Develop Reference

How to manually call onSaveInstanceState()

I am writing a program where I call multiple layouts on the same activity but then i noted that when i switch layouts, the changes made before the switch are not restored and onSavedInstanceState(Bundle outState) is not called. I have tried to manually call the method but i can't get the Bundle outState.
So the question really is: How do I get and store the current state of an activity to be recalled and/or restored at a time of my choosing?
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_contact_view);
// more code
}
#Override
public void onBackPressed() {
if (layoutId == R.layout.activity_contact_view) exit();
else if (layoutId == R.layout.main) {
Toast.makeText(NsdChatActivity.this, "Successful back button action", Toast.LENGTH_SHORT).show();
setContentView(R.layout.activity_contact_view);
refreshContactList();
}
}
And then from a seperate class
public void updateList(final int found) {
LinearLayout layxout = (LinearLayout) ((Activity)mContext).getWindow().getDecorView().findViewById(R.id.others);
TextView t = new TextView(mContext);
t.setClickable(true);
t.setText(found + ". " + activity.sNames.get(found));
t.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
t.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//show chat view
activity.setContentView(R.layout.main);
TextView name = (TextView)activity.findViewById(R.id.clientName);
name.setText(activity.sNames.get(found).split(" \\(")[0]);
final ScrollView scroll = (ScrollView)activity.findViewById(R.id.scroll);
scroll.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View view, boolean b) {
scroll.fullScroll(View.FOCUS_DOWN);
}
});
}
});
layxout.addView(t);
}

I might be late for that but what you could do is to keep your sate as a member of the class. That way you can restore the state anytime you want.
Bundle mState;
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save the state
savedInstanceState = mState;
super.onSaveInstanceState(savedInstanceState);
}
#Overrite
public void onRestoreInstanceState(Bundle savedInstance){
mState = savedInstance;
Restore();
}
public void Restore(){
//access your state and restore
}
Also you shouldn't use setContentView to switch between views it's expensive way to do it. You might want to check ViewSwitcher or ViewFlipper or someway to implement Fragments.

May be you should have a look at Application Fundamentals
Android calls onSaveInstanceState() before the activity becomes vulnerable to being destroyed by the system, but does not bother calling it when the instance is actually being destroyed by a user action (such as pressing the BACK key)
so you call multiple layouts on the same activity may not cause the above situation. For more details, you can refer to the question Android: Saving a state during Android lifecycle. Hope that helps!

Show popup activity only once the app starts

I have added a popup activity inside my app which is popping after 15 seconds of my app start. But when I am opening another activity and coming back to my main activity the popup showing again. I want it to appear only the first time when user is opening the app. What changes I should make? Appreciate the help.
Here is the popup code:
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if (context != null) {
AlertDialog.Builder alert = new AlertDialog.Builder(context, R.style.MyAlertDialogStyle)
.setTitle("Title")
.setMessage("Message")
.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// continue with delete
Intent intent = new Intent(MainActivity.this, WebActivity.class);
startActivity(intent);
}
})
.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialogInterface, int which) {
dialogInterface.dismiss();
// do nothing
}
});
mDialog = alert.create();
mDialog.getWindow().getAttributes().windowAnimations = R.style.MyAlertDialogStyle;
if (!((Activity) context).isFinishing())
mDialog.show();
// .setIcon(R.drawable.inr1)
// .show();
}
}
}, 15000);

You can do this if it needs to pop up only on application start
public class MyApplication extends Application {
#Override
public void onCreate() {
super.onCreate();
//Set some flag on global constant
}
}

save a tag(counter) in sharedPrefrances for that When the application starts up interpretation is the first time app start

You can use a global variable in the application class like this.
public class global extends Application
// some Boolean variable to hold status
And make sure you put this class inside android manifests application tag
android:name

Add this code in your MainActivity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
if(sharedPreferences.getBoolean("IS_FIRST_TIME", true)) {
//show your dialog here
//...
//change the value of your sharedPreferences
sharedPreferences.edit().putBoolean("IS_FIRST_TIME", false).apply();
}
}

please check the activity lifecycle.
Note:Remove Handler.
Note 2:Create method and call the dialog
Note 3:check the below method in lifecycle.
onPause ():
Called as part of the activity lifecycle when an activity is going into the background, but has not (yet) been killed. The counterpart to onResume(). When activity B is launched in front of activity A, this callback will be invoked on A. B will not be created until A's onPause() returns, so be sure to not do anything lengthy here.

save a boolean inside sharedpreferences read its value and determine weather running for the first time or not.
here is the code that will help you.
public void firstimeRun(boolean value) {
SharedPreferences sharedPreferences = getPrefrenceManager();
sharedPreferences.edit().putBoolean("key", value).apply();
}
public boolean isRunningForthefirstTime() {
SharedPreferences sharedPreferences = getPrefrenceManager();
return sharedPreferences.getBoolean("key", false);
}
private SharedPreferences getPrefrenceManager() {
return PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
}

Type finish(); after your startActivity(intent);

how help screen show for one time only in android

in the following code work properly and show help screen when open activity but I want show one time forever,
what can i do?
What should I add in the code?
my code:
public class KhatmMain extends Activity implements OnClickListener{
Context ctx;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ctx = this;
setContentView(R.layout.khatmmain);
showOverLay();
.
.
.
}
private void showOverLay(){
final Dialog dialog = new Dialog(ctx, android.R.style.Theme_Translucent_NoTitleBar);
dialog.setContentView(R.layout.overlay_view);
LinearLayout layout = (LinearLayout) dialog.findViewById(R.id.overlayLayout);
layout.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
dialog.dismiss();
}
});
dialog.show();
}
}

You can use SharedPrefereces to set a variable that will check if you've shown the dialog yet to the user or not, here's an example:
SharedPreferences prefs = this.getSharedPreferences("com.you.app", Context.MODE_PRIVATE);
Boolean dialogShown = prefs.getBoolean("dialogShown", false);
Then check if the value of dialogShown is false (you don't need to set it first since it will default to false the way we are calling it), then on the following code we execute some code, only if dialogShown is false, meaning we can do all the dialog stuff inside that conditional:
if(!dialogShown){
//Your show dialog code
prefs.edit().putBoolean("dialogShown",true).commit();
}
So the next time we check for the dialogShown value on the shared preferences it will be true therefor not showing the dialog. I believe this is the most common way of doing it.

There is a solution ..
when application first time start then save the shared preference to the app..
Now each and every time You retrieve the shared preference and check if it is there then move to next screen

Use this code:
public class KhatmMain extends Activity implements OnClickListener{
Context ctx;
Boolean showOneTime = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ctx = this;
setContentView(R.layout.khatmmain);
showOverLay();
.
.
.
}
private void showOverLay(){
if (showOneTime == false) {
return;
}
final Dialog dialog = new Dialog(ctx, android.R.style.Theme_Translucent_NoTitleBar);
dialog.setContentView(R.layout.overlay_view);
LinearLayout layout = (LinearLayout) dialog.findViewById(R.id.overlayLayout);
layout.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
dialog.dismiss();
}
});
dialog.show();
showOneTime = false;
}
}

How to retain EditText data on orientation change?

I have a Login screen which consists of 2 EditTexts for Username and Password. My requirement is that on orientation change , input data(if any) in EditText should remain as it is and a new layout should also be drawn. I have 2 layout xml files- one in layout folder and other in layout-land folder. I am trying to implement following 2 approaches but none of them is perfect:
(1) configChanges:keyboardHidden - In this approach, I don't provide "orientation" in configChanges in manifest file. So I call setContentView() method in both onCreate() and onConfigurationChanged() methods. It fulfills both my requirements. Layout is changed and input data in EditTexts also remains as it is. But it has a big problem :
When user clicks on Login button, a ProgressDialog shows until server-response is received. Now if user rotates the device while ProgressDialog is running, app crashes. It shows an Exception saying "View cannot be attached to Window." I have tried to handle it using onSaveInstanceState (which DOES get called on orientation change) but app still crashes.
(2) configChanges:orientation|keyboardHidden - In this approach, I provide "orientation" in manifest. So now I have 2 scenarios:
(a) If I call setContentView() method in both onCreate() and onConfigurationChanged(), Layout is changed accordingly but EditText data is lost.
(b) If I call setContentView() method in onCreate() , but not in onConfigurationChanged(), then EditText data is not lost but layout also not changes accordingly.
And in this approach, onSaveInstanceState() is not even called.
So I am in a really intimidating situation. Is there any solution to this problem? Please help. Thanx in advance.

By default, Edittext save their own instance when changing orientation.
Be sure that the 2 Edittexts have unique IDs and have the same IDs in both Layouts.
That way, their state should be saved and you can let Android handle the orientation change.
If you are using a fragment, be sure it has a unique ID also and you dont recreate it when recreating the Activity.

A better approach is to let android handle the orientation change. Android will automatically fetch the layout from the correct folder and display it on the screen. All you need to do is to save the input values of the edit texts in the onSaveInsanceState() method and use these saved values to initialize the edit texts in the onCreate() method.
Here is how you can achieve this:
#Override
protected void onCreate (Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.login_screen);
...
...
String userName, password;
if(savedInstanceState!=null)
{
userName = savedInstanceState.getString("user_name");
password= savedInstanceState.getString("password");
}
if(userName != null)
userNameEdtTxt.setText(userName);
if(password != null)
passEdtTxt.setText(password);
}
>
#Override
protected void onSaveInstanceState (Bundle outState)
{
outState.putString("user_name", userNameEdtTxt.getText().toString());
outState.putString("password", passEdtTxt.getText().toString());
}

Give the element an id and Android will manage it for you.
android:id="#id/anything"

in onConfigurationChanged method, first get the data of both the edit texts in global variables and then call setContentView method. Now set the saved data again into the edit texts.

There are many ways to do this. The simplest is 2(b) in your question. Mention android:configChanges="orientation|keyboardHidden|screenSize" in your manifest so that Activity doesn't get destroyed on Orientation changes.
Call setContentView() in onConfigChange(). but before calling setContentView() get the EditText data into a string and set it back after calling setContentView()
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mEditTextData = mEditText.getText().tostring();//mEditTextData is a String
//member variable
setContentView(R.layout.myLayout);
initializeViews();
}
private void initializeViews(){
mEditText = (EditText)findViewById(R.id.edittext1);
mEdiText.setText(mEditTextData);
}

The following should work and is standard to the activities and fragments
#Override
public void onSaveInstanceState (Bundle outState)
{
outState.putString("editTextData1", editText1.getText().toString());
outState.putString("editTextData2", editText2.getText().toString());
super.onSaveInstanceState(outState);
}
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate();
... find references to editText1, editText2
if (savedInstanceState != null)
{
editText1.setText(savedInstanceState.getString("editTextData1");
editText2.setText(savedInstanceState.getString("editTextData2");
}
}

Im restoring instance to restore values and it works fine for me :)
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.addtask2);
if(savedInstanceState!=null)
onRestoreInstanceState(savedInstanceState);
}

Remove android:configChanges attribute from the menifest file and let android handle the orientation change your data in edittext will automatically remain.
Now The problem you mentioned is with the progress dialog force close this is because when the orientation is changed the thread running in backgroud is trying to update the older dialog component whihc was visible. You can handle it by closing the dialog on savedinstancestate method and recalling the proceess you want to perform onRestoreInstanceState method.
Below is a sample hope it helps solving your problem:-
public class MyActivity extends Activity {
private static final String TAG = "com.example.handledataorientationchange.MainActivity";
private static ProgressDialog progressDialog;
private static Thread thread;
private static boolean isTaskRunnig;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "onCreate");
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new EditText.OnClickListener() {
#Override
public void onClick(View v) {
perform();
isTaskRunnig = true;
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void perform() {
Log.d(TAG, "perform");
progressDialog = android.app.ProgressDialog.show(this, null,
"Working, please wait...");
progressDialog
.setOnDismissListener(new DialogInterface.OnDismissListener() {
#Override
public void onDismiss(DialogInterface dialog) {
//isTaskRunnig = false;
}
});
thread = new Thread() {
public void run() {
Log.d(TAG, "run");
int result = 0;
try {
// Thread.sleep(5000);
for (int i = 0; i < 20000000; i++) {
}
result = 1;
isTaskRunnig = false;
} catch (Exception e) {
e.printStackTrace();
result = 0;
}
Message msg = new Message();
msg.what = result;
handler.sendMessage(msg);
};
};
thread.start();
}
// handler to update the progress dialgo while the background task is in
// progress
private static Handler handler = new Handler() {
public void handleMessage(Message msg) {
Log.d(TAG, "handleMessage");
int result = msg.what;
if (result == 1) {// if the task is completed successfully
Log.d(TAG, "Task complete");
try {
progressDialog.dismiss();
} catch (Exception e) {
e.printStackTrace();
isTaskRunnig = true;
}
}
}
};
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
Log.d(TAG, "onRestoreInstanceState" + isTaskRunnig);
if (isTaskRunnig) {
perform();
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Log.d(TAG, "onSaveInstanceState");
if (thread.isAlive()) {
thread.interrupt();
Log.d(TAG, thread.isAlive() + "");
progressDialog.dismiss();
}
}

As pointed out by Yalla T it is important to not recreate the fragment. The EditText will not lose its content if the existing fragment is reused.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// setContentView(R.layout.activity_frame);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// Display the fragment as the main content.
// Do not do this. It will recreate the fragment on orientation change!
// getSupportFragmentManager().beginTransaction().replace(android.R.id.content, new Fragment_Places()).commit();
// Instead do this
String fragTag = "fragUniqueName";
FragmentManager fm = getSupportFragmentManager();
Fragment fragment = (Fragment) fm.findFragmentByTag(fragTag);
if (fragment == null)
fragment = new Fragment_XXX(); // Here your fragment
FragmentTransaction ft = fm.beginTransaction();
// ft.setCustomAnimations(R.xml.anim_slide_in_from_right, R.xml.anim_slide_out_left,
// R.xml.anim_slide_in_from_left, R.xml.anim_slide_out_right);
ft.replace(android.R.id.content, fragment, fragTag);
// ft.addToBackStack(null); // Depends on what you want to do with your back button
ft.commit();
}

Saving state = Saving (Fragment State + Activity State)
When it comes to saving the state of a Fragment during orientation change, I usually do this way.
1) Fragment State:
Save and Restore EditText value
// Saving State
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString("USER_NAME", username.getText().toString());
outState.putString("PASSWORD", password.getText().toString());
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.user_name_fragment, parent, false);
username = (EditText) view.findViewById(R.id.username);
password = (EditText) view.findViewById(R.id.password);
// Retriving value
if (savedInstanceState != null) {
username.setText(savedInstanceState.getString("USER_NAME"));
password.setText(savedInstanceState.getString("PASSWORD"));
}
return view;
}
2) Activity State::
Create a new Instance when the activity launches for the first time
else find the old fragment using a TAG and the FragmentManager
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
fragmentManager = getSupportFragmentManager();
if(savedInstanceState==null) {
userFragment = UserNameFragment.newInstance();
fragmentManager.beginTransaction().add(R.id.profile, userFragment, "TAG").commit();
}
else {
userFragment = fragmentManager.findFragmentByTag("TAG");
}
}
You can see the the full working code HERE

Below code is work for me. Need to care two things.
Each Input Field (Edit Text or TextInputEditText) assign unique id.
Manifest activity declaration should have on configuration change attribute with below values.
android:configChanges="orientation|keyboardHidden|screenSize"
Sample activity declaration in manifest.
<activity
android:name=".screens.register.RegisterActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:exported="true"
android:label="Registration"
android:theme="#style/AppTheme.NoActionBar" />
Sample declaration of
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/inputLayout"
style="#style/Widget.MaterialComponents.TextInputLayout.OutlinedBox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:boxCornerRadiusBottomEnd="#dimen/boxCornerRadiusDP"
app:boxCornerRadiusBottomStart="#dimen/boxCornerRadiusDP"
app:boxCornerRadiusTopEnd="#dimen/boxCornerRadiusDP"
app:boxCornerRadiusTopStart="#dimen/boxCornerRadiusDP">
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/inputEditText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:focusable="true"
android:fontFamily="#font/proxima_nova_semi_bold"
android:inputType="textCapWords"
android:lines="1"
android:textColor="#color/colorInputText"
android:textColorHint="#color/colorInputText" />
</com.google.android.material.textfield.TextInputLayout>

this may help you
if your android:targetSdkVersion="12" or less
android:configChanges="orientation|keyboardHidden">
if your android:targetSdkVersion="13" or more
android:configChanges="orientation|keyboardHidden|screenSize">

Android: Can i show multiple Dialogs one over another? Is there something like Dialog Z-Level?

Is it possible to show multiple Dialogs one over another? Is there something like Dialog Z-Level?
I am using DialogFragment where user chooses elements, when he comfirms his choice, it is saved to database and sent on server. if the save action fails I would like to inform user with ... another dialog is it possible? And will it not clear off my first dialog?
Thanks in advance.

Indeed, it's possible to show multiple dialog Fragments one inside another one. The z-order depends on the order they are created.
In the code below there is an example of a FragmentActivity with the behavior that you require.
public class MyActivity extends FragmentActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
//...
}
public void onSave(View view) {
Intent intent = getIntent();
this.setResult(RESULT_OK, intent);
finish();
}
public void onCancel(View view) {
finish();
}
public void SelectWeekDay(View view) {
DialogFragment selectWeekDayFragment = new SelectWeekDayFragment();
selectWeekDayFragment.show(getSupportFragmentManager(), "WeekDayDialog");
}
public class SelectWeekDayFragment extends DialogFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.week_day_dialog, container, true);
Button saveButton = (Button) view.findViewById(R.id.button_save);
saveButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
CheckBox checkboxMonday = (CheckBox) getDialog().findViewById(R.id.checkBox_monday);
if (!checkboxMonday.isChecked()) {
DialogFragment saveErrorFragment = new SaveErrorFragment();
saveErrorFragment.show(getSupportFragmentManager(), "SaveErrorFragment");
}
else {
SaveToDb(); //Perform actions to store on db or what you wish
dismiss();
}
}
});
Button cancelButton = (Button) view.findViewById(R.id.button_cancel);
cancelButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dismiss();
}
});
return view;
}
}
public class SaveErrorFragment extends DialogFragment {
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return new AlertDialog.Builder(getActivity())
.setMessage("You must select Monday").setPositiveButton("Ok", null).create();
}
}
}

My advice is to use a custom layout with a ViewFlipper inside your dialog so you can easily switch between a progress-bar or whatever different layouts you want to show. If you want to show multiple Dialogs my guess is that the z-order depends on the order they were created the latest beeing shown on top.

You usually can, however, just be a little careful. Use the dialog's lifecycle to your advantage to avoid side-effects. For example: you can do a check on a function like onStop() to see if the child dialog is open, and if so, close it.
Ideally, cutting down on the amount of layers of dialogs you have is ideal, as long as it's sane (for example: doing it ends up being hundreds of lines of code more)