将项目从列表视图存储到应用程序的 SqLite 数据库

Question

我正在开发一个应用程序，该应用程序可以从电话联系人中选择联系人并将其显示在列表视图中。我想将列表视图项目存储到 SQLite 数据库中，但应用程序每次都崩溃。我没有 LogCat 报告，因为 AVD 正在运行，我正在使用我的安卓设备 （Moto G2）。请耐心等待我，我只是一个寻求指导的初学者。

以下是我正在使用的类：

数据库处理程序类

public class DatabaseHandler extends SQLiteOpenHelper {
// database details
public static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "contactsManager";
// table name
public static final String TABLE_CONTACTS = "contacts";
// public static final String KEY_NAME="name";
// column names
// public static final String KEY_ID="id";
public static final String KEY_ListItem = "listitem";
public DatabaseHandler(Context context, String name, CursorFactory factory,
        int version) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    // TODO Auto-generated constructor stub
}
// table creation
@Override
public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub
    String CREATE_CONTACTS_TABLE = "CREATE TABLE" + TABLE_CONTACTS + "("
            + KEY_ListItem + "TEXT" + ")";
    db.execSQL(CREATE_CONTACTS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub
    db.execSQL("DROP TABLE IF EXISTS" + TABLE_CONTACTS);
    onCreate(db);
}
}

拾取适配器类

public class PickAdapter {
SQLiteDatabase database_obj;
DatabaseHandler handler_obj;
Context context;
public PickAdapter(Context c) {
    context = c;
}
void addListItem(ArrayList<String> numbers) {
    handler_obj = new DatabaseHandler(context,
            DatabaseHandler.DATABASE_NAME, null,
            DatabaseHandler.DATABASE_VERSION);
    database_obj = handler_obj.getWritableDatabase();
    ContentValues values = new ContentValues();
    for (int i = 0; i < numbers.size(); i++) {
        Log.e("vlaue inserting==", "" + numbers.get(i));
        values.put(DatabaseHandler.KEY_ListItem, numbers.get(i));
        database_obj.insert(DatabaseHandler.TABLE_CONTACTS, null, values);
    }
    database_obj.close(); // Closing database connection
}
Cursor getListItem() {
    String selectQuery = "SELECT  * FROM " + DatabaseHandler.TABLE_CONTACTS;
    handler_obj = new DatabaseHandler(context,
            DatabaseHandler.DATABASE_NAME, null,
            DatabaseHandler.DATABASE_VERSION);
    database_obj = handler_obj.getWritableDatabase();
    Cursor cursor = database_obj.rawQuery(selectQuery, null);
    return cursor;
}
}

选择活动类

public class PickActivity extends Activity {
    /** Called when the activity is first created. */
    ListView nlist;
    Button b, saveButton;
    DatabaseHandler handler;
    PickAdapter pickAdapterObj;
    ArrayList<String> phoneNumbers = new ArrayList<String>();
    ArrayList<String> names = new ArrayList<String>();
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    saveButton = (Button) findViewById(R.id.button2);
    b = (Button) findViewById(R.id.button1);
    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent intent = new Intent(Intent.ACTION_PICK);
            intent.setType(ContactsContract.CommonDataKinds.Phone.CONTENT_TYPE);
            startActivityForResult(intent, 1);
        }
    });
    saveButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            pickAdapterObj.addListItem(phoneNumbers);
            Cursor cursor = pickAdapterObj.getListItem();
            Log.e("count", "" + cursor.getCount());
            if (cursor != null) {
                cursor.moveToNext();
                do {
                    Log.e("value==", "" + cursor.getString(1));
                } while (cursor.moveToNext());
            }
        }
    });
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    if (data != null) {
        Uri uri = data.getData();
        if (uri != null) {
            Cursor c = null;
            try {
                c = getContentResolver()
                        .query(uri,
                                new String[] {
                                        ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,
                                        ContactsContract.CommonDataKinds.Phone.NUMBER,
                                        ContactsContract.CommonDataKinds.Phone.TYPE },
                                null, null, null);
                if (c != null && c.moveToFirst()) {
                    String name = c.getString(0);
                    String number = c.getString(1);
                    // int type = c.getInt(2);
                    storeInArrays(name, number);
                }
            } finally {
                if (c != null) {
                    c.close();
                }
            }
        }
    }
}
public void storeInArrays(String name, String number) {
    ListView noList = (ListView) findViewById(R.id.listView2);
    ListView nameList = (ListView) findViewById(R.id.listView1);
    names.add(name);
    phoneNumbers.add(number);
    ArrayAdapter<String> numberAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, phoneNumbers);
    noList.setAdapter(numberAdapter);
    ArrayAdapter<String> nameAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, names);
    nameList.setAdapter(nameAdapter);
    Toast.makeText(getApplicationContext(), "added", Toast.LENGTH_LONG)
            .show();
}
}

Answer 1

您应该采用 Google 推荐的标准"内容提供程序、数据加载器、光标适配器"方法，采用更可靠的方法。

看看这个实现，它有这种方法的完整骨架。这是更多的代码，但数据内容提供程序的分离最终应该为您节省很多悲伤（即数据更改时的列表更新）。

祝你好运

Answer 2

你没有给 Logcat，所以我无法得到正确的错误。但我认为您的表创建中的错误。你必须以适当的方式给予空间。喜欢。。

String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
        + KEY_ListItem + " TEXT" + ")";