Question

我的列表视图活动，这里是我想查看列表，最终我会过滤它，现在在某个阶段我可以添加活动从列表中获取行并进行编辑吗？

public class CBFilter extends Activity{

ListView RecipeNames;
Cursor cursor;
SimpleCursorAdapter adapter;
CBDataBaseHelper DH;

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.main);

RecipeNames = (ListView) findViewById(R.id.List1);

adapter = new SimpleCursorAdapter (this, 0, cursor, null, null);

CBDataBaseHelper data = new CBDataBaseHelper(this);
data.open();
cursor = data.query();
startManagingCursor(cursor);

String[] from = { CBDataBaseHelper.KEY_NAME};
int[] to = { R.id.recipeText};

adapter = new SimpleCursorAdapter(this, R.layout.row, cursor, from, to);
RecipeNames.setAdapter(adapter);

}


public void CreateNew(View view){

    Intent myIntent = new Intent(this, CBCreate.class);
    startActivity(myIntent);


}





}

我的DatabaseHelper类，以帮助编辑我的数据库

public class CBDataBaseHelper {

public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "Recipe_Name";
public static final String KEY_CATEGORY = "Recipe_Category";
public static final String KEY_DESCRIPTION = "Recipe_Description";

public static final String KEY_ROWID2 = "_id";
public static final String KEY_NAME2 = "Ingredient_Name";

private static final String DATABASE_NAME = "Recipedb";
private static final String DATABASE_TABLE = "RecipeData";
//private static final String DATABASE_TABLE2 = "IngredientData";
private static final int DATABASE_VERSION = 1;

private DBHelper myHelper;
private final Context mycontext;
private SQLiteDatabase mydatabase;

private static class DBHelper extends SQLiteOpenHelper {
    public DBHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub

        db.execSQL("CREATE TABLE " + DATABASE_TABLE + "( " + KEY_ROWID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_NAME
                + " TEXT NOT NULL, " + KEY_CATEGORY + " TEXT NOT NULL,"
                + KEY_DESCRIPTION + " TEXT NOT NULL" + ")");

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

        db.execSQL("DROP IF EXISTS " + DATABASE_TABLE);
        onCreate(db);

    }
}

public CBDataBaseHelper(Context c){
    mycontext = c;

}

public CBDataBaseHelper open() throws SQLException{
    myHelper = new DBHelper(mycontext);
    mydatabase = myHelper.getWritableDatabase();
    return this;
}

public void close(){
    myHelper.close();
}


public long createEntry(String name){

    ContentValues cv = new ContentValues();
    cv.put(KEY_NAME, name);
    return mydatabase.insert(DATABASE_TABLE, null, cv);

}

public Cursor query() {
    // Open Database

    String[] columns = new String[]{KEY_ROWID, KEY_NAME, KEY_CATEGORY, KEY_DESCRIPTION};
    Cursor cursor = mydatabase.query(DATABASE_TABLE, columns, null, null, null, null, null); 
    return cursor;


  }



}

我的创建Record类，现在我有一个try catch来查看这个insert命令是否会起作用并返回true所以我不知道这是否是我获取行等的方式。

public class CBCreate extends Activity   {

EditText EditRecipe;
Button Rname;

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.create); // sets the content view to main

    EditRecipe = (EditText) findViewById(R.id.updateRecipe);
    Rname = (Button) findViewById(R.id.RecipeName);
    //Rname.setOnClickListener(this);

}

public void doIt(View view) {

boolean didItWork = true;
        try {
            String Name = EditRecipe.getText().toString();

            CBDataBaseHelper entry = new     CBDataBaseHelper(CBCreate.this);
            entry.open();
            entry.createEntry(Name);
            Dialog d = new Dialog(this);
            d.setTitle(Name);
            TextView tv = new TextView(this);
            tv.setText(Name);
            d.setContentView(tv);
            d.show();
            entry.close();

        } catch (Exception e ) {
            didItWork = false;
            Dialog d = new Dialog(this);
            String error = e.toString();
            d.setTitle("dang it!");
            TextView tv = new TextView(this);
            tv.setText(error);
            d.setContentView(tv);
            d.show();
        } finally {
            if (didItWork){
                Dialog d = new Dialog(this);
                d.setTitle("Heck ya!");
                TextView tv = new TextView(this);
                tv.setText("Success");
                d.setContentView(tv);
                d.show();
            }
        }
}

public void goBack(View view){

    Intent myIntent = new Intent(this, CBFilter.class);
    startActivity(myIntent);
}

}

创建记录并返回过滤器活动后，没有带lisview的记录

谢谢Stefan

Answer 1

当您返回到过滤器活动时，请通过调用适配器上的notifydatasetchanged告诉listview刷新。

为什么此代码不返回列表视图中的任何行

1 个答案: