {
         if (mIs24HourView){
             return getCurrentHourOfDay();
@@ -361,11 +338,7 @@ public class DateTimePicker extends FrameLayout {
         }
     }
 
-    /**
-     * Set current hour in 24 hour mode, in the range (0~23)
-     *
-     * @param hourOfDay
-     */
+    // 设置当前小时
     public void setCurrentHour(int hourOfDay) {
         if (!mInitialising && hourOfDay == getCurrentHourOfDay()) {
             return;
@@ -389,18 +362,12 @@ public class DateTimePicker extends FrameLayout {
         onDateTimeChanged();
     }
 
-    /**
-     * Get currentMinute
-     *
-     * @return The Current Minute
-     */
+    // 获取当前分钟
     public int getCurrentMinute() {
         return mDate.get(Calendar.MINUTE);
     }
 
-    /**
-     * Set current minute
-     */
+    // 设置当前分钟
     public void setCurrentMinute(int minute) {
         if (!mInitialising && minute == getCurrentMinute()) {
             return;
@@ -411,16 +378,18 @@ public class DateTimePicker extends FrameLayout {
     }
 
     /**
-     * @return true if this is in 24 hour view else false.
+     * 是否是24小时制
+     *
+     * @return 如果是24小时制返回true，否则返回false
      */
     public boolean is24HourView () {
         return mIs24HourView;
     }
 
     /**
-     * Set whether in 24 hour or AM/PM mode.
+     * 设置是否是24小时制或上午/下午模式
      *
-     * @param is24HourView True for 24 hour mode. False for AM/PM mode.
+     * @param is24HourView true 表示24小时制，false 表示上午/下午模式
      */
     public void set24HourView(boolean is24HourView) {
         if (mIs24HourView == is24HourView) {
@@ -434,6 +403,7 @@ public class DateTimePicker extends FrameLayout {
         updateAmPmControl();
     }
 
+    // 更新日期控件
     private void updateDateControl() {
         Calendar cal = Calendar.getInstance();
         cal.setTimeInMillis(mDate.getTimeInMillis());
@@ -448,6 +418,7 @@ public class DateTimePicker extends FrameLayout {
         mDateSpinner.invalidate();
     }
 
+    // 更新上午/下午控件
     private void updateAmPmControl() {
         if (mIs24HourView) {
             mAmPmSpinner.setVisibility(View.GONE);
@@ -458,6 +429,7 @@ public class DateTimePicker extends FrameLayout {
         }
     }
 
+    // 更新小时控件
     private void updateHourControl() {
         if (mIs24HourView) {
             mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW);
@@ -469,13 +441,15 @@ public class DateTimePicker extends FrameLayout {
     }
 
     /**
-     * Set the callback that indicates the 'Set' button has been pressed.
-     * @param callback the callback, if null will do nothing
+     * 设置日期时间改变监听器
+     *
+     * @param callback 回调函数，如果为null将不进行任何操作
      */
     public void setOnDateTimeChangedListener(OnDateTimeChangedListener callback) {
         mOnDateTimeChangedListener = callback;
     }
 
+    // 日期时间改变回调
     private void onDateTimeChanged() {
         if (mOnDateTimeChangedListener != null) {
             mOnDateTimeChangedListener.onDateTimeChanged(this, getCurrentYear(),

src/net/micode/notes/ui/DateTimePickerDialog.java

@@ -1,17 +1,20 @@
-/*
- * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+/**
+ * DateTimePickerDialog类实现了一个日期时间选择对话框，用于在Android应用程序中选择特定的日期和时间。
  *
- * 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
+ * 该类继承自AlertDialog，并实现了OnClickListener接口来处理“确定”按钮的点击事件。
+ * 它包含一个回调接口OnDateTimeSetListener，用于在日期时间发生更改时通知用户。
  *
- *        http://www.apache.org/licenses/LICENSE-2.0
+ * 日期和时间的选择由内部的DateTimePicker完成，它是一个自定义的View。
  *
- * 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.
+ * 构造函数接收一个Context和一个初始日期时间值，并进行了相应的初始化操作。
+ *
+ * 主要方法包括set24HourView、setOnDateTimeSetListener和updateTitle。
+ *
+ * set24HourView用于设置是否使用24小时制；
+ * setOnDateTimeSetListener用于设置OnDateTimeSetListener回调接口；
+ * updateTitle用于在日期时间更改时更新对话框的标题。
+ *
+ * onClick方法是OnClickListener接口的回调方法，当用户点击“确定”按钮时，会触发该方法，其中会回调OnDateTimeSetListener接口的回调方法，通知用户已更改日期时间。
  */
 
 package net.micode.notes.ui;
@@ -31,45 +34,45 @@ import android.text.format.DateUtils;
 
 public class DateTimePickerDialog extends AlertDialog implements OnClickListener {
 
-    private Calendar mDate = Calendar.getInstance();
-    private boolean mIs24HourView;
-    private OnDateTimeSetListener mOnDateTimeSetListener;
-    private DateTimePicker mDateTimePicker;
+    private Calendar mDate = Calendar.getInstance(); // 创建一个表示日期时间的Calendar对象，初始化为当前时间
+    private boolean mIs24HourView; // 是否使用24小时制
+    private OnDateTimeSetListener mOnDateTimeSetListener; // 回调接口，用于在日期时间发生更改时通知用户
+    private DateTimePicker mDateTimePicker; // 日期时间选择器
 
     public interface OnDateTimeSetListener {
-        void OnDateTimeSet(AlertDialog dialog, long date);
+        void OnDateTimeSet(AlertDialog dialog, long date); // 回调方法，用于通知用户已更改日期时间
     }
 
     public DateTimePickerDialog(Context context, long date) {
-        super(context);
-        mDateTimePicker = new DateTimePicker(context);
-        setView(mDateTimePicker);
-        mDateTimePicker.setOnDateTimeChangedListener(new OnDateTimeChangedListener() {
+        super(context); // 调用父类的构造方法
+        mDateTimePicker = new DateTimePicker(context); // 创建一个DateTimePicker对象
+        setView(mDateTimePicker); // 将DateTimePicker设置为对话框的视图
+        mDateTimePicker.setOnDateTimeChangedListener(new OnDateTimeChangedListener() { // 设置日期时间选择器的回调接口
             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());
+                mDate.set(Calendar.YEAR, year); // 设置年份
+                mDate.set(Calendar.MONTH, month); // 设置月份
+                mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth); // 设置日
+                mDate.set(Calendar.HOUR_OF_DAY, hourOfDay); // 设置小时
+                mDate.set(Calendar.MINUTE, minute); // 设置分钟
+                updateTitle(mDate.getTimeInMillis()); // 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());
+        mDate.setTimeInMillis(date); // 设置Calendar对象的时间值为传入的时间值
+        mDate.set(Calendar.SECOND, 0); // 将秒数设为0
+        mDateTimePicker.setCurrentDate(mDate.getTimeInMillis()); // 设置日期时间选择器的初始值
+        setButton(context.getString(R.string.datetime_dialog_ok), this); // 设置“确定”按钮，并将当前对象作为OnClickListener
+        setButton2(context.getString(R.string.datetime_dialog_cancel), (OnClickListener)null); // 设置“取消”按钮，点击不做任何操作
+        set24HourView(DateFormat.is24HourFormat(this.getContext())); // 根据系统设置，设置是否使用24小时制
+        updateTitle(mDate.getTimeInMillis()); // 更新对话框标题
     }
 
     public void set24HourView(boolean is24HourView) {
-        mIs24HourView = is24HourView;
+        mIs24HourView = is24HourView; // 设置是否使用24小时制
     }
 
     public void setOnDateTimeSetListener(OnDateTimeSetListener callBack) {
-        mOnDateTimeSetListener = callBack;
+        mOnDateTimeSetListener = callBack; // 设置回调接口，用于在日期时间发生更改时通知用户
     }
 
     private void updateTitle(long date) {
@@ -77,13 +80,13 @@ public class DateTimePickerDialog extends AlertDialog implements OnClickListener
                 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));
+        flag |= mIs24HourView ? DateUtils.FORMAT_24HOUR : DateUtils.FORMAT_24HOUR; // 如果使用24小时制，则加上DateUtils.FORMAT_24HOUR，否则加上0
+        setTitle(DateUtils.formatDateTime(this.getContext(), date, flag)); // 更新对话框标题
     }
 
-    public void onClick(DialogInterface arg0, int arg1) {
+    public void onClick(DialogInterface arg0, int arg1) { // OnClickListener接口的回调方法，用户点击“确定”按钮时触发
         if (mOnDateTimeSetListener != null) {
-            mOnDateTimeSetListener.OnDateTimeSet(this, mDate.getTimeInMillis());
+            mOnDateTimeSetListener.OnDateTimeSet(this, mDate.getTimeInMillis()); // 调用回调接口的回调方法，通知用户已更改日期时间
         }
     }
 

src/net/micode/notes/ui/DropdownMenu.java

@@ -1,17 +1,20 @@
-/*
- * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+/**
+ * DropdownMenu类实现了下拉菜单功能，用于在Android应用程序中展示一个弹出式菜单。
  *
- * 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
+ * 它包含一个回调接口OnMenuItemClickListener，用于在用户选择一个菜单项时通知应用程序。
  *
- *        http://www.apache.org/licenses/LICENSE-2.0
+ * 构造函数接收一个Context、一个Button和一个菜单资源ID，并进行了相应的初始化操作。
  *
- * 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.
+ * 主要方法包括setOnDropdownMenuItemClickListener、findItem和setTitle。
+ *
+ * setOnDropdownMenuItemClickListener用于设置OnMenuItemClickListener回调接口；
+ * findItem用于查找指定ID的菜单项；
+ * setTitle用于设置下拉菜单按钮的文本。
+ *
+ * 构造函数中创建了一个PopupWindow对象和一个Menu对象，它们用于显示下拉菜单和保存菜单项。
+ * 在构造函数中还将菜单资源ID传递给MenuInflater，用于加载菜单项，并将下拉菜单绑定到指定的Button上。
+ *
+ * onClick方法是OnClickListener接口的回调方法，用于在用户点击下拉菜单按钮时展示菜单。
  */
 
 package net.micode.notes.ui;
@@ -28,34 +31,39 @@ import android.widget.PopupMenu.OnMenuItemClickListener;
 import net.micode.notes.R;
 
 public class DropdownMenu {
-    private Button mButton;
-    private PopupMenu mPopupMenu;
-    private Menu mMenu;
+    private Button mButton; // 下拉菜单绑定的Button
+    private PopupMenu mPopupMenu; // 弹出式菜单
+    private Menu mMenu; // 菜单
+
+    public interface OnMenuItemClickListener {
+        boolean onMenuItemClick(MenuItem item); // 回调方法，用于在用户选择一个菜单项时通知应用程序
+    }
 
+    // 构造函数接收一个Context、一个Button和一个菜单资源ID，并进行了相应的初始化操作。
     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);
-        mButton.setOnClickListener(new OnClickListener() {
+        mPopupMenu.getMenuInflater().inflate(menuId, mMenu); // 加载菜单项
+        mButton.setOnClickListener(new OnClickListener() { // 设置Button的点击事件
             public void onClick(View v) {
-                mPopupMenu.show();
+                mPopupMenu.show(); // 展示下拉菜单
             }
         });
     }
 
     public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {
         if (mPopupMenu != null) {
-            mPopupMenu.setOnMenuItemClickListener(listener);
+            mPopupMenu.setOnMenuItemClickListener(listener); // 设置OnMenuItemClickListener回调接口
         }
     }
 
     public MenuItem findItem(int id) {
-        return mMenu.findItem(id);
+        return mMenu.findItem(id); // 查找指定ID的菜单项
     }
 
     public void setTitle(CharSequence title) {
-        mButton.setText(title);
+        mButton.setText(title); // 设置下拉菜单按钮的文本
     }
 }

src/net/micode/notes/ui/FoldersListAdapter.java

@@ -1,19 +1,19 @@
 /*
- * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+* FoldersListAdapter类是一个继承自CursorAdapter的适配器类，用于显示文件夹列表。
+* 它接收一个Cursor对象作为数据源，并根据数据源的内容来展示文件夹列表项。
 *
- * 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
+* 构造函数接收一个Context和一个Cursor对象，并进行了相应的初始化操作。
+* 主要方法包括newView和bindView。
 *
- *        http://www.apache.org/licenses/LICENSE-2.0
+* newView方法在适配器需要创建一个新的视图时被调用，返回一个FolderListItem对象作为列表项的视图。
+* bindView方法在适配器需要绑定数据到视图时被调用，根据Cursor中的数据来更新FolderListItem的内容。
 *
- * 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.
+* getFolderName方法用于获取指定位置的文件夹名称。
+*
+* FolderListItem是一个自定义的LinearLayout子类，用于表示文件夹列表项的视图。
+* 构造函数中将folder_list_item布局文件实例化，并通过findViewById找到对应的TextView。
+* bind方法用于更新文件夹名称的显示。
 */
-
 package net.micode.notes.ui;
 
 import android.content.Context;
@@ -28,53 +28,58 @@ import net.micode.notes.R;
 import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 
-
 public class FoldersListAdapter extends CursorAdapter {
+    // 声明常量数组PROJECTION，用于指定需要查询的列名
     public static final String[] PROJECTION = {
             NoteColumns.ID,
             NoteColumns.SNIPPET
     };
 
+    // 声明常量ID_COLUMN和NAME_COLUMN，代表查询结果中ID和名称所在的列索引
     public static final int ID_COLUMN = 0;
     public static final int NAME_COLUMN = 1;
 
+    // 构造函数，接收Context和Cursor对象，并调用父类的构造函数进行初始化
     public FoldersListAdapter(Context context, Cursor c) {
         super(context, c);
-        // TODO Auto-generated constructor stub
     }
 
+    // 当需要创建新的视图时被调用，返回一个FolderListItem对象作为列表项的视图
     @Override
     public View newView(Context context, Cursor cursor, ViewGroup parent) {
         return new FolderListItem(context);
     }
 
+    // 当需要将数据绑定到视图时被调用，根据Cursor中的数据更新FolderListItem的内容
     @Override
     public void bindView(View view, Context context, Cursor cursor) {
         if (view instanceof FolderListItem) {
-            String folderName = (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context
-                    .getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
+            // 根据查询结果中的ID和名称更新FolderListItem的内容
+            String folderName = (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context.getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
             ((FolderListItem) view).bind(folderName);
         }
     }
 
+    // 获取指定位置的文件夹名称
     public String getFolderName(Context context, int position) {
         Cursor cursor = (Cursor) getItem(position);
-        return (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context
-                .getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
+        return (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context.getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
     }
 
+    // FolderListItem是一个自定义的LinearLayout子类，用于表示文件夹列表项的视图
     private class FolderListItem extends LinearLayout {
         private TextView mName;
 
+        // 构造函数中将folder_list_item布局文件实例化，并通过findViewById找到对应的TextView
         public FolderListItem(Context context) {
             super(context);
             inflate(context, R.layout.folder_list_item, this);
-            mName = (TextView) findViewById(R.id.tv_folder_name);
+            mName = findViewById(R.id.tv_folder_name);
         }
 
+        // 更新文件夹名称的显示
         public void bind(String name) {
             mName.setText(name);
         }
     }
-
 }