列表视图仅显示少数元素

代码如下:

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_titoli);

        btt_backHome = (Button) findViewById(R.id.btt_backHome);
        lV_titoli = (ListView) findViewById(R.id.lV_titoli);
        eT_search = (EditText) findViewById(R.id.eT_search);

        adapter = ArrayAdapter.createFromResource(this, R.array.titoli, android.R.layout.simple_list_item_1);
        adapter_testi = ArrayAdapter.createFromResource(this, R.array.testi, android.R.layout.simple_list_item_1);
        lV_titoli.setAdapter(adapter);

        final Intent refresh = new Intent(this, activity_titoli.class);
        final Intent to_Home = new Intent (this , Activity_Main.class);
        final Intent to_Canzone_from_titoli = new Intent (this , activity_canzone.class);

        eT_search.addTextChangedListener(new TextWatcher() {

            @Override
            public void afterTextChanged(Editable arg0) {
                // TODO Auto-generated method stub

            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1,
                                          int arg2, int arg3) {
                // TODO Auto-generated method stub
            }

            @Override
            public void onTextChanged(CharSequence arg0, int arg1, int arg2,
                                      int arg3) {
                (activity_titoli.this).adapter.getFilter().filter(arg0);
            }
        });