我一直致力于一个应用程序，用户可以在Android工作室点击GoogleMap上的某个位置，在该位置添加标记。然后它会提示您3个按钮，一个用于关闭，一个用于添加标题和说明，另一个用于添加照片。
如果我只是按下dismiss，我点击的位置的坐标会自动保存在SQLite中，但如果我添加一个注释然后确认并返回到屏幕，则标记不会显示。这没有意义，因为位置肯定会保存到数据库中，但是当我将标题或描述或照片添加到数据库并返回时，它几乎会删除SQLite中的坐标。
添加标记时应保存坐标，使用此代码
mydb = openOrCreateDatabase("locationmarkersqlite", Context.MODE_PRIVATE, null);
Cursor cursor = mydb.rawQuery("select _id from locations where lat = '" + latiString + "' and lng = '" + lngiString + "'", null);
if (cursor.moveToFirst()) {
do {
lastId = cursor.getString(0);//can be lastId = cursor.getString("_id");
}
while (cursor.moveToNext());
}
数据库由此SQLiteOpenHelper
管理public class LocationsDB extends SQLiteOpenHelper{
/** Database name */
private static String DBNAME = "locationmarkersqlite";
/** Version number of the database */
private static int VERSION = 1;
/** Field 1 of the table locations, which is the primary key */
public static final String FIELD_ROW_ID = "_id";
/** Field 2 of the table locations, stores the latitude */
public static final String FIELD_LAT = "lat";
/** Field 3 of the table locations, stores the longitude*/
public static final String FIELD_LNG = "lng";
/** Field 4 of the table locations, stores the zoom level of map*/
public static final String FIELD_ZOOM = "zom";
public static final String FIELD_TITLE = "title";
public static final String FIELD_BODY = "body";
public static final String FIELD_PHOTO = "photo";
/** A constant, stores the the table name */
private static final String DATABASE_TABLE = "locations";
/** An instance variable for SQLiteDatabase */
private SQLiteDatabase mDB;
/** Constructor */
public LocationsDB(Context context) {
super(context, DBNAME, null, VERSION);
this.mDB = getWritableDatabase();
}
@Override
public void onCreate(SQLiteDatabase db) {
String sql = "create table " + DATABASE_TABLE + " ( " +
FIELD_ROW_ID + " integer primary key autoincrement , " +
FIELD_LNG + " text , " +
FIELD_LAT + " text , " +
FIELD_ZOOM + " text ," +
FIELD_TITLE + " text ," +
FIELD_BODY + " text ," +
FIELD_PHOTO + " text " +
" ) ";
db.execSQL(sql);
}
/** Inserts a new location to the table locations */
public long insert(ContentValues contentValues){
long rowID = mDB.insert(DATABASE_TABLE, null, contentValues);
return rowID;
}
public int update(ContentValues contentValues,String contactID){
int cnt = mDB.update(DATABASE_TABLE, contentValues, "_id=" + contactID, null);
return cnt;
}
/** Deletes all locations from the table */
public int del(){
int cnt = mDB.delete(DATABASE_TABLE, null , null);
return cnt;
}
/** Returns all the locations from the table */
public Cursor getAllLocations(){
return mDB.query(DATABASE_TABLE, new String[] { FIELD_ROW_ID, FIELD_LAT , FIELD_LNG, FIELD_ZOOM } , null, null, null, null, null);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
关于我应该做什么的任何想法？其他一切都在运行。