我有一个使用此数据库处理程序类的简单字典应用程序。 （我已经使用数据库浏览器填充了数据库，并希望通过应用程序发送它）
public class DictionaryDatabase extends SQLiteOpenHelper {
private static final String DB_NAME = "dict.db";
private static String DB_PATH = "/data/data/com.dictshop.dict/databases/";
private static final String TABLE_DICTIONARY = "dictionary";
private static final String FIELD_WORD = "word";
private static final String FIELD_DEFINITION = "definition";
private static final int DATABASE_VERSION = 1;
private Context myContext;
DictionaryDatabase(Context context) {
super(context, DB_NAME, null, DATABASE_VERSION);
this.myContext = context;
}
public void crateDatabase() throws IOException {
boolean vtVarMi = isDatabaseExist();
if (!vtVarMi) {
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private boolean isDatabaseExist() {
SQLiteDatabase kontrol = null;
try {
String myPath = DB_PATH + DB_NAME;
kontrol = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
kontrol = null;
}
if (kontrol != null) {
kontrol.close();
}
return kontrol != null ? true : false;
}
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();
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_DICTIONARY +
"(_id integer PRIMARY KEY," +
FIELD_WORD + " TEXT, " +
FIELD_DEFINITION + " TEXT);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//Handle database upgrade as needed
}
public void saveRecord(String word, String definition) {
long id = findWordID(word);
if (id>0) {
updateRecord(id, word,definition);
} else {
addRecord(word,definition);
}
}
public long addRecord(String word, String definition) {
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put(FIELD_WORD, word);
values.put(FIELD_DEFINITION, definition);
return db.insert(TABLE_DICTIONARY, null, values);
}
public int updateRecord(long id, String word, String definition) {
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put("_id", id);
values.put(FIELD_WORD, word);
values.put(FIELD_DEFINITION, definition);
return db.update(TABLE_DICTIONARY, values, "_id = ?",
new String[]{String.valueOf(id)});
}
public int deleteRecord(long id) {
SQLiteDatabase db = getWritableDatabase();
return db.delete(TABLE_DICTIONARY, "_id = ?", new
String[]{String.valueOf(id)});
}
public long findWordID(String word) {
long returnVal = -1;
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery(
"SELECT _id FROM " + TABLE_DICTIONARY +
" WHERE " + FIELD_WORD + " = ?", new String[]{word});
Log.i("findWordID","getCount()="+cursor.getCount());
if (cursor.getCount() == 1) {
cursor.moveToFirst();
returnVal = cursor.getInt(0);
}
return returnVal;
}
public String getWord(long id) {
String returnVal = "";
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery(
"SELECT word FROM " + TABLE_DICTIONARY +
" WHERE _id = ?", new String[]{String.valueOf(id)});
if (cursor.getCount() == 1) {
cursor.moveToFirst();
returnVal = cursor.getString(0);
}
return returnVal;
}
public String getDefinition(long id) {
String returnVal = "";
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery(
"SELECT definition FROM " + TABLE_DICTIONARY +
" WHERE _id = ?", new String[]{String.valueOf(id)});
if (cursor.getCount() == 1) {
cursor.moveToFirst();
returnVal = cursor.getString(0);
}
return returnVal;
}
public Cursor getWordList() {
SQLiteDatabase db = getReadableDatabase();
String query = "SELECT _id, " + FIELD_WORD +
" FROM " + TABLE_DICTIONARY + " ORDER BY " + FIELD_WORD +
" ASC";
return db.rawQuery(query, null);
}
}
我已将dict.db推送到项目中：
me@pc:~$ ~/Android/Sdk/platform-tools/adb -s emulator-5554 push /home/me/Desktop/Dict/dict.db /data/data/com.dictshop.Dict/databases/dict.db
并且应用程序在模拟器上工作正常，也就是说，我看到数据正在显示。
然而，当我在设备上尝试应用程序（一个已根，一个无根）时，没有显示任何数据。这可能有什么问题？
我尝试过不同的技巧让这门课成功。这是我的第一个应用程序，并且我已经存在了好几天。非常感谢您的提示。
更新：这是使用数据库的MainActivity：
public class MainActivity extends AppCompatActivity {
EditText mEditTextWord;
EditText mEditTextDefinition;
DictionaryDatabase mDB;
ListView mListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Get a support ActionBar corresponding to this toolbar
ActionBar ab = getSupportActionBar();
// Enable the Up button
ab.setDisplayHomeAsUpEnabled(true);
mDB = new DictionaryDatabase(this);
mListView = (ListView)findViewById(R.id.listView);
mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View
view, int position, long id) {
String nextId = String.valueOf(id+1);
Intent intent = new Intent(view.getContext(),DetailActivity.class);
intent.putExtra("key" ,mDB.getWord(id)+"");
intent.putExtra("value",mDB.getDefinition(id)+"");
intent.putExtra("nextId",nextId+"");
startActivity(intent);
}
});
mListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(MainActivity.this,
"Records deleted = " + mDB.deleteRecord(id),
Toast.LENGTH_SHORT).show();
updateWordList();
return true;
}
});
updateWordList();
}
private void saveRecord() {
mDB.saveRecord(mEditTextWord.getText().toString(),
mEditTextDefinition.getText().toString());
mEditTextWord.setText("");
mEditTextDefinition.setText("");
updateWordList();
}
private void updateWordList() {
SimpleCursorAdapter simpleCursorAdapter = new
SimpleCursorAdapter( this,
android.R.layout.simple_list_item_1,
mDB.getWordList(),
new String[]{"word"},
new int[]{android.R.id.text1},
0);
mListView.setAdapter(simpleCursorAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.share_app:
Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_TEXT, "this is the app");
sendIntent.setType("text/plain");
startActivity(sendIntent);
return true;
default:
// If we got here, the user's action was not recognized.
// Invoke the superclass to handle it.
return super.onOptionsItemSelected(item);
}
}
}
答案 0 :(得分：0)
SQLiteAssetHelper就是你想要的。执行以下操作：
将依赖项添加到app模块的build.gradle文件中：
dependencies {
compile 'com.readystatesoftware.sqliteasset:sqliteassethelper:+'
}
将数据库复制到assets目录中，名为assets/databases的子目录中。所以：
assets/databases/dict.db
创建一个类：
public class MyDatabase extends SQLiteAssetHelper {
private static final String DATABASE_NAME = "dict.db";
private static final int DATABASE_VERSION = 1;
public MyDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
}
答案 1 :(得分：0)
这是示例sqlite local
public class SqliteHelper extends SQLiteOpenHelper {
public static String DB_PATH = "/data/data/com.dictshop.dict/databases/";
private static String DB_NAME = "dict.db";
private final Context context;
public SqliteHelper(Context context) {
super(context, DB_NAME, null, 1);
this.context = context;
}
/**
* copy database from assets to the device if not existed
**/
public boolean isCreatedDatabase() throws IOException {
// Default is database have data
boolean result = true;
// check data
if (!checkExistDataBase()) {
this.getReadableDatabase();
try {
copyDataBase();
result = false;
} catch (Exception e) {
throw new Error("Error copying database");
}
}
return result;
}
/**
* check database exist on the device?
*/
private boolean checkExistDataBase() {
try {
String myPath = DB_PATH + DB_NAME;
File fileDB = new File(myPath);
if (fileDB.exists()) {
return true;
} else
return false;
} catch (Exception e) {
return false;
}
}
/**
* copy database from assets folder to the device
*
* @throws IOException
*/
private void copyDataBase() throws IOException {
InputStream myInput = context.getAssets().open(DB_NAME);
OutputStream myOutput = new FileOutputStream(DB_PATH + DB_NAME);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
// create DB
isCreateDB();
}
/*
* Copy db from asset to database
*/
private boolean isCreateDB() {
SqliteHelper data = new SqliteHelper(this);
try {
return data.isCreatedDatabase();
} catch (IOException e) {
Toast.makeText(this, "Error Copy data", Toast.LENGTH_LONG).show();
e.printStackTrace();
return false;
}
}
希望。它会帮助你!!!