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我試圖使用baseadapter顯示來自sqlite的數據，但是當我運行我的代碼時。 theres沒有在列表視圖中顯示。不知道我的代碼有什麼問題。需要你的幫助的人只是初學者在編程。生病發布我的代碼如下。數據不能從SQLite中使用BaseAdapter顯示
MainActivity.java
public class MainActivity extends Activity {
DatabaseHelper db;
DoctorListAdapter adapter;
Context context = MainActivity.this;
List<Doctor> doctor = new ArrayList<Doctor>();
ListView l1;
int startIndex = 0;
private static final int DISPLAY_LIMIT = 20;
public MainActivity() {
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = new DatabaseHelper(getApplication());
l1 = (ListView) findViewById(R.id.listView);
l1.setAdapter(new DoctorListAdapter(context,doctor));
// set data
}
}
> DoctorListAdapter.java
public class DoctorListAdapter extends BaseAdapter {
private Context context;
private List<Doctor> doctorData = new ArrayList<Doctor>();
public DoctorListAdapter(Context context, List<Doctor> doctorData){
this.context = context;
this.doctorData = doctorData;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return doctorData.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return doctorData.get(position);
}
@Override
public long getItemId(int positionId) {
// TODO Auto-generated method stub
return positionId;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holder;
Doctor doctor = doctorData.get(position);
if(convertView == null){
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.item_doctor, parent, false);
holder = new ViewHolder();
holder.doctorlist_image = (ImageView)convertView.findViewById(R.id.doctorlist_image);
holder.doctorlist_name = (TextView)convertView.findViewById(R.id.doctorlist_name);
holder.doctorlist_id = (TextView)convertView.findViewById(R.id.doctorlist_id);
holder.doctorlist_gender = (TextView)convertView.findViewById(R.id.doctorlist_gender);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
return convertView;
}
static class ViewHolder{
ImageView doctorlist_image;
TextView doctorlist_name,
doctorlist_gender,
doctorlist_id;
}
}
Doctor.java
public class Doctor implements Serializable {
private int doctorId;
private String fullName;
private String gender;
public Doctor(){
}
public Doctor(int doctorId,
String gender,
String fullName){
this.doctorId = doctorId;
this.gender = gender;
this.fullName = fullName;
}
public int getDoctorId() {
return doctorId;
}
public void setDoctorId(int doctorId) {
this.doctorId = doctorId;
}
public String getFullName() {
return fullName;
}
public void setFullName(String fullName) {
this.fullName = fullName;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
}
DatabaseHelper.class
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DB_PATH = "/data/data/com.example.jathniel.myapplication/databases/";
private static final String DB_NAME = "mydoctorfinder_new_migrate.sqlite";
private SQLiteDatabase myDataBase;
private Context myContext = null;
private static final String TABLE_DOCTOR = "doctors";
final static String KEY_ID = "id",
KEY_FULLNAME = "full_name",
KEY_GENDER = "gender";
public DatabaseHelper(Context context) {
super(context, DB_NAME, (SQLiteDatabase.CursorFactory) null, 1);
this.myContext = context;
}
public void createDataBase() throws IOException {
boolean dbExist = this.checkDataBase();
if(!dbExist) {
this.getReadableDatabase();
try {
this.copyDataBase();
} catch (IOException e) {
throw new Error("Error");
}
}
}
public void copyDataBase() throws IOException {
InputStream myInput = this.myContext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
FileOutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String e = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(e, (SQLiteDatabase.CursorFactory)null, 0);
} catch (SQLiteException e) {
;
}
if(checkDB != null) {
checkDB.close();
}
return checkDB != null;
}
public void openDataBase() throws SQLException {
String myPath = DB_PATH + DB_NAME;
this.myDataBase = SQLiteDatabase.openDatabase(myPath, (SQLiteDatabase.CursorFactory)null, 0);
}
public synchronized void close() {
if(this.myDataBase != null) {
this.myDataBase.close();
}
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public void createDatabase() {
}
private Doctor getDoctor(int doctor_id){
Doctor doctor = new Doctor();
String selectQuery = "SELECT * FROM " + TABLE_DOCTOR + " WHERE id = "+doctor_id;
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, null);
if (c.moveToFirst()) {
//System.out.println("KEY_FIRSTNAME: "+c.getString(c.getColumnIndex(KEY_FIRSTNAME)));
doctor.setDoctorId(c.getInt(c.getColumnIndex(KEY_ID)));
doctor.setGender(c.getString(c.getColumnIndex(KEY_GENDER)));
doctor.setFullName(c.getString(c.getColumnIndex(KEY_FULLNAME)));
}
c.close();
return doctor;
}
public List<Doctor> getAllDoctor(int start) {
//@http://www.androidhive.info/2013/09/android-sqlite-database-with-multiple-tables/
final int maxCount = 20;
List<Doctor> doctorList = new ArrayList<Doctor>();
String selectQuery = "SELECT * FROM " + TABLE_DOCTOR + " LIMIT "+maxCount+" OFFSET "+start;
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (c.moveToFirst()) {
do {
Doctor doctor = new Doctor();
doctor.setDoctorId(c.getInt(c.getColumnIndex(KEY_ID)));
doctor.setGender(c.getString(c.getColumnIndex(KEY_GENDER)));
doctor.setFullName(c.getString(c.getColumnIndex(KEY_FULLNAME)));
doctorList.add(doctor);
} while (c.moveToNext());
}
c.close();
return doctorList;
}
}
您沒有在getview方法設定數據viwe。 –