Android-在ListView中显示所有SQLite数据库条目

Question

What I am trying to do is display the contents of the database in a ListView. The layout contains a ListView which I have used and implemented but I can't seem to get them working together (or even the cursor), could someone give me a hand and an explanation of why my cursor implementation doesn't work?

I have a method to return the database entries as a Cursor:

public Cursor getAllRecords() {
     return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TEXT}, null, null, null, null, null);
 }

I have the class where I want to insert and display the database entries:

Button add;
EditText tM;
ListView generalList;
DBAdapter dba = new DBAdapter(this);

 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_general);

        add = (Button) findViewById(R.id.button1);
        tM = (EditText) findViewById(R.id.editText1);
        generalList = (ListView) findViewById(R.id.generalList);

        Cursor c = dba.getAllRecords();
        c.moveToFirst();

        SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.id.generalList, c, new String[] {dba.KEY_TEXT}, new int[] {R.id.generalList}, 0);
            // This doesn't seem to work for me, I don't know how to fix it
            // or how to then get it working with the ListView

        generalList.setAdapter(adapter);

        add.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                insertIntoDatabase();
            }
        });
    }

 public void insertIntoDatabase() {
     dba.open();
     dba.insertRecord(textMessage.getText().toString());
     Toast.makeText(this, "Added:\n" + tM.getText().toString(), Toast.LENGTH_LONG).show();
     dba.close();
 }

Answer 1

if the list contains only 1 TextView , you can use android.R.layout.simple_list_item_1 instead of your R.id.generalList .

and change the new int[] {R.id.generalList} to new int[] {android.R.id.text1}

like :

SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, c, new String[] {dba.KEY_TEXT}, new int[] {android.R.id.text1}, 0);

Answer 2

on the arguments that receives the simplecursoradapter, remember the layout it receives is the layout for the actual item not the listview. so remove the R.id.generalList from there, cause that is the id that identified the listview not a full layout. so replace that with a layout that contains a textview. now, on the int array goes the id of the textview that will show the text you want and on the string array pass on the names of the fields in the record read from the database. do as mentioned by aprian and know that you can customize items as much as you need.

Answer 3

When using a ListView with a CursorAdapter, the Cursor returned from the column must contain a column with the name _id uniquely identifying each row. I'm guessing that the one column you are fetching (dba.KEY_TEXT) is not named "_id". You can either add a column to your table named _id or when you perform your SELECT have the database return the name as _id

ie

SELECT col_name as _id FROM my_table;

OR

SELECT col_name _id FROM my_table;