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Q&A Why is the switch statement not executing the correct case blocks?

In the code below, the value of order variable should change according to i's value: String order; switch (i){ case 0: order = CallLog.Calls.DATE + " DESC "; contactViewAda...

1 answer · posted 2y ago by Anonymous‭ · last activity 2y ago by hkotsubo‭

Question java android switch-statement

#3: Post edited by

hkotsubo‭ · 2021-09-24T15:42:23Z (over 2 years ago)
Rephrasing based on the comments, removed irrelevant tags

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~~how to change adapter without looking at adapter?~~

Why is the switch statement not executing the correct case blocks?

```java
~~String order;~~
~~switch (i){~~
~~case 0:~~
~~order = CallLog.Calls.DATE + " DESC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter,true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~case 1:~~
~~order = CallLog.Calls.DATE+" ASC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter,true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~case 2:~~
~~order = CallLog.Calls.CACHED_NAME+" ASC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter,true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~default:~~
~~// contactViewAdapter = adapter(CallLog.Calls.DATE+" DESC ");~~
~~// recyclerViewCallLog.invalidate();~~
~~// recyclerViewCallLog.setAdapter(contactViewAdapter);~~
}
```
I was trying to change adapter above way. But I noticed. it doesn't affect earlier data. How can I remove earlier data and set new data without looking at adapter. Even, using the above code sort order is working for DATE ASC. But case 0 is default one. Hence the date DESC had to work. But it doesn't. How can I change adapter? If I add case 0 to default then it works fine. I have recently updated my code.
```java
final String[] order = new String[1];
~~switch (i){~~
~~case 0:~~
~~new Handler().postDelayed(() -> {~~
~~order[0] = CallLog.Calls.DATE + " DESC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter, true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~},1000);~~
~~case 1:~~
~~new Handler().postDelayed(() -> {~~
~~order[0] = CallLog.Calls.DATE+" ASC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter,true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~},1000);~~
~~case 2:~~
~~new Handler().postDelayed(() -> {~~
~~order[0] = CallLog.Calls.CACHED_NAME+" ASC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter,true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~},1000);~~
~~default:~~
~~new Handler().postDelayed(() -> {~~
~~order[0] = CallLog.Calls.DATE + " DESC ";~~
~~contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");~~
~~recyclerViewCallLog.swapAdapter(contactViewAdapter, true);~~
~~recyclerViewCallLog.setAdapter(contactViewAdapter);~~
~~recyclerViewCallLog.invalidate();~~
~~recyclerViewCallLog.getAdapter().notifyDataSetChanged();~~
~~},1000);~~
}
```
I earlier thought that I must change or add and delete values in Adapter. But I wanted to directly change adapter instead of doing "something" inside adapter. That's why I said "how to change adapter without looking at adapter?". When I was using switch statement, my data wasn't changing that's why I thought I must work on adapter but It was worse idea. Why adapter isn't changing whenever I am clicking on some other button (which returning i=1,2,3 or whatever)?

In the code below, the value of `order` variable should change according to `i`'s value:
```java
String order;
switch (i){
case 0:
order = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
case 1:
order = CallLog.Calls.DATE+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
case 2:
order = CallLog.Calls.CACHED_NAME+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
default:
//contactViewAdapter = adapter(CallLog.Calls.DATE+" DESC ");
//recyclerViewCallLog.invalidate();
//recyclerViewCallLog.setAdapter(contactViewAdapter);
}
```
When `i` is `0`, the order should be `DESC`, but it's actually `ASC`. I've updated the code to this:
```java
final String[] order = new String[1];
switch (i){
case 0:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
case 1:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
case 2:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.CACHED_NAME+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
default:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
}
```
But now it doesn't work when `i` is `1` or `2`: it should be `ASC` but in those cases it ends up being `DESC`.
How can I fix this?

java android switch-statement adapter

java android switch-statement

#2: Post edited by

Anonymous‭ · 2021-09-24T09:08:08Z (over 2 years ago)

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```java
String order;
switch (i){
case 0:
order = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
case 1:
order = CallLog.Calls.DATE+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
case 2:
order = CallLog.Calls.CACHED_NAME+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
default:
// contactViewAdapter = adapter(CallLog.Calls.DATE+" DESC ");
// recyclerViewCallLog.invalidate();
// recyclerViewCallLog.setAdapter(contactViewAdapter);
}
```
I was trying to change adapter above way. But I noticed. it doesn't affect earlier data. How can I remove earlier data and set new data without looking at adapter. Even, using the above code sort order is working for DATE ASC. But case 0 is default one. Hence the date DESC had to work. But it doesn't. How can I change adapter? If I add case 0 to default then it works fine. I have recently updated my code.
```java
final String[] order = new String[1];
switch (i){
case 0:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
case 1:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
case 2:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.CACHED_NAME+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
default:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
}
~~```~~

```java
String order;
switch (i){
case 0:
order = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
case 1:
order = CallLog.Calls.DATE+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
case 2:
order = CallLog.Calls.CACHED_NAME+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
default:
// contactViewAdapter = adapter(CallLog.Calls.DATE+" DESC ");
// recyclerViewCallLog.invalidate();
// recyclerViewCallLog.setAdapter(contactViewAdapter);
}
```
I was trying to change adapter above way. But I noticed. it doesn't affect earlier data. How can I remove earlier data and set new data without looking at adapter. Even, using the above code sort order is working for DATE ASC. But case 0 is default one. Hence the date DESC had to work. But it doesn't. How can I change adapter? If I add case 0 to default then it works fine. I have recently updated my code.
```java
final String[] order = new String[1];
switch (i){
case 0:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
case 1:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
case 2:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.CACHED_NAME+" ASC ";
contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
default:
new Handler().postDelayed(() -> {
order[0] = CallLog.Calls.DATE + " DESC ";
contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
recyclerViewCallLog.setAdapter(contactViewAdapter);
recyclerViewCallLog.invalidate();
recyclerViewCallLog.getAdapter().notifyDataSetChanged();
},1000);
}
```
I earlier thought that I must change or add and delete values in Adapter. But I wanted to directly change adapter instead of doing "something" inside adapter. That's why I said "how to change adapter without looking at adapter?". When I was using switch statement, my data wasn't changing that's why I thought I must work on adapter but It was worse idea. Why adapter isn't changing whenever I am clicking on some other button (which returning i=1,2,3 or whatever)?

#1: Initial revision by

Anonymous‭ · 2021-09-23T16:44:22Z (over 2 years ago)

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Raw

Markdown

how to change adapter without looking at adapter?

```java
 String order;
        switch (i){
            case 0:
                order = CallLog.Calls.DATE + " DESC ";
                contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
                recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
                recyclerViewCallLog.setAdapter(contactViewAdapter);
                recyclerViewCallLog.invalidate();
                recyclerViewCallLog.getAdapter().notifyDataSetChanged();
            case 1:
                order = CallLog.Calls.DATE+" ASC ";
                contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
                recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
                recyclerViewCallLog.setAdapter(contactViewAdapter);
                recyclerViewCallLog.invalidate();
                recyclerViewCallLog.getAdapter().notifyDataSetChanged();
            case 2:
                order = CallLog.Calls.CACHED_NAME+" ASC ";
                contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order),"dialer");
                recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
                recyclerViewCallLog.setAdapter(contactViewAdapter);
                recyclerViewCallLog.invalidate();
                recyclerViewCallLog.getAdapter().notifyDataSetChanged();
            default:
//                contactViewAdapter = adapter(CallLog.Calls.DATE+" DESC ");
//                recyclerViewCallLog.invalidate();
//                recyclerViewCallLog.setAdapter(contactViewAdapter);
        }
```

I was trying to change adapter above way. But I noticed. it doesn't affect earlier data. How can I remove earlier data and set new data without looking at adapter. Even, using the above code sort order is working for DATE ASC. But case 0 is default one. Hence the date DESC had to work. But it doesn't. How can I change adapter? If I add case 0 to default then it works fine. I have recently updated my code. 

```java
final String[] order = new String[1];
        switch (i){
            case 0:
                new Handler().postDelayed(() -> {
                    order[0] = CallLog.Calls.DATE + " DESC ";
                    contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
                    recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
                    recyclerViewCallLog.setAdapter(contactViewAdapter);
                    recyclerViewCallLog.invalidate();
                    recyclerViewCallLog.getAdapter().notifyDataSetChanged();
                },1000);
            case 1:
                new Handler().postDelayed(() -> {
                    order[0] = CallLog.Calls.DATE+" ASC ";
                    contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
                    recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
                    recyclerViewCallLog.setAdapter(contactViewAdapter);
                    recyclerViewCallLog.invalidate();
                    recyclerViewCallLog.getAdapter().notifyDataSetChanged();
                },1000);
            case 2:
                new Handler().postDelayed(() -> {
                    order[0] = CallLog.Calls.CACHED_NAME+" ASC ";
                    contactViewAdapter = new ContactViewAdapter(getActivity(),getActivity(),new ReadContacts().CallLog(getActivity(), order[0]),"dialer");
                    recyclerViewCallLog.swapAdapter(contactViewAdapter,true);
                    recyclerViewCallLog.setAdapter(contactViewAdapter);
                    recyclerViewCallLog.invalidate();
                    recyclerViewCallLog.getAdapter().notifyDataSetChanged();
                },1000);
            default:
                new Handler().postDelayed(() -> {
                    order[0] = CallLog.Calls.DATE + " DESC ";
                    contactViewAdapter = new ContactViewAdapter(getActivity(), getActivity(), new ReadContacts().CallLog(getActivity(), order[0]), "dialer");
                    recyclerViewCallLog.swapAdapter(contactViewAdapter, true);
                    recyclerViewCallLog.setAdapter(contactViewAdapter);
                    recyclerViewCallLog.invalidate();
                    recyclerViewCallLog.getAdapter().notifyDataSetChanged();
                },1000);
        }
```

java android switch-statement recyclerview adapter

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