I am new to Android development. I am trying to call a method of one of my classes when a button on my main activity is pressed.
On my Main Activity I have this button:
public void buttonTest(){
Button b = (Button) findViewById(R.id.test);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
String s = "changeText:myText";
Intent in = new Intent(PlusActivity.this, Test.class);
in.putExtra("method",s);
startActivity(in);
}
});
}
And here is is the class (without imports) which that intent above is calling to.
public class Test extends Activity {
static String text = "test";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
TextView mTextView = (TextView) findViewById(R.id.textView);
mTextView.setText(text);
}
public void changeText(String s){
this.text = s;
}
#Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
String[] array = intent.getStringExtra("method").split(":");
if(array[0].equals("changeText")){
changeText(array[1]);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.test, menu);
return true;
}
}
Basically I want to know if it is possible to change the value of that String text, before onCreate(). Basically each button will have a correspondent text, and I want to be able to modify that text based on which button.
If it is, what should I do/change?
Thanks in advance.
The right way to do it is to send the string you want it to be as an extra in the intent, and to read the extra from the intent and assign it to that variable in the onCreate function.
Use SharedPreference. Save in OnCLick of first class and retrieve in OnCreate of second class.
Initialization
SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0); // 0 - for private mode
Editor editor = pref.edit();
Storing Data
editor.putBoolean("key_name", true); // Storing boolean - true/false
editor.putString("key_name", "string value"); // Storing string
editor.putInt("key_name", "int value"); // Storing integer
editor.putFloat("key_name", "float value"); // Storing float
editor.putLong("key_name", "long value"); // Storing long
editor.commit(); // commit changes
Retrieving Data
// returns stored preference value
// If value is not present return second param value - In this case null
pref.getString("key_name", null); // getting String
pref.getInt("key_name", null); // getting Integer
pref.getFloat("key_name", null); // getting Float
pref.getLong("key_name", null); // getting Long
pref.getBoolean("key_name", null); // getting boolean
Deleting Data
editor.remove("name"); // will delete key name
editor.remove("email"); // will delete key email
editor.commit(); // commit changes
Clearing Storage
editor.clear();
editor.commit(); // commit changes
String text;
if (savedInstanceState == null) {
extras = getIntent().getExtras();
if(extras == null) {
text= null;
} else {
text= extras.getString("your default string message");
}
} else {
String s = "your default string message";
text= (String) savedInstanceState.getSerializable(s);
}
Related
i have successfully implemented a calculator with a history activity in which it will show old results in a list view
but i am facing a problem that the first line is always null
https://imgur.com/a/jvXms
i tried to make default string " Old Calculation "
> String w = "Old Calculation";
but this didn't work,
my app save the result in a multiline String in SharedPreferences and pass it to another activity through an intent
>SharedPreferences.Editor editor ; // saving shared preferences editor as MainAcitivty class attribute
under the onCreate i set the String value to sharedpref
> SharedPreferences prefs = getPreferences(MODE_PRIVATE);
w = prefs.getString("saved", null);
update method in which i update the result string value with the String s( String s is the calculated result)
> public void update(String s){
editor= getPreferences(MODE_PRIVATE).edit();
w = w
+ System.getProperty ("line.separator")
+ s
+ System.getProperty ("line.separator");
editor.putString("saved", w);
editor.apply();
}
Passing W value to the activity in which i will show the result in TextView list
> public void History(View v){
Intent myIntent = new Intent(MainActivity.this, History.class);
myIntent.putExtra("message", w);
startActivity(myIntent);
overridePendingTransition(R.anim.anim_slide_in_left,
R.anim.anim_slide_out_left);
}
History activity
public class History extends AppCompatActivity {
TextView tv1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_history);
String w ="Old calculation is showed here";
tv1 = (TextView) findViewById(R.id.tv1);
print(w);
}
public void print(String w) {
Bundle bundle = getIntent().getExtras();
w = bundle.getString("message");
tv1.setMovementMethod(new ScrollingMovementMethod());
tv1.setText(w);
}
#Override
public void onBackPressed() {
super.onBackPressed();
overridePendingTransition(R.anim.anim_slide_in_right, R.anim.anim_slide_out_right);
}
public void deleteAppData(View v) {
try {
// clearing app data
String packageName = getApplicationContext().getPackageName();
Runtime runtime = Runtime.getRuntime();
runtime.exec("pm clear "+packageName);
} catch (Exception e) {
e.printStackTrace();
}
}
}
when you store data from activity A and you want retrieve it from another activity, You must use SharedPreferences as below:
SharedPreferences prefs = getSharedPreferences(String, int);
String is FileName like "result"
int is Mode like MODE_PRIVATE
for example see this link
in addition i wrote a simple code for help you
I want create content application, i load data from JSON and when users click on button save this content into SQLitedatabase.
I want use this library for button.
And for checkable button, I use this code
I write below codes, when click on button i save this content into SQLitedatabase, but i can't save button sate into SharedPreferences!
When click on button (boolean checked) button is turn on, and when click again on the button turn off this button.
I want when click on button, turn on this button and save in SharedPreferences and when go to other activity and again back this activity, see turn on this button NOT turn off. when click again this button at that time turn off button!
Activity codes:
private ShineButton postShow_favPost;
private String favData = "FavPrefsList";
private Boolean favState;
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.post_show_page);
bindActivity();
//Give Data
Bundle bundle = getIntent().getExtras();
if (bundle != null) {
title = bundle.getString("title");
image = bundle.getString("image");
content = bundle.getString("content");
dateTime = bundle.getString("dateTime");
author = bundle.getString("author");
category = bundle.getString("category");
categoryID = bundle.getString("categoryID");
}
mAppBarLayout.addOnOffsetChangedListener(this);
//// Save Fav state
final SharedPreferences saveFavPrefs = getSharedPreferences(favData, MODE_PRIVATE);
final SharedPreferences.Editor editor = saveFavPrefs.edit();
favState = saveFavPrefs.getBoolean("isChecked", false);
postShow_favPost = (ShineButton) mToolbar.findViewById(R.id.post_FavImage);
postShow_favPost.init(this);
postShow_favPost.setOnCheckStateChangeListener(new ShineButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(View view, boolean checked) {
if (checked == true) {
editor.putBoolean("isChecked", true);
editor.commit();
//////////// Database
favDB = new FavHelper(context);
long addNewFAV = favDB.insertFAV(title, image, content, dateTime, author, category);
if (addNewFAV < 0) {
TastyToast.makeText(context, "Not save in database", TastyToast.LENGTH_LONG, TastyToast.ERROR);
} else {
TastyToast.makeText(context, "Save in database", TastyToast.LENGTH_LONG, TastyToast.SUCCESS);
}
////////////////////
} else {
editor.putBoolean("isChecked", false);
editor.commit();
Toast.makeText(context, "Checked False", Toast.LENGTH_SHORT).show();
}
}
});
How can i fix my issue ?
Well you need to save the state when you click the button.
For example :
postShow_favPost.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (postShow_favPost.isChecked()){
editor.putBoolean("isChecked", true);
editor.apply();
}
else{
editor.putBoolean("isChecked", false);
editor.apply();
}
}
});
Then you have to load it in your onCreate():
#Override
protected void onCreate(Bundle savedInstanceState)
{
SharedPreferences saveFavPrefs = getSharedPreferences(favData, MODE_PRIVATE);;
postShow_favPost.setChecked(saveFavPrefs.getBoolean("isChecked", true));
}
Maybe this example will help you.
EDIT
Ok let's presume in your f function you just finished doing whatever you're doing to your database, after that, set the state as on or off, let's say you want on.
So :
public void loadPrefs(SharedPreferences prefs){
favState = prefs.getBoolean("isChecked",false);
}
public void f(SharedPreferences.Editor editor){
//database stuff
editor.putBoolean("isChecked", true); // or false
editor.apply();
loadPrefs(prefs);
// in here your state will be saved for your button as soon as you
finish working with your database, after that in your onResume() you
may change that state to false(off) in case you want it just for that post
}
I am just trying to store the users input from an editText in a Shared Preference, but it is not working:
editText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
#Override
public boolean onEditorAction(TextView v, int keycode, KeyEvent event) {
Log.v(TAG, keyword.getString("keyword", "mDefault")); //IT LOGS OUT THE DEFAULT STRING EVEN **AFTER** STORING THE PREFERENCES BEFORE
if (keycode == EditorInfo.IME_ACTION_SEND) {
editText.setText(editText.getText().toString());
keywordEditor.putString("keyword", editText.getText().toString());
keywordEditor.commit();
Log.v(TAG, keyword.getString("keyword", "default")); //CORRECT! THIS LINE WORKS
}
}
return true;
});
When I first edit the text, I will first get a log of "mDefault" which is normal, since nothing is stored in the shared preference.
Then, I store something in the shared preference, and to make sure it stored, I log and I get a log of what I typed. Which means the shared preference data WAS stored.
Heres the problem: After I have stored something in the shared preference, I go to a different activity, and I come back, and all the data stored in the shared preference is GONE!
The very first log still says mDefault after navigating through activities.
What could the problem be?
EDIT:
Here is my instantiation:
onCreate:
keyword = PreferenceManager.getDefaultSharedPreferences(this); //Making a shared preferences
keywordEditor = keyword.edit();
Maybe you don't save on setOnEditorActionListener. Save when you go to a different activity. Because when it goes to different activity the setOnEditorActionListener editText.getText().toString() it returns null.
STORING PREFERENCES:
SharedPreferences pref = getSharedPreferences("MyPrefs",Context.MODE_PRIVATE);
// We need an editor object to make changes
SharedPreferences.Editor edit = pref.edit();
// Set/Store data
edit.putString("username", "Rishabh");
edit.putString("password", "rishabh123");
// Commit the changes
edit.commit();
RETRIEVING PREFERENCES:
SharedPreferences pref = getSharedPreferences("MyPrefs", Context.MODE_PRIVATE);
String username = pref.getString("username", "");
String password= pref.getString("password", "");
Log.d(TAG, username);
Log.d(TAG, password);
Adding this as an example in case you missed a key components. This is currently working for me:
public class Main2Activity extends ActionBarActivity {
private SharedPreferences keyword;
private SharedPreferences.Editor keywordEditor;
private String TAG = "TAG";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
keyword = PreferenceManager.getDefaultSharedPreferences(this); //Making a shared preferences
keywordEditor = keyword.edit();
final EditText editText = (EditText) findViewById(R.id.et_text);
findViewById(R.id.btn_launch).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(Main2Activity.this, Main22Activity.class);
startActivity(intent);
}
});
editText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
#Override
public boolean onEditorAction(TextView v, int keycode, KeyEvent event) {
Log.v(TAG, "Initial: " + keyword.getString("keyword", "mDefault")); //IT LOGS OUT THE DEFAULT STRING EVEN **AFTER** STORING THE PREFERENCES BEFORE
if (keycode == EditorInfo.IME_ACTION_SEND) {
editText.setText(editText.getText().toString());
keywordEditor.putString("keyword", editText.getText().toString());
keywordEditor.commit();
Log.v(TAG, "Saving in prefs: " + keyword.getString("keyword", "default")); //CORRECT! THIS LINE WORKS
}
return true;
}
});
}
}
From a fresh install:
I typed in "test" and hit the send button on keyboard therefore invoked the onEditorAction
Then clicked on launch new activity -> hit back button and typed in "test2" and hit send button.
The following is the log out put:
02-29 23:26:42.068 18105-18105/com.example.naveed.myapplication V/TAG: Initial: mDefault
02-29 23:26:42.136 18105-18105/com.example.naveed.myapplication V/TAG: Saving in prefs: test
02-29 23:26:53.281 18105-18105/com.example.naveed.myapplication V/TAG: Initial: test
02-29 23:26:53.338 18105-18105/com.example.naveed.myapplication V/TAG: Saving in prefs: test2
As you can see initially it was "mDefault" then "test" was saved. I launched a new activity and came back. Next time the initial was "test" since it was saved last time and "test2" was the new value saved.
Create SharedPreferences class
public class SharedPreferenceClass
{
// Shared Preferences
SharedPreferences pref;
// Editor for Shared preferences
SharedPreferences.Editor editor;
// Context
Context _context;
// Shared pref mode
int PRIVATE_MODE = 0;
// Sharedpref file name
private static final String PREF_NAME = "INTELLIJ_AMIYO";
public static final String KEY_SET_VALUE= "KEY_SET_VALUE";
public SharedPreferenceClass(Context context){
this._context = context;
pref = _context.getSharedPreferences(PREF_NAME, 0);
editor = pref.edit();
}
public void setUserDATA(String data)
{
editor.remove(KEY_SET_VALUE);
editor.putString(KEY_SET_VALUE, data);
editor.commit();
}
public String getUserDATA()
{
String getData= pref.getString(KEY_SET_VALUE, null);
return getData;
}
}
Now call this in your Activity section globally
SharedPreferenceClass sharedPrefClassObj;
& call onCreate(Bundle savedInstanceState) section
sharedPrefClassObj = new SharedPreferenceClass(getApplicationContext());
Now add this
editText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
#Override
public boolean onEditorAction(TextView v, int keycode, KeyEvent event) {
if (keycode == EditorInfo.IME_ACTION_SEND) {
editText.setText(editText.getText().toString());
sharedPrefClassObj.setUserDATA(editText.getText().toString()); // Set data
// Get data sharedPrefClassObj.getUserDATA();
}
}
return true;
});
Very important: you need a Preference name (for example: "MY_PREFS_NAME") to set and retrieve the values:
SharedPreferences.Editor keywordEditor = context.getSharedPreferences("MY_PREFS_NAME", MODE_PRIVATE).edit();
Use the same constant Preference name and it will give you the same preferences in any point of your app.
I am using shared preferences but my code is not working. I don't know what's wrong with it. Am I implementing something wrong?
My main java activity(relevant bit of code) is:
public class MainActivity extends AppCompatActivity {
private String s;
public static final String subjectKey = "SubjectID";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final SharedPreferences sharedPreferences = getSharedPreferences(subjectKey, Context.MODE_PRIVATE);
TextView calc_monday = (TextView) findViewById(R.id.monday_calc);
calc_monday.setOnClickListener(
new Button.OnClickListener(){
public void onClick(View v){
CustomDialogClass cdd = new CustomDialogClass(MainActivity.this);
cdd.show();
TextView text1 = (TextView) cdd.findViewById(R.id.Subject_ID);
String text = sharedPreferences.getString(subjectKey, " ");
if(text != " ")
{
text1.setText(text); /* Edit the value here*/
}
TextView text2 = (TextView) cdd.findViewById(R.id.Room_ID);
text2.setText("6 (SEECS)");
TextView text3 = (TextView) cdd.findViewById(R.id.Time_ID);
text3.setText("09:00am - 09:50am");
}
}
);
calc_monday.setOnLongClickListener(
new Button.OnLongClickListener() {
public boolean onLongClick(View v) {
SettingDialogClass SDC = new SettingDialogClass(MainActivity.this);
SDC.show();
EditText texii = (EditText) SDC.findViewById(R.id.set_Subject_ID);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(subjectKey, texii.getText().toString());
editor.apply();
return true;
}
}
);
Basically I want that when I longClick a textbox (calc_monday), a dialog box should appear which appears. Now I should be able to write something on the EditText field which appears on this dialog box. Whatever I write should be stored and then displayed when I SINGLE CLICK on the same textbox (calc_monday)
Please see the 2 methods: onClick and onLongClick to understand.
The code is not working, i.e the text I write on EditText field on onLongCLick dialog box is not being displayed when I single click on the textbox.
What's wrong with the code
When you long press calc_monday, it just show your custom dialog with empty value for EditText. To save your text when input in EditText, create a button in your custom dialog, and call onClickListener action for this button, then save value to SharePreferences.
calc_monday.setOnLongClickListener(
new Button.OnLongClickListener() {
public boolean onLongClick(View v) {
SettingDialogClass SDC = new SettingDialogClass(MainActivity.this);
EditText texii = (EditText) SDC.findViewById(R.id.set_Subject_ID);
Button btnSave = (Button)SDC.findViewById(R.id.your_custom_button);
btnSave.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(subjectKey, texii.getText().toString());
editor.apply();
SDC.dismiss();
}
});
SDC.show();
return true;
}
}
);
I think it's should be :
String text = sharedPreferences.getString("Name", " ");
Try these methods for saving and loading Strings with preferences:
//save prefs
public void savePrefs(String key, String value){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
//get prefs
public String loadPrefs(String key, String value){
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
String data = sharedPreferences.getString(key, value);
return data;
}
You can call the load method like this:
subjectKey = loadPrefs("YouCanNameThisAnything", subjectKey);
And you can call the save method like this:
savePrefs("YouCanNameThisAnything", subjectKey);
More details on how to use shared preferences is also available in the documentation here:
http://developer.android.com/reference/android/content/SharedPreferences.html
//create and initialize the intance of shared preference
SharedPreferences sharedPreferences = getSharedPreferences("Session", MODE_PRIVATE);
//save a string
SharedPreferences.Editor edit = sharedPreferences.edit();
edit.putString(subjectKey , texii.getText().toString());
edit.commit();
//retrieve the string
String subject = sharedPreferences.getString(subjectKey, "");
I'm trying to store a user entry into an EditText field however when I exit the application it does not appear.
So for example a user types in his/her name and then exits the application. When the user returns and launches the Application the users name appears in the EditText field. However I can't get this to work. I believe its to do with sharedPreferences but I'm not sure where I'm going wrong.
I'm quite new to android and java so finding this quite difficult. Any help would be much appreciated.
public class MainActivity extends Activity {
public final static String EXTRA_FROM = "com.example.assignment1.FROM";
#Override
protected void onSaveInstanceState(Bundle outState)
{
super.onSaveInstanceState(outState);
EditText emailFrom =(EditText) findViewById(R.id.editEmailFrom);
String from = emailFrom.getText().toString();
outState.putString(EXTRA_FROM, from);
}
#Override
protected void onRestoreInstanceState(Bundle savedState)
{
EditText emailFrom =(EditText) findViewById(R.id.editEmailFrom);
String from = savedState.getString(EXTRA_FROM);
emailFrom.setText(from);
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void emailSend (View sendButton)
{
Intent intent = new Intent(this,DisplayEmailActivity.class);
EditText emailFrom =(EditText) findViewById(R.id.editEmailFrom);
String from = emailFrom.getText().toString();
intent.putExtra(EXTRA_FROM,from);
SharedPreferences saveFrom = getSharedPreferences(EXTRA_FROM, MODE_PRIVATE);
Editor editor = saveFrom.edit();
editor.putString(EXTRA_FROM, from);
editor.commit();
String storedfrom = saveFrom.getString(EXTRA_FROM, from);
emailFrom.setText(storedfrom);
startActivity(intent);
}
Second Activity
public class DisplayEmailActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_email);
Intent intent = getIntent();
String from = intent.getStringExtra(MainActivity.EXTRA_FROM);
TextView textFrom =(TextView)findViewById(R.id.displayEmailFrom);
textFrom.setText(from);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_display_email, menu);
return true;
}
Ok, so after you store value in your EditText emailFrom, you have to save it in SharedPreferences like this:
String from = emailFrom.getText().toString(); // Getting String value from EditText and storing it in "from" String
SharedPreferences settings = getSharedPreferences("MyPreferencesFile", 0); // Opening SharedPreferences
SharedPreferences.Editor editor = settings.edit(); // Opening editor for SharedPreferences
editor.putString("exampleName", from); // You are putting here a String "from" and give it a "exampleName" name. Later you will use this name to restore data.
And then when you launch your application, you need to load data from SharedPreferences:
SharedPreferences settings = getSharedPreferences("MyPreferencesFile", 0); // Again opening SharedPreferences
String from = settings.getString("exampleName", ""); // The second argument is the default value. The default value will be set if there wasn't saved any data with "exampleName" name
if(from != "") // If "from" is not empty, it means that the data was stored in SharedPreferences
emailFrom.setText(from); // Setting text in your EditText
You are using onSaveInstanceState() and onRestoreInstanceState() to save and restore the content of the EditText. However, this methods are called only when the application is being terminated by the OS to be immediatlly recreated (i.e. device rotation).
If you want to preserve values when the application is terminated by the user, you need to store it somewhere, a file, a database or in your case I would suggest SharedPreferences.
I've posted an answer to a similar question in: SharePreferences
Good luck.