Question

我正在尝试填充ListView ....但我无法在SimpleCursorAdapter中使用的数据库中添加2个字符串值.... 任何人，帮助我

代码

ListView.java

public class ListView extends ListActivity {

SQLiteDatabase messagedb;
List<String> senderArray = new ArrayList<String>();
List<String> bodyArray = new ArrayList<String>();

String[] simpleSenderArray = new String[ senderArray.size() ];

String[] simpleBodyArray = new String[ bodyArray.size() ];

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.my_list);

    senderArray.toArray( simpleSenderArray );
    bodyArray.toArray( simpleBodyArray );

    messagedb=ListView.this.openOrCreateDatabase("message",0, null);

            //This database created already and add sender and body values...here just open that database
    Cursor  cur=messagedb.rawQuery("select sender, body from tab2", null);
    while(cur.moveToNext())
    {
        String sender = cur.getString(cur.getColumnIndex("sender"));
        String body = cur.getString(cur.getColumnIndex("body"));
        senderArray.add(sender);
        bodyArray.add(body);
    }
    cur.close();


    messagedb.close();

     int[] to = new int[] { R.id.sender_entry, R.id.body_entry };

     SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, R.layout.my_list_entry, cur,simpleSenderArray, to);

     this.setListAdapter(mAdapter);


}

}

my_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" >

<ListView

    android:id="@android:id/android:list"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />


</LinearLayout>

my_list_entry.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" >
<TextView
    android:id="@+id/sender_entry"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="28dip" />
 <TextView
    android:id="@+id/body_entry"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="28dip" />
</LinearLayout>

有人可以帮助我填充ListView吗？

Answer 1

您已将活动ListView命名为内置类名，我强烈建议您将其更改为独特的内容，以防止出现任何混淆或命名冲突。

在您的SQLite表中，您应该将_id INTEGER列设置为PRIMARY KEY，Android需要此_id列将数据绑定到任何ListView，Spinner等（从技术上讲，SQLite3会自动创建一个这样的列，但我相信最好自己定义它。）

    messagedb.execSQL(
        "CREATE TABLE IF NOT EXISTS tab2(" +
        " _id INTEGER PRIMARY KEY," +
        " sender INT(13)," +
        " body varchar)");

您的代码应该更像这样：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.my_list);

    // Using a SQLiteOpenHelper might be best, but I'll assume that this command works
    messagedb=ListView.this.openOrCreateDatabase("message",0, null);

    Cursor cur = messagedb.rawQuery("select _id, sender, body from tab2", null);
    String[] from = new String[] { "_id", "sender", "body" }
    int[] to = new int[] { R.id.sender_entry, R.id.body_entry };

    SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, R.layout.my_list_entry, cur, from, to);

    this.setListAdapter(mAdapter);
}

您可能需要考虑使用SQLiteDatabase.query（）方法，我相信它更快一点：

Cursor cur = messagedb.query("tab2", new String[] {"_id", "sender", "body"}, null, null, null, null, null);

我还建议为所有列名定义静态变量，以便将来轻松编码。

最后，这应该适用于没有_id列的表，但我不建议这样做：

Cursor cur = messagedb.rawQuery("select rowid as _id, sender, body from tab2", null);

向listView添加值

1 个答案: