添加注释

src/Notes-master1/app/src/main/java/net/micode/notes/data/Contact.java

@@ -26,9 +26,12 @@ import android.util.Log;
 import java.util.HashMap;
 
 public class Contact {
+    // 定义一个HashMap类型的静态变量sContactCache
     private static HashMap<String, String> sContactCache;
+    // 定义一个字符串类型的静态变量TAG
     private static final String TAG = "Contact";
 
+    // 定义一个字符串类型的静态变量CALLER_ID_SELECTION
     private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
     + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
     + " AND " + Data.RAW_CONTACT_ID + " IN "
@@ -36,17 +39,23 @@ public class Contact {
             + " FROM phone_lookup"
             + " WHERE min_match = '+')";
 
-    public static String getContact(Context context, String phoneNumber) {
+   public static String getContact(Context context, String phoneNumber) {
+        // 判断sContactCache是否为空
         if(sContactCache == null) {
+            // 初始化sContactCache
             sContactCache = new HashMap<String, String>();
         }
 
+        // 判断sContactCache中是否包含phoneNumber
         if(sContactCache.containsKey(phoneNumber)) {
+            // 返回sContactCache中phoneNumber对应的value
             return sContactCache.get(phoneNumber);
         }
 
+        // 替换+号，生成查询语句
         String selection = CALLER_ID_SELECTION.replace("+",
                 PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        // 查询数据
         Cursor cursor = context.getContentResolver().query(
                 Data.CONTENT_URI,
                 new String [] { Phone.DISPLAY_NAME },
@@ -54,10 +63,14 @@ public class Contact {
                 new String[] { phoneNumber },
                 null);
 
+        // 判断cursor是否为空
         if (cursor != null && cursor.moveToFirst()) {
             try {
+                // 获取查询结果
                 String name = cursor.getString(0);
+                // 将查询结果存入sContactCache中
                 sContactCache.put(phoneNumber, name);
+                // 返回查询结果
                 return name;
             } catch (IndexOutOfBoundsException e) {
                 Log.e(TAG, " Cursor get string error " + e.toString());
@@ -70,4 +83,4 @@ public class Contact {
             return null;
         }
     }
-}
+}