我正在创建简单的数据库和我显示给 ListView 的数据库值，但我的 ListView 无法显示我的数据库值
这是我创建数据库的代码
public class MyDb extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "MyDb.db";
private SQLiteDatabase myDataBase;
public MyDb(Context context) {
super(context, DATABASE_NAME, null, 1);
}
public void createTable(SQLiteDatabase db){
db.execSQL("DROP TABLE IF EXISTS users");
db.execSQL("CREATE TABLE if not exists users (id_user INTEGER PRIMARY KEY AUTOINCREMENT, username VARCHAR);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
public ArrayList<ArrayList<Object>> getAllRows(SQLiteDatabase db) {
ArrayList<ArrayList<Object>> dataArray = new ArrayList<ArrayList<Object>>();
Cursor cur;
final String ROW_ID = "id_user";
final String ROW_NAME = "username";
try {
cur = db.query("users", new String[] { ROW_ID, ROW_NAME }, null, null, null, null, null);
cur.moveToFirst();
if (!cur.isAfterLast()) {
do {
ArrayList<Object> dataList = new ArrayList<Object>();
dataList.add(cur.getString(0));
dataList.add(cur.getString(1));
dataArray.add(dataList);
} while (cur.moveToNext());
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("DEBE ERROR", e.toString());
}
return dataArray;
}
public void insert(String table, ContentValues values) throws SQLException {
myDataBase.insert(table, null, values);
}
}
这是我向 ListView 显示数据库值的代码
public class DbScriptActivity extends Activity {
private MyDb dbHelper;
SQLiteDatabase db;
Cursor customAdapter;
ListView list;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_db_script);
dbHelper = new MyDb (this);
db = dbHelper.getWritableDatabase();
dbHelper.createTable(db);
//dbHelper.openDataBase();
//ListView list = (ListView)findViewById(R.id.list);
list= (ListView)findViewById(R.id.list);
getData();
Button btn = (Button)findViewById(R.id.button1);
btn.setOnClickListener(new View.OnClickListener() {
ContentValues values = new ContentValues();
public void onClick(View v) {
LayoutInflater inflater = DbScriptActivity.this.getLayoutInflater();
final View v1 =inflater.inflate(R.layout.dialog , null) ;
new AlertDialog.Builder(DbScriptActivity.this)
.setTitle("input your name:")
.setView(v1)
.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
EditText name= (EditText)v1.findViewById(R.id.name);
String yourname = name.getText().toString();
values.put("username",yourname);
Log.v("aaaa", yourname);
db.insert("users",null,values);
}
})
.show();
}
});
}
private void getData() {
String[] name = { "" };
ArrayList<ArrayList<Object>> data = dbHelper.getAllRows(db) ;
name = new String[data.size()];
for (int i = 0; i < data.size(); i++) {
ArrayList<Object> row = data.get(i);
name[i] = row.get(1).toString();
}
ArrayAdapter<String> aname = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, name);
list.setAdapter(aname);
}
}
这是我的 xml 文件，用于在我的 ListView 中查看数据库值
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".DbScriptActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:text="Register Name" />
<ListView
android:id="@+id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/button1" >
</ListView>
</RelativeLayout>
我的代码有什么问题？