我创建了一个ListActivity并从SQLite读取数据以在ListView中显示。
然后，我需要点击列表并以新的布局显示我的数据，但是当我使用
时我遇到了问题onClickListener所以这是我的代码
MainActivity.java
import com.hci.Entry.NoteEntry;
import com.hci.data.Constants;
import com.hci.data.ReminderDB;
import java.util.ArrayList;
public class MainActivity extends ListActivity {
private ReminderDB dba;
@Override
protected void onCreate(Bundle savedInstanceState) {
dba = new ReminderDB(this);
dba.open();
setContentView(R.layout.reminder_main);
super.onCreate(savedInstanceState);
this.setListAdapter(new NoteAdapter(this));
}
}
private class NoteAdapter extends BaseAdapter{
private LayoutInflater mInflater;
private ArrayList<NoteEntry> notes;
public NoteAdapter(Context context){
mInflater = LayoutInflater.from(context);
notes = new ArrayList<NoteEntry>();
getData();
}
public void getData(){
Cursor c = dba.getNote();
startManagingCursor(c);
if(c.moveToFirst()){
do {
String title = c.getString(c.getColumnIndex(Constants.TITLE_NAME));
String subject = c.getString(c.getColumnIndex(Constants.SUBJECT_NAME));
String content = c.getString(c.getColumnIndex(Constants.CONTENT_NAME));
NoteEntry temp = new NoteEntry(title,content,subject);
notes.add(temp);
}while(c.moveToNext());
}
}
private Holder holder;
@Override
public int getCount() {
return notes.size();
}
@Override
public NoteEntry getItem(int i) {
return notes.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int position, View view, ViewGroup viewGroup) {
if(view == null){
view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.note_row,null);
holder = new Holder();
holder.subject = (TextView) view.findViewById(R.id.subject_name);
holder.title = (TextView) view.findViewById(R.id.Note_content);
view.setTag(holder);
}else{
holder = (Holder) view.getTag();
}
holder.mNote = getItem(position);
holder.title.setText(holder.mNote.getTitle());
holder.subject.setText(holder.mNote.getSubject());
view.setTag(holder);
return view;
}
private class Holder {
NoteEntry mNote;
public TextView subject;
public TextView title;
}
}
@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.create_button:
newActivities();
return true;
case R.id.action_settings:
openSetting();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void newActivities() {
Intent newActivities = new Intent(getApplicationContext(),NewActivities.class);
startActivity(newActivities);
}
private void openSetting() {
// TODO Auto-generated method stub
}
@Override
public void onBackPressed(){
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
//now I have a problem
Cursor selectNote = (Cursor) l.getItemAtPosition(position);
String title = selectNote.getString(selectNote.getColumnIndex(Constants.TITLE_NAME));
String subject = selectNote.getString(selectNote.getColumnIndex(Constants.SUBJECT_NAME));
String content = selectNote.getString(selectNote.getColumnIndex(Constants.CONTENT_NAME));
Log.d("Title = ",title);
Log.d("Subject = ",subject);
Log.d("Content = ",content);
}
}
NoteDBHelper.java
public class NoteDBHelper extends SQLiteOpenHelper {
private static final String CREATE_TABLE = "create table "+Constants.TABLE_NAME+"("+
Constants.NOTE_ID+" integer primary key autoincrement, "+
Constants.TITLE_NAME+" text not null, "+
Constants.SUBJECT_NAME+" text not null, "+
Constants.CONTENT_NAME+" text not null);";
public NoteDBHelper(Context context) {
super(context, Constants.TABLE_NAME, null, Constants.DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w("TaskDBAdapter","Upgrading from version"+oldVersion+"to"+newVersion+",which will destroy all old data");
db.execSQL("drop table if exists"+Constants.TABLE_NAME);
onCreate(db);
}
}
ReminderDB.java
public class ReminderDB {
private SQLiteDatabase db;
private final Context context;
private final NoteDBHelper dbhelper;
private String[] allcolumns = {Constants.SUBJECT_NAME,Constants.TITLE_NAME,Constants.CONTENT_NAME};
public ReminderDB(Context c){
context = c;
dbhelper = new NoteDBHelper(context);
db = dbhelper.getWritableDatabase();
}
public void close(){
db.close();
}
public void open() throws SQLiteException {
db = dbhelper.getWritableDatabase();
}
public long insertNotes(String title,String content,String S_name){
ContentValues newTaskValue = new ContentValues();
newTaskValue.put(Constants.TITLE_NAME, title);
newTaskValue.put(Constants.CONTENT_NAME, content);
newTaskValue.put(Constants.SUBJECT_NAME, S_name);
return db.insert(Constants.TABLE_NAME, null,newTaskValue );
}
public Cursor getNote(){
Cursor cursor = db.query(Constants.TABLE_NAME,allcolumns,null,null,null,null,null);
return cursor;
}
}
NoteEntry.java
public class NoteEntry {
int id;
String title, subject, content;
public NoteEntry(String t,String c,String s){
title = t;subject = s;content = c;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getSubject() {
return subject;
}
public void setSubject(String subject) {
this.subject = subject;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
感谢您的帮助：））
答案 0 :(得分：0)
我猜你得到了ClassCastException错误。在尝试将其转换为Cursor实例时，将使用NoteEntry对象实例填充适配器。所以，而不是
(Cursor)l.getItemAtPosition(position);
使用以下内容：
(NoteEntry)l.getItemAtPosition(position);