修复操作数据库时的一个bug(cursor.close())

sleepingAnt · Dec 12, 2012 · c84e98d · c84e98d
1 parent 6c1ec63
commit c84e98d
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Showing 4 changed files with 152 additions and 141 deletions.
diff --git a/bin/Timetable.apk b/bin/Timetable.apk
diff --git a/bin/classes.dex b/bin/classes.dex
diff --git a/bin/resources.ap_ b/bin/resources.ap_
diff --git a/src/com/ant/timetable/db/MainDB.java b/src/com/ant/timetable/db/MainDB.java
@@ -10,34 +10,85 @@
 import android.util.Log;
 
 public class MainDB extends SQLiteOpenHelper {
-	@Override
-	public synchronized void close() {
-		super.close();
-		closeDB();
-	}
-
 	private static final String dbName = "timetable.db";
-	private SQLiteDatabase db;
 
+	private SQLiteDatabase db;
 	public MainDB(Context context) {
 		super(context, dbName, null, 1);
 	}
 
-	@Override
-	public void onCreate(SQLiteDatabase sdb) {
-		String sqlTableCourse = "create table table_course(t_week integer,t_section integer,"
-				+ "course_name varchar(50),course_classroom varchar(50),course_teacher varchar(50)"
-				+ ")";
-		String sqlTableCourseName = "create table table_course_name(course_name varchar(50))";
-		sdb.execSQL(sqlTableCourse);
-		sdb.execSQL(sqlTableCourseName);
+	/**
+	 * 添加课程信息
+	 * 
+	 * @param week
+	 *            第几周
+	 * @param section
+	 *            第几节
+	 * @param name
+	 *            课程名字
+	 * @param room
+	 *            上课教室
+	 * @param teacher
+	 *            上课教师
+	 * @return 成功则返回true
+	 */
+	public boolean addCourse(int week, int section, String courseName,
+			String classroom, String teacher) {
+		boolean result = false;
+		try {
+			db = this.getWritableDatabase();
+			String sql = String
+					.format("insert into table_course (t_week,t_section,course_name,course_classroom,course_teacher)"
+							+ " values (%d,%d,'%s','%s','%s')", week, section,
+							courseName, classroom, teacher);
+			db.execSQL(sql);
+			closeDB();
+			result = true;
+		} catch (Exception e) {
+			closeDB();
+		}
+		return result;
+
 	}
 
-	@Override
-	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+	/**
+	 * 添加课程信息（用于编辑课程表时的自动提示）
+	 * @param courseName
+	 * @return
+	 */
+	public boolean addNewCourseName(String courseName) {
+		boolean result = false;
+		try {
+			db = this.getWritableDatabase();
+			String sql = String
+					.format("insert into table_course_name (course_name) values ('%s')", courseName);
+			if(!isCourseNameExist(courseName)) {
+				db.execSQL(sql);
+			}
+			closeDB();
+			result = true;
+		} catch (Exception e) {
+			result = false;
+			closeDB();
+		}
+		return result;
+	}
 
+	@Override
+	public synchronized void close() {
+		super.close();
+		closeDB();
 	}
 
+	/**
+	 * 关闭打开的数据库
+	 */
+	public void closeDB() {
+		if (db.isOpen()) {
+			db.close();
+		}
+	}
+
 	/**
 	 * 清空课程表数据
 	 * @return
@@ -56,6 +107,7 @@ public boolean deleteAllCourse() {
 			closeDB();
 		} catch (Exception e) {
 			result = false;
+			closeDB();
 		}
 		return result;
 	}
@@ -76,26 +128,68 @@ public boolean deleteAllCourseName() {
 			closeDB();
 		} catch (Exception e) {
 			result = false;
+			closeDB();
 		}
 		return result;
 	}
 
 	/**
-	 * 添加课程信息（用于编辑课程表时的自动提示）
-	 * @param courseName
-	 * @return
+	 * 修改课程信息
+	 * 
+	 * @param week
+	 *            第几周
+	 * @param section
+	 *            第几节
+	 * @param name
+	 *            课程名字
+	 * @param room
+	 *            上课教室
+	 * @param teacher
+	 *            上课教师
+	 * @return 成功则返回true
 	 */
-	public boolean addNewCourseName(String courseName) {
+	public boolean editCourse(int week, int section, String courseName,
+			String classroom, String teacher) {
 		boolean result = false;
 		try {
 			db = this.getWritableDatabase();
 			String sql = String
-					.format("insert into table_course_name (course_name) values ('%s')", courseName);
-			if(!isCourseNameExist(courseName)) {
-				db.execSQL(sql);
-			}
+					.format("update table_course set course_name='%s',course_classroom='%s',course_teacher='%s'"
+							+ " where t_week="
+							+ week
+							+ " and t_section="
+							+ section, courseName, classroom, teacher);
+			db.execSQL(sql);
 			closeDB();
 			result = true;
+		} catch (Exception e) {
+			closeDB();
+		}
+		return result;
+	}
+
+	/**
+	 * 判断要更新的课程信息在更新之前是否为空
+	 * 
+	 * @param week
+	 *            准备更新的课程是第几周
+	 * @param section
+	 *            准备更新的课程是第几节
+	 * @return 如果为空返回false,不为空返回true
+	 */
+	public boolean isCourseExist(int week, int section) {
+		boolean result = true;
+		try {
+			db = this.getWritableDatabase();
+			String sql = "select course_name from table_course where t_week="
+					+ week + " and t_section=" + section;
+			Cursor cursor = db.rawQuery(sql, null);
+			if (cursor.getCount() == 0) {
+				result = false;
+			}
+			cursor.close();
+			Log.i("my", "count" + cursor.getCount());
+			closeDB();
 		} catch (Exception e) {
 			result = false;
 		}
@@ -115,24 +209,26 @@ private boolean isCourseNameExist(String courseName) {
 		if(cursor.getCount() == 0) {
 			result = false;
 		}
+		cursor.close();
+		closeDB();
 		return result;
 	}
 
-	/**
-	 * 获取课程名称（用于编辑课程表时的自动提示）
-	 * @return
-	 */
-	public List<String> queryCourseName() {
-		List<String> list = new ArrayList<String>();
-		db = this.getWritableDatabase();
-		String sql = "select * from table_course_name";
-		Cursor cursor = db.rawQuery(sql, null);
-		while(cursor.moveToNext()) {
-			list.add(cursor.getString(0));
-		}
-		return list;
+	@Override
+	public void onCreate(SQLiteDatabase sdb) {
+		String sqlTableCourse = "create table table_course(t_week integer,t_section integer,"
+				+ "course_name varchar(50),course_classroom varchar(50),course_teacher varchar(50)"
+				+ ")";
+		String sqlTableCourseName = "create table table_course_name(course_name varchar(50))";
+		sdb.execSQL(sqlTableCourse);
+		sdb.execSQL(sqlTableCourseName);
 	}
-
+
+	@Override
+	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+
+	}
+
 	/**
 	 * 查询一条课程的相关信息（包括课程名称、老师、上课地点）
 	 * @param week 当前课程所在的周
@@ -149,11 +245,12 @@ public Course queryCourse(int week, int section) {
 					+ week + " and t_section=" + section;
 			Cursor cursor = db.rawQuery(sql, null);
 			while(cursor.moveToNext()) {
-				myCourse.classroom = cursor.getString(3);
-				myCourse.courseName = cursor.getString(2);
-				myCourse.teacher = cursor.getString(4);
-				Log.i("my", "courseName" + cursor.getString(2));
+				myCourse.classroom = cursor.getString(cursor.getColumnIndex("course_classroom"));
+				myCourse.courseName = cursor.getString(cursor.getColumnIndex("course_name"));
+				myCourse.teacher = cursor.getString(cursor.getColumnIndex("course_teacher"));
+				Log.i("my", "courseName" + cursor.getString(cursor.getColumnIndex("course_name")));
 			}
+			cursor.close();
 			closeDB();
 		} catch (Exception e) {
 			myCourse.classroom = "上课地点";
@@ -165,108 +262,22 @@ public Course queryCourse(int week, int section) {
 		}
 		return myCourse;
 	}
-
-	/**
-	 * 判断要更新的课程信息在更新之前是否为空
-	 * 
-	 * @param week
-	 *            准备更新的课程是第几周
-	 * @param section
-	 *            准备更新的课程是第几节
-	 * @return 如果为空返回false,不为空返回true
-	 */
-	public boolean isCourseExist(int week, int section) {
-		boolean result = true;
-		try {
-			db = this.getWritableDatabase();
-			String sql = "select course_name from table_course where t_week="
-					+ week + " and t_section=" + section;
-			Cursor cursor = db.rawQuery(sql, null);
-			if (cursor.getCount() == 0) {
-				result = false;
-			}
-			Log.i("my", "count" + cursor.getCount());
-			closeDB();
-		} catch (Exception e) {
-			result = false;
-		}
-		return result;
-	}
-
-	/**
-	 * 添加课程信息
-	 * 
-	 * @param week
-	 *            第几周
-	 * @param section
-	 *            第几节
-	 * @param name
-	 *            课程名字
-	 * @param room
-	 *            上课教室
-	 * @param teacher
-	 *            上课教师
-	 * @return 成功则返回true
-	 */
-	public boolean addCourse(int week, int section, String courseName,
-			String classroom, String teacher) {
-		boolean result = false;
-		try {
-			db = this.getWritableDatabase();
-			String sql = String
-					.format("insert into table_course (t_week,t_section,course_name,course_classroom,course_teacher)"
-							+ " values (%d,%d,'%s','%s','%s')", week, section,
-							courseName, classroom, teacher);
-			db.execSQL(sql);
-			closeDB();
-			result = true;
-		} catch (Exception e) {
-		}
-		return result;
-
-	}
-
-	/**
-	 * 修改课程信息
-	 * 
-	 * @param week
-	 *            第几周
-	 * @param section
-	 *            第几节
-	 * @param name
-	 *            课程名字
-	 * @param room
-	 *            上课教室
-	 * @param teacher
-	 *            上课教师
-	 * @return 成功则返回true
-	 */
-	public boolean editCourse(int week, int section, String courseName,
-			String classroom, String teacher) {
-		boolean result = false;
-		try {
-			db = this.getWritableDatabase();
-			String sql = String
-					.format("update table_course set course_name='%s',course_classroom='%s',course_teacher='%s'"
-							+ " where t_week="
-							+ week
-							+ " and t_section="
-							+ section, courseName, classroom, teacher);
-			db.execSQL(sql);
-			closeDB();
-			result = true;
-		} catch (Exception e) {
-		}
-		return result;
-	}
 
 	/**
-	 * 关闭打开的数据库
+	 * 获取课程名称（用于编辑课程表时的自动提示）
+	 * @return
 	 */
-	public void closeDB() {
-		if (db.isOpen()) {
-			db.close();
+	public List<String> queryCourseName() {
+		List<String> list = new ArrayList<String>();
+		db = this.getWritableDatabase();
+		String sql = "select * from table_course_name";
+		Cursor cursor = db.rawQuery(sql, null);
+		while(cursor.moveToNext()) {
+			list.add(cursor.getString(0));
 		}
+		cursor.close();
+		closeDB();
+		return list;
 	}
 
 }