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首先一般会创建一个BaseColumns的子类，来定义你需要用的栏位 public final class FeedReaderContract {     // To prevent someone from accidentally instantiating the contract class,     // give it an empty constructor.     public FeedReaderContract() {}     /* Inner class that defines the table contents */     public static abstract class FeedEntry implements BaseColumns {         public static final String TABLE_NAME = "entry";         public static final String COLUMN_NAME_ENTRY_ID = "entryid";         public static final String COLUMN_NAME_TITLE = "title";         public static final String COLUMN_NAME_SUBTITLE = "subtitle";         ...     } } 第二步一般就是写sql语句。用数据库保存的数据适合app绑定的，其他app不能访问. private static final String TEXT_TYPE = " TEXT"; private static final String COMMA_SEP = ","; private static final String SQL_CREATE_ENTRIES =     "CREATE TABLE " + FeedEntry.TABLE_NAME + " (" +     FeedEntry._ID + " INTEGER PRIMARY KEY," +     FeedEntry.COLUMN_NAME_ENTRY_ID + TEXT_TYPE + COMMA_SEP +     FeedEntry.COLUMN_NAME_TITLE + TEXT_TYPE + COMMA_SEP +     ... // Any other options for the CREATE command     " )"; private static final String SQL_DELETE_ENTRIES =     "DROP TABLE IF EXISTS " + FeedEntry.TABLE_NAME 第三步要实现SQLiteOpenHelper的子类. public class FeedReaderDbHelper extends SQLiteOpenHelper {     // If you change the database schema, you must increment the database version.     public static final int DATABASE_VERSION = 1;     public static final String DATABASE_NAME = "FeedReader.db";     public FeedReaderDbHelper(Context context) {         super(context, DATABASE_NAME, null, DATABASE_VERSION);     }     public void onCreate(SQLiteDatabase db) {         db.execSQL(SQL_CREATE_ENTRIES);     }     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {         // This database is only a cache for online data, so its upgrade policy is         // to simply to discard the data and start over         db.execSQL(SQL_DELETE_ENTRIES);         onCreate(db);     }     public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {         onUpgrade(db, oldVersion, newVersion);     } } 这个时候数据库创建完毕，如果要访问数据库的话，可以通过如下语句进行。 FeedReaderDbHelper mDbHelper = new FeedReaderDbHelper(getContext()); 往数据库中存数据可以参考下面的code： // Gets the data repository in write mode SQLiteDatabase db = mDbHelper.getWritableDatabase(); // Create a new map of values, where column names are the keys ContentValues values = new ContentValues(); values.put(FeedEntry.COLUMN_NAME_ENTRY_ID, id); values.put(FeedEntry.COLUMN_NAME_TITLE, title); values.put(FeedEntry.COLUMN_NAME_CONTENT, content); // Insert the new row, returning the primary key value of the new row long newRowId; newRowId = db.insert(          FeedEntry.TABLE_NAME,          FeedEntry.COLUMN_NAME_NULLABLE,          values); 从数据库中读取数据： SQLiteDatabase db = mDbHelper.getReadableDatabase(); // Define a projection that specifies which columns from the database // you will actually use after this query. String[] projection = {     FeedEntry._ID,     FeedEntry.COLUMN_NAME_TITLE,     FeedEntry.COLUMN_NAME_UPDATED,     ...     }; // How you want the results sorted in the resulting Cursor String sortOrder =     FeedEntry.COLUMN_NAME_UPDATED + " DESC"; Cursor c = db.query(     FeedEntry.TABLE_NAME,  // The table to query     projection,                               // The columns to return     selection,                                // The columns for the WHERE clause     selectionArgs,                            // The values for the WHERE clause     null,                                     // don't group the rows     null,                                     // don't filter by row groups     sortOrder                                 // The sort order     ); 可以调用moverofirst 来移动游标，通过cursor.gerLong()可以获得column里面的数据 cursor.moveToFirst(); long itemId = cursor.getLong(     cursor.getColumnIndexOrThrow(FeedEntry._ID) ); 可以通过如下code来删掉数据。 // Define 'where' part of query. String selection = FeedEntry.COLUMN_NAME_ENTRY_ID + " LIKE ?"; // Specify arguments in placeholder order. String[] selectionArgs = { String.valueOf(rowId) }; // Issue SQL statement. db.delete(table_name, selection, selectionArgs); 可以通过如下code来更新数据. SQLiteDatabase db = mDbHelper.getReadableDatabase(); // New value for one column ContentValues values = new ContentValues(); values.put(FeedEntry.COLUMN_NAME_TITLE, title); // Which row to update, based on the ID String selection = FeedEntry.COLUMN_NAME_ENTRY_ID + " LIKE ?"; String[] selectionArgs = { String.valueOf(rowId) }; int count = db.update(     FeedReaderDbHelper.FeedEntry.TABLE_NAME,     values,     selection,     selectionArgs); 数据库属于重型资源，一般可能会运行很长时间，一般不建议在UI线程中操作。一般都通过AysncTask 或者IntentService.

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