我使用自定义列表视图在右侧添加字母列表。我也使用了Indexer节。现在，当我可以在我的应用程序的屏幕上看到列表及其内容时，但是当我点击特定行时，它应该转到下一页。但该应用程序未能在此时做出响应
这是我的代码
<SearchView
android:id="@+id/searchView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
</SearchView>
<com.deiontech.masjidtimetableapp.CustomListView
android:id="@+id/listViewformasjid"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:layout_below="@+id/searchView1"
android:clickable="true"/>
</RelativeLayout>
错误日志中出现此错误：ava.lang.NullPointerException Window＆gt;中记录了异常详细信息。显示视图＆gt;错误日志
java.lang.NullPointerException
at com.deiontech.masjidtimetableapp.CustomListView.onDraw(CustomListView.java:66)
at android.view.View.draw(View.java:13712)
at android.widget.AbsListView.draw(AbsListView.java:3653)
at android.view.View.draw(View.java:13596)
at android.view.ViewGroup.drawChild(ViewGroup.java:2928)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2797)
at android.view.View.draw(View.java:13594)
at android.view.ViewGroup.drawChild(ViewGroup.java:2928)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2797)
at android.view.View.draw(View.java:13594)
at android.view.ViewGroup.drawChild(ViewGroup.java:2928)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2797)
at android.view.View.draw(View.java:13715)
at android.view.View.draw(View.java:13596)
at android.view.ViewGroup.drawChild(ViewGroup.java:2928)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2797)
at android.view.View.draw(View.java:13715)
这是我的CustomListView
public class CustomListView extends ListView {
private Context ctx;
private static int indWidth = 20;
private String[] sections;
private float scaledWidth;
private float sx;
private int indexSize;
private String section;
private boolean showLetter = true;
private Handler listHandler;
public CustomListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
ctx = context;
}
public CustomListView(Context context, AttributeSet attrs) {
super(context, attrs);
ctx = context;
}
public CustomListView(Context context, String keyList) {
super(context);
ctx = context;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
scaledWidth = indWidth * getSizeInPixel(ctx);
sx = this.getWidth() - this.getPaddingRight() - scaledWidth;
Paint p = new Paint();
p.setColor(Color.WHITE);
p.setAlpha(100);
canvas.drawRect(sx, this.getPaddingTop(), sx + scaledWidth,
this.getHeight() - this.getPaddingBottom(), p);
//this is line 61 where I am getting error in errorlog
indexSize = (this.getHeight() - this.getPaddingTop() - getPaddingBottom())
/ sections.length;
Paint textPaint = new Paint();
textPaint.setColor(Color.DKGRAY);
textPaint.setTextSize(scaledWidth / 2);
for (int i = 0; i < sections.length; i++)
canvas.drawText(sections[i].toUpperCase(),
sx + textPaint.getTextSize() / 2, getPaddingTop()
+ indexSize * (i + 1), textPaint);
// We draw the letter in the middle
if (showLetter & section != null && !section.equals("")) {
Paint textPaint2 = new Paint();
textPaint2.setColor(Color.DKGRAY);
textPaint2.setTextSize(2 * indWidth);
canvas.drawText(section.toUpperCase(), getWidth() / 2, getHeight() / 2, textPaint2);
}
}
private static float getSizeInPixel(Context ctx) {
return ctx.getResources().getDisplayMetrics().density;
}
@Override
public void setAdapter(ListAdapter adapter) {
super.setAdapter(adapter);
if (adapter instanceof SectionIndexer)
sections = (String[]) ((SectionIndexer) adapter).getSections();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
if (x < sx)
return super.onTouchEvent(event);
else {
// We touched the index bar
float y = event.getY() - this.getPaddingTop() - getPaddingBottom();
int currentPosition = (int) Math.floor(y / indexSize);
section = sections[currentPosition];
this.setSelection(((SectionIndexer) getAdapter())
.getPositionForSection(currentPosition));
}
break;
}
case MotionEvent.ACTION_MOVE: {
if (x < sx)
return super.onTouchEvent(event);
else {
float y = event.getY();
int currentPosition = (int) Math.floor(y / indexSize);
section = sections[currentPosition];
this.setSelection(((SectionIndexer) getAdapter())
.getPositionForSection(currentPosition));
}
break;
}
case MotionEvent.ACTION_UP: {
listHandler = new ListHandler();
listHandler.sendEmptyMessageDelayed(0, 30 * 1000);
break;
}
}
return true;
}
private class ListHandler extends Handler {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
showLetter = false;
CustomListView.this.invalidate();
}
}
}
正如我所说我使用的是ArrayAdapter和sectionIndexer，这里是代码
public class SelectMasjidAdapter extends ArrayAdapter< MasjidForListClass> implements SectionIndexer{
private List< MasjidForListClass> itemList;
private Context context;
private static String sections = "abcdefghilmnopqrstuvz";
ArrayList< MasjidForListClass> data;
public SelectMasjidAdapter(List< MasjidForListClass> itemList, Context ctx) {
super(ctx,R.layout.select_masjid_list_row, itemList);
this.itemList = itemList;
this.context = ctx;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return itemList.size();
}
@Override
public MasjidForListClass getItem(int position) {
// TODO Auto-generated method stub
return super.getItem(position);
}
@Override
public long getItemId(int arg0) {
return itemList.get(arg0).hashCode();
}
@Override
public View getView(int arg0, View arg1, ViewGroup arg2) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View vi=arg1;
if(arg1==null)
vi = inflater.inflate(R.layout.select_masjid_list_row, null);
TextView masjid_name_text = (TextView)vi.findViewById(R.id.textView_name);
TextView masjid_country_text = (TextView)vi.findViewById(R.id.textView_country);
TextView masjid_localarea_text = (TextView)vi.findViewById(R.id.textView_localarea);
MasjidForListClass m = itemList.get(arg0);
masjid_name_text.setText(m.getMasjidname());
masjid_country_text.setText(m.getMasjidcountry());
masjid_localarea_text.setText(m.getMasjidlocalarea());
return vi;
}
@Override
public int getPositionForSection(int sectionIndex) {
Log.d("ListView", "Get position for section");
for (int i=0; i < this.getCount(); i++) {
String item = this.getItem(i).getMasjidname().toLowerCase();
if (item.charAt(0) == sections.charAt(sectionIndex))
return i;
}
return 0;
}
@Override
public int getSectionForPosition(int position) {
Log.d("ListView", "Get section");
return 0;
}
@Override
public Object[] getSections() {
Log.d("ListView", "Get sections");
String[] sectionsArr = new String[sections.length()];
for (int i=0; i < sections.length(); i++)
sectionsArr[i] = "" + sections.charAt(i);
return sectionsArr;
}
}
And Finally this is my acivity class
public class SelectMasjid extends Activity{
SelectMasjidAdapter adapter;
ListView masjidListView;
List <MasjidForListClass> masjidnames;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.select_masjid_activity);
GetJsonList l = new GetJsonList();
AsyncTask<Void, Void, ArrayList<MasjidForListClass>> gLiat = l.execute();
try {
gLiat.get();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
masjidnames=l.masjidlist;
Collections.sort(masjidnames, new Comparator<MasjidForListClass>() {
public int compare(MasjidForListClass result1, MasjidForListClass result2) {
return result1.getMasjidname().compareTo(result2.getMasjidname());
}
});
masjidListView = (ListView)findViewById(R.id.listViewformasjid);
adapter = new SelectMasjidAdapter(masjidnames,this);
masjidListView.setAdapter(adapter);
masjidListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
Intent i = new Intent(SelectMasjid.this, MasjidDetailedActivity.class);
i.putParcelableArrayListExtra("selected", (ArrayList<? extends Parcelable>) masjidnames);
i.putExtra("index", arg2);
startActivity(i);
}
});
}
}
一旦我认为问题应该存在，请通过customListView。请帮我解决一下这个。提前致谢。