我在这里搜索很多，但我没有找到适用于我的应用程序的东西。
我有3个活动（活动1，活动2和活动3）。
活动1是从我的数据库填充的列表视图
活动2是从我的数据库中的另一个表填充的列表视图（关于在我的活动1中选择的项目）。
活动3是一个文本视图，我们可以在其中找到活动2中所选项目的描述。
我的问题是我可以获取所选项目的ID，但我需要显示其他列的值。
活动2代码：
public final static String ID_EXTRA="com.example.testdb5._ID";
String passedVar=null;
private TextView passedView=null;
private BooklistHelper dbBookHelper = null;
private Cursor ourCursor = null;
private BookAdapter adapter=null;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.act2);
passedVar=getIntent().getStringExtra(Tutorial16.ID_EXTRA);
ListView myListView = (ListView)findViewById(R.id.myListView);
dbBookHelper=new BooklistHelper(this);
ourCursor=dbBookHelper.getBooksByAuthor(passedVar);
startManagingCursor(ourCursor);
adapter=new BookAdapter(ourCursor);
myListView.setAdapter(adapter);
myListView.setOnItemClickListener(onListClick);
}
private AdapterView.OnItemClickListener onListClick=new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent,
View view, int position,
long id)
{
Intent i=new Intent(Activity2.this, Activity3.class);
i.putExtra(ID_EXTRA, String.valueOf(id));
startActivity(i);
}
};
class BookAdapter extends CursorAdapter {
BookAdapter(Cursor c) {
super(Activity2.this, c);
}
public void bindView(View row, Context ctxt,
Cursor c) {
BookHolder holder=(BookHolder)row.getTag();
holder.populateFrom(c, dbBookHelper);
}
public View newView(Context ctxt, Cursor c,
ViewGroup parent) {
LayoutInflater inflater=getLayoutInflater();
View row=inflater.inflate(R.layout.row2, parent, false);
BookHolder holder=new BookHolder(row);
row.setTag(holder);
return(row);
}
}
static class BookHolder {
private TextView name=null;
BookHolder(View row) {
name=(TextView)row.findViewById(R.id.bookText);
}
void populateFrom(Cursor c, BooklistHelper r) {
name.setText(r.getName(c));
}
}
活动3代码：
public class Activity3 extends Activity{
String passedVar=null;
private TextView passedView=null;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.act3);
passedVar=getIntent().getStringExtra(Activity2.ID_EXTRA);
passedView=(TextView)findViewById(R.id.passed);
passedView.setText("You Clicked item Id="+passedVar);
}
BooklistHelper
public class BooklistHelper extends SQLiteOpenHelper{
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.testdb5/databases/";
private static String DB_NAME = "booklist.db";
private static final String TABLE_NAME = "Authors";
private static final String COLUMN_ID = "_id";
public static final String COLUMN_TITLE = "author_name";
private static final String SECOND_TABLE_NAME = "Books";
private static final String SECOND_COLUMN_ID = "_id";
public static final String SECOND_COLUMN_TITLE = "book_name";
private SQLiteDatabase myDataBase;
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
* @param context
*/
public BooklistHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
public Cursor getCursor() {
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(TABLE_NAME);
String[] asColumnsToReturn = new String [] { COLUMN_ID, COLUMN_TITLE};
//make sure get search by string pass correctly
Cursor mCursor = queryBuilder.query(myDataBase, asColumnsToReturn, null,
null, null, null, "author_name ASC");
return mCursor;
}
public String getName(Cursor c) {
return(c.getString(1));
}
public Cursor getBooksByAuthor(String id) {
String[] args={id};
return(getReadableDatabase()
.rawQuery("SELECT _id, book_name FROM Books WHERE author_id=?",
args));
}
} 感谢您的帮助，如果您需要更多信息，请不要犹豫。
答案 0 :(得分：2)
我不完全理解您的问题，但我认为您希望不仅仅将ID传递给活动3，
你可以将你正在使用的整个对象作为可序列化的项目传递，
只需实施Serializable（class xxx implement Serializable），您就可以了，
intent.putExtra("key", object);
yourObjectInstance = (YourObject) getIntent().getSerializableExtra("key");
希望这会有所帮助，否则，如果我不是您需要的，请向我们提供更多信息，
答案 1 :(得分：0)
对于您的第一个活动，您需要从数据库中获取包含您要在ListView中显示的内容的数据以及您需要传递给活动2的任何其他数据，以便活动2具有获取来自数据库的信息。
活动2与Activty 1做同样的事情。获取显示和信息所需的内容以传递给活动3。
在onItemClick（）中，您需要使用该项的位置获取从ArrayList中单击的项。单击项目的ID对此无用。它与数据库中项目的ID不同。
您的问题表明您基本上不了解如何使用ArrayList和ListView。互联网上有很多例子。只是Google＆＃34; android listview示例＆＃34;。
答案 2 :(得分：0)
如果其他列在listView中，您可以获取这些值：
private AdapterView.OnItemClickListener onListClick=new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent,
View view, int position,
long id)
{
TextView view1 = (TextView)view.findViewById(R.id.yourTextView1);
TextView view2 = (TextView)view.findViewById(R.id.yourTextView2);
....
....
Intent i=new Intent(Activity2.this, Activity3.class);
i.putExtra(ID_EXTRA, String.valueOf(id));
i.putExtra(VALUE1_EXTRA, view1.getText().toString());
i.putExtra(VALUE2_EXTRA, view2.getText().toString());
.....
.....
startActivity(i);
}
};
答案 3 :(得分：0)
这是另一种从数据库中检索数据的方法，使其适应您的需求
public ArrayList<MyObject> getDataById(String mId) {
String query = "select * from table where id=" + mId;
ArrayList<MyObject> mObjects = new ArrayList<MyObject>();
Cursor c = myDataBase.rawQuery(query, null);
int id = c.getColumnIndex("id");
int val1 = c.getColumnIndex("val1");
int val2 = c.getColumnIndex("val2");
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
MyObject d = new MyObject();
d.setId(c.getString(id));
d.setVal1(c.getString(val1));
d.setVal2(c.getString(val2));
mObjects .add(d);
}
return mObjects ;
}
所以这会向您返回所有数据的ArrayList，从这里可以很容易地管理，希望这有帮助