我正在尝试将数据从SQLite数据库显示到自定义列表视图，但它没有显示。当我使用单个数据的简单列表视图时，它正在工作但在我尝试在自定义列表视图上显示时无效。
MainActivity.java
package com.example.addressbook;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.AddressBook.MESSAGE";
private ListView lv;
List<Listcollection> collectionlist;
DBHelper mydb;
private Context context = this;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.listView1);
mydb = new DBHelper(this);
// CustomListAdapter customListAdapter = new
// CustomListAdapter(MainActivity.this, );
lv.setAdapter(new ViewAdapter(mydb.listfromdb()));
// lv.setAdapter(ViewAdapter);
// adding it to the list view.
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
int id_To_Search = arg2 + 1;
Bundle dataBundle = new Bundle();
dataBundle.putInt("id", id_To_Search);
Intent intent = new Intent(getApplicationContext(),
com.example.addressbook.Display.class);
intent.putExtras(dataBundle);
startActivity(intent);
}
});
}
public class ViewAdapter extends BaseAdapter {
LayoutInflater mInflater;
List<Listcollection> collectionlist;
public ViewAdapter(List<Listcollection> c) {
collectionlist = c;
mInflater = LayoutInflater.from(context);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return collectionlist.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = mInflater.inflate(R.layout.list_item, null);
}
Listcollection o = collectionlist.get(position);
if (o != null) {
TextView idText = (TextView) convertView
.findViewById(R.id.lvid);
TextView nameText = (TextView) convertView
.findViewById(R.id.lvname);
TextView dateText = (TextView) convertView
.findViewById(R.id.lvdate);
TextView phoneText = (TextView) convertView
.findViewById(R.id.lvphone);
if (idText != null) {
idText.setText(Integer.toString(o.getId()));
}
if (nameText != null) {
nameText.setText("Name : "
+ collectionlist.get(position).getName());
}
if (dateText != null) {
dateText.setText("Date: "
+ collectionlist.get(position).getDate());
}
if (phoneText != null) {
phoneText.setText("Phone: "
+ collectionlist.get(position).getPhone());
}
}
return convertView;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.mainmenu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
switch (item.getItemId()) {
case R.id.item1:
Bundle dataBundle = new Bundle();
dataBundle.putInt("id", 0);
Intent intent = new Intent(getApplicationContext(),
com.example.addressbook.Display.class);
intent.putExtras(dataBundle);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public boolean onKeyDown(int keycode, KeyEvent event) {
if (keycode == KeyEvent.KEYCODE_BACK) {
moveTaskToBack(true);
}
return super.onKeyDown(keycode, event);
}}
DBHelper.java
public class DBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "MyDBName.db";
public static final String CONTACTS_TABLE_NAME = "contacts";
public static final String CONTACTS_COLUMN_ID = "id";
public static final String C_NAME = "name";
public static final String C_TYPE = "type";
public static final String C_ADDRESS = "address";
public static final String C_DATE = "date";
public static final String C_PHONE = "phone";
private HashMap hp;
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("create table contacts "
+ "(id integer primary key, name text,phone text,type text, address text,date text)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS contacts");
onCreate(db);
}
public boolean insertContact(String name, String phone, String type,
String address, String date) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("name", name);
contentValues.put("phone", phone);
contentValues.put("type", type);
contentValues.put("address", address);
contentValues.put("date", date);
db.insert("contacts", null, contentValues);
return true;
}
public Cursor getData(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery("select * from contacts where id=" + id + "",
null);
return res;
}
public int numberOfRows() {
SQLiteDatabase db = this.getReadableDatabase();
int numRows = (int) DatabaseUtils.queryNumEntries(db,
CONTACTS_TABLE_NAME);
return numRows;
}
public boolean updateContact(Integer id, String name, String phone,
String type, String address, String date) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("name", name);
contentValues.put("phone", phone);
contentValues.put("type", type);
contentValues.put("address", address);
contentValues.put("date", date);
db.update("contacts", contentValues, "id = ? ",
new String[] { Integer.toString(id) });
return true;
}
public Integer deleteContact(Integer id) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete("contacts", "id = ? ",
new String[] { Integer.toString(id) });
}
public ArrayList<Listcollection> listfromdb() {
SQLiteDatabase db = this.getReadableDatabase();
Listcollection lcollection;
Listcollection list = new Listcollection();
ArrayList<Listcollection> results = new ArrayList<Listcollection>();
Cursor crs = db.rawQuery("select * from contacts", null);
crs.moveToFirst();
list.setId(crs.getInt(crs.getColumnIndex(CONTACTS_COLUMN_ID)));
list.setName(crs.getString(crs.getColumnIndex(C_NAME)));
list.setDate(crs.getString(crs.getColumnIndex(C_DATE)));
list.setPhone(crs.getString(crs.getColumnIndex(C_PHONE)));
db.close();
return results;
}
}
enter code here
Listcollection.java
public class Listcollection {
// private variables
int id;
String name;
String type;
String address;
String date;
String phone;
// Empty constructor
public Listcollection(Parcel in) {
}
// constructor
public Listcollection(int id, String name, String type, String address,
String date, String phone) {
this.id = id;
this.name = name;
this.type = type;
this.address = address;
this.phone = phone;
this.date = date;
}
public Listcollection() {
// TODO Auto-generated constructor stub
}
// getting id
public int getId() {
return this.id;
}
// setting id
public void setId(int id) {
this.id = id;
}
// getting name
public String getName() {
return this.name;
}
// setting name
public void setName(String name) {
this.name = name;
}
public String getType() {
return this.type;
}
public void setType(String type) {
this.type = type;
}
public String getAddress() {
return this.address;
}
public void setAddress(String address) {
this.address = address;
}
public String getDate() {
return this.date;
}
public void setDate(String date) {
this.date = date;
}
public String getPhone() {
return this.phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String toString() {
return "Complain [id=" + id + ", name=" + name + ", type=" + type
+ ", address=" + address + ", date=" + date + ", phone="
+ phone + ",";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + id;
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Listcollection other = (Listcollection) obj;
if (id != other.id)
return false;
return true;
}
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel parcel, int flags) {
parcel.writeInt(getId());
parcel.writeString(getName());
parcel.writeString(getType());
parcel.writeString(getAddress());
parcel.writeString(getPhone());
parcel.writeString(getDate());
}
public static final Parcelable.Creator<Listcollection> CREATOR = new Parcelable.Creator<Listcollection>() {
public Listcollection createFromParcel(Parcel in) {
return new Listcollection(in);
}
public Listcollection[] newArray(int size) {
return new Listcollection[size];
}
};
}
答案 0 :(得分：1)
您实际上并未将数据库记录添加到results中的listfromdb()集合。
应该是这样的：
public ArrayList<Listcollection> listfromdb() {
SQLiteDatabase db = this.getReadableDatabase();
ArrayList<Listcollection> results = new ArrayList<Listcollection>();
Cursor crs = db.rawQuery("select * from contacts", null);
while (crs.moveToNext()) {
Listcollection item = new Listcollection();
item.setId(crs.getInt(crs.getColumnIndex(CONTACTS_COLUMN_ID)));
item.setName(crs.getString(crs.getColumnIndex(C_NAME)));
item.setDate(crs.getString(crs.getColumnIndex(C_DATE)));
list.setPhone(crs.getString(crs.getColumnIndex(C_PHONE)));
results.add(item);
}
db.close();
return results;
}