I have to implement a return method of a class. So the structure is as simple as
public boolean yesNo(String message){
//return something
}
The problem here is that there is an EditText object and a Button and I want return a boolean depending on the answer entered by the User in the EditText. So naturally I have to wait for the user to write and click the Button when he finishes. I already tried setting up an onClicklistener inside the method but then I would not be able to pass anything to the outer method.
I know that in android everything is asynchronous so I you are not supposed to wait for the user to do something but in this case I have no other idea. Also FYI the method that I'm implementing is of the UserInfo class of the Jsch library. From what i understood this UserInfo is designed for user interaction so I figured it would somehow manage "prompt" the user by calling the yesNo method and then "wait" for the user to react. Any ideas? Also I would be happy if anyone would explain to me if there is some error in my logic. Im not quite confident in using AsynTask or runnables but I think its got something to do with this.
The only available documentation of UserInfo class
Thanks a lot!
EDIT: code so far:
public static class MyUserInfo implements UserInfo, UIKeyboardInteractive {
public Button goButton = (Button) MainActivity.contentView.findViewById(R.id.startSSH);
public EditText editText = (EditText) MainActivity.contentView.findViewById(R.id.commandSSH);
public boolean yesNo = false;
public boolean promptYesNo(String str) {
goButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
String answer = editText.getText().toString();
if(answer.equals("yes")){yesNo = true;}
else {yesNo = false;}
}
});
return yesNo;
}
}
Put an OnClickListener on the Button when the screen is initialized, for example at onCreate lifecycle method. At the listener's onClick method you can call the yesNo method with the EditText content.
Try this way at the screen's onCreate method:
mButton = (Button)findViewById(R.id.my_button);
mEditText = (EditText) findViewById(R.id.my_edittext);
mButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
yesNo(mEditText.getText().toString());
}
});
I already tried setting up an onClicklistener inside the method but
then i would not be able to pass anything to the outer method.
What do you want to pass to the outer method? You can create class variables to make it available inside the whole class.
The promptYesNo method:
public void promptYesNo(String s) {
if(s.equals("Yes") //do something
else if(s.equals("No") //do something
}
Change your code this way:
public static class MyUserInfo implements UserInfo, UIKeyboardInteractive {
public Button goButton = (Button) MainActivity.contentView.findViewById(R.id.startSSH);
public EditText editText = (EditText) MainActivity.contentView.findViewById(R.id.commandSSH);
goButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
if (prompt) {
promptYesNo(editText.getText().toString());
}
}
});
}
Related
I have successfully implemented a custom Dialog box that appears when the user tries to leave an activity via a back button or by using onBackPressed(). They can simply cancel the dialog box or continue, and leave the activity. This function has been implemented in multiple activities, however its making my code a lot longer than it needs to be. I wanted to know how to create a util that can be referenced in different activities, without the need for the chunk of code to copy pasted multiple times. Please note that I am retrieving the dialog title and description from string.xml
This is my code:
Dialog customDialog;
Button button_one, button_two;
TextView dialog_title, dialog_description;
customDialog = new Dialog(this);
//Back button will close app
#Override
public void onBackPressed() {
customDialog.setContentView(R.layout.custom_dialog_box);
dialog_title = customDialog.findViewById(R.id.dialog_title);
dialog_title.setText(getString(R.string.leaving_activity_warning_title));
dialog_description = customDialog.findViewById(R.id.dialog_description); dialog_description.setText(getString(R.string.leaving_activity_warning_description));
button_one = customDialog.findViewById(R.id.button_one);
button_one.setText(getString(R.string.cancel));
button_two = customDialog.findViewById(R.id.button_two);
button_two.setText(getString(R.string.leave_anyway));
button_one.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
customDialog.dismiss();
}
});
button_two.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
customDialog.dismiss();
finish();
overridePendingTransition(R.anim.slide_in_left, R.anim.slide_out_right);
}
});
Objects.requireNonNull(customDialog.getWindow()).setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
customDialog.show();
}
UPDATE
Created a Java file called "DialogBoxMessage"
DialogBoxMessage Code:
class DialogBoxMessage {
private Dialog customDialog;
private TextView dialog_title, dialog_description;
private Button button_one, button_two;
//Custom Dialog Box Initialization
DialogBoxMessage(Button myButtonOne, TextView myDialogTitle, TextView myDialogDescription, Dialog myCustomDialog) {
customDialog = myCustomDialog;
button_one = myButtonOne;
button_two = myButtonOne;
dialog_title = myDialogTitle;
dialog_description = myDialogDescription;
}
void leaveActivity() {
customDialog.setContentView(R.layout.custom_dialog_box);
dialog_title = customDialog.findViewById(R.id.dialog_title);
dialog_title.setText(Resources.getSystem().getString(R.string.leaving_activity_warning_title));
dialog_description = customDialog.findViewById(R.id.dialog_description);
dialog_description.setText(Resources.getSystem().getString(R.string.leaving_activity_warning_description));
button_one = customDialog.findViewById(R.id.button_one);
button_one.setText(Resources.getSystem().getString(R.string.cancel));
button_two = customDialog.findViewById(R.id.button_two);
button_two.setText(Resources.getSystem().getString(R.string.leave_anyway));
button_one.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
customDialog.dismiss();
}
});
button_two.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
customDialog.dismiss();
}
});
Objects.requireNonNull(customDialog.getWindow()).setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
customDialog.show();
}
}
I input the following code in another activity
Other activity code:
//Reusable exit dialog message
DialogBoxMessage dialogBoxMessage;
//Back button will close app
#Override
public void onBackPressed() {
dialogBoxMessage.leaveActivity();
finish();
}
But it doesn't seem to work, I think there are a lot of issues... please help :(
I assume customDialog is a seperate class you wrote - therefore i would suggest you put main information like contentview, title, message or type in the constructor when you initialize ur Dialog.
For your onClick Method I suggest you create an Interface to handle Button Clicks in your
customDialog class.
This could be implemented as a static method in a utilities class. The method would require 'this' as a parameter, which contains the activity context. The method should return the result of the button press. The activity can use this response to determine if finish() should be called or not.
UPDATE
I had suggested a simple static method, but you've gone down the object-oriented route. That's fine.
However, your constructor requires passing in several views, which wouldn't appear to achieve the code efficiency you are after.
Your constructor should just require the Activity context; everything else is encapsulated in your new class.
In each Activity's onBackPressed method you will need to create the object with
dialogBoxMessage = new DialogBoxMessage(this);
before you can call any of that object's methods.
At first my main problem was at how to call a method from the same class, even tough I think I found a way to do this, it's not working as I expected, and I would like to know what would be the best approach to my case.
This is the code I'm working on:
public class EscolhaAtendimento extends AppCompatActivity {
private ViewPager mSlideViewPager;
private LinearLayout mDotLayout;
String TAG = "TasksSample";
private TextView[] mDots;
private SliderAdapter sliderAdapter;
Dialog myDialog;
#Override
public void onCreate (Bundle SavedInstanceState){
super.onCreate(SavedInstanceState);
setContentView(R.layout.escolha_atendimento);
mSlideViewPager = findViewById(R.id.slideViewPager);
mDotLayout = findViewById(R.id.dotsLayout);
sliderAdapter = new SliderAdapter(this);
mSlideViewPager.setAdapter(sliderAdapter);
addDotsIndicator(0);
mSlideViewPager.addOnPageChangeListener(viewListener);
myDialog = new Dialog(this);
}
public void addDotsIndicator(int position){
mDots = new TextView[8];
mDotLayout.removeAllViews();
for (int i= 0; i < mDots.length; i++){
mDots[i] = new TextView(this);
mDots[i].setText(Html.fromHtml("•"));
mDots[i].setTextSize(35);
mDots[i].setTextColor(getResources().getColor(R.color.colorTransparentWhite));
mDotLayout.addView(mDots[i]);
}
if (mDots.length > 0){
mDots[position].setTextColor(getResources().getColor(R.color.colorWhite));
}
}
ViewPager.OnPageChangeListener viewListener = new ViewPager.OnPageChangeListener(){
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected (int i) {
switch (i) {
case 0: {
myDialog.show();
}
addDotsIndicator(i);
}
}
#Override
public void onPageScrollStateChanged(int state) {
}
};
public void ShowPopup(View v) {
TextView txtclose;
//Button btnFollow;
myDialog.setContentView(R.layout.pop_upfinal);
txtclose = myDialog.findViewById(R.id.txtclose);
txtclose.setText("X");
//btnFollow = (Button) myDialog.findViewById(R.id.btnfollow);
txtclose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myDialog.dismiss();
}
});
myDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
myDialog.show();
}
}
This class is an activity that on user swipe, the text and image from the buttons will change, even though their IDs will stay the same. (That's controlled by another class, it's working well).
Now, I wanted the image button on the activity do something different depending on which page is selected, and that's why there is a initial switch on the onPageSelected method, inside the Page change listener. The image button in the layout has the android:onClick="ShowPopup" tag, and I guess that also complicates things for me, if I wanted it to do something different in that same activity? Also, calling it that way on the switch, every time I change pages, and go back to the first one the popup window will open, since my call is explicit there. (As I said, even tough I found a way to somehow call my method, or at least it's result, it's not working as I expected).
Edit
I tried then changing it like this, so that the button wouldn't rely on the android:onClick="ShowPopup" Tag, and also wouldn't need to call a void method directly on the switch:
Added
public ImageButton popupchoice;
And also this to onCreate method:
popupchoice = this.findViewById(R.id.imgslide1);
Inside the switch I called it like this to get the button ID:
popupchoice.setOnClickListener(image1);
And set the View.OnClickListener like this:
View.OnClickListener image1 = new View.OnClickListener() {
public void onClick(View v) {
TextView txtclose;
//Button btnFollow;
myDialog.setContentView(R.layout.pop_upfinal);
txtclose = myDialog.findViewById(R.id.txtclose);
txtclose.setText("X");
//btnFollow = (Button) myDialog.findViewById(R.id.btnfollow);
txtclose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myDialog.dismiss();
}
});
myDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
myDialog.show();
}
};
But that returns me:
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference at .EscolhaAtendimento$1.onPageSelected(EscolhaAtendimento.java:81) Line 81 is the one inside the switch with the popupchoice.setOnClickListener(image1).
This error happens on page change, when coming back to the first Page, and also the button click won't work anymore.
I think you can use
EscolhaAtendimento.this.ShowPopup from inside your switch.
I have been looking for my question on Google and inside the forum but I cannot an answer so far. I am using android studio to code an app in Java
The thing is : inside a class, I have overrided the OnClick() method because I have to implement a lot of views.
Now I want to call a function just before OnClick() is called.
What I mean is, for instance, if the user taps on a button, before OnClick() is called I want one of my methods to be called.
Does anyone know how to do this ?
Thank you in advance
I want to call a function just before OnClick() is called
You can use a logic inside onClick() like,
if(userhaspermission())//your method to check if the user has permission
{
//your onclick operation code
}
Make your checking permission method with return type as boolean
Implement your custom OnClickListener as follows
public abstract class MyOnClickListener implements OnClickListener {
#Override
public void onClick(View v) {
//Do common action
if(condidtionSatisfied){
performClick(v);
}
}
public abstract void performClick(View v);
}
Set onClickListener to any component as follows:
button.setOnClickListener(new MyOnClickListener() {
#Override
public void performClick(View v) {
//Execute post click action
}
});
This will ensure your common code will be called for all the views and it would be much cleaner approach.
Override the onClick() method and write your first logic which you want.
Write your own Listener like Sagar said
This logic is quite similar to Sagar's Answers.
Write abstract class as given below
public abstract class OnClick implements View.OnClickListener {
public void beforeClick(View v) {
}
#Override
public void onClick(View v) {
beforeClick(v);
performClick(v);
afterClick(v);
}
public void performClick(View v) {
}
public void afterClick(View v) {
}
}
NOTE : See in above code it implements View.OnClickListener, so this logic will works for views which extends View super class. If you want above logic for object's which needs Dialog interface onClick then you need to modify it for DialogInterface.OnClickListener.
So you can use above logic as below
//Let say you need it for button with id button
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new OnClick() {
#Override
public void beforeClick(View v) {
Toast.makeText(MainActivity.this, "Before", Toast.LENGTH_SHORT).show();
}
#Override
public void performClick(View v) {
Toast.makeText(MainActivity.this, "Click", Toast.LENGTH_SHORT).show();
}
#Override
public void afterClick(View v) {
Toast.makeText(MainActivity.this, "After", Toast.LENGTH_SHORT).show();
}
});
I have trouble understanding this code. I get that findViewById will get the button widget and then it'll cast it. Then, it's going to use the button to call the setOnClickListener method. However, I don't know what is that argument being passed into the setOnClickListener and I have never seen code like that before. How is it that it creates a new object but is able to create a method of its own within another method's argument? Would be great if someone could explain that. Also, what type of object is the setOnClickListener method taking in?
btn = (Button)findViewById(R.id.firstButton);
btn.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
tv.setText(months[rand.nextInt(12)]);
tv.setTextColor(Color.rgb(rand.nextInt(255)+1, rand.nextInt(255)+1, rand.nextInt(255)+1));
}
});
It works like this. View.OnClickListenere is defined -
public interface OnClickListener {
void onClick(View v);
}
As far as we know you cannot instantiate an object OnClickListener, as it doesn't have a method implemented. So there are two ways you can go by - you can implement this interface which will override onClick method like this:
public class MyListener implements View.OnClickListener {
#Override
public void onClick (View v) {
// your code here;
}
}
But it's tedious to do it each time as you want to set a click listener. So in order to avoid this you can provide the implementation for the method on spot, just like in an example you gave.
setOnClickListener takes View.OnClickListener as its parameter.
This is the best way to implement Onclicklistener for many buttons in a row
implement View.onclicklistener.
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
This is a button in the MainActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bt_submit = (Button) findViewById(R.id.submit);
bt_submit.setOnClickListener(this);
}
This is an override method
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.submit:
//action
break;
case R.id.secondbutton:
//action
break;
}
}
That what manual says about setOnClickListener method is:
public void setOnClickListener (View.OnClickListener l)
Added in API level 1 Register a callback to be invoked when this view
is clicked. If this view is not clickable, it becomes clickable.
Parameters
l View.OnClickListener: The callback that will run
And normally you have to use it like this
public class ExampleActivity extends Activity implements OnClickListener {
protected void onCreate(Bundle savedValues) {
...
Button button = (Button)findViewById(R.id.corky);
button.setOnClickListener(this);
}
// Implement the OnClickListener callback
public void onClick(View v) {
// do something when the button is clicked
}
...
}
Take a look at this lesson as well Building a Simple Calculator using Android Studio.
its an implementation of anonymouse class object creation to give ease of writing less code and to save time
It works by same principle of anonymous inner class where we can instantiate an interface without actually defining a class :
Ref: https://www.geeksforgeeks.org/anonymous-inner-class-java/
I have two classes. I am trying to change a boolean value depending on if the user clicks a checkbox. Then, depending on whether that value is true/false (whether the checkbox was checked or not), I want to display specific text in a textview. Here is the MainActivity class:
public class BoiseActivity extends ActionBarActivity {
CheckBox cb;
public boolean isTrue;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_boise);
cb = (CheckBox) findViewById(R.id.boiseCheckBox);
cb.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
isTrue = true;
}
});
public boolean isTrue() {
if (isTrue == true) {
return true;
}
return false;
}
Here is the new Activity that is opened once the user presses the "submit" button:
public class BoiseResults extends BoiseActivity {
TextView TV;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_boise_results);
TV = (TextView) findViewById(R.id.textView1);
if (isTrue() == true) {
TV.setText("checkbox checked");
}
}
The boolean value is never changed in the BoiseActivity class onCreate-> onClick method. Can anyone see what is wrong here? Thanks
Apart from what has been said on you picking up a book on OOP (come on guys, everybody started somewhere):
The isTrue instance variable of your BoiseActivity will be present in it's child class BoiseResults because it (BoiseResults) inherits isTrue from BoiseActivity, but it's value will not be set and therefore interpreted als false, as Vikram pointed out.
What to do to straighten this out:
use onCheckedChangeListener for CheckBox
pass the boolean ('if the checkbox has been ticked') to your second Activity via the Intent you are starting it with, links on how to do this have been given in comments
ask yourself if BoiseResults really needs to subclass BoiseActivity (I do not think it does, it is just another Activity)
get rid of all the boolean mayhem you created with the isTrue() method returning the value of your isTrue variable
Rename BoiseResults to BoiseResultsActivity for clarity
Your onCreate{...} method for BoiseActivity doesn't seem to be a closed method.
You don't need the isTrue() method as it is really only returning the value of isTrue and isTrue is already a public instance variable. Regardless of that detail, you should look into (Explicit) Intents for passing data between activities: http://www.vogella.com/tutorials/AndroidIntent/article.html
Consider the use of the OnCheckedChangeListener;
checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
// DO SOMETHING HERE WHEN CHECKED/UNCHECKED
}
});
You can then check whether it is checked or not using the checkBox.isChecked() method.
It's also best for you to avoid performing unnecessary checks on a boolean value like;
public boolean isTrue() {
if (isTrue == true) {
return true;
}
return false;
}
The following would achieve the same;
public boolean isTrue(){
return isTrue;
}
With regards to your BoiseResults Activity, take a look at Intents if you are going to be changing from the BoiseActivity Activity to the BoiseResults Activity from your submit and need to pass data to BoiseResults.