I have the following issue.I'm having an activity,part of an animal shelter app, where an user has to enter or edit pet-related data like weight,name and breed.What I want to achieve is to show a dialog asking if the user wants to keep editing or leave the activity,depending on whether he actually changed any of the text in the EditText views.
To do so I have created a boolean variable ,which should turn to true if the text was edited /trigger the dialog/ or remain false/do nothing/ if the user didn't edit anything.
I have attached TextWatcher to my EditText fields and tried to change the variable to true by doing that in onTextChangedor in beforeTextChanged.I tried comparing the hash or string values of the EditText fields to the CharSequence charSequence in the onTextChanged method but it only works for one of the EditText fields/meaning it triggers the dialog when the user changed the text/.Whenever I try to apply similar logic to the rest of the EditText fields as well the functionality breaks and the boolean variable stays "true" no matter what/meaning user sees dialog no matter if they changed the text or not/.
I tried various comparisson,if-logic,switch statement in an inner class and nothing seems to work.Kindly see code below.Thank you.
/**
* Allows user to create a new pet or edit an existing one.
*/
public class EditorActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>, TextWatcher {
/**
* EditText field to enter the pet's name
*/
private EditText mNameEditText;
/**
* EditText field to enter the pet's breed
*/
private EditText mBreedEditText;
/**
* EditText field to enter the pet's weight
*/
private EditText mWeightEditText;
/**
* EditText field to enter the pet's gender
*/
private Spinner mGenderSpinner;
/**
* Gender of the pet. The possible values are:
* 0 for unknown gender, 1 for male, 2 for female.
*/
public static int mGender;
public static String mPetName;
public static String mPetBreed;
public static String mPetWeight;
private static ArrayAdapter mGenderSpinnerAdapter;
private static Uri mSinglePetUri;
private static ContentValues mContentValues;
// we will show warning dialog to the user,if the below variable is true
private boolean mPetHasChanged;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_editor);
// checks if we are about to edit the information about an existing pet or add
// a new pet record , adjusts the activity title accordingly and initializes/
// activates Loader only if we are updating an existing pet
mSinglePetUri = getIntent().getData();
if (mSinglePetUri != null) {
setTitle(R.string.edit_pet_activity_title);
getSupportLoaderManager().initLoader(0, null, this);
} else {
setTitle(getString(R.string.add_a_pet_activity_title));
}
// Find all relevant views that we will need to read user input from
mNameEditText = findViewById(R.id.edit_pet_name);
mBreedEditText = findViewById(R.id.edit_pet_breed);
mWeightEditText = findViewById(R.id.edit_pet_weight);
mGenderSpinner = findViewById(R.id.spinner_gender);
setupSpinner();
// watch for text changes
mNameEditText.addTextChangedListener(this);
mBreedEditText.addTextChangedListener(this);
mWeightEditText.addTextChangedListener(this);
}
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
int nameTextHashCode = mNameEditText.getText().hashCode();
int breedTextHashCode = mBreedEditText.getText().hashCode();
int weightTextHashCode = mWeightEditText.getText().hashCode();
boolean nameChanged = nameTextHashCode == charSequence.hashCode();
boolean breedChanged = breedTextHashCode == charSequence.hashCode();
boolean weightChanged = weightTextHashCode == charSequence.hashCode();
//this works-mPetHasChanged properly changes value
mPetHasChanged = nameChanged ;
//this doesn't work - the value is always true even when user didn't change a thing
mPetHasChanged = nameChanged||breedChanged||weightChanged;
}
@Override
public void afterTextChanged(Editable editable) {
}
}
Then in another method the boolean value is tested in order to show or not the dialog
if (!mPetHasChanged) {
NavUtils.navigateUpFromSameTask(EditorActivity.this);
return true;
}
// Otherwise if there are unsaved changes, setup a dialog to warn the user.
// Create a click listener to handle the user confirming that
// changes should be discarded.
DialogInterface.OnClickListener discardButtonClickListener =
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
// User clicked "Discard" button, navigate to parent activity.
NavUtils.navigateUpFromSameTask(EditorActivity.this);
}
};
// Show a dialog that notifies the user they have unsaved changes
showUnsavedChangesDialog(discardButtonClickListener);
return true;
XML of the layout:
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2016 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- Layout for the editor -->
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="@dimen/activity_margin"
tools:context=".EditorActivity">
<!-- Overview category -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<!-- Label -->
<TextView
android:text="@string/category_overview"
style="@style/CategoryStyle" />
<!-- Input fields -->
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="2"
android:paddingLeft="4dp"
android:orientation="vertical">
<!-- Name field -->
<EditText
android:id="@+id/edit_pet_name"
android:hint="@string/hint_pet_name"
android:inputType="textCapWords"
style="@style/EditorFieldStyle" />
<!-- Breed field -->
<EditText
android:id="@+id/edit_pet_breed"
android:hint="@string/hint_pet_breed"
android:inputType="textCapWords"
style="@style/EditorFieldStyle" />
</LinearLayout>
</LinearLayout>
<!-- Gender category -->
<LinearLayout
android:id="@+id/container_gender"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<!-- Label -->
<TextView
android:text="@string/category_gender"
style="@style/CategoryStyle" />
<!-- Input field -->
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="2"
android:orientation="vertical">
<!-- Gender drop-down spinner -->
<Spinner
android:id="@+id/spinner_gender"
android:layout_height="48dp"
android:layout_width="wrap_content"
android:paddingRight="16dp"
android:spinnerMode="dropdown"/>
</LinearLayout>
</LinearLayout>
<!-- Measurement category -->
<LinearLayout
android:id="@+id/container_measurement"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<!-- Label -->
<TextView
android:text="@string/category_measurement"
style="@style/CategoryStyle" />
<!-- Input fields -->
<RelativeLayout
android:layout_height="wrap_content"
android:layout_width="0dp"
android:layout_weight="2"
android:paddingLeft="4dp">
<!-- Weight field -->
<EditText
android:id="@+id/edit_pet_weight"
android:hint="@string/hint_pet_weight"
android:inputType="number"
style="@style/EditorFieldStyle" />
<!-- Units for weight (kg) -->
<TextView
android:id="@+id/label_weight_units"
android:text="@string/unit_pet_weight"
style="@style/EditorUnitsStyle"/>
</RelativeLayout>
</LinearLayout>
</LinearLayout>
It took me quite some time in trial and error but I managed to make the code work in correct way.
@LalitFauzdar - thank you very much for helping me find out a part of the EditText - related solution.:
@Override
public void onTextChanged(CharSequence charSequence, int start, int before, int i2) {
mPetHasChanged = start!= before;
}
The other part turned out to be listening to delete key strokes when the user modifies the data. Then I also had to notify the user of pending changes, if he modified his selection in the spinner,showing the pet's gender in my activity. https://stackoverflow.com/a/24399683/10632237 this answer is the one that gave me idea how to listen for "real" changes, which the user made to the spinner. Here are the parts of the code,related to the initial question:
/**
* Allows user to create a new pet or edit an existing one.
*/
public class EditorActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>, TextWatcher, View.OnKeyListener, View.OnTouchListener {
/**
* EditText field to enter the pet's name
*/
private EditText mNameEditText;
/**
* EditText field to enter the pet's breed
*/
private EditText mBreedEditText;
/**
* EditText field to enter the pet's weight
*/
private EditText mWeightEditText;
/**
* EditText field to enter the pet's gender
*/
private Spinner mGenderSpinner;
/**
* Gender of the pet. The possible values are:
* 0 for unknown gender, 1 for male, 2 for female.
*/
public static int mGender;
public static String mPetName;
public static String mPetBreed;
public static String mPetWeight;
private static ArrayAdapter mGenderSpinnerAdapter;
private static Uri mSinglePetUri;
/**we will show warning dialog to the user,if the below variable is true*/
private boolean mPetHasChanged;
/**This flag turns to true if the spinner was actually touched by the user */
private boolean spinnerActivated;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_editor);
// checks if we are about to edit the information about an existing pet or add
// a new pet record , adjusts the activity title accordingly and initializes/
// activates Loader only if we are updating an existing pet
mSinglePetUri = getIntent().getData();
if (mSinglePetUri != null) {
setTitle(R.string.edit_pet_activity_title);
getSupportLoaderManager().initLoader(0, null, this);
} else {
setTitle(getString(R.string.add_a_pet_activity_title));
}
// Find all relevant views that we will need to read user input from
mNameEditText = findViewById(R.id.edit_pet_name);
mBreedEditText = findViewById(R.id.edit_pet_breed);
mWeightEditText = findViewById(R.id.edit_pet_weight);
mGenderSpinner = findViewById(R.id.spinner_gender);
setupSpinner();
mNameEditText.addTextChangedListener(this);
mBreedEditText.addTextChangedListener(this);
mWeightEditText.addTextChangedListener(this);
mNameEditText.setOnKeyListener(this);
mBreedEditText.setOnKeyListener(this);
mWeightEditText.setOnKeyListener(this);
mGenderSpinner.setOnTouchListener(this);
}
/**
* Setup the dropdown spinner that allows the user to select the gender of the pet.
*/
private void setupSpinner() {
// Create adapter for spinner. The list options are from the String array it will use
// the spinner will use the default layout
mGenderSpinnerAdapter = ArrayAdapter.createFromResource(this,
R.array.array_gender_options, android.R.layout.simple_spinner_item);
// Specify dropdown layout style - simple list view with 1 item per line
mGenderSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
// Apply the adapter to the spinner
mGenderSpinner.setAdapter(mGenderSpinnerAdapter);
// attach listener to the spinner to handle user selection from the pet's gender list.
mGenderSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String selection = (String) parent.getItemAtPosition(position);
if (selection.equals(getString(R.string.gender_male))) {
mGender = PetsEntry.PET_GENDER_MALE;
} else if (selection.equals(getString(R.string.gender_female))) {
mGender = PetsEntry.PET_GENDER_FEMALE;
} else {
mGender = PetsEntry.PET_GENDER_UNKNOWN;
}
// if the Spinner was not actually touched by the user, the
//spinnerActivated flag is
//false and the method is exited earlier as there was not actual selection
//change,
//made by the user.This manages the behaviour of onItemSelected ,where the
// method is
//called twice - once when the spinner is initialized and once again if
// the user changes
//selection.
if (!spinnerActivated){
return;
}
mPetHasChanged=true;
}
// Because onItemSelectedListener is an interface, onNothingSelected must be
// defined
@Override
public void onNothingSelected(AdapterView<?> parent) {
mGender = PetsEntry.PET_GENDER_UNKNOWN;
}
});
}
//more code between,unrelated to topic
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
/**The logic in this method gets triggered if the user changes existing pet's data by
using
* any key except the delete one*/
@Override
public void onTextChanged(CharSequence charSequence, int start, int before, int count) {
if (start != before){
mPetHasChanged=true;
}
}
@Override
public void afterTextChanged(Editable editable) {
}
/** The logic in this method gets triggered if the user presses the delete button,
* while editing pet's data, so we won't miss any type of editing action*/
@Override
public boolean onKey(View view, int keyCode, KeyEvent keyEvent) {
if (keyCode== KeyEvent.KEYCODE_DEL){
mPetHasChanged=true;
}
return false;
}
/**This method checks if the spinner was actually touched by the user and turns the
* flag variable to true and based on the flag's value we trigger the further logic in
* {#onItemSelected}*/
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
spinnerActivated=true;
return false;
}
}