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[英]onActivityResult in First Activity not returning result after finish second activity
[英]Update Listview in first activity after returning from second activity
我在一個活動中有一個列表視圖,在自定義適配器中有一個信息圖標。 當用戶點擊該信息按鈕時,下一個活動將打開,當用戶點擊更新按鈕時,在下一個活動中標記出勤后,第二個活動應該完成,第一個活動列表視圖應該更新。
我成功地做了什么:我已經成功地標記了出席人數並更改了列表視圖的顏色,但我在關閉第二個活動並重新啟動第一個活動后這樣做了。 通過這種方式,列表視圖會因為再次啟動活動而更新。
我無法做的事情:我希望當用戶點擊更新按鈕時,只有完成()會調用並且用戶返回到上一個更新列表視圖的第一個活動。 但是當我這樣做時,列表視圖不會更新。 我必須返回並再次打開該活動,然后列表視圖才會更新,否則不會。 我不想那樣。 我還嘗試在第一個活動的 onResume 方法中通知適配器,以便當用戶從第二個活動返回時,第一個活動列表視圖適配器將因 onResume 方法而更新,但它不起作用。 請幫助
我的列表視圖活動代碼:
public class TeacherWebserviceMainList extends Activity {
int attentedncemarkedCount = 0;
TextView addteacher;
DatabaseHandler databasehandler;
DetailsTeacherwebservice details;
String emis;
ArrayList<DetailsTeacherwebservice> addas = new ArrayList<DetailsTeacherwebservice>();
CustomAdapterTeacherWebservice cusadapter;
ArrayList<DetailsTeacherwebservice> teacherList;
private ListView listcontent = null;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.teacherwebservicemainlist );
addteacher = (TextView) findViewById(R.id.addteachermenu);
databasehandler = new DatabaseHandler(TeacherWebserviceMainList.this);
listcontent = (ListView) findViewById(R.id.teacher_list);
teacherList = databasehandler.teacherwebserviceList(emis);
Rsults();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1) {
if(resultCode == RESULT_OK) {
String update = data.getStringExtra("update");
if(update.equals("1"))
{
//cusadapter.
CustomAdapterTeacherWebservice adapter = new CustomAdapterTeacherWebservice(this, addas);
listcontent.setAdapter(adapter);
}
}
}
}
private void Rsults() {
addas.clear();
//DatabaseHandler databaseHandler=new DatabaseHandler(this);
//ArrayList<ArrayList<Object>> data = databaseHandler.abcTeacherNew();
for (int p = 0; p < teacherList.size(); p++) {
details = new DetailsTeacherwebservice();
//ArrayList<Object> baris = data.get(p);
details.setId(teacherList.get(p).getId());
details.setTeachername(teacherList.get(p).getTeachername());
details.setTeachercnic(teacherList.get(p).getTeachercnic());
details.setTeacherno(teacherList.get(p).getTeacherno());
details.setTeachergender(teacherList.get(p).getTeachergender());
details.setAttendance(teacherList.get(p).getAttendance());
details.setTeacherattendancedetails(teacherList.get(p).getTeacherattendancedetails());
details.setAttendancedatesince(teacherList.get(p).getAttendancedatesince());
details.setAttendancetrasnferschool(teacherList.get(p).getAttendancetrasnferschool());
addas.add(details);
}
cusadapter = new CustomAdapterTeacherWebservice(TeacherWebserviceMainList.this, addas);
listcontent.setAdapter(cusadapter);
listcontent.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
}
});
}
我的列表適配器代碼
public class CustomAdapterTeacherWebservice extends BaseAdapter {
private static ArrayList<DetailsTeacherwebservice> searchArrayList;
DatabaseHandler databaseHandler;
private Context context;
private LayoutInflater mInflater;
public CustomAdapterTeacherWebservice(Context context, ArrayList<DetailsTeacherwebservice> results) {
searchArrayList = results;
mInflater = LayoutInflater.from(context);
databaseHandler = new DatabaseHandler(context);
}
@Override
public int getCount() {
return searchArrayList.size();
}
@Override
public Object getItem(int p) {
return searchArrayList.get(p);
}
@Override
public long getItemId(int p) {
return p;
}
public int getViewTypeCount() {
return 500;
}
@Override
public int getItemViewType(int position) {
return position;
}
@Override
public View getView(final int p, View v, ViewGroup parent) {
ViewHolder holder;
context = parent.getContext();
if (v == null) {
v = mInflater
.inflate(R.layout.teacherwebserviceadapter, null);
holder = new ViewHolder();
holder.name = (TextView) v.findViewById(R.id.teacher_name);
holder.cnic = (TextView) v.findViewById(R.id.teacher_cnic);
holder.no = (TextView) v.findViewById(R.id.teacher_phone);
holder.gender = (TextView) v.findViewById(R.id.gender);
holder.status = (TextView) v.findViewById(R.id.status);
holder.info = (ImageView) v.findViewById(R.id.edit);
holder.l1 = (LinearLayout) v.findViewById(R.id.main);
v.setTag(holder);
} else {
holder = (ViewHolder) v.getTag();
}
holder.name.setText(searchArrayList.get(p).getTeachername());
holder.cnic.setText(searchArrayList.get(p).getTeachercnic());
holder.no.setText(searchArrayList.get(p).getTeacherno());
holder.gender.setText(searchArrayList.get(p).getTeachergender());
holder.status.setText(searchArrayList.get(p).getAttendance());
if (searchArrayList.get(p).getAttendance().equals("Absent"))
{
holder.l1.setBackgroundColor(Color.parseColor("#DB674D"));
}
if (searchArrayList.get(p).getAttendance().equals("Present"))
{
holder.l1.setBackgroundColor(Color.parseColor("#7EB674"));
}
if (searchArrayList.get(p).getAttendance().equals("Transfer Out"))
{
holder.l1.setBackgroundColor(Color.parseColor("#FBE87C"));
}
if (searchArrayList.get(p).getAttendance().equals("Resigned"))
{
holder.l1.setBackgroundColor(Color.parseColor("#4FC3F7"));
}
holder.info.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent view_order_intent = new Intent(context, Teacherwebservicemainlistupdate.class);
view_order_intent.putExtra("ID", searchArrayList.get(p).getId());
view_order_intent.putExtra("tname", searchArrayList.get(p).getTeachername());
view_order_intent.putExtra("tgender", searchArrayList.get(p).getTeachergender());
view_order_intent.putExtra("tcnic", searchArrayList.get(p).getTeachercnic());
view_order_intent.putExtra("tno", searchArrayList.get(p).getTeacherno());
view_order_intent.putExtra("tatt", searchArrayList.get(p).getAttendance());
view_order_intent.putExtra("tattdetails", searchArrayList.get(p).getTeacherattendancedetails());
view_order_intent.putExtra("tattdatesince", searchArrayList.get(p).getAttendancedatesince());
view_order_intent.putExtra("tatttrasnferout", searchArrayList.get(p).getAttendancetrasnferschool());
//context.startActivity(view_order_intent);
((Activity)context).startActivityForResult(view_order_intent, 1);
}
});
return v;
}
static class ViewHolder {
TextView name, cnic, no, gender,status;
ImageView info;
LinearLayout l1;
}
在適配器代碼中,單擊 INFO 按鈕后,將啟動另一個活動,用戶可以在其中更新出勤率。
這是單擊按鈕時更新活動代碼:
update.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
DetailsTeacherwebservice schoolinfo = new DetailsTeacherwebservice();
schoolinfo.setTeachername(teachername.getText().toString());
schoolinfo.setTeacherno(teacherno.getText().toString());
schoolinfo.setTeachercnic(teachercnic.getText().toString());
schoolinfo.setTeachergender(teachergender.getText().toString());
schoolinfo.setAttendance(teachergroupstr);
schoolinfo.setTeacherattendancedetails(absentgrpstr);
schoolinfo.setAttendancedatesince(txtDate.getText().toString());
schoolinfo.setAttendancetrasnferschool(transferOutSchool.getText().toString());
databasehandler.updateteacherwebservice(schoolinfo, emis, identity);
Toast.makeText(Teacherwebservicemainlistupdate.this, "Updated Successfully", Toast.LENGTH_SHORT).show();
Intent intent = new Intent();
intent.putExtra("update", "1");
setResult(RESULT_OK, intent);
finish();
}
}
});
單擊更新按鈕時,我可以再次啟動 listview 活動,但這會更改單擊的列表項的索引,即因為活動再次啟動。 我想要的是,如果我點擊第 10 個項目,那么當下一個活動打開並且用戶更新出勤率時,它會返回到相同索引位置的上一個活動,這樣用戶就不必再次滾動以返回第 10 個項目
為列表項單擊添加此代碼:
Intent i = new Intent(context, YourAcitivityName.class);
i.putExtra("position",p);
startActivityForResult(i, 1);
在更新按鈕中添加此代碼:
Intent intent = new Intent();
intent.putExtra("update", "1");
intent.putExtra("position",getIntent().getIntExtra("position",0));
setResult(RESULT_OK, intent);
finish();
當您從活動返回到實施列表視圖的活動時,此方法調用:
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1) {
if(resultCode == RESULT_OK) {
String update = data.getStringExtra("update");
if(update.equals("1"))
{
// add your code to update list view
teacherList = databasehandler.teacherwebserviceList(emis);
Rsults();
YourAdapterClassName adapter = new YourAdapterClassName(this, arrList);
listView.setAdapter(adapter);
listView.smoothScrollToPosition(getIntent().getIntExtra("position",0));
}
}
}
}
下面是兩個例子,第一個是 ListView 的源是一個 List(在這種情況下使用自定義適配器),第二個是源是一個 Cursor(使用 SimpleCursorAdapter)
許多人陷入的陷阱只是使用以下內容更新列表:-
myList = method();
myAdapter.notifyDataSetChanged();
猜測一下,這就是你掉入的陷阱。
什么時候應該做的是使用 List 的方法來改變它(例如clear
、 add
、 addAll
、 remove
)。
我相信這解釋了推理 - Java 是“按引用傳遞”還是“按值傳遞”?
/**
* Build or rebuild the List of TaskData's, instantiate the
* Custom Array Adapter if needed and also notify the adapter
* if the List may have been changed.
*/
private void prepTasksCustomArrayList() {
// Determine if the adpater needs to be notified of changes
boolean notify_dataset_changed = (mCsr != null && mCustomArrayAdapter != null);
// If the List is not null then assume that it has changed
// otherwise just get the List
if (mTasks != null) {
mTasks.clear();
mTasks.addAll(dbhlpr.getAllTasks());
} else {
mTasks = dbhlpr.getAllTasks();
}
// If the adapter is null then instantiate it
if (mCustomArrayAdapter == null) {
mCustomArrayAdapter = new CustomArrayAdapter(
this,
R.layout.taskdata_item,
mTasks);
}
// Notify the adapter that the List has changed
if (notify_dataset_changed) {
mCustomArrayAdapter.notifyDataSetChanged();
}
}
筆記
ListView
。mTaskList = this.findViewById(R.id.tasklist); // The ListView
prepTasksCustomArrayList()
mTaskList.setAdapter(mCustomArrayAdapter)
onresume
(結合onCreate
的 3 行)prepTasksCustomArrayList()
onCreate
看到正在設置的適配器。mTasks.addAll(dbhlpr.getAllTasks());
是什么獲取源數據。/**
* Build or rebuild the List via Cursor using the bespoke layout
*/
private void prepCursorListBespoke() {
boolean swapcursor = (mCsr != null && mCursorAdapter2 != null);
if (mCursorAdapter2 == null) {
mCursorAdapter2 = new SimpleCursorAdapter(this,R.layout.taskdata_item,mCsr,
new String[]{ Datasource.TASKS_ID_COL,
Datasource.TASKS_TYPE_COL,
Datasource.TASKS_NAME_COL,
Datasource.TASKS_OWNER_COL,
Datasource.TASKS_EXPIRATION_COL},
new int[]{R.id.task_id,
R.id.task_type,
R.id.task_name,
R.id.task_owner,
R.id.task_expiration},
0);
}
if (swapcursor) {
mCursorAdapter2.swapCursor(mCsr);
}
}
筆記
prepCursorListBespoke
方法的使用方式與示例 1 相同。notifyDataSetChanged
可以用來代替的swapCursor
swapCursor
因為它更具描述性)。swapCursor
用於游標。以下更改可能會起作用,粗略地說,我已經應用了上面的 List 示例。
即Rsults
由onResume
(添加)調用,它將通知適配器數據已更改。
由於代碼不足,該代碼尚未經過測試。 (a DatabaseHandler
類沒有代碼,b) DetailsTeacherwebservice
類沒有代碼)。 因此可能會出現錯誤。
尋找//++++++++++++++...
應該有注釋來說明已完成/更改的內容。
public class MainActivity extends Activity {
int attentedncemarkedCount = 0;
TextView addteacher;
DatabaseHandler databasehandler;
DetailsTeacherwebservice details;
String emis;
ArrayList<DetailsTeacherwebservice> addas = new ArrayList<DetailsTeacherwebservice>();
CustomAdapterTeacherWebservice cusadapter;
ArrayList<DetailsTeacherwebservice> teacherList;
private ListView listcontent = null;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.teacherwebservicemainlist);
addteacher = (TextView) findViewById(R.id.addteachermenu);
databasehandler = new DatabaseHandler(TeacherWebserviceMainList.this);
listcontent = (ListView) findViewById(R.id.teacher_list);
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//MOVED On ItemClickListener block FROM Rsults to here.
listcontent.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
}
});
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
teacherList = databasehandler.teacherwebserviceList(emis);
Rsults();
}
// Probably don't even need onActivityResult
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1) {
if (resultCode == RESULT_OK) {
String update = data.getStringExtra("update");
if (update.equals("1")) {
//cusadapter.
//CustomAdapterTeacherWebservice adapter = new CustomAdapterTeacherWebservice(this, addas);
//+++++++++++++++++++++++++++++++++++
// Commented out
//listcontent.setAdapter(adapter);
}
}
}
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Added onResume to call Rsults
@Override
public void onResume() {
super.onResume();
Rsults();
}
private void Rsults() {
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ADDED 4 lines to see if the notifyDataSetChanged is required
boolean notifydschg_needed = false;
if (cusadapter != null) {
notifydschg_needed = true;
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// YOU NEED TO GET THE TEACHER LIST AGAIN AS THE DB HAS CHANGED
teacherList = databasehandler.teacherwebserviceList(emis);
addas.clear();
//DatabaseHandler databaseHandler=new DatabaseHandler(this);
//ArrayList<ArrayList<Object>> data = databaseHandler.abcTeacherNew();
for (int p = 0; p < teacherList.size(); p++) {
details = new DetailsTeacherwebservice();
//ArrayList<Object> baris = data.get(p);
details.setId(teacherList.get(p).getId());
details.setTeachername(teacherList.get(p).getTeachername());
details.setTeachercnic(teacherList.get(p).getTeachercnic());
details.setTeacherno(teacherList.get(p).getTeacherno());
details.setTeachergender(teacherList.get(p).getTeachergender());
details.setAttendance(teacherList.get(p).getAttendance());
details.setTeacherattendancedetails(teacherList.get(p).getTeacherattendancedetails());
details.setAttendancedatesince(teacherList.get(p).getAttendancedatesince());
details.setAttendancetrasnferschool(teacherList.get(p).getAttendancetrasnferschool());
addas.add(details);
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Just create the adapter and attach it to the listview once
if (cusadapter == null) {
cusadapter = new CustomAdapterTeacherWebservice(TeacherWebserviceMainList.this, addas);
listcontent.setAdapter(cusadapter);
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Notify the adapter that the data has been changed
if(notifydschg_needed) {
cusadapter.notifyDataSetChanged();
}
}
}
// 你必須在 onResume 方法中設置適配器中的數據
@Override
protected void onResume() {
super.onResume();
}
您可以在這種情況下使用 eventbus:
這是一個例子:
在你的 build.gradle 文件中
compile 'org.greenrobot:eventbus:3.0.0'
在活動中有列表視圖:
@Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this); // register event
}
@Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this); // unregister event
}
@Subscribe(threadMode = ThreadMode.MAIN)
public void onEvent(EventBusInfo eventBusInfo) {
if (eventBusInfo.getProcessId() == 99) {
// eventBusInfo.getData();
notifyDataSetChanged();
}
}
在更新活動中
yourButtonFinish.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
finish();
EventBusInfo event = new EventBusInfo();
event.setProcessId(99);
//event.setData(object) //if you want get data back
EventBus.getDefault().post(event);
}
});
類 EventBusInfo
public class EventBusInfo {
private int processId;
private Object data;
public EventBusInfo(int processId, Object data) {
this.processId = processId;
this.data = data;
}
public EventBusInfo() {
}
public EventBusInfo(int processId) {
this.processId = processId;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
public int getProcessId() {
return processId;
}
public void setProcessId(int processId) {
this.processId = processId;
}
}
在每次更改時保存列表項,然后使用intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
重新啟動適配器的 Activity 以關閉舊的 ListView。 是我所做的,它工作正常。 如果列表不為空,我會使用適配器重新啟動活動,並且我有一個新的 ListView 關閉前一個。 或者如果它是空的,我開始一個不同的活動(沒有一個空的 ListView) 每次使用 Gson 保存和加載列表項到SharedPreferences
出於某種原因, notifyDataSetChanged()
在我的情況下不起作用,所以我更喜歡這個解決方案。
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