我正在使用自定义listView和ArrayAdapter来实现sectionIndexer。我正在使用Json来解析来自我的服务器的数据。我可以在listView上显示数据，但是当我点击我的listView时，它应该转到下一个详细页面，但此时它不起作用。
这是代码
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);
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();
}
}
}
在这个课程中，我将在xml，activity
中创建listview <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<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>
这是listView
中每一行的xml<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="3dp"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/textView_name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:focusable="false"
android:text="t1" />
<TextView
android:id="@+id/textView_country"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView_name"
android:layout_below="@+id/textView_name"
android:layout_marginTop="19dp"
android:focusable="false"
android:text="t2" />
<TextView
android:id="@+id/textView_localarea"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView_country"
android:layout_below="@+id/textView_country"
android:layout_marginTop="15dp"
android:focusable="false"
android:text="t3" />
</RelativeLayout>
这是我的数组适配器类
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;
}
}
这是我的活动课
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();
masjidnames = l.getlistOfMasjids();
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);
}
});
}
}
我没有在logcat中收到任何错误信息，或者应用程序没有意外关闭这就是为什么我无法解决这个问题
请提前帮助我。
答案 0 :(得分：0)
ANR正在发生，因为您正在SelectMasjid活动的主要线程中执行长任务。 GetJsonList代码应该在异步任务中移动。
以下是AsyncTask
的文档答案 1 :(得分：0)
对于自定义listView，当从服务器获取数据时，使用AsyncTask是很好的：
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllItems extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(YourActivityName.this);
pDialog.setMessage("Loading Items. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
//your method that get data from server which getlistOfMasjids()
//Then save them in arrays or ArrayList, after that you can save them in listview
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
listview();
pDialog.dismiss();
}
}
正如你在doInBackground方法中所提到的，你可以使用你的函数getlistOfMasjids（），之后你可以将数据保存在数组或Arraylist中以将它们放在listview中。
对于onPostExecute（）方法中的listview，它是这样的：
public void listview(){
adapter =new SelectMasjidAdapter(this, array1, array2,array3);
lv.setAdapter(adapter);
}
for listview actionlistener：
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
showInfo(position); // here you can put the call for another class or details item for specific position
}
});
希望真有帮助，
答案 2 :(得分：0)
Android已经提供了关于ANR以及如何保持应用程序响应的非常好的文档......当我遇到ANR时，我经常会参考该文档。
http://developer.android.com/training/articles/perf-anr.html
我为自己设置了规则，因为只为UI处理留下UI线程，db，io，网络应该在非ui线程上完成...我使用线程和处理程序...仍然有时需要让ui线程等待，在这种情况下你没有选项，但尽可能避免这种情况......
你也可以使用runOnUiThread方法从其他非ui线程更新ui ...