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我想使用預先填充數據的多個表的數據庫。所有表格的一列中都有一份飲料清單。我正在嘗試將飲料列表添加到我的活動的ListView中。我在ListView上查找了Vogel的站點，我也從一本書中閱讀了一個教程，我基本上覆制了這些代碼，我還閱讀了Fluxa關於使用自己的數據庫的教程。我不知道我的代碼是否不正確，但它不會加載我正在查找的飲料列表。有人可能會看我的代碼，並可能指出我可能會丟失或看不到的任何錯誤嗎？列表將不會創建數據庫信息
HotEspresso.java
public class HotEspresso extends ListActivity {
private DrinkDbAdapter mDbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.hot_espresso);
mDbHelper = new DrinkDbAdapter(this);
mDbHelper.openToRead();
fillData();
}
private void fillData() {
Cursor drinkCursor = mDbHelper.getHotTitles();
startManagingCursor(drinkCursor);
String[] from = new String[]{DrinkDbAdapter.KEY_DRINK};
int[] to = new int[] {R.id.hot_espresso_row};
SimpleCursorAdapter drinks = new SimpleCursorAdapter(this, R.layout.hot_espresso_list, drinkCursor, from, to);
setListAdapter(drinks);
}
}
DrinkDbAdapter.java
public class DrinkDbAdapter extends Activity {
private static final String DATABASE_NAME = "drinks";
private static final String DATABASE_TABLE_HOT = "hot";
private static final String DATABASE_TABLE_COFFEE = "coffee";
private static final String DATABASE_TABLE_HOTTEA = "hottea";
private static final String DATABASE_TABLE_COLD = "cold";
private static final String DATABASE_TABLE_BLENDED = "blended";
private static final String DATABASE_TABLE_COLDTEA = "coldtea";
private static final int DATABASE_VERSION = 1;
public static final String KEY_ROWID = "_id";
public static final String KEY_DRINK = "drink";
public static final String KEY_CATEGORY = "category";
public static final String KEY_LIQUID = "liquid";
public static final String KEY_LIQUID_AMOUNT = "liquid_amount";
public static final String KEY_POWDER = "powder";
public static final String KEY_POWDER_AMOUNT = "powder_amount";
public static final String KEY_SHOTS = "shots";
public static final String KEY_ADDITIVE1 = "add1";
public static final String KEY_ADDITIVE1_AMOUNT = "add1_amount";
public static final String KEY_ADDITIVE2 = "add2";
public static final String KEY_ADDITIVE2_AMOUNT = "add2_amount";
private static final String TAG = "DrinkDbAdapter";
private DatabaseHelper myDbHelper;
private SQLiteDatabase myDbDrinks;
private static final String DATABASE_CREATE_HOT =
"create table " + DATABASE_TABLE_HOT + " (" + KEY_ROWID
+ " integer primary key autoincrement, " + KEY_DRINK + " text not null, "
+ KEY_CATEGORY + " text not null, " + KEY_LIQUID + " text not null, "
+ " text not null, " + KEY_LIQUID_AMOUNT + " text not null, "
+ KEY_POWDER + " text not null, " + KEY_POWDER_AMOUNT
+ " text not null, " + KEY_SHOTS + " text not null, " + KEY_ADDITIVE1
+ " text not null, " + KEY_ADDITIVE1_AMOUNT + " text not null, "
+ KEY_ADDITIVE2 + " text not null, " + KEY_ADDITIVE2_AMOUNT + " text not null);";
private static final String DATABASE_CREATE_COFFEE =
"create table " + DATABASE_TABLE_COFFEE + " (" + KEY_ROWID
+ " integer primary key autoincrement, " + KEY_DRINK + " text not null, "
+ KEY_CATEGORY + " text not null, " + KEY_LIQUID + " text not null, "
+ " text not null, " + KEY_LIQUID_AMOUNT + " text not null, "
+ KEY_POWDER + " text not null, " + KEY_POWDER_AMOUNT
+ " text not null, " + KEY_SHOTS + " text not null, " + KEY_ADDITIVE1
+ " text not null, " + KEY_ADDITIVE1_AMOUNT + " text not null, "
+ KEY_ADDITIVE2 + " text not null, " + KEY_ADDITIVE2_AMOUNT + " text not null);";
private static final String DATABASE_CREATE_HOTTEA =
"create table " + DATABASE_TABLE_HOTTEA + " (" + KEY_ROWID
+ " integer primary key autoincrement, " + KEY_DRINK + " text not null, "
+ KEY_CATEGORY + " text not null, " + KEY_LIQUID + " text not null, "
+ " text not null, " + KEY_LIQUID_AMOUNT + " text not null, "
+ KEY_POWDER + " text not null, " + KEY_POWDER_AMOUNT
+ " text not null, " + KEY_SHOTS + " text not null, " + KEY_ADDITIVE1
+ " text not null, " + KEY_ADDITIVE1_AMOUNT + " text not null, "
+ KEY_ADDITIVE2 + " text not null, " + KEY_ADDITIVE2_AMOUNT + " text not null);";
private static final String DATABASE_CREATE_COLD =
"create table " + DATABASE_TABLE_COLD + " (" + KEY_ROWID
+ " integer primary key autoincrement, " + KEY_DRINK + " text not null, "
+ KEY_CATEGORY + " text not null, " + KEY_LIQUID + " text not null, "
+ " text not null, " + KEY_LIQUID_AMOUNT + " text not null, "
+ KEY_POWDER + " text not null, " + KEY_POWDER_AMOUNT
+ " text not null, " + KEY_SHOTS + " text not null, " + KEY_ADDITIVE1
+ " text not null, " + KEY_ADDITIVE1_AMOUNT + " text not null, "
+ KEY_ADDITIVE2 + " text not null, " + KEY_ADDITIVE2_AMOUNT + " text not null);";
private static final String DATABASE_CREATE_BLENDED =
"create table " + DATABASE_TABLE_BLENDED + " (" + KEY_ROWID
+ " integer primary key autoincrement, " + KEY_DRINK + " text not null, "
+ KEY_CATEGORY + " text not null, " + KEY_LIQUID + " text not null, "
+ " text not null, " + KEY_LIQUID_AMOUNT + " text not null, "
+ KEY_POWDER + " text not null, " + KEY_POWDER_AMOUNT
+ " text not null, " + KEY_SHOTS + " text not null, " + KEY_ADDITIVE1
+ " text not null, " + KEY_ADDITIVE1_AMOUNT + " text not null, "
+ KEY_ADDITIVE2 + " text not null, " + KEY_ADDITIVE2_AMOUNT + " text not null);";
private static final String DATABASE_CREATE_COLDTEA =
"create table " + DATABASE_TABLE_COLDTEA + " (" + KEY_ROWID
+ " integer primary key autoincrement, " + KEY_DRINK + " text not null, "
+ KEY_CATEGORY + " text not null, " + KEY_LIQUID + " text not null, "
+ " text not null, " + KEY_LIQUID_AMOUNT + " text not null, "
+ KEY_POWDER + " text not null, " + KEY_POWDER_AMOUNT
+ " text not null, " + KEY_SHOTS + " text not null, " + KEY_ADDITIVE1
+ " text not null, " + KEY_ADDITIVE1_AMOUNT + " text not null, "
+ KEY_ADDITIVE2 + " text not null, " + KEY_ADDITIVE2_AMOUNT + " text not null);";
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.miskitup.CoffeeNutrition/databases/";
private static String DB_NAME = "drinks";
private SQLiteDatabase myDataBase;
private final Context myContext;
//Constructor
//Takes and keeps a reference of the passed context in order to access to the application assets and resources.
//@param context
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.myContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE_HOT);
db.execSQL(DATABASE_CREATE_COFFEE);
db.execSQL(DATABASE_CREATE_HOTTEA);
db.execSQL(DATABASE_CREATE_COLD);
db.execSQL(DATABASE_CREATE_BLENDED);
db.execSQL(DATABASE_CREATE_COLDTEA);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS notes");
onCreate(db);
}
//Creates a empty database on the system and rewrites it with your own database.
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
//Check if the database already exist to avoid re-copying the file each time you open the application.
//@return true if it exists, false if it doesn't
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database doesn't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
//Copies your database from your local assets-folder to the just created empty database in the
//system folder, from where it can be accessed and handled.
//This is done by transfering bytestream.
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
}
public DrinkDbAdapter(Context ctx) {
this.mCtx = ctx;
}
public DrinkDbAdapter openToRead() throws android.database.SQLException {
myDbHelper = new DatabaseHelper(mCtx);
myDbDrinks = myDbHelper.getReadableDatabase();
return this;
}
public DrinkDbAdapter openToWrite() throws android.database.SQLException {
myDbHelper = new DatabaseHelper(mCtx);
myDbDrinks = myDbHelper.getWritableDatabase();
return this;
}
public void close() {
myDbHelper.close();
}
public Cursor getTitle(long rowId, String table) throws SQLException {
Cursor mCursor =myDbDrinks.query(true, table, new String[] {KEY_ROWID, KEY_DRINK, KEY_LIQUID, KEY_LIQUID_AMOUNT,
KEY_POWDER, KEY_POWDER_AMOUNT, KEY_SHOTS, KEY_ADDITIVE1, KEY_ADDITIVE1_AMOUNT, KEY_ADDITIVE2, KEY_ADDITIVE2_AMOUNT},
KEY_ROWID + "=" + rowId, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public Cursor getHotTitles() {
return myDbDrinks.query(DATABASE_TABLE_HOT, new String[] {KEY_ROWID, KEY_DRINK}, null, null, null, null, null);
}
}
hot_espresso.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<ListView android:id="@+id/android:list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#e9ddc8"
android:divider="#44059f"
android:dividerHeight="1dp"
android:cacheColorHint="#e9ddc8" />
<TextView android:id="@+id/android:empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
hot_espresso_list.xml
<?xml version="1.0" encoding="utf-8"?>
<TextView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/hot_espresso_row"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dp"
android:textColor="#44059f" />
任何想法或建議將不勝感激。