我正在尝试使用具有多个预先填充了数据的表的数据库。在所有表格的一栏中，有一份饮料清单。我正在尝试将该饮料列表放入我的活动的 ListView 中。我在 ListView 上查找了 Vogel 的网站，我还阅读了一本我基本上复制代码的书中的教程，我还阅读了 Fluxa 关于使用自己的数据库的教程。我不知道我的代码是否不正确，但它不会加载我正在寻找的饮料列表。有人可以查看我的代码并可能指出我可能遗漏或看不到的任何错误吗？
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" />
任何想法或建议将不胜感激。