然后，数据库将数据传输到微调器，我想将位置0留为空白，这样我就可以将一个没有值的项目添加到微调器中，使其看起来像是提示。我整天都在努力。失败后失败
主要活动
public class MainActivity extends Activity {
Button AddBtn;
EditText et;
EditText cal;
Spinner spn;
SQLController SQLcon;
ProgressDialog PD;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
AddBtn = (Button) findViewById(R.id.addbtn_id);
et = (EditText) findViewById(R.id.et_id);
cal = (EditText) findViewById(R.id.et_cal);
spn = (Spinner) findViewById(R.id.spinner_id);
spn.setOnItemSelectedListener(new OnItemSelectedListenerWrapper(
new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent,
View view, int pos, long id) {
SQLcon.open();
Cursor c = SQLcon.readData();
if (c.moveToPosition(pos)) {
String name = c.getString(c
.getColumnIndex(DBhelper.MEMBER_NAME));
String calories = c.getString(c
.getColumnIndex(DBhelper.KEY_CALORIES));
et.setText(name);
cal.setText(calories);
}
SQLcon.close();
// closing database
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
}));
SQLcon = new SQLController(this);
// opening database
SQLcon.open();
loadtospinner();
AddBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
new MyAsync().execute();
}
});
}
public void loadtospinner() {
ArrayList<String> al = new ArrayList<String>();
Cursor c = SQLcon.readData();
c.moveToFirst();
while (!c.isAfterLast()) {
String name = c.getString(c.getColumnIndex(DBhelper.MEMBER_NAME));
String calories = c.getString(c
.getColumnIndex(DBhelper.KEY_CALORIES));
al.add(name + ", Calories: " + calories);
c.moveToNext();
}
ArrayAdapter<String> aa1 = new ArrayAdapter<String>(
getApplicationContext(), android.R.layout.simple_spinner_item,
al);
spn.setAdapter(aa1);
// closing database
SQLcon.close();
}
private class MyAsync extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
PD = new ProgressDialog(MainActivity.this);
PD.setTitle("Please Wait..");
PD.setMessage("Loading...");
PD.setCancelable(false);
PD.show();
}
@Override
protected Void doInBackground(Void... params) {
String name = et.getText().toString();
String calories = cal.getText().toString();
// opening database
SQLcon.open();
// insert data into table
SQLcon.insertData(name, calories);
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
loadtospinner();
PD.dismiss();
}
}
}
数据库
public class SQLController {
private DBhelper dbhelper;
private Context ourcontext;
private SQLiteDatabase database;
public SQLController(Context c) {
ourcontext = c;
}
public SQLController open() throws SQLException {
dbhelper = new DBhelper(ourcontext);
database = dbhelper.getWritableDatabase();
return this;
}
public void close() {
dbhelper.close();
}
public void insertData(String name, String calories) {
ContentValues cv = new ContentValues();
cv.put(DBhelper.MEMBER_NAME, name);
cv.put(DBhelper.KEY_CALORIES, calories);
database.insert(DBhelper.TABLE_MEMBER, null, cv);
}
public Cursor readData() {
String[] allColumns = new String[] { DBhelper.MEMBER_ID,
DBhelper.MEMBER_NAME, DBhelper.KEY_CALORIES };
Cursor c = database.query(DBhelper.TABLE_MEMBER, allColumns, null,
null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
}
帮手
public class DBhelper extends SQLiteOpenHelper {
// TABLE INFORMATTION
public static final String TABLE_MEMBER = "member";
public static final String MEMBER_ID = "_id";
public static final String MEMBER_NAME = "name";
public static final String KEY_CALORIES = "calories";
// DATABASE INFORMATION
static final String DB_NAME = "MEMBER.DB";
static final int DB_VERSION = 2;
// TABLE CREATION STATEMENT
private static final String CREATE_TABLE = "create table " + TABLE_MEMBER
+ "(" + MEMBER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ MEMBER_NAME + " TEXT NOT NULL," + KEY_CALORIES
+ " INT NOT NULL);";
public DBhelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS " + TABLE_MEMBER);
onCreate(db);
}
}
最佳答案
使用以下内容：
Spinner spinner = (Spinner) findViewById(R.id.yourSpinner);
ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, spinnerArray);
spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(spinnerArrayAdapter);
更新：
您的spinnerArray应该具有数据库中的值，并以第一个值作为提示
例如：
List<String> spinnerArray = new ArrayList<String>();
spinnerArray.add("YOU MESSAGE");
然后可以使用for循环将值添加到spinnerArray，如下所示：
for(//loop until you need values to be added)
将值添加到spinnerArray为：
spinnerArray.add(value1);
spinnerArray.add(value1);
spinnerArray.add(value1);
//so on.
最后在如上所述创建spinnerArrayAdapter时将其作为最后一个参数传递。这应该可以解决您的问题。
更新1：
如果您不想在第0位获得商品，可以执行以下操作：
if(spinner.getSelectedItem().equals("YOUR MESSAGE"){//may be you want to ignorecase using equalsIgnoreCase() method
//display message that you haven't selected anything
}else{
//do anything you want
}
填充伪数据：
将DBhelper类中的onCreate（）更改为：
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE);
ContentValues cv = new ContentValues();
cv.put(DBhelper.MEMBER_NAME, "DUMMY NAME");
cv.put(DBhelper.KEY_CALORIES, "DUMMY CALORIES");
database.insert(DBhelper.TABLE_MEMBER, null, cv);
}