我是android编程新手,希望您能帮助我一开始我有些问题,我想从Sqlite数据库中填充数据,但我不知道最好的方法是什么,我的数据库有时有很多数据,我想要一个优化的方式来获取数据。我搜索了很多,发现SimpleCursorAdapter很适合我的目的,但我找不到任何方法使它工作。这是我的代码
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_read_book);
ListView Peot_list = (ListView) findViewById(R.id.list_poet_name);
String SDcardPath = Environment.getExternalStorageDirectory().getPath();
String DbPath = SDcardPath + "/Tosca/" + "persian_poem.db";
try {
db = SQLiteDatabase.openDatabase(DbPath,null,SQLiteDatabase.CREATE_IF_NECESSARY);
// here you do something with your database ...
getData();
db.close();
}
catch (SQLiteException e) {
}
}
private void getData() {
TextView txtMsg;
txtMsg=(TextView) findViewById(R.id.txtmsg);
try {
// obtain a list from DB
String TABLE_NAME = "classicpoems__poet_contents";
String COLUMN_ID = "poet_id";
String COLUMN_NAME = "poet_name";
String COLUMN_CENTURY = "century_start";
String [] columns ={COLUMN_ID,COLUMN_NAME,COLUMN_CENTURY};
Cursor c = db.query(TABLE_NAME, columns,null, null, null, null, COLUMN_ID);
int theTotal = c.getCount();
Toast.makeText(this, "Total: " + theTotal, 1).show();
int idCol = c.getColumnIndex(COLUMN_ID);
int nameCol = c.getColumnIndex(COLUMN_NAME);
int centuryCol = c.getColumnIndex(COLUMN_CENTURY);
while (c.moveToNext()) {
columns[0] = Integer.toString((c.getInt(idCol)));
columns[1] = c.getString(nameCol);
columns[2] = c.getString(centuryCol);
txtMsg.append( columns[0] + " " + columns[1] + " "
+ columns[2] + "n" );
}
} catch (Exception e) {
Toast.makeText(this, e.getMessage(), 1).show();
}
}
现在我可以从数据库中读取我想要的内容它们显示在txtMsg中但我想将它们显示在列表视图中。我根本不能定义SimpleCursorAdapter并且总是得到错误或空列表
After:
Cursor c = db.query(TABLE_NAME, columns,null, null, null, null, COLUMN_ID);
简单地创建一个CursorAdapter,像SimpleCursorAdapter,用这个游标,然后传递适配器给你的ListView。比如:
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_2, c,
new String[] {COLUMN_NAME,COLUMN_CENTURY}, new int[] {android.R.id.text1, android.R.id.text2}, 0);
ListView list = (ListView) findViewById(R.id.list);
list.setAdapter(adapter);
(您实际上不需要Cursor c = db.query(...);
以下的任何其他代码)
每行的外观取决于您在适配器中使用的布局,在本例中为android.R.layout.simple_list_item_2
。如果您想自定义信息的显示方式,请编写自己的布局。