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The value of QR Code Scanner cannot show on new activity

I am trying to make a simple QR Code scanner and run well if the result shows in the MainActivity. But when I'm trying to generate new Activity as a result, it can't show. Would you like to help me with this problem? Thank you.
Here is the result of the scanner code in the scanner.java:
#Override
public void handleResult(Result rawResult) {
startActivity(new Intent(getApplicationContext(),ResultActivity.class));
ResultActivity.scanText2.setText(rawResult.getText());
onBackPressed();
}
And here is the code of my new Activity for showing the result:
public class ResultActivity extends AppCompatActivity {
public static TextView scanText2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_patient);
scanText2 = (TextView) findViewById(R.id.scanText2);
}
}

There are a lot of issues with this:
You are launching PatientActivity, not ResultActivity in handleResult()
You are trying to set the value of a TextView in another Activity with this code:
ResultActivity.scanText2.setText(rawResult.getText());
This is an absolute no-no. Pass the data to ResultActivity as an Intent extra when you launch it. You cannot access the views of another Activity like that.
You expect that ResultActivity.scanText2 will contain a reference to a TextView, but at this point it will only contain null. The reason is that it takes some time for ResultActivity to actually start and call its onCreate(). You have not accounted for this timing in your code. To solve this problem, just see (2) above.
Also, you should have gotten a bunch of crashes with useful messages in your logcat. In the future please look there to solve problems and/or post the messages with stacktrace in your Stackoverflow questions.

How to hide keyboard onResume when returning from another app for sharing [duplicate]

This question already has answers here:
How to close/hide the Android soft keyboard programmatically?
(126 answers)
Closed 3 years ago.
I am sharing some text to other apps using android default sharing
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
shareIntent.putExtra(Intent.EXTRA_TEXT, sharingString);
shareIntent.setType("text/plain");
startActivity(shareIntent);
The Issue:
When I share to another app i.e (WhatsApp, slack, etc) open the keyboard in that app (i.e. to edit the message, etc.), and then send or return back to my application. in some cases the keyboard remains open in that app and when I try to close the keyboard on resume using the following code it is not working.
public static void hideKeyBoard(Activity activity, View view) {
InputMethodManager imm = (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
if (view == null) {
view = new View(activity);
}
if (imm != null) {
if(view.getWindowToken()!=null)
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
if(view.getApplicationWindowToken()!=null)
imm.hideSoftInputFromWindow(view.getApplicationWindowToken(), 0);
}
view.clearFocus();
}
And calling the function from onResume() of the fragment
if(getActivity()!=null){
Utils.hideKeyBoard(getActivity(),getActivity().getCurrentFocus());
}
I have found many answers related to hiding the keyboard but any answer is not working in this case.
Note: in the normal case, when I use the hideKeyBoard() method, it is working perfectly. It is just this case that is not working. Can anyone help me?
Edit
As I've mentioned above. that why this quesiton is not like the prviosly answered ones is explained in the above note. So kindle Plesase read that. And I've also tried this link. but not working.

You can try below code that may help you.
public static void hideKeyboard(Activity activity) {
InputMethodManager imm = (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
//Find the currently focused view, so we can grab the correct window token from it.
View view = activity.getCurrentFocus();
//If no view currently has focus, create a new one, just so we can grab a window token from it
if (view == null) {
view = new View(activity);
}
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
Here is some bonus
create activity instance instead use getActivity() methos on fragment. getActivity() returns null when fragment not visible
on your fragment host activity
public static MainActivity mainActivity;
public static MainActivity getInstance() {
return mainActivity;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainActivity = this;
}
inside onResume() call hideKeyboard(MainActivity.getInstance())
Also, don't forget to add android:windowSoftInputMode="stateAlwaysHidden" in your Manifest

opening the same dialog from a list in android

I have a listActivity with many items.
For each item, I want to open the same popup while sending an item id\position\other
info object unique to that item.
But basically all the time I open the exact same popup.
Its buttons will send the extra unique data to the server.
I have read few tutorials, and saw a dialog is usually opened like this:
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.custom);
dialog.setTitle("Title...");
// set the custom dialog components - text, image and button
TextView text = (TextView) dialog.findViewById(R.id.text);
text.setText("Android custom dialog example!");
ImageView image = (ImageView) dialog.findViewById(R.id.image);
image.setImageResource(R.drawable.ic_launcher);
Button dialogButton = (Button) dialog.findViewById(R.id.dialogButtonOK);
// if button is clicked, close the custom dialog
dialogButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
}
});
dialog.show();
}
I think it's more readable to create a different file to the dialog.
like this:
public class SocialActionsDialog extends Dialog {
public SocialActionsDialog(Context context) {
super(context);
mContext = context;
}
Context mContext;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.social_actions);
setTitle("Title...");
}
but then I get a syntax error on the OnCreate.
Is it common and good practice to create new file? and if so- how to do it properly?
is it more efficient somehow - just showing the same dialog instead of initializing a new one each time? or is both ways the same?

For the syntax error, make sure you are importing the R class from your app and not the Android SDK class R resources.
For an experienced programmer your instinct is to move the dialog to a separate file, especially if it contains a lot of code. And that can be the right decision at times.
However, it is often convenient to have the dialog as an embedded class or to just create it inline (as in your example) because then it is within the scope of your activity and can access your state variables and protected methods on the Activity itself.
So you end up passing all this information to the dialog if you have it in a separate file, and at some point it just isn't worth it because the code becomes more complex and less maintainable.

Android; Declaring edittext in class body (Out of any method)

I have experience with programming languages but am a bit new to android programming.
I have a program with some fields that function as labels(textview), buttons, and data entry(edittext).
Whenever i declare them at the beginning of the program out of any methods(but in the class of course), when I start my application it crashes and simulation gives a "unfortunately, your program has stopped" alert.
Eclipse doesn't give any errors for the declaration and i did use the same way for defining regular variables with no issue. It also gives the same error when i declare a mediaplayer object in the class body.
Does anyone know why it gives error?
And is there another way to declare global objects like edittext, viewtext, etc... Declaring them over and over again in methods sounds weird to me.
Thank you!!
public class TrainerActivity extends Activity {
Button stopTimer = (Button)findViewById(R.id.StopTimer);
Button startTimer = (Button)findViewById(R.id.StartTimer);
EditText totalTime = (EditText)findViewById(R.id.TotalTime);
EditText enterMin = (EditText)findViewById(R.id.EnterMin);
EditText enterSec = (EditText)findViewById(R.id.EnterSec);
private boolean breaker = false;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startTimer.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Button_StartTimer();
}
});
stopTimer.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Button_StopTimer();
}
});
}

Without seeing example code of what you're trying it's impossible to say for definite (we don't do mind-reading here). But let me guess, you're doing something like this?...
public class MyActivity extends Activity {
TextView tv1; // This is fine.
  TextView tv2 = (TextView) findViewById(R.id.textview2); // Don't do this.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv1 = (TextView) findViewById(R.id.textview1); // This is fine
tv1.setText("Some text"); // This works
tv2.setText("Some text"); // NullPointerException here
}
}
The tv2.setText(...) will fail because you used findViewById(...) BEFORE you call setContenetView(...) and as a result, tv2 will be null.
It's quite acceptable to declare your widgets as instance members in your Activity but don't try to use findViewById(...) until AFTER you have set your content view.

try declaring the widget objects names only outside the onCreate() method
Button stopTimer;
Button startTimer;
EditText totalTime;
EditText enterMin;
EditText enterSec;
then initialise them after setContentView() inside onCreate()
setContentView(R.layout.main);
stopTimer = (Button)findViewById(R.id.StopTimer);
startTimer = (Button)findViewById(R.id.StartTimer);
totalTime = (EditText)findViewById(R.id.TotalTime);
enterMin = (EditText)findViewById(R.id.EnterMin);
enterSec = (EditText)findViewById(R.id.EnterSec);

Can you post a bit of sample code that illustrates the issue? It is fine to declare a member variable that is an EditText or TextView in the class.
logcat(in DDMS) should be give you some info about the error as well. If you are using eclipse there is a tab for DDMS, if not you can just run DDMS from a command line look at the logcat tab and launch your app (with your phone plugged in via usb, of course.) You should be able to see the actual error being reported.

You can declare these variables inside the Class body or inside the method body. In the former case, the variables are global and thus can be accessed within the whole class; in the latter case, they are local and thus can be only accessed within that method. Both of them could be commonly seen in proramming.
In Android, the typical application is that you declare the variables in the Class body and instantiate them in the onCreate() method. Something like this:
public Class MyClass extends Activity{
TextView label;// so this variable can be accessed within any methods in this Class
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(Bundle savedInstanceState);
setContentView(R.layout.main) // load the layout of the activity
label=(TextView)findViewById(R.id.<the TextView id defined in the layout file>); //this variable get instantiated. From now on you can manipulate it anywhere inside the class.
Button submit=(Button)findViewById(R.id.<the Button id defined in the layout file>);//you declared and instantiated it, but it could only be used within this method since you declared it here.
}
}
If you just declare a variable in the Class body,in most caeses, you can't use it until you instantiate it, because they are null before the instantiation. I think this is why you have problems. Please post the logcat so we can specify the real problem.

Custom AlertDialog fails to initialize in onCreate()

I'm trying to build a custom AlertDialog by extending the AlertDialog class.
As usual, I'm setting up the dialog inside its onCreate() method. Or, I'm trying to do so:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setTitle("Some title");
this.setButton(BUTTON_POSITIVE, "Click me", (DialogInterface.OnClickListener)null);
final FrameLayout custom = (FrameLayout) this
.findViewById(android.R.id.custom);
custom.addView(this.getLayoutInflater().inflate(R.layout.mydlg, null),
LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
}
Now, when it comes to displaying an instance of this dialog, nothing is shown. The current Activity fades out and loses focus but not a single pixel of my dialog is displayed. Pressing Back brings the Activity back to the foreground, indicating to me that a dialog actually is shown, but just a completely empty one.
However, when I create an AlertDialog and use, for instance, dlg.setButton(BUTTON_POSITIVE, "Click me", (DialogInterface.OnClickListener)null);
the dialog is shown with the respective button.
Even when I set up my custom dialog in its constructor using the very same code as above everything seems to work ok.
Now, how can this be? Why can't I seem to initialize my dialog in its onCreate() method? Isn't this the way you're supposed to initialize any GUI element? What am I missing?
EDIT
Please note, that something is 'shown', fading out the Activity and taking focus from it. It's just that it seems to be completely empty/invisible.
Here another attempt:
this.setTitle("Some title");
this.setButton(BUTTON_POSITIVE, "Click me", (DialogInterface.OnClickListener)null);
final View v = this.getLayoutInflater().inflate(R.layout.mydlg, null);
this.setView(v);
These exact lines do work when put into my dialog's constructor.
These exact lines do not work when put into my dialog's onCreate().
What is going on here?!
Generally, am I not supposed to do it in onCreate()? - Am I facing trouble if I resort to doing the above initialization in the constructor instead? (This does not seem too clean to me, anyway.)

You need to call the show() method in order to see something.

You should consider using AlertDialog.Builder instead of subclassing AlertDialog itself. It allows you to do all the things you need in your example (in order: setTitle(),setPositiveButton() and setView() ). Don't forget to call create() at the end to actually get your dialog.
Also, check if your onCreateDialog() and onPrepareDialog() activity methods are implemented correctly. If you don't have them implemented at all (an unmanaged dialog), consider doing that anyway, especially if your app allows for orientation changes. You probably know about this, but here is a tutorial:
http://developer.android.com/guide/topics/ui/dialogs.html
also, DialogFragments are a bit easier way to implement this, but you need a newer API version or the Compatibility package:
http://developer.android.com/reference/android/app/DialogFragment.
One final issue - where are you calling show() in your activity? onResume() should be OK, onCreate() not as much.

Sorry I'm late to the party :)
You have to thing differently for the alert dialog.
The way I did it is to customize the view before creating the alert dialog:
// This is the activity that is the background of the AlertDialog
public class Main extends Activity {
public static final int DIALOG_CONFIG = 1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.emptybackground);
}
#Override
protected void onStart() {
super.onStart();
// Open the alert dialog on openning the Activity
showDialog(Main.DIALOG_CONFIG );
}
protected Dialog onCreateDialog(int id) {
LayoutInflater factory = LayoutInflater.from(this);
switch (id) {
case DIALOG_CONFIG:
// Here, we load the existing view R.layout.config
configView = factory.inflate(R.layout.config, null);
configDialog = new AlertDialog.Builder(this)
.setTitle("Configuration")
.setView(configView)
.create();
// Using configView, you can do whatever you want with the view. Here, we add value to a spinner.
Spinner spinner = (Spinner)configView.findViewById(R.id.config_select_conn);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
adapter.add("TCP");
adapter.add("Bluetooth");
spinner.setAdapter(adapter);
return configPrinter;
}
return null;
}
}

you should call custom_alertDialog.create(); before custom_alertDialog.show();