So I have this code :
back --; //when it starts doing that back's value is 5
if (back == 0) {
back_button.setClickable(false);
}
if (back != 0) {
back_button.setClickable(true);
}
My back_button never sets itself to Clickable(true) after it set to Clickable(false), even when back wasn't equal to 0 caused by another button(back++;).
Why isn't my back_button onClick realizing that?
Actually view.setClickable() doesn't works at runtime that's why your toggling of back_button doesn't works at runtime .
Solution: Use view.setEnabled(boolean enabled) for your back_button.
Refer to :setEnabled() vs setClickable(), what is the difference?
Related
I have a view. The view might become visible at some time in the future. When this view is visible I want to call a method. How to do this?
val editText = findViewById<EditText>(R.id.editText)
// editText might become invisible in some time in future
// and in some in future it might visible
if(editText.isVisible(){
// code to be executed
}
Code for View.isVisible() :
fun View.isVisible() = this.visibility == View.VISIBLE // check if view is visible
Is there anything like View.setOnClickListener which could be applied and triggered when the view is visible-
editText.setOnClickListener { view ->
}
click listener is callback when the view is being clicked. it has no concern with its visibility. There is no method like isVisible(). to check Visibility
if(yourView.getVisiblity()==View.VISIBLE){ //your task}
for kotlin:
if(youView.visibility==View.VISIBLE){//your task}
I might initialize a variable int status of visibility and set it to 0 with the view invisible.
Now I would create a function instead directly setting the visibility of the view.
For example a function named onVisibilityChanged();
In that function add the set visibility code followed by setting the int to 0 or 1 as per the visibility an if-else block.
If you just set the view to visible, set the int to 1.
The reason for adding if-else block is to configure your actions based on the visibility status.
So that gives you the freedom to do whatever you want bases on the visibility.
Make sure you add this code in such a way that it is executed anytime you want.
Use the performClick() function to click any button or any other view.
I hope you understand. Or comment any query. I would have posted the code for the same but it looks like you are using Kotlin. So I'll try to post it in Kotlin if possible.
The main intention of doing such a thing is when the value of int changes, the app knows what to do and also knows that visibility has changed.
Just call the function wherever you want. It will be easy.
So this is what I am trying to do:
int visibilityStatus;
textview = findViewById(R.id.textview);
getInitialVisibility();
funcOnVisibilityChange();
}
private void getCurrentVisibility() {
if (textview.getVisibility() == View.VISIBLE) {
visibilityStatus = 1;
} else {
visibilityStatus = 0;
}
}
private void funcOnVisibilityChange() {
//Now change the visibility in thia function
textview.setVisibility(View.VISIBLE);
int currentVisibilityStatus;
if (textview.getVisibility() == View.VISIBLE) {
currentVisibilityStatus = 1;
} else {
currentVisibilityStatus = 0;
}
if (visibilityStatus != currentVisibilityStatus) {
//Visibility status has changed. Do your task
else {
//visibility status not changed
}
}
}
So all that we are doing is getting visibility of the view when the app is started and when you somehow change its visibility. Here in the example, I've directly changed the visibility. So wherever you know that visibility is going to change just put the funcOnVisibilityChange() and it will do your job... hope it helps. Let me know if you need more clarification.
Problem is shown in picture , please go light on me , i'm not that experienced in android
but trying my best to do so...
Tried this in my Main.java:
package com.faisal.my_calculator;
import android.content.SharedPreferences;
// all remaining imports here.
public class Main extends ActionBarActivity implements View.OnClickListener {
// Buttons
Button btnOne, btnTwo, btnThree, btnFour, btnFive, btnSix, btnSeven,..., btnTan, btnExit;
case R.id.three:
if (y != 0) {
y = 0;
etDisp.setText("");
}
str = str.append(btnThree.getText());
etDisp.setText(str);
break;
.
.
.
.
case R.id.add:
if (TextUtils.isEmpty(etDisp.getText().toString())) {
return;
}
operator = "+";
if (x == 0) {
x = Double.parseDouble(etDisp.getText().toString());
etDisp.setText("");
} else if (y != 0) {
y = 0;
etDisp.setText("");
} else {
y = Double.parseDouble(etDisp.getText().toString());
etDisp.setText("");
x = x + y;
etDisp.setText(Double.toString(x));
}
break;
I tried for:
appconfigchanges solution = it is not even in my AndroidManifest.xml,
Now to the layout part : In emulator all things are fully spaced on screen but when i run app below(2nd screen comes as a result not like on Emulator which i worked hard and adjusted its full screen) more when i run it on my LG_OG in landscape only starting three rows come on the screen o.O ....? need help here as well ...!
If anything needed more i will post it....!(now almost all code i have posted) Again, be patient to your brother :)
Please don't handle any exception if it is not realy needed to handle. Remove your try catch while initializing the UI and setting clicklistener to buttons and check where your code is failing.
Second you don't need to handle UI changes on orientation change as it will be handled by android itself. This will be done like -on orientation change your activity will be recreated and your oncreate will be again called so set layout and initialize all the UI element in oncrete itself and remove unnecessary code from onConfigurationChanged method.
Always check for the null value in suspected code
if(btnDiv == null)
{
//condition
}
Add following code just before try
if(btnDiv == null)
{
throw new NullPointerException("Button are not initialized");
}
if exception is thrown then your buttons are not initialized.
Yes , what a pain it was , as debugger is the best friend of programmer , i debugged it and it directly took me to the buttons which i didn't make in Landscape but were present in portrait so Eclipse doesn't like this and was causing my different buttons to stay idle but after putting those buttons in landscape xml now everything works all awesome...!
Now just layout make-up is remained as two buttons are running here and there when i run it.! :p
Thanks guys for your time...!
I have one activity and here i have 100 buttons, i want that when i press Button 1 then press another Button the Button 1 should get unpressed.
i know i can make this with
if(Button1.isPressed()) {
Button2.setPressed(false);
Button3.setPressed(false);
Button4.setPressed(false);
Button5.setPressed(false);
Button6.setPressed(false);
Button7.setPressed(false);
Button8.setPressed(false);
......................... }
else { do nothing }
.... BUT!
it's too much code
Coders will kill me or will just laugh on me.
any ideas?
maybe there is a way to unpress the all buttons from the activity?
Not the prettiest solution ever, but you could make an OnClickListener like this:
View.OnClickListener listener = new View.OnClickListener() {
public void onClick(View v) {
ViewGroup parent = (ViewGroup) v.getParent();
for (int i = 0; i < parent.getChildCount(); i++) {
View current = parent.getChildAt(i);
if (current != v && current instanceof Button) {
((Button) current).setPressed(false);
}
}
((Button) v).setPressed(true);
}
}
and attach it to all of your buttons.
Then, whenever a button is clicked, it will iterate over all views that are in the same layout (or actually, view group) as the clicked button, and, for any of those views that are buttons except for the clicked button, it will call setPressed(false).
Note that this only works out of the box if all the buttons are in the same layout. If they are in nested layouts, you will have to adapt it a little.
Off topic: What do you need 100 buttons for? That's a lot of buttons. You may want to redesign your user interface
Ok so instead of looping through all the buttons on over and over again when one button is pressed, you can just store a variable which stores the button number of the button that was last pressed. Now, when the second button is pressed, disable the button that was pressed earlier, you get its index from the saved variable, enable the button that was pressed and store its index in the variable.
Heres an example pseudo code to give you and idea:
int buttonLastPressed = 0;
void onButtonClick(Button buttonPressed){
if(buttonLastPressed != 0){
disableButton(buttonLastPressed);
enableButton(buttonPressed);
buttonLastPressed = buttonPressed.getIndex()
}
}
Saves you from looping through each and every button to disable it.
Define id of button 1 to 100
When press button occurs save it's id in some member variable like previous_pressed
Before updating a previous_pressed value find and unpress previous pressed button like this
Button previous_pressed_button = (Button) findViewById(previous_pressed);
Now you have the previous pressed button, So upress it or whatever.
I'm Making simple app for project
That App contains lot of text so i want,
"when a button is pressed, text should Change in same layout"
like PowerPoint slide.
I want change text only not scroll.
Now i made my app, have lots of Windows or Layouts.
It is not looking good, too much layout in simple app so please help me .
Thanks in advance
Doing this is very easy, I will quickly walk you through the Algorithm:
Set a class level variable called as FLAG initialize it to 1.
Let us assume that FLAG = 1 will represent the first slide. FLAG = 2 the second slide and so on.
Now in your button click you can use a switch case or an if else condition, based on the value of the flag display the relevant text in textview.
Once done, increment the flag, for the next set of sentence(s).
Class level:
int FLAG = 1;
onCreate:
Initialize your textView:
TextView mtv = (TextView)findViewById(R.id.yourid);
Set a button click listener:
private View.OnClickListener slides = new View.OnClickListener() {
#Override
public void onClick(View v) {
if(FLAG ==1)
mtv.setText("First slide");
else if(FLAG ==2)
mtv.setText("Second Slide");
//and so on...
FLAG = FLAG+1;//increment flag
}
};
I am implementing a quiz and here am having a method for my button as
public void playquiz(final int arrayIndex) {
setContentView(R.layout.quiz);
next = (Button) findViewById(R.id.nextBtn);
next.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if (arrayIndex == TourDescription.currentTour.getTriviaArray().size()) {
int totalpoints = correctAnswerCount*10;
Intent scoreintent = new Intent(TriviaQuiz.this,ScoreBoard.class);
startActivity(scoreintent);
}
else
{
playquiz(arrayIndex+1);
}
}
What I am trying to do is, inside the method I am loading another layout and assigning an onclick for the button in that layout.
Now my problem is, the arrayIndex which I get initially, I have to update this on click of the next button and based on this I have some other conditions to check.
But if I do like playquiz(arrayIndex+1);, it asks me to declare the arrayIndex as final, why is this?
And even then it is not behaving in the exact way as it supposed to be.
The if (arrayIndex == TourDescription.currentTour.getTriviaArray().size()) inside onClick is not happening
Any suggestion?
But if I do like playquiz(arrayIndex+1);, it asks me to declare the arrayIndex as final, why is this?
This is because you are using it inside another class - OnClickListener() and arrayIndex is probably a local variable. There are two ways to getting around this.
declare it in the global declaration area.
your class should implement OnClickListener and override OnClick method within which you must include your codes.
The if (arrayIndex == TourDescription.currentTour.getTriviaArray().size()) inside onClick is not happening
I am not sure if you have provided enough code here but by just looking at it i cannot see arrayIndex being incremented and hence it will never get to TourDescription.currentTour.getTriviaArray().size(). You need to increment arrayIndex
it in the else clause.