我有三个班级，其中流程是..
输入要搜索的条目:(来自MainActivity）
try {
String input = etSearch.getText().toString();
Intent i = new Intent(this, SearchViewList.class);
i.putExtra("input", input);
Log.i("input", input + "");
startActivity(i);
} catch (Exception e) {
// TODO: handle exception
String error = e.toString();
Dialog d = new Dialog(this);
d.setTitle("Row Empty or ID not found!");
TextView tv = new TextView(this);
tv.setText(error);
d.setContentView(tv);
d.show();
break;
}
然后类SearchViewList将按照意图
中搜索到的值显示列表 Intent i = getIntent();
input = i.getStringExtra("input");
String l = input;
datasource = new DatabaseHelper(this);
datasource.openDataBase();
List<Definition> values = datasource.getSearchedDefinition(l);
// use the SimpleCursorAdapter to show the
// elements in a ListView
ArrayAdapter<Definition> adapter = new ArrayAdapter<Definition>(this,
android.R.layout.simple_list_item_1, values);
setListAdapter(adapter);
ListView listView = getListView();
listView.setTextFilterEnabled(true);
listView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// When clicked, show a toast with the TextView text
Toast.makeText(getApplicationContext(),
((TextView) view).getText(), Toast.LENGTH_SHORT).show();
String str = ((TextView) view).getText().toString();
Log.i(str, str + "");
Intent i = new Intent(getApplicationContext(),
SearchedView.class);
i.putExtra("value", str);
startActivity(i);
}
});
然后单击列表中搜索到的条目后，错误开始
Intent i = getIntent();
l = i.getStringExtra("value");
TextView entry = (TextView) findViewById(R.id.tvEntry);
datasource = new DatabaseHelper(this);
datasource.openDataBase();
String dataEntry = datasource.getEntry(l);
datasource.close();
entry.setText(dataEntry);
}
这是我在DatabaseHelper类中的getEntry（）方法
public String getEntry(String l) throws SQLException {
Cursor c = myDataBase.rawQuery(
"SELECT entry FROM defintionstbl where entry = '"
+ l + "'", null);
if (c != null) {
c.moveToFirst();
if (c.getCount() <= 0) {
return null;
}
String entry = c.getString(0);
return entry;
}
return null;
}
这个下一个方法也来自DatabaseHelper类
public List<Definition> getSearchedDefinition(String l) throws SQLException {
List<Definition> entries = new ArrayList<Definition>();
Cursor cursor = myDataBase.rawQuery(
"SELECT entry FROM definitionstbl where entry like '" + l + "%'", null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
Definition entry = cursorToDefinition(cursor);
entries.add(entry);
cursor.moveToNext();
}
// make sure to close the cursor
cursor.close();
return entries;
}
private Definition cursorToDefinition(Cursor cursor) {
Definition entry = new Definition();
entry.setId(cursor.getLong(0));
entry.setEntry(cursor.getString(0));
return entry;
}
这个方法编译得很好，但我从方法getEntry（）得到一个“没有这样的表定义stbl”错误。
additional note:
database = dictionary.sqlite
table = definitionstbl
column1 = _id
column2 = entry
column3 = definitions
这是从外部源复制数据库的代码：
public class DatabaseHelper extends SQLiteOpenHelper {
// The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.gtxradeon.newversioncomputerdictionary/databases/";
private static String DB_NAME = "dictionary.sqlite";
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
*/
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/**
* 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 does'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();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
从MainActivity创建表
try {
myDbHelper.createDataBase();
myDbHelperTrivia.createDataBase();
Log.i("CREATING", "DATABASE CREATED");
} catch (Exception e) {
Log.i("CREATE", "Exception Caught! ", e);
}
try {
myDbHelper.openDataBase();
Log.i("OPENING", "DATABASE OPENED");
} catch (SQLException e) {
Log.i("OPEN", "Exception Caught! ", e);
}
答案 0 :(得分：0)
感谢帮助人员，但我刚刚将getEntry方法更改为此... rawQuery给出了很多错误但是这个新方法很好用..
public String getEntry(String l) throws SQLException {
String[] columns = new String[] { "_id",
"entry", "definition" };
Cursor c = myDataBase.query("definitionstbl", columns,
"entry" + "='" + l + "'", null, null, null, null);
if (c != null) {
c.moveToFirst();
if (c.getCount() <= 0) {
return null;
}
String entry = c.getString(1);
return entry;
}
return null;
}