我有一个 ContentObserver onChange() 在我的活动中声明为子类。但它总是返回 false。谁能告诉我为什么？
（更新） 如果 CallLog 内容提供程序发生更改，此代码必须调用 fillList。我的意思是，如果我进行一个新的调用，那么调用的数据将被插入到内容提供者中，所以它必须向观察者返回那里发生了一些变化，所以它会调用 fillList()。但它总是返回假的，即使我在模拟器上打了一个新电话。
这是代码。
public class RatedCalls extends ListActivity {
private static final String LOG_TAG = "RatedCallsObserver";
private Handler handler = new Handler();
private RatedCallsContentObserver callsObserver = null;
private SQLiteDatabase db;
private CallDataHelper dh = null;
StringBuilder sb = new StringBuilder();
OpenHelper openHelper = new OpenHelper(RatedCalls.this);
class RatedCallsContentObserver extends ContentObserver {
public RatedCallsContentObserver(Handler h) {
super(h);
}
public void onChange(boolean selfChange) {
Log.d(LOG_TAG, "RatedCallsContentObserver.onChange( " + selfChange
+ ")");
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
registerContentObservers();
fillList();
}
@Override
public void onStart() {
super.onStart();
registerContentObservers();
}
@Override
public void onStop() {
super.onStop();
unregisterContentObservers();
}
private void fillList() {
Cursor cursor = getContentResolver().query(
android.provider.CallLog.Calls.CONTENT_URI, null, null, null,
android.provider.CallLog.Calls.DATE + " DESC ");
cursor.setNotificationUri(getBaseContext().getContentResolver(),
android.provider.CallLog.Calls.CONTENT_URI);
dh = new CallDataHelper(this);
db = openHelper.getWritableDatabase();
startManagingCursor(cursor);
int numberColumnId = cursor
.getColumnIndex(android.provider.CallLog.Calls.NUMBER);
int durationId = cursor
.getColumnIndex(android.provider.CallLog.Calls.DURATION);
int contactNameId = cursor
.getColumnIndex(android.provider.CallLog.Calls.CACHED_NAME);
int dateId = cursor.getColumnIndex(android.provider.CallLog.Calls.DATE);
int numTypeId = cursor
.getColumnIndex(android.provider.CallLog.Calls.CACHED_NUMBER_TYPE);
// int contactIdColumnId =
// cursor.getColumnIndex(android.provider.ContactsContract.RawContacts.CONTACT_ID);
Date dt = new Date();
int hours = dt.getHours();
int minutes = dt.getMinutes();
int seconds = dt.getSeconds();
String currTime = hours + ":" + minutes + ":" + seconds;
ArrayList<String> callList = new ArrayList<String>();
if (cursor.moveToFirst()) {
do {
String contactNumber = cursor.getString(numberColumnId);
String contactName = cursor.getString(contactNameId);
String duration = cursor.getString(durationId);
String callDate = DateFormat.getDateInstance().format(dateId);
String numType = cursor.getString(numTypeId);
ContentValues values = new ContentValues();
values.put("contact_id", 1);
values.put("contact_name", contactName);
values.put("number_type", numType);
values.put("contact_number", contactNumber);
values.put("duration", duration);
values.put("date", callDate);
values.put("current_time", currTime);
values.put("cont", 1);
getBaseContext().getContentResolver().notifyChange(
android.provider.CallLog.Calls.CONTENT_URI, null);
callList.add("Contact Number: " + contactNumber
+ "\nContact Name: " + contactName + "\nDuration: "
+ duration + "\nDate: " + callDate);
this.db.insert(CallDataHelper.TABLE_NAME, null, values);
Toast.makeText(getBaseContext(), "Inserted!", Toast.LENGTH_LONG);
} while (cursor.moveToNext());
setListAdapter(new ArrayAdapter<String>(this, R.layout.listitem,
callList));
ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(getApplicationContext(),
((TextView) view).getText(), Toast.LENGTH_SHORT)
.show();
}
});
}
}
private void registerContentObservers() {
ContentResolver cr = getContentResolver();
callsObserver = new RatedCallsContentObserver(handler);
cr.registerContentObserver(android.provider.CallLog.Calls.CONTENT_URI,
true, callsObserver);
}
private void unregisterContentObservers() {
ContentResolver cr = getContentResolver();
if (callsObserver != null) { // just paranoia
cr.unregisterContentObserver(callsObserver);
callsObserver = null;
}
}
}