使用 sql 数据库项填充列表视图
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【中文标题】使用 sql 数据库项填充列表视图【英文标题】：populating a list view with sql database items 【发布时间】：2013-06-27 12:08:49 【问题描述】：我的应用程序基于在用户输入“添加类别”按钮时显示一个对话框。然后它应该将数据保存到 SQL 数据库中，并使用用户添加的每个项目填充列表视图。我选择 SQL 数据库是因为我希望在用户结束应用程序时保存数据。我如何实际使用这些项目填充列表视图？这是我目前所拥有的：
public class CategoryDatabase
public static final String KEY_ROWID = "_id";
public static final String KEY_CATEGORY = "category";
private static final String DATABASE_NAME = "DBCategory";
private static final String DATABASE_TABLE = "categoryTable";
private static final int DATABASE_VERSION = 1;
private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;
public CategoryDatabase(Context c)
ourContext = c;
public CategoryDatabase open() throws SQLException
ourHelper = new DbHelper(ourContext);
ourDatabase = ourHelper.getWritableDatabase();
return this;
public void close()
ourHelper.close();
private static class DbHelper extends SQLiteOpenHelper
public DbHelper(Context context)
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
@Override
public void onCreate(SQLiteDatabase db)
db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
KEY_CATEGORY + " TEXT NOT NULL);"
);
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
onCreate(db);
public long createEntry(String category)
ContentValues cv = new ContentValues();
cv.put(KEY_CATEGORY, category);
return ourDatabase.insert(DATABASE_TABLE, null, cv);
和主要活动：
public class MainActivity extends Activity
final Context context = this;
ArrayAdapter<String> arrayAdapter;
ArrayList<String> listItems = new ArrayList<String>();
ListView lv;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
lv = (ListView)findViewById(R.id.listView1);
arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, listItems);
lv.setAdapter(arrayAdapter);
@Override
public boolean onCreateOptionsMenu(Menu menu)
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
@Override
public boolean onOptionsItemSelected(MenuItem item)
switch(item.getItemId())
case R.id.menu_add_cat:
LayoutInflater li = LayoutInflater.from(context);
View promptAdd = li.inflate(R.layout.prompt_add, null);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
//set prompts.xml to alertDialogBuilder
alertDialogBuilder.setView(promptAdd);
final EditText etAddCat = (EditText)promptAdd.findViewById(R.id.etDialogInput);
//set a dialog message
alertDialogBuilder.setPositiveButton("Done", new DialogInterface.OnClickListener()
@Override
public void onClick(DialogInterface dialog, int which)
/*
* add a cat here
* if(null != input && input.length() > 0)
listItems.add(input);
arrayAdapter.notifyDataSetChanged();
else
Toast.makeText(getApplicationContext(), "Please enter a new category", Toast.LENGTH_LONG).show();
*/
boolean didItWork = true;
try
String category = etAddCat.getText().toString();
CategoryDatabase entry = new CategoryDatabase(MainActivity.this);
entry.open();
entry.createEntry(category);
entry.close();
catch(Exception e)
didItWork = false;
String error = e.toString();
Dialog d = new Dialog(MainActivity.this);
d.setTitle("Dang it ! ");
TextView tv = new TextView(MainActivity.this);
tv.setText(error);
d.setContentView(tv);
d.show();
finally
if(didItWork)
Dialog d = new Dialog(MainActivity.this);
d.setTitle("Heck yea ! ");
TextView tv = new TextView(MainActivity.this);
tv.setText("Success");
d.setContentView(tv);
d.show();
)
.setNegativeButton("Cancel", new DialogInterface.OnClickListener()
@Override
public void onClick(DialogInterface dialog, int which)
dialog.cancel();
);
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
break;
//return super.onOptionsItemSelected(item);
return true;
// end of MainActivity
【问题讨论】：
我已经用按钮而不是菜单项单击尝试了您的代码。如果您添加以下内容，它会起作用。如果您需要进一步的帮助，请告诉我 Populating a list view from SQLite Database的可能重复 【参考方案1】：在CategoryDatabase 类中创建一个函数getAllCategory()。
public List<String> getAllCategory()
List<String> List = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT * FROM " + DATABASE_TABLE;
Cursor cursor = ourDatabase.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst())
do
List.add(cursor.getString(1));
while (cursor.moveToNext());
return List;
将项目填充到列表视图。
在您的MainActivity 中说单击按钮。
CategoryDatabase entry = new CategoryDatabase(MainActivity.this);
entry.open();
List<String> all = entry.getAllCategory();
lv = (ListView)findViewById(R.id.listView1);
arrayAdapter = new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1, all);
lv.setAdapter(arrayAdapter);
编辑：
在onCreate
CategoryDatabase entry = new CategoryDatabase(MainActivity.this);
entry.open();
List<String> all = entry.getAllCategory();
if(all.size()>0) // check if list contains items.
lv = (ListView)findViewById(R.id.listView1);
arrayAdapter = new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1, all);
lv.setAdapter(arrayAdapter);
else
Toast.makeText(MainActivity.this,"No items to display",1000).show();
【讨论】：
只有当我点击添加猫按钮时才有效，最初当我启动应用程序时，它是空白的，当我点击按钮时，所有类别都会出现 @Frugo 您可以将代码的第二部分移至onCreate。我将编辑我的答案
@Frugo 欢迎您。如果有帮助，你能投票给答案吗？以上是关于使用 sql 数据库项填充列表视图的主要内容，如果未能解决你的问题，请参考以下文章