我需要在应用程序关闭时删除所有Sqlite数据。
有没有办法做到这一点？
我正在使用一个名为HostProvider的类来启动数据库。
这是HostProvider.java的代码
public class HostProvider extends ContentProvider {
private static final String TAG = "HostProvider";
public static final String AUTHORITY = "org.xbmc.android.provider.remote";
private static final int DATABASE_VERSION = 4;
private static final String DATABASE_NAME = "xbmc_hosts.db";
private static final String HOSTS_TABLE_NAME = "hosts";
private static HashMap<String, String> sHostsProjectionMap;
private static final int HOSTS = 1;
private static final int HOST_ID = 2;
private static final UriMatcher sUriMatcher;
/**
* This class helps open, create, and upgrade the database file.
*/
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + HOSTS_TABLE_NAME + " ("
+ Hosts._ID + " INTEGER PRIMARY KEY,"
+ Hosts.NAME + " TEXT,"
+ Hosts.ADDR + " TEXT,"
+ Hosts.PORT + " INTEGER,"
+ Hosts.USER + " TEXT,"
+ Hosts.PASS + " TEXT,"
+ Hosts.ESPORT + " INTEGER,"
+ Hosts.TIMEOUT + " INTEGER,"
+ Hosts.WIFI_ONLY + " INTEGER,"
+ Hosts.ACCESS_POINT + " TEXT,"
+ Hosts.MAC_ADDR + " TEXT,"
+ Hosts.WOL_PORT + " INTEGER,"
+ Hosts.WOL_WAIT + " INTEGER"
+ ");");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String altertable;
switch (oldVersion) {
case 2:
Log.d(TAG, "Upgrading database from version 2 to 3");
altertable = "ALTER TABLE " + HOSTS_TABLE_NAME + " ADD COLUMN " + Hosts.WIFI_ONLY
+ " INTEGER DEFAULT 0;";
db.execSQL(altertable);
Log.d(TAG, "executed: " + altertable);
altertable = "ALTER TABLE " + HOSTS_TABLE_NAME + " ADD COLUMN " + Hosts.ACCESS_POINT
+ " TEXT;";
db.execSQL(altertable);
Log.d(TAG, "executed: " + altertable);
altertable = "ALTER TABLE " + HOSTS_TABLE_NAME + " ADD COLUMN " + Hosts.MAC_ADDR
+ " TEXT;";
db.execSQL(altertable);
Log.d(TAG, "executed: " + altertable);
case 3:
Log.d(TAG, "Upgrading database from version 3 to 4");
altertable = "ALTER TABLE " + HOSTS_TABLE_NAME + " ADD COLUMN " + Hosts.WOL_PORT
+ " INTEGER;";
db.execSQL(altertable);
Log.d(TAG, "executed: " + altertable);
altertable = "ALTER TABLE " + HOSTS_TABLE_NAME + " ADD COLUMN " + Hosts.WOL_WAIT
+ " INTEGER;";
db.execSQL(altertable);
Log.d(TAG, "executed: " + altertable);
//WARNING!!! ADD A break; BEFORE THE DEFAULT BLOCK OF THE DATABASE WILL BE DROPPED!!!
break;
default:
Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS " + HOSTS_TABLE_NAME);
onCreate(db);
}
}
}
private DatabaseHelper mOpenHelper;
@Override
public boolean onCreate() {
mOpenHelper = new DatabaseHelper(getContext());
return true;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
switch (sUriMatcher.match(uri)) {
case HOSTS:
qb.setTables(HOSTS_TABLE_NAME);
qb.setProjectionMap(sHostsProjectionMap);
break;
case HOST_ID:
qb.setTables(HOSTS_TABLE_NAME);
qb.setProjectionMap(sHostsProjectionMap);
qb.appendWhere(Hosts._ID + "=" + uri.getPathSegments().get(1));
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// If no sort order is specified use the default
String orderBy;
if (TextUtils.isEmpty(sortOrder)) {
orderBy = Hosts.DEFAULT_SORT_ORDER;
} else {
orderBy = sortOrder;
}
// Get the database and run the query
SQLiteDatabase db = mOpenHelper.getReadableDatabase();
Log.d(TAG, "SQLite database version: " + db.getVersion());
Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, orderBy);
// Tell the cursor what uri to watch, so it knows when its source data
// changes
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
@Override
public String getType(Uri uri) {
switch (sUriMatcher.match(uri)) {
case HOSTS:
return Hosts.CONTENT_TYPE;
case HOST_ID:
return Hosts.CONTENT_ITEM_TYPE;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
}
@Override
public Uri insert(Uri uri, ContentValues initialValues) {
// Validate the requested uri
if (sUriMatcher.match(uri) != HOSTS) {
throw new IllegalArgumentException("Unknown URI " + uri);
}
ContentValues values;
if (initialValues != null) {
values = new ContentValues(initialValues);
} else {
values = new ContentValues();
}
if (values.containsKey(Hosts.NAME) == false) {
Resources r = Resources.getSystem();
values.put(Hosts.NAME, r.getString(android.R.string.untitled));
}
if (values.containsKey(Hosts.ADDR) == false) {
values.put(Hosts.ADDR, "");
}
if (values.containsKey(Hosts.PORT) == false) {
values.put(Hosts.PORT, 0);
}
if (values.containsKey(Hosts.USER) == false) {
values.put(Hosts.USER, "");
}
if (values.containsKey(Hosts.PASS) == false) {
values.put(Hosts.PASS, "");
}
if (values.containsKey(Hosts.ESPORT) == false) {
values.put(Hosts.ESPORT, 0);
}
if (values.containsKey(Hosts.TIMEOUT) == false) {
values.put(Hosts.TIMEOUT, -1);
}
if (values.containsKey(Hosts.WIFI_ONLY) == false) {
values.put(Hosts.WIFI_ONLY, 0);
}
if (values.containsKey(Hosts.ACCESS_POINT) == false) {
values.put(Hosts.ACCESS_POINT, "");
}
if (values.containsKey(Hosts.MAC_ADDR) == false) {
values.put(Hosts.MAC_ADDR, "");
}
if (values.containsKey(Hosts.WOL_PORT) == false) {
values.put(Hosts.WOL_PORT, 0);
}
if (values.containsKey(Hosts.WOL_WAIT) == false) {
values.put(Hosts.WOL_WAIT, 0);
}
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
long rowId = db.insert(HOSTS_TABLE_NAME, Hosts.ADDR, values);
if (rowId > 0) {
Uri noteUri = ContentUris.withAppendedId(Hosts.CONTENT_URI, rowId);
getContext().getContentResolver().notifyChange(noteUri, null);
return noteUri;
}
throw new SQLException("Failed to insert row into " + uri);
}
@Override
public int delete(Uri uri, String where, String[] whereArgs) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
int count;
switch (sUriMatcher.match(uri)) {
case HOSTS:
count = db.delete(HOSTS_TABLE_NAME, where, whereArgs);
break;
case HOST_ID:
String hostId = uri.getPathSegments().get(1);
count = db.delete(HOSTS_TABLE_NAME, Hosts._ID + "=" + hostId + (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
int count;
switch (sUriMatcher.match(uri)) {
case HOSTS:
count = db.update(HOSTS_TABLE_NAME, values, where, whereArgs);
break;
case HOST_ID:
String hostId = uri.getPathSegments().get(1);
count = db.update(HOSTS_TABLE_NAME, values, Hosts._ID + "=" + hostId + (!TextUtils.isEmpty(where) ? " AND (" + where + ')' : ""), whereArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
static {
sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
sUriMatcher.addURI(AUTHORITY, "hosts", HOSTS);
sUriMatcher.addURI(AUTHORITY, "hosts/#", HOST_ID);
sHostsProjectionMap = new HashMap<String, String>();
sHostsProjectionMap.put(Hosts._ID, Hosts._ID);
sHostsProjectionMap.put(Hosts.NAME, Hosts.NAME);
sHostsProjectionMap.put(Hosts.ADDR, Hosts.ADDR);
sHostsProjectionMap.put(Hosts.PORT, Hosts.PORT);
sHostsProjectionMap.put(Hosts.USER, Hosts.USER);
sHostsProjectionMap.put(Hosts.PASS, Hosts.PASS);
sHostsProjectionMap.put(Hosts.ESPORT, Hosts.ESPORT);
sHostsProjectionMap.put(Hosts.TIMEOUT, Hosts.TIMEOUT);
sHostsProjectionMap.put(Hosts.WIFI_ONLY, Hosts.WIFI_ONLY);
sHostsProjectionMap.put(Hosts.ACCESS_POINT, Hosts.ACCESS_POINT);
sHostsProjectionMap.put(Hosts.MAC_ADDR, Hosts.MAC_ADDR);
sHostsProjectionMap.put(Hosts.WOL_PORT, Hosts.WOL_PORT);
sHostsProjectionMap.put(Hosts.WOL_WAIT, Hosts.WOL_WAIT);
}
/**
* Notes table
*/
public static final class Hosts implements BaseColumns {
// This class cannot be instantiated
private Hosts() {
}
/**
* The name of the host (as in label/title)
* <P>
* Type: TEXT
* </P>
*/
public static final String NAME = "name";
/**
* The address or IP of the host
* <P>
* Type: TEXT
* </P>
*/
public static final String ADDR = "address";
/**
* The note itself
* <P>
* Type: INTEGER
* </P>
*/
public static final String PORT = "http_port";
/**
* The user name if HTTP Auth is used
* <P>
* Type: TEXT
* </P>
*/
public static final String USER = "user";
/**
* The password if HTTP Auth is used
* <P>
* Type: TEXT
* </P>
*/
public static final String PASS = "pass";
/**
* The event server port
* <P>
* Type: INTEGER
* </P>
*/
public static final String ESPORT = "esport";
/**
* The socket read timeout in milliseconds
* <P>
* Type: INTEGER
* </P>
*/
public static final String TIMEOUT = "timeout";
/**
* If this connection is for wireless lan only
* <P>
* Type: BOOLEAN
* </P>
*/
public static final String WIFI_ONLY = "wifi_only";
/**
* If WIFI_ONLY is set this may or may not include an access point name
* <P>
* Type: TEXT
* </P>
*/
public static final String ACCESS_POINT = "access_point";
/**
* The MAC address of this host
* <P>
* Type: TEXT
* </P>
*/
public static final String MAC_ADDR = "mac_addr";
/**
* The time in seconds to wait after sending WOL paket
* <P>
* Type: INTEGER
* </P>
*/
public static final String WOL_WAIT = "wol_wait";
/**
* The port the WOL packet should be send to
* <P>
* Type: INTEGER
* </P>
*/
public static final String WOL_PORT = "wol_port";
/**
* The content:// style URL for this table
*/
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + HOSTS_TABLE_NAME);
/**
* The MIME type of {@link #CONTENT_URI} providing a directory of notes.
*/
public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.xbmc.host";
/**
* The MIME type of a {@link #CONTENT_URI} sub-directory of a single
* note.
*/
public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.xbmc.host";
/**
* The default sort order for this table
*/
public static final String DEFAULT_SORT_ORDER = NAME + " ASC";
}
}
在Manifest.xml中，我添加了以下代码：
<provider
android:name="org.xbmc.android.remote.business.provider.HostProvider"
android:authorities="org.xbmc.android.provider.remote" />
当应用程序加载时，将调用此类。为了使用这个类，我需要在关闭应用程序时删除所有SQLite数据。
我该怎么做？或者还有其他方法吗？
答案 0 :(得分：1)
当您使用文件名:memory:时，数据库永远不会被放入文件中，并且当连接（SQLiteDatabase对象）关闭时，所有数据都将丢失。
请注意SQLiteOpenHelper的自动创建/升级处理是专为永久数据库设计的;你应该手动使用SQLiteDatabase。