How to disable back press action for an intent? - java

I have an Activity which makes use of KeyguardManager.
The intention is to disallow the user to use the app, if they are unable to successfully supply their credentials.
Though the keyguard intent appears at the start of the app, pressing the device back button moves the intent away, showing the activity which started it.
Overriding the onBackPressed does not seem to help, as it isn't associated with the intent.
#Override
public void onBackPressed() {
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
KeyguardManager km = (KeyguardManager) getSystemService(KEYGUARD_SERVICE);
if (km.isKeyguardSecure()) {
setShowWhenLocked(true);
Intent i = km.createConfirmDeviceCredentialIntent("Authentication required", "password");
startActivityForResult(i, CODE_AUTHENTICATION_VERIFICATION);
}
}

What if you use finish() after startActivity() ?
EDIT:
Add finish() on your onActivityResult() if the pattern is false.

What you want to achieve can be done using a "Staging" Activity. For example, you can have a LoginActivity that will check if the user is authenticate or not then from there decide where to redirect him.
The LoginActivity should look something like this, of course you need to adapt it to your business logic :
public class LoginActivity extends AppCompatActivity {
private static final int CODE_AUTHENTICATION_VERIFICATION = 24;
private boolean isFirstLaunch = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
isFirstLaunch = false;
//startActivityForResult With your intent to authenticate the user
}
#Override
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == CODE_AUTHENTICATION_VERIFICATION){
Log.i("LOGIN", "return from key guard");
//Check the data and decide if you redirect the user to main activity or not
}
}
#Override
protected void onResume() {
super.onResume();
if(!isFirstLaunch){
Log.i("LOGIN", "resume not first launch");
// the user tried to cancel the authentication either present him with the authentication process again or finish() the activity
}
}
}

Please, N/B: Overriding the onBackPressed does help only when you create a conditional statement controlled by a boolean variable in the onBackPressed method and call it in the onActivityResult i.e when the resultCode != RESULT_OK. Another option is to exit the app when resultCode != RESULT_OK (moveTaskToBack(true)) Here is what I mean below:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == INTENT_AUTHENTICATE) {
if (resultCode == RESULT_OK) {
//do something you want when pass the security
} else //resultCode != RESULT_OK
//Option 1 Ensure you override onBackPressed() with a conditional
//statement controlled by a boolean variable.
onBackPressed();
//Option 2
moveTaskToBack(true); //Exit app when a user click the back button.
}
}

Related

How do I know/get notified that my activity (android) has ended? [duplicate]

In my activity, I'm calling a second activity from the main activity by startActivityForResult. In my second activity, there are some methods that finish this activity (maybe without a result), however, just one of them returns a result.
For example, from the main activity, I call a second one. In this activity, I'm checking some features of a handset, such as does it have a camera. If it doesn't have then I'll close this activity. Also, during the preparation of MediaRecorder or MediaPlayer if a problem happens then I'll close this activity.
If its device has a camera and recording is done completely, then after recording a video if a user clicks on the done button then I'll send the result (address of the recorded video) back to the main activity.
How do I check the result from the main activity?
From your FirstActivity, call the SecondActivity using the startActivityForResult() method.
For example:
int LAUNCH_SECOND_ACTIVITY = 1
Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, LAUNCH_SECOND_ACTIVITY);
In your SecondActivity, set the data which you want to return back to FirstActivity. If you don't want to return back, don't set any.
For example: In SecondActivity if you want to send back data:
Intent returnIntent = new Intent();
returnIntent.putExtra("result",result);
setResult(Activity.RESULT_OK,returnIntent);
finish();
If you don't want to return data:
Intent returnIntent = new Intent();
setResult(Activity.RESULT_CANCELED, returnIntent);
finish();
Now in your FirstActivity class, write the following code for the onActivityResult() method.
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == LAUNCH_SECOND_ACTIVITY) {
if(resultCode == Activity.RESULT_OK){
String result=data.getStringExtra("result");
}
if (resultCode == Activity.RESULT_CANCELED) {
// Write your code if there's no result
}
}
} //onActivityResult
To implement passing data between two activities in a much better way in Kotlin, please go through 'A better way to pass data between Activities'.
How to check the result from the main activity?
You need to override Activity.onActivityResult() and then check its parameters:
requestCode identifies which app returned these results. This is defined by you when you call startActivityForResult().
resultCode informs you whether this app succeeded, failed, or something different
data holds any information returned by this app. This may be null.
Example
To see the entire process in context, here is a supplemental answer. See my fuller answer for more explanation.
MainActivity.java
public class MainActivity extends AppCompatActivity {
// Add a different request code for every activity you are starting from here
private static final int SECOND_ACTIVITY_REQUEST_CODE = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
// "Go to Second Activity" button click
public void onButtonClick(View view) {
// Start the SecondActivity
Intent intent = new Intent(this, SecondActivity.class);
startActivityForResult(intent, SECOND_ACTIVITY_REQUEST_CODE);
}
// This method is called when the second activity finishes
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// check that it is the SecondActivity with an OK result
if (requestCode == SECOND_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) { // Activity.RESULT_OK
// get String data from Intent
String returnString = data.getStringExtra("keyName");
// set text view with string
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText(returnString);
}
}
}
}
SecondActivity.java
public class SecondActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
}
// "Send text back" button click
public void onButtonClick(View view) {
// get the text from the EditText
EditText editText = (EditText) findViewById(R.id.editText);
String stringToPassBack = editText.getText().toString();
// put the String to pass back into an Intent and close this activity
Intent intent = new Intent();
intent.putExtra("keyName", stringToPassBack);
setResult(RESULT_OK, intent);
finish();
}
}
Complementing the answer from Nishant, the best way to return the activity result is:
Intent returnIntent = getIntent();
returnIntent.putExtra("result",result);
setResult(RESULT_OK,returnIntent);
finish();
I was having a problem with
new Intent();
Then I found out that the correct way is using
getIntent();
to get the current intent.
startActivityForResult: Deprecated in Android X
For the new way we have registerForActivityResult.
In Java :
// You need to create a launcher variable inside onAttach or onCreate or global, i.e, before the activity is displayed
ActivityResultLauncher<Intent> launchSomeActivity = registerForActivityResult(
new ActivityResultContracts.StartActivityForResult(),
new ActivityResultCallback<ActivityResult>() {
#Override
public void onActivityResult(ActivityResult result) {
if (result.getResultCode() == Activity.RESULT_OK) {
Intent data = result.getData();
// your operation....
}
}
});
public void openYourActivity() {
Intent intent = new Intent(this, SomeActivity.class);
launchSomeActivity.launch(intent);
}
In Kotlin :
var resultLauncher = registerForActivityResult(StartActivityForResult()) { result ->
if (result.resultCode == Activity.RESULT_OK) {
val data: Intent? = result.data
// your operation...
}
}
fun openYourActivity() {
val intent = Intent(this, SomeActivity::class.java)
resultLauncher.launch(intent)
}
Advantage:
The new way is reduce complexity which we faced when we call the activity from a fragment or from another activity
Easily ask for any permission and get callback
For those who have problem with wrong requestCode in onActivityResult
If you are calling startActivityForResult() from your Fragment, the requestCode is changed by the Activity that owns the Fragment.
If you want to get the correct resultCode in your activity try this:
Change:
startActivityForResult(intent, 1); To:
getActivity().startActivityForResult(intent, 1);
The ActivityResultRegistry is the recommended approach
ComponentActivity now provides an ActivityResultRegistry that lets you handle the startActivityForResult()+onActivityResult() as well as requestPermissions()+onRequestPermissionsResult() flows without overriding methods in your Activity or Fragment, brings increased type safety via ActivityResultContract, and provides hooks for testing these flows.
It is strongly recommended to use the Activity Result APIs introduced in Android 10 Activity 1.2.0-alpha02 and Fragment 1.3.0-alpha02.
Add this to your build.gradle
def activity_version = "1.2.0-beta01"
// Java language implementation
implementation "androidx.activity:activity:$activity_version"
// Kotlin
implementation "androidx.activity:activity-ktx:$activity_version"
How to use the pre-built contract
This new API has the following pre-built functionalities
TakeVideo
PickContact
GetContent
GetContents
OpenDocument
OpenDocuments
OpenDocumentTree
CreateDocument
Dial
TakePicture
RequestPermission
RequestPermissions
An example that uses the takePicture contract:
private val takePicture = prepareCall(ActivityResultContracts.TakePicture()) { bitmap: Bitmap? ->
// Do something with the Bitmap, if present
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
button.setOnClickListener { takePicture() }
}
So what’s going on here? Let’s break it down slightly. takePicture is just a callback which returns a nullable Bitmap - whether or not it’s null depends on whether or not the onActivityResult process was successful. prepareCall then registers this call into a new feature on ComponentActivity called the ActivityResultRegistry - we’ll come back to this later. ActivityResultContracts.TakePicture() is one of the built-in helpers which Google have created for us, and finally invoking takePicture actually triggers the Intent in the same way that you would previously with Activity.startActivityForResult(intent, REQUEST_CODE).
How to write a custom contract
A simple contract that takes an Int as an input and returns a string that the requested Activity returns in the result Intent.
class MyContract : ActivityResultContract<Int, String>() {
companion object {
const val ACTION = "com.myapp.action.MY_ACTION"
const val INPUT_INT = "input_int"
const val OUTPUT_STRING = "output_string"
}
override fun createIntent(input: Int): Intent {
return Intent(ACTION)
.apply { putExtra(INPUT_INT, input) }
}
override fun parseResult(resultCode: Int, intent: Intent?): String? {
return when (resultCode) {
Activity.RESULT_OK -> intent?.getStringExtra(OUTPUT_STRING)
else -> null
}
}
}
class MyActivity : AppCompatActivity() {
private val myActionCall = prepareCall(MyContract()) { result ->
Log.i("MyActivity", "Obtained result: $result")
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
...
button.setOnClickListener {
myActionCall(500)
}
}
}
Check this official documentation for more information.
If you want to update the user interface with the activity result, you can't to use this.runOnUiThread(new Runnable() {}. Doing this, the UI won't refresh with the new value. Instead, you can do this:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_CANCELED) {
return;
}
global_lat = data.getDoubleExtra("LATITUDE", 0);
global_lng = data.getDoubleExtra("LONGITUDE", 0);
new_latlng = true;
}
#Override
protected void onResume() {
super.onResume();
if(new_latlng)
{
PhysicalTagProperties.this.setLocation(global_lat, global_lng);
new_latlng=false;
}
}
This seems silly, but it works pretty well.
In Kotlin
Suppose A & B are activities the navigation is from A -> B
We need the result back from A <- B
in A
// calling the Activity B
resultLauncher.launch(Intent(requireContext(), B::class.java))
// we get data in here from B
private var resultLauncher =
registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
when (result.resultCode) {
Activity.RESULT_OK -> {
result.data?.getStringExtra("VALUE")?.let {
// data received here
}
}
Activity.RESULT_CANCELED -> {
// cancel or failure
}
}
}
In B
// Sending result value back to A
if (success) {
setResult(RESULT_OK, Intent().putExtra("VALUE", value))
} else {
setResult(RESULT_CANCELED)
}
It is a very common problem on Android
It can be broken down into three pieces
Start Activity B (happens in Activity A)
Set requested data (happens in activity B)
Receive requested data (happens in activity A)
startActivity B
Intent i = new Intent(A.this, B.class);
startActivity(i);
Set requested data
In this part, you decide whether you want to send data back or not when a particular event occurs.
E.g.: In activity B there is an EditText and two buttons b1, b2.
Clicking on Button b1 sends data back to activity A.
Clicking on Button b2 does not send any data.
Sending data
b1......clickListener
{
Intent resultIntent = new Intent();
resultIntent.putExtra("Your_key", "Your_value");
setResult(RES_CODE_A, resultIntent);
finish();
}
Not sending data
b2......clickListener
{
setResult(RES_CODE_B, new Intent());
finish();
}
The user clicks the back button
By default, the result is set with Activity.RESULT_CANCEL response code
Retrieve result
For that override onActivityResult method
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RES_CODE_A) {
// b1 was clicked
String x = data.getStringExtra("RES_CODE_A");
}
else if(resultCode == RES_CODE_B){
// b2 was clicked
}
else{
// The back button was clicked
}
}
I will post the new "way" with Android X in a short answer (because in some case you does not need custom registry or contract). If you want more information, see: Getting a result from an activity
Important: there is actually a bug with the backward compatibility of Android X so you have to add fragment_version in your Gradle file. Otherwise you will get an exception "New result API error : Can only use lower 16 bits for requestCode".
dependencies {
def activity_version = "1.2.0-beta01"
// Java language implementation
implementation "androidx.activity:activity:$activity_version"
// Kotlin
implementation "androidx.activity:activity-ktx:$activity_version"
def fragment_version = "1.3.0-beta02"
// Java language implementation
implementation "androidx.fragment:fragment:$fragment_version"
// Kotlin
implementation "androidx.fragment:fragment-ktx:$fragment_version"
// Testing Fragments in Isolation
debugImplementation "androidx.fragment:fragment-testing:$fragment_version"
}
Now you just have to add this member variable of your activity. This use a predefined registry and generic contract.
public class MyActivity extends AppCompatActivity{
...
/**
* Activity callback API.
*/
// https://developer.android.com/training/basics/intents/result
private ActivityResultLauncher<Intent> mStartForResult = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(),
new ActivityResultCallback<ActivityResult>() {
#Override
public void onActivityResult(ActivityResult result) {
switch (result.getResultCode()) {
case Activity.RESULT_OK:
Intent intent = result.getData();
// Handle the Intent
Toast.makeText(MyActivity.this, "Activity returned ok", Toast.LENGTH_SHORT).show();
break;
case Activity.RESULT_CANCELED:
Toast.makeText(MyActivity.this, "Activity canceled", Toast.LENGTH_SHORT).show();
break;
}
}
});
Before new API you had :
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MyActivity .this, EditActivity.class);
startActivityForResult(intent, Constants.INTENT_EDIT_REQUEST_CODE);
}
});
You may notice that the request code is now generated (and hold) by the Google framework.
Your code becomes:
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MyActivity .this, EditActivity.class);
mStartForResult.launch(intent);
}
});
First you use startActivityForResult() with parameters in the first Activity and if you want to send data from the second Activity to first Activity then pass the value using Intent with the setResult() method and get that data inside the onActivityResult() method in the first Activity.
In your Main Activity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.takeCam).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent=new Intent(getApplicationContext(),TakePhotoActivity.class);
intent.putExtra("Mode","Take");
startActivity(intent);
}
});
findViewById(R.id.selectGal).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent=new Intent(getApplicationContext(),TakePhotoActivity.class);
intent.putExtra("Mode","Gallery");
startActivity(intent);
}
});
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
}
In Second Activity to Display
private static final int CAMERA_REQUEST = 1888;
private ImageView imageView;
private static final int MY_CAMERA_PERMISSION_CODE = 100;
private static final int PICK_PHOTO_FOR_AVATAR = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_take_photo);
imageView=findViewById(R.id.imageView);
if(getIntent().getStringExtra("Mode").equals("Gallery"))
{
pickImage();
}
else {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_PERMISSION_CODE);
} else {
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
}
}
}
public void pickImage() {
Intent intent = new Intent(Intent.ACTION_PICK);
intent.setType("image/*");
startActivityForResult(intent, PICK_PHOTO_FOR_AVATAR);
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults)
{
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == MY_CAMERA_PERMISSION_CODE)
{
if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
{
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
else
{
Toast.makeText(this, "Camera Permission Denied..", Toast.LENGTH_LONG).show();
}
}
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) {
Bitmap photo = (Bitmap) data.getExtras().get("data");
imageView.setImageBitmap(photo);
}
if (requestCode == PICK_PHOTO_FOR_AVATAR && resultCode == Activity.RESULT_OK) {
if (data == null) {
Log.d("ABC","No Such Image Selected");
return;
}
try {
Uri selectedData=data.getData();
Log.d("ABC","Image Pick-Up");
imageView.setImageURI(selectedData);
InputStream inputStream = getApplicationContext().getContentResolver().openInputStream(selectedData);
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
Bitmap bmp=MediaStore.Images.Media.getBitmap(getContentResolver(),selectedData);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch(IOException e){
}
}
}
You need to override Activity.onActivityResult():
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_CODE_ONE) {
String a = data.getStringExtra("RESULT_CODE_ONE");
}
else if(resultCode == RESULT_CODE_TWO){
// b was clicked
}
else{
}
}

How to inflate a layout dialog on another activity?

I am currently on SecondActivity.class . On my code, when I backpress, I want the dialog to appear on my MainActivity.class .
This is my code on inflating the dialog layout.
This appears on SecondActivity.class instead of my main activity.
View dialog = LayoutInflater.from(this).inflate(R.layout.dialog_fmcg_popup, null);
TextView tvfmcg2 = dialog.findViewById(R.id.tv_fmcg2);
tvfmcg2.setText(message);
swipeDismissDialog = new SwipeDismissDialog.Builder(this)
.setView(dialog)
.setOnSwipeDismissListener(new OnSwipeDismissListener() {
#Override
public void onSwipeDismiss(View view, SwipeDismissDirection direction) {
Preferences.setString(Prefkey.last_qualified_fmcg_voucher_on_remove, message);
}
})
.setFlingVelocity(0)
.setOverlayColor(0)
.build()
.show();
Well what you can use is ActivityForResult() method.
You need to start the activity a little bit different of what you are doing.
startActivityForResult(new Intent(this, SecondActivity.class), 80);
Then in your SecondActivity.class you override the onBackPressed() method as follows
#Override
public void onBackPressed() {
setResult(Activity.RESULT_OK,new Intent());
finish();
}
And in your FirstActivity.class you have to override the onActivityResult() method
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 80) {
if(resultCode == Activity.RESULT_OK){
View dialog = LayoutInflater.from(this).inflate(R.layout.dialog_fmcg_popup, null);
TextView tvfmcg2 = dialog.findViewById(R.id.tv_fmcg2);
tvfmcg2.setText(message);
swipeDismissDialog = new SwipeDismissDialog.Builder(this)
.setView(dialog)
.setOnSwipeDismissListener(new OnSwipeDismissListener()
{
#Override
public void onSwipeDismiss(View view, SwipeDismissDirection direction)
{
Preferences.setString(Prefkey.last_qualified_fmcg_voucher_on_remove, message);
}
})
.setFlingVelocity(0)
.setOverlayColor(0)
.build()
.show();
}
}
}
Try to call method than show dialog in onStart or onResume in MainActivity
If you want to display this on your MainActivity instead of your SecondActivity you must start the SecondActivity like this:
startActivityForResult(yourIntent, SECOND_ACTIVITY_KEY)
On BackPresses you can set the result like this
Intent intent=Intent()
intent.putExtra("MESSAGE",message)
setResult(2,intent)
Then on MainActivity you can listen for results and call your dialog.
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent) {
// Check which request we're responding to
if (requestCode == SECOND_ACTIVITY_KEY) {
// Make sure the request was successful
if (resultCode == Activity.RESULT_OK) {
// The user picked a contact.
// The Intent's data Uri identifies which contact was selected.
// Do something with the contact here (bigger example below)
}
}
}

Updating some fields in main activity after exiting from another activity

My MainActivity has an EditText with the hint "Weight (lb)", as well as a button that goes to the SettingsActivity. In SettingsActivity, the user is able to change the units used from US to metric. Upon exiting SettingsActivity via the built-in back button on the phone, I want the hint for the EditText to immediately change from "Weight (lb)" to "Weight (kg)".
The farthest I've gotten is using the onBackPressed() method in SettingsActivity. The button press is detected, and the code inside it is executed, but I don't want to change anything related to MainActivity's inside the SettingsActivity class.
Is there an on___() method that I should be using here that I don't know about? Any help would be appreciated.
You can use startActivityForResult for SettingsActivity and after that handle the return result as:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == PICK_CONTACT_REQUEST) {
// Make sure the request was successful
if (resultCode == RESULT_OK) {
// The user picked a contact.
// The Intent's data Uri identifies which contact was selected.
// Do something with the contact here (bigger example below)
}
}
More detail: https://developer.android.com/training/basics/intents/result.html
You can use startActivityForResult for SettingsActivity and after that handle the return result as:
In your MainActivity:
public static int CALL_SETTINGS = 1000;
startActivityForResult(new Intent(this,SettingsActivity.class),CALL_SETTINGS);
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == PICK_CONTACT_REQUEST) {
// Make sure the request was successful
if (resultCode == RESULT_OK) {
// The user picked a contact.
// The Intent's data Uri identifies which contact was selected.
// Do something with the contact here (bigger example below)
}
}
In your Settings Activity:
on backpressed write this:
Intent returnIntent = new Intent();
returnIntent.putExtra("result",data);
setResult(Activity.RESULT_OK,returnIntent);
finish();
Easy option is to store the waitUnit in shared preference and on OnResume() of the Main activity read it from there and update the widget.
You can update the preferences in your Settings activity like below:
preferences = context.getSharedPreferences(context.getString(R.string.preference_file_key),
Context.MODE_PRIVATE);
preferences.edit().putString("unit", "kg");
And you can read this changed value in OnResume() of your Main Activity
preferences.getString("unit", "default unit")

How to use one activity call back's in other activity

I have two activities:
In FirstActivity(which also contains List<MapGroup>) I implemented my Interface(GetMaps).
SecondActivity contains my list of maps with an adapter, where I can select or deselect the maps. Whenever I select or deselect I would like to update in FirstActivity my List<MapGroup>: if I select I would like to add, if I deselect I would like to remove from ArrayList.
I know one solution: this can be done using Intent in android.
But I am looking for a solution where add or remove can be done automatically in parallel.
1) Using BroadcastReceiver
When you change any data send BroadcastReceiver
Intent broadcast = new Intent();
broadcast.setAction("UpdateData");
sendBroadcast(broadcast);
For catch receiver you have to do like below.
IntentFilter intentFilter = new IntentFilter(Intent.ACTION_DEFAULT);
intentFilter.addAction("UpdateData");
this.registerReceiver(this.broadcastReceiver, intentFilter);
And..
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("UpdateData")){
// Your code goes here.
}
}
};
Unregister receiver when app is destroyed.
#Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(broadcastReceiver);
};
2) using Intent.
In your current activity do like this.
Intent nextAct = new Intent(CurrentAct.this,NextAct.class);
nextAct.putExtra("Key",value);
startActivityForResult(nextAct,1000);
Override onActivityResult() method in your current activity.
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == 100 && resultCode == 1000){
}
}
In your NextAct you have to set Result code like below.
setResult(1000);
Example : setResult code in onBackPress();
#Override
public void onBackPressed() {
setResult(1000);
}

Calling onActivityResult to determine when a file has been received

I have a WebActivity that sets a JavascriptInterface for a WebView, on the Interface I have created various methods to be called with Javascript for different tasks, one of them is to send a file through Bluetooth.
The file sends just fine, but I want to inform the user when the file has already been accepted and transmited completely on the other end.
I am trying to use onActivityResult on my main WebActivity and also have tried on the separate class that handles the Bluetooth transmission and has a method called on the JavascriptInterface but I am not getting any callback results after the file is succesfully sent:
//First attempt
public class WebActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
//some code here
//Here I set the interface
myWebView.addJavascriptInterface(new WebAppInterface(this), "Android");
}
#Override
protected void onActivityResult(int requestCode, int resultCode,
Intent data) {
if (requestCode == 0) {
//This message is shown after the file transfer has started but no
//finished
Toast.makeText(this, "File Sent", Toast.LENGTH_SHORT).show();
if(resultCode == Activity.RESULT_OK){
//It doesn't work here either I always get Activity.RESULT_CANCELED (0)
//flag afer the file transfer has started
}
}
}
}
//Second Attempt
public class BluetoothTasks {
//code here
private void startTransferIntent() {
//some more code here
Intent intent = new Intent();
intent.setAction(Intent.ACTION_SEND);
intent.setType("text/plain");
File file_to_transfer = new File(Environment.getExternalStorageDirectory() +
"/txtTransfer.txt");
intent.putExtra(Intent.EXTRA_STREAM,Uri.fromFile(file_to_transfer));
//some more code here
Activity act = (Activity) mContext;
act.startActivityForResult(intent, TRANSFER_RESULT);
}
protected void onActivityResult(int requestCode, int resultCode,
Intent data) {
if (requestCode == TRANSFER_RESULT) {
//Not working here either
//code that is not executed
}
}
}
Could you please tell me if there is a way to do this and if so how would be accomplished?. Thank you.

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