我正在编写以下代码，此代码用于创建一个调用 class 的类DataBaseAdapter。该类DataBaseAdapter负责所有数据库连接，并且有用于在数据库中存储值的方法。：
public class Main extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DataBaseAdapter db = new DataBaseAdapter(getApplicationContext());
Alarm al = new Alarm(1,"qwer",new int[] {1,1,1,0,1,0,1}, 1, 382562495,"App", 1);
db.addAlarm(al);
ScrollView sc= (ScrollView) findViewById(R.id.scrollBody);
TableLayout tb = db.getAllAlarmList(getApplicationContext());
sc.addView(tb);
}
}
这是我的日志：
03-13 17:09:33.388: D/SqliteDatabaseCpp(1095): Registering sqlite logging func: /data/data/com.example.devicecontrolpanel/databases/AlarmSystem
03-13 17:09:33.408: D/SqliteDatabaseCpp(1095): DB info: open db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, flag = 6, cannot stat file, errno = 2, message = No such file or directory
03-13 17:09:33.408: D/SqliteDatabaseCpp(1095): DB info: path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle: 0x8ccc98, type: w, r/w: (0,1), mode: truncate, disk free size: 777 M
03-13 17:09:33.588: D/SqliteDatabaseCpp(1095): DB info: close db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle = 0x8ccc98, type = w, r/w = (0, 0)
03-13 17:09:33.588: D/SqliteDatabaseCpp(1095): DB info: open db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, flag = 6, file size = 4096
03-13 17:09:33.588: D/SqliteDatabaseCpp(1095): DB info: path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle: 0x8f3100, type: w, r/w: (0,1), mode: truncate, disk free size: 777 M
03-13 17:09:33.588: D/SqliteDatabaseCpp(1095): DB info: close db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle = 0x8f3100, type = w, r/w = (0, 0)
03-13 17:09:33.598: D/AndroidRuntime(1095): Shutting down VM
03-13 17:09:33.598: W/dalvikvm(1095): threadid=1: thread exiting with uncaught exception (group=0x40ae0228)
03-13 17:09:33.618: E/AndroidRuntime(1095): FATAL EXCEPTION: main
03-13 17:09:33.618: E/AndroidRuntime(1095): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.devicecontrolpanel/com.example.devicecontrolpanel.Main}: java.lang.IllegalStateException: database /data/data/com.example.devicecontrolpanel/databases/AlarmSystem (conn# 0) already closed
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2205)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2240)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.ActivityThread.access$600(ActivityThread.java:139)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1262)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.os.Handler.dispatchMessage(Handler.java:99)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.os.Looper.loop(Looper.java:156)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.ActivityThread.main(ActivityThread.java:4987)
03-13 17:09:33.618: E/AndroidRuntime(1095): at java.lang.reflect.Method.invokeNative(Native Method)
03-13 17:09:33.618: E/AndroidRuntime(1095): at java.lang.reflect.Method.invoke(Method.java:511)
03-13 17:09:33.618: E/AndroidRuntime(1095): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-13 17:09:33.618: E/AndroidRuntime(1095): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-13 17:09:33.618: E/AndroidRuntime(1095): at dalvik.system.NativeStart.main(Native Method)
03-13 17:09:33.618: E/AndroidRuntime(1095): Caused by: java.lang.IllegalStateException: database /data/data/com.example.devicecontrolpanel/databases/AlarmSystem (conn# 0) already closed
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.database.sqlite.SQLiteDatabase.verifyDbIsOpen(SQLiteDatabase.java:2194)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:448)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:435)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:79)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:176)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:168)
03-13 17:09:33.618: E/AndroidRuntime(1095): at com.example.devicecontrolpanel.DataBaseAdapter.getAlarmsCount(DataBaseAdapter.java:190)
03-13 17:09:33.618: E/AndroidRuntime(1095): at com.example.devicecontrolpanel.DataBaseAdapter.getAllAlarmList(DataBaseAdapter.java:117)
03-13 17:09:33.618: E/AndroidRuntime(1095): at com.example.devicecontrolpanel.Main.onCreate(Main.java:19)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.Activity.performCreate(Activity.java:4538)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
03-13 17:09:33.618: E/AndroidRuntime(1095): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2161)
03-13 17:09:33.618: E/AndroidRuntime(1095): ... 11 more
03-13 17:16:48.144: D/SqliteDatabaseCpp(2080): Registering sqlite logging func: /data/data/com.example.devicecontrolpanel/databases/AlarmSystem
03-13 17:16:48.144: D/SqliteDatabaseCpp(2080): DB info: open db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, flag = 6, cannot stat file, errno = 2, message = No such file or directory
03-13 17:16:48.164: D/SqliteDatabaseCpp(2080): DB info: path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle: 0x86b220, type: w, r/w: (0,1), mode: truncate, disk free size: 777 M
03-13 17:16:48.384: D/SqliteDatabaseCpp(2080): DB info: close db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle = 0x86b220, type = w, r/w = (0, 0)
03-13 17:16:48.384: D/SqliteDatabaseCpp(2080): DB info: open db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, flag = 6, file size = 5120
03-13 17:16:48.384: D/SqliteDatabaseCpp(2080): DB info: path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle: 0x897800, type: w, r/w: (0,1), mode: truncate, disk free size: 777 M
03-13 17:16:48.384: D/SqliteDatabaseCpp(2080): DB info: close db, path = /data/data/com.example.devicecontrolpanel/databases , key = 9lYvmWqw, handle = 0x897800, type = w, r/w = (0, 0)
03-13 17:16:48.394: D/AndroidRuntime(2080): Shutting down VM
03-13 17:16:48.414: W/dalvikvm(2080): threadid=1: thread exiting with uncaught exception (group=0x40ae0228)
03-13 17:16:48.424: E/AndroidRuntime(2080): FATAL EXCEPTION: main
03-13 17:16:48.424: E/AndroidRuntime(2080): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.devicecontrolpanel/com.example.devicecontrolpanel.Main}: java.lang.IllegalStateException: database /data/data/com.example.devicecontrolpanel/databases/AlarmSystem (conn# 0) already closed
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2205)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2240)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.ActivityThread.access$600(ActivityThread.java:139)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1262)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.os.Handler.dispatchMessage(Handler.java:99)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.os.Looper.loop(Looper.java:156)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.ActivityThread.main(ActivityThread.java:4987)
03-13 17:16:48.424: E/AndroidRuntime(2080): at java.lang.reflect.Method.invokeNative(Native Method)
03-13 17:16:48.424: E/AndroidRuntime(2080): at java.lang.reflect.Method.invoke(Method.java:511)
03-13 17:16:48.424: E/AndroidRuntime(2080): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-13 17:16:48.424: E/AndroidRuntime(2080): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-13 17:16:48.424: E/AndroidRuntime(2080): at dalvik.system.NativeStart.main(Native Method)
03-13 17:16:48.424: E/AndroidRuntime(2080): Caused by: java.lang.IllegalStateException: database /data/data/com.example.devicecontrolpanel/databases/AlarmSystem (conn# 0) already closed
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.database.sqlite.SQLiteDatabase.verifyDbIsOpen(SQLiteDatabase.java:2194)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:448)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:435)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:79)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:176)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:168)
03-13 17:16:48.424: E/AndroidRuntime(2080): at com.example.devicecontrolpanel.DataBaseAdapter.getAlarmsCount(DataBaseAdapter.java:196)
03-13 17:16:48.424: E/AndroidRuntime(2080): at com.example.devicecontrolpanel.DataBaseAdapter.getAllAlarmList(DataBaseAdapter.java:123)
03-13 17:16:48.424: E/AndroidRuntime(2080): at com.example.devicecontrolpanel.Main.onCreate(Main.java:19)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.Activity.performCreate(Activity.java:4538)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1071)
03-13 17:16:48.424: E/AndroidRuntime(2080): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2161)
03-13 17:16:48.424: E/AndroidRuntime(2080): ... 11 more
我收到错误，SQL 异常，数据库已经关闭。但我不明白为什么以及如何。？该怎么办。请帮忙。
这是 getAllAlarmList 的代码：
public Alarm getAlarm(int id)
{
SQLiteDatabase db = this.getReadableDatabase();
String[] colum = {KEY_ALARM_ID, KEY_DESC, KEY_REPEAT_DAY, KEY_REPEAT_TYPE, KEY_CALENDAR, KEY_APP, KEY_ACTIVE};
Cursor cursor = db.query(TABLE_NAME, colum, KEY_ALARM_ID +"=?", new String[] { String.valueOf(id) }, null, null, null);
if (cursor != null)
cursor.moveToFirst();
else
return null;
int alarm_id=Integer.parseInt(cursor.getString(0));
String desc = cursor.getString(1);
String dayRepeat = cursor.getString(2);
int[] repeatDay = new int[7];
for(int m=0;m<7;m++)
{
repeatDay[m]=Integer.parseInt(Character.toString(dayRepeat.charAt(m)));
}
int repeatType = Integer.parseInt(cursor.getString(3));
Calendar cal = Calendar.getInstance();
cal.setTimeInMillis(Long.parseLong(cursor.getString(4)));
String app = cursor.getString(5);
int active = Integer.parseInt(cursor.getString(6));
//change dayRepeat String to int[]
Alarm alarm = new Alarm(alarm_id, desc, repeatDay, repeatType, cal.getTimeInMillis(), app, active);
db.close();
return alarm;
}
public TableLayout getAllAlarmList(Context con)
{
SQLiteDatabase db = this.getReadableDatabase();
TableLayout body = new TableLayout(con);
TableLayout.LayoutParams TbodyLayout = new TableLayout.LayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
body.setLayoutParams(TbodyLayout);
body.setBackgroundColor(Color.BLACK);
LayoutParams layout = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
if(getAlarmsCount()>0)
{
int maxCount = getAlarmsCount();
String selectQuery = "SELECT * FROM " + TABLE_NAME;
Cursor cursor = db.rawQuery(selectQuery, null);
if(cursor.moveToFirst())
{
TableRow[] tr = new TableRow[maxCount];
CheckBox[] check = new CheckBox[maxCount];
initializeCheckBoxId(maxCount);
int checkboxid = 100;
int alarm_id;
for(int i=0;i<maxCount;i++)
{
tr[i] = new TableRow(con);
check[i]= new CheckBox(con);
alarm_id=Integer.parseInt(cursor.getString(0));
Alarm alarm = getAlarm(alarm_id);
check[i].setText(alarm.getTimeInString()+"\n"+alarm.getDesc()+"\n"+alarm.getRepeatTypeInString());
check[i].setVisibility(1);
check[i].setEnabled(false);
if(alarm.getActive()==1)
{
check[i].setEnabled(true);
}
setCheckBoxId(checkboxid+alarm.getAlarmId());
check[i].setId(checkboxid+alarm.getAlarmId());
check[i].setTextColor(Color.WHITE);
tr[i].addView(check[i]);
tr[i].setLayoutParams(layout);
if(i%2==0)
{
tr[i].setBackgroundColor(Color.DKGRAY);
}
else
{
tr[i].setBackgroundColor(Color.GRAY);
}
body.addView(tr[i]);
}
}
else
{
TextView TV = new TextView(con);
TV.setText("No Alarms Set.");
TV.setTextColor(Color.WHITE);
TV.setVisibility(1);
TableRow tableRow = new TableRow(con);
tableRow.setLayoutParams(layout);
body.addView(tableRow);
}
}
else
{
TextView TV = new TextView(con);
TV.setText("No Alarms Set.");
TV.setTextColor(Color.WHITE);
TV.setVisibility(1);
TableRow tableRow = new TableRow(con);
tableRow.setLayoutParams(layout);
body.addView(tableRow);
}
db.close();
return body;
}
这是将警报添加到数据库的代码：
public void addAlarm(Alarm alarm)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
//values.put(KEY_ALARM_ID, alarm.getAlarmId());
values.put(KEY_DESC, alarm.getDesc());
values.put(KEY_REPEAT_DAY, alarm.getRepeatDay());
values.put(KEY_REPEAT_TYPE, alarm.getRepeatType());
values.put(KEY_CALENDAR, Long.toString(alarm.getCalendarInMillis()));
values.put(KEY_APP, alarm.getApp());
values.put(KEY_ACTIVE, alarm.getActive());
db.insert(TABLE_NAME, null, values);
db.close();
}
这是获取警报计数的代码：
public int getAlarmsCount() {
String countQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
db.close();
return cursor.getCount();
}