我不知道为什么，但ListView没有显示任何项目。它应该从数据库中获取所有记录并在屏幕上显示。但它不起作用。我在LogCat中没有错误。
这是我的代码：
public class Teste extends Activity {
public static final String PREFS_NAME = "MyPrefsFile1";
private ListView mListView;
ArrayList<WordDefinition> allWordDefinitions=new ArrayList<WordDefinition>();
DictionaryDatabase DictionaryDatabase;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mListView = (ListView) findViewById(R.id.list);
DictionaryDatabase=new DictionaryDatabase(this);
allWordDefinitions=DictionaryDatabase.getAllWords();
mListView.setAdapter(new BaseAdapter() {
@Override
public View getView(int position, View View, ViewGroup parent) {
View v = View;
if (v==null) {
v=getLayoutInflater().inflate(R.layout.list_item, parent, false);
}
TextView textView=(TextView) v.findViewById(R.id.listItemTextView);
textView.setText(allWordDefinitions.get(position).word);
return v;
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return allWordDefinitions.size();
}
});
mListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int position,
long arg3) {
Intent intent =new Intent(Teste.this, WordDefinitionDetailActivity.class);
intent.putExtra("word", allWordDefinitions.get(position).word);
intent.putExtra("definition", allWordDefinitions.get(position).definition);
startActivity(intent);
}
});
}
}
DictionaryDatabase
public class DictionaryDatabase {
private static final String TAG = "DictionaryDatabase";
public static final String KEY_WORD = SearchManager.SUGGEST_COLUMN_TEXT_1;
public static final String KEY_DEFINITION = SearchManager.SUGGEST_COLUMN_TEXT_2;
private static final String DATABASE_NAME = "dictionary";
private static final String FTS_VIRTUAL_TABLE = "FTSdictionary";
private static final int DATABASE_VERSION = 2;
private final DictionaryOpenHelper mDatabaseOpenHelper;
private static final HashMap<String,String> mColumnMap = buildColumnMap();
public DictionaryDatabase(Context context) {
mDatabaseOpenHelper = new DictionaryOpenHelper(context);
}
private static HashMap<String,String> buildColumnMap() {
HashMap<String,String> map = new HashMap<String,String>();
map.put(KEY_WORD, KEY_WORD);
map.put(KEY_DEFINITION, KEY_DEFINITION);
map.put(BaseColumns._ID, "rowid AS " +
BaseColumns._ID);
map.put(SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID, "rowid AS " +
SearchManager.SUGGEST_COLUMN_INTENT_DATA_ID);
map.put(SearchManager.SUGGEST_COLUMN_SHORTCUT_ID, "rowid AS " +
SearchManager.SUGGEST_COLUMN_SHORTCUT_ID);
return map;
}
public Cursor getWord(String rowId, String[] columns) {
String selection = "rowid = ?";
String[] selectionArgs = new String[] {rowId};
return query(selection, selectionArgs, columns);
}
public Cursor getWordMatches(String query, String[] columns) {
String selection = KEY_WORD + " MATCH ?";
String[] selectionArgs = new String[] {query+"*"};
return query(selection, selectionArgs, columns);
}
private Cursor query(String selection, String[] selectionArgs, String[] columns) {
SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
builder.setTables(FTS_VIRTUAL_TABLE);
builder.setProjectionMap(mColumnMap);
Cursor cursor = builder.query(mDatabaseOpenHelper.getReadableDatabase(),
columns, selection, selectionArgs, null, null, KEY_WORD + " ASC");
if (cursor == null) {
return null;
} else if (!cursor.moveToFirst()) {
cursor.close();
return null;
}
return cursor;
}
private static class DictionaryOpenHelper extends SQLiteOpenHelper {
private final Context mHelperContext;
private SQLiteDatabase mDatabase;
private static final String FTS_TABLE_CREATE =
"CREATE VIRTUAL TABLE " + FTS_VIRTUAL_TABLE +
" USING fts3 (" +
KEY_WORD + ", " +
KEY_DEFINITION + ");";
DictionaryOpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
mHelperContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
mDatabase = db;
mDatabase.execSQL(FTS_TABLE_CREATE);
loadDictionary();
}
private void loadDictionary() {
new Thread(new Runnable() {
public void run() {
try {
loadWords();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}).start();
}
private void loadWords() throws IOException {
Log.d(TAG, "Loading words...");
final Resources resources = mHelperContext.getResources();
InputStream inputStream = resources.openRawResource(R.raw.definitions);
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
try {
String line;
while ((line = reader.readLine()) != null) {
String[] strings = TextUtils.split(line, "//");
if (strings.length < 2) continue;
long id = addWord(strings[0].trim(), strings[1].trim());
if (id < 0) {
Log.e(TAG, "unable to add word: " + strings[0].trim());
}
}
} finally {
reader.close();
}
Log.d(TAG, "DONE loading words.");
}
public long addWord(String word, String definition) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_WORD, word);
initialValues.put(KEY_DEFINITION, definition);
return mDatabase.insert(FTS_VIRTUAL_TABLE, null, initialValues);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS " + FTS_VIRTUAL_TABLE);
onCreate(db);
}
}
public long insertData(WordDefinition wordDefinition) {
SQLiteDatabase database=mDatabaseOpenHelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put(KEY_WORD, wordDefinition.word);
values.put(KEY_DEFINITION, wordDefinition.definition);
return database.insert(FTS_VIRTUAL_TABLE, null, values);
}
public long updateData(WordDefinition wordDefinition) {
SQLiteDatabase database=mDatabaseOpenHelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put(KEY_WORD, wordDefinition.word);
values.put(KEY_DEFINITION, wordDefinition.definition);
return database.update(FTS_VIRTUAL_TABLE, values, KEY_WORD+" =?", new String[]{wordDefinition.word});
}
public void deleteData(WordDefinition wordDefinition) {
SQLiteDatabase database=mDatabaseOpenHelper.getWritableDatabase();
String queryString="DELETE FROM "+FTS_VIRTUAL_TABLE+" WHERE "+KEY_WORD+" = '"+wordDefinition.word+"'";
database.execSQL(queryString);
}
public ArrayList<WordDefinition> getAllWords() {
ArrayList<WordDefinition> arrayList=new ArrayList<WordDefinition>();
SQLiteDatabase database=mDatabaseOpenHelper.getReadableDatabase();
String selectAllQueryString="SELECT * FROM "+FTS_VIRTUAL_TABLE;
Cursor cursor=database.rawQuery(selectAllQueryString, null);
if (cursor.moveToFirst()) {
do {
WordDefinition wordDefinition=new WordDefinition(cursor.getString(cursor.getColumnIndex(KEY_WORD)), cursor.getString(cursor.getColumnIndex(KEY_DEFINITION)));
arrayList.add(wordDefinition);
} while (cursor.moveToNext());
}
return arrayList;
}
public WordDefinition getWordDefinition(String word) {
SQLiteDatabase database=mDatabaseOpenHelper.getReadableDatabase();
WordDefinition wordDefinition=null;
String selectQueryString="SELECT * FROM "+FTS_VIRTUAL_TABLE+ " WHERE "+KEY_WORD+" = '"+word+ "'";
Cursor cursor=database.rawQuery(selectQueryString, null);
if (cursor.moveToFirst()) {
wordDefinition=new WordDefinition(cursor.getString(cursor.getColumnIndex(KEY_WORD)), cursor.getString(cursor.getColumnIndex(KEY_DEFINITION)));
}
return wordDefinition;
}
public WordDefinition getWordDefinition(long id) {
SQLiteDatabase database=mDatabaseOpenHelper.getReadableDatabase();
WordDefinition wordDefinition=null;
String selectQueryString="SELECT * FROM "+FTS_VIRTUAL_TABLE+ " WHERE "+BaseColumns._ID+" = '"+id+ "'";
Cursor cursor=database.rawQuery(selectQueryString, null);
if (cursor.moveToFirst()) {
wordDefinition=new WordDefinition(cursor.getString(cursor.getColumnIndex(KEY_WORD)), cursor.getString(cursor.getColumnIndex(KEY_DEFINITION)));
}
return wordDefinition;
}
public void initializeDatabaseFortheFirstTime(ArrayList<WordDefinition> wordDefinitions) {
SQLiteDatabase database=mDatabaseOpenHelper.getWritableDatabase();
database.execSQL("BEGIN");
ContentValues contentValues=new ContentValues();
for (WordDefinition wordDefinition : wordDefinitions) {
contentValues.put(KEY_WORD, wordDefinition.word);
contentValues.put(KEY_DEFINITION, wordDefinition.definition);
database.insert(FTS_VIRTUAL_TABLE, null, contentValues);
}
database.execSQL("COMMIT");
}
}
WordDefinition
public class WordDefinition {
String word,definition;
public WordDefinition(String word,ArrayList<String> alldefinition) {
this.word=word;
StringBuilder stringBuilder=new StringBuilder();
for (String string : alldefinition) {
stringBuilder.append(string);
}
this.word=stringBuilder.toString();
}
public WordDefinition(String word,String alldefinition) {
this.word=word;
this.definition=alldefinition;
}
}
答案 0 :(得分：0)
将您的代码更改为..
Log.e("List size",""+allWordDefinitions.size());
mListView.setAdapter(new BaseAdapter() {
@Override
public View getView(int position, View View, ViewGroup parent) {
View v = View;
LayoutInflater mInflater = (LayoutInflater)
YourActivity.this.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
if (v==null) {
v = mInflater.inflate(R.layout.list_item, parent, false);
}
TextView textView=(TextView) v.findViewById(R.id.listItemTextView);
textView.setText(allWordDefinitions.get(position).word);
return v;
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return arg0;
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return allWordDefinitions.get(arg0);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return allWordDefinitions.size();
}
});
并检查你的日志猫..列表的大小是多少。
此行Log.e("List size",""+allWordDefinitions.size());将打印尺寸。