我有两个问题。他们是相关的，因此我在一起问他们。
Q1：自定义BaseAdapter类中的 getFilter（）方法无法正常工作
我在我的应用中使用自定义BaseAdapter class来在自定义listview中实现搜索功能。搜索栏中有一个edittext，它会过滤listview。但getFilter() method无效，因为当我在edittext中输入文字时，列表视图不会被过滤。代码如下。
Q2：自定义列表视图无法正常工作
我使用自定义listview布局将两个textviews放入一个列表项中。但结果并不像预期的那样。 This就是我所做的，This就是我想要做的。
Q1代码：
的 MainActivity.java
//this is the MainActivity where I have my navigation drawer.
public class MainActivity extends Activity {
final String[] elename ={"Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Flourine","Noen","Sodium","Magnesium","Aluminium","Silicon","Phosphorous","Sulphur","Chlorine","Argon","Potassium","Calcium","Scandium","Titanium","Vanadium","Chromium","Manganese","Iron","Cobalt","Nickel","Copper","Zinc","Gallium","Germanium","Arsenic","Selenium","Bromine","Krypton","Rubidium","Strontium","Yttrium","Zirconium","Niobium","Molybdenum","Technetium","Ruthenium","Rhodium","Palladium","Silver","Cadmium","Indium","Tin","Antimony","Tellurium","Iodine","Xenon","Caesium","Barium","Lanthanum","Cerium","Praseodymium","Neodymium","Promethium","Samarium","Europium","gadoliium","Terbium","Dysprosium","Holmium","Erbium","Thulium","Ytterbium","Lutetium","Hafnium","Tantalum","Tungsten","Rhenium","Osmium","Iridium","Platinum","Gold","Mercury","Thallium","Lead","Bismuth","Polonium","Astatine","Radon","Francium","Radium","Actinium","Thorium","Protactinium","Uranium","Neptunium","Plutonium","Americium","Curium","Berkelium","Californium","Einstenium","Fermium","Mendelevium","Nobelium","Lawrencium","Rutherfordium","Dubnium","Seaborgium","Bohrium","Hassium","Meitnerium","Darmstadtium","Roentgenium","Copernicium","Ununtrium","Ununquadium","Ununpentium","Ununhexium","Ununseptium","Ununoctium"};
final String[] nos = {"1","2","3","4","5","6","7","8","9","10","11","12","13","14","15","16","17","18","19","20","21","22","23","24","25","26","27","28","29","30","31","32","33","34","35","36","37","38","39","40","41","42","43","44","45","46","47","48","49","50","51","52","53","54","55","56","57","58","59","60","61","62","63","64","65","66","67","68","69","70","71","72","73","74","75","76","77","78","79","80","81","82","83","84","85","86","87","88","89","90","91","92","93","94","95","96","97","98","99","100","101","102","103","104","105","106","107","108","109","110","111","112","113","114","115","116","117","118"};
ListViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
adapter = new ListViewAdapter(this, elename, nos);
final EditText searchBar = (EditText) findViewById(R.id.searchbar);
final DrawerLayout drawer = (DrawerLayout)findViewById(R.id.drawer_layout);
final ListView navList = (ListView) findViewById(R.id.left_drawer);
final LinearLayout linearLayout = (LinearLayout)findViewById(R.id.left_drawer_layout);
navList.setAdapter(adapter);
navList.setOnItemClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, final int pos,long id){
//Change view according to numbers
drawer.closeDrawer(linearLayout);
}
});
//filter list view after search instantly
searchBar.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
// When user changed the Text
MainActivity.this.adapter.getFilter().filter(cs);
}
@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,int arg3) {
}
@Override
public void afterTextChanged(Editable s) {
}
});
//hide the keyboard after search on touch list view
navList.setOnScrollListener(new AbsListView.OnScrollListener() {
public void onScrollStateChanged(AbsListView view, int scrollState) {
//hide keyboard
InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(navList.getWindowToken(), 0);
}
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
}
});
navList.setEmptyView(findViewById(R.id.empty));
}
}
ListViewAdapter.java
//This is the cutom BaseAdapter that has the getFilter() method
public class ListViewAdapter extends BaseAdapter implements Filterable
{
Activity context;
String title[];
String description[];
public ListViewAdapter(Activity context, String[] title, String[] description) {
super();
this.context = context;
this.title = title;
this.description = description;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return title.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
private class ViewHolder {
TextView txtViewTitle;
TextView txtViewDescription;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
// TODO Auto-generated method stub
ViewHolder holder;
LayoutInflater inflater = context.getLayoutInflater();
if (convertView == null)
{
convertView = inflater.inflate(R.layout.listitem_row, null);
holder = new ViewHolder();
holder.txtViewTitle = (TextView) convertView.findViewById(R.id.textView1);
holder.txtViewDescription = (TextView) convertView.findViewById(R.id.textView2);
convertView.setTag(holder);
}
else
{
holder = (ViewHolder) convertView.getTag();
}
holder.txtViewTitle.setText(title[position]);
holder.txtViewDescription.setText(description[position]);
return convertView;
}
@Override
public Filter getFilter() {//method not working!
Filter filter = new Filter() {
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
List<String> arrayListNames;
arrayListNames = (List<String>) results.values;
notifyDataSetChanged();
}
@Override
protected FilterResults performFiltering(CharSequence constraint) {
Filter.FilterResults results = new FilterResults();
ArrayList<String> FilteredArrayNames = new ArrayList<String>();
List<String> mDatabaseOfNames = null;
// perform your search here using the searchConstraint String.
constraint = constraint.toString().toLowerCase();
for (int i = 0; i < mDatabaseOfNames.size(); i++) {
String dataNames = mDatabaseOfNames.get(i);
if (dataNames.toLowerCase().startsWith(constraint.toString())) {
FilteredArrayNames.add(dataNames);
}
}
results.count = FilteredArrayNames.size();
results.values = FilteredArrayNames;
Log.e("VALUES", results.values.toString());
return results;
}
};
return filter;
}
}
Q2代码：
的 main_activity.xml
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:background="#000000"
android:layout_height="match_parent" >
</FrameLayout>
<LinearLayout
android:id="@+id/left_drawer_layout"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:layout_marginLeft="-65dp"
android:background="#111"
android:orientation="vertical"
android:layout_gravity="start" >
<EditText
android:id="@+id/searchbar"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:textColor="#bfc2d1"
android:singleLine="true"
android:drawableLeft="@drawable/search"
android:padding="10dp"
android:background="@drawable/search_bar"
android:layout_marginLeft="3dp"
android:layout_marginRight="3dp"
android:imeOptions="flagNoExtractUi"
android:hint="Search" >
</EditText>
<RelativeLayout
android:id="@+id/empty"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:layout_marginLeft="-65dp"
android:background="#111"
android:orientation="vertical"
android:layout_gravity="start" >
<TextView
android:id="@+id/empty_text"
android:text="@string/notfound"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:textColor="#ffababab"
android:textSize="15dp"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp"
android:gravity="center">
</TextView>
</RelativeLayout>
<ListView android:id="@+id/left_drawer"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</LinearLayout>
</android.support.v4.widget.DrawerLayout>
listitem_row.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="60dp"
android:weightSum="1.0">
<TextView
android:id="@+id/textView1"
android:text="TextView"
android:layout_weight="0.8"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:textAppearance="?android:attr/textAppearanceLarge">
</TextView>
<TextView
android:text="TextView"
android:id="@+id/textView2"
android:layout_weight="0.2"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
请帮帮我！提前谢谢。
答案 0 :(得分：0)
对于第一个问题，我不知道为什么它不会抛出NULL指针，请检查
@Override
protected FilterResults performFiltering(CharSequence constraint) {
Filter.FilterResults results = new FilterResults();
ArrayList<String> FilteredArrayNames = new ArrayList<String>();
List<String> mDatabaseOfNames = new ArrayList<String>();
for(int i = 0; i < title.size; i++){
mDatabaseOfNames.add(title.get(i));
}
// perform your search here using the searchConstraint String.
constraint = constraint.toString().toLowerCase();
//OVER HERE IT SHOULD BE NULL POINTER for mDatabaseOfNames
for (int i = 0; i < mDatabaseOfNames.size(); i++) {
String dataNames = mDatabaseOfNames.get(i);
if (dataNames.toLowerCase().startsWith(constraint.toString())) {
FilteredArrayNames.add(dataNames);
}
}
results.count = FilteredArrayNames.size();
results.values = FilteredArrayNames;
Log.e("VALUES", results.values.toString());
return results;
}
对于Q2，我认为这应该有效
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="60dp"
android:orientation="horizontal"
android:padding="20dp"
android:gravity="center_vertical"
android:weightSum="1.0" >
<TextView
android:id="@+id/textView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:text="TextView"
android:textAppearance="?android:attr/textAppearanceLarge" >
</TextView>
<TextView
android:id="@+id/textView2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0.8"
android:text="TextView" >
</TextView>
</LinearLayout>
答案 1 :(得分：0)
for Q1）列出mDatabaseOfNames = null;那你怎么能在你的for循环中使用它
// MainActivity
public static ArrayList al = new ArrayList()
for(i=0 ;i< elename.length ;i++)
{
al.add(elename[i] +" "+nos[i])
}
// Adapter class
List<String> mDatabaseOfNames = MainActivity.al;