I programmatically am creating buttons as depending on certain factors their will either be 3 or 4 buttons.
In some instances I would like to create all of the buttons but disable them all. At the moment the problem I have is that I cannot access the buttons from outside of this loop
if (4val != null && 4val.length() > 0){
Button b4 = new Button(this);
b4.setText(answer4val);
b4.setTextSize(18);
layout.addView(b4, layoutParams);
b4.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
reason(4);
}
});
}
I would like to disable / enable all of the buttons outside of these if statements. Is this possible?
Declare them in a wider scopre (maybe as class members):
// in the class scope
Button b4 = null;
// in the method scope
if (4val != null && 4val.length() > 0){
b4 = new Button(this);
b4.setText(answer4val);
b4.setTextSize(18);
layout.addView(b4, layoutParams);
b4.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
reason(4);
}
});
}
Don't create the buttons in that loop. Make the buttons fields for the class and you can access them throughout the class. Then just initialize them in that loop.
If you only need them in one method you can make them local to the method rather than fields for the class.
Sure you can save the Buttons in an List and do stuff on them later on
ArrayList<Button> buttons = new ArrayList<Button>();
if (4val != null && 4val.length() > 0){
Button b4 = new Button(this);
b4.setText(answer4val);
b4.setTextSize(18);
layout.addView(b4, layoutParams);
b4.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
reason(4);
}
});
buttons.add(b4);
}
foreach(Button b : buttons) {
b.setEnable(false);
}
If you want to disable the Buttons you have two option methods depending of how you want to disable them:
button.setClickable(false);
button.setVisibility(int visibility);
the first will make the setOnCLickListener useless
The second will set the parameter Visibility to "visible", "invisible", or "gone"
to disable them outside the loop also you have to initialize them before, and add
b4.setId();
before adding it to the view
Related
I recently started learning to code with Android Studio. And I wanted a button when clicked to toggle between two images, but I cant seem to compare them.
I tried comparing them but it doesn't think they are the same.
ImageView dog = new ImageView(this);
dog.setImageResource(R.drawable.dog);
ImageView goofy = new ImageView(this);
goofy.setImageResource(R.drawable.goofydog);
if(img==dog)
{
img.setImageResource(R.drawable.goofydog);
}
else{
img.setImageResource(R.drawable.dog);
}
You can only compare primitive types (String, Int, Double...) in If statements, if you compare object it will compare the instance of each object which in your case is different.
If you want to toggle between two images based on what your imageView is actually displaying you should compare the Int resources that is displayed like that :
Image img = findViewById(R.id.image_view);
Button button = findViewById(R.id.button);
String current = "";
button.setOnClickListener(new View.OnClickListener( v-> {
#Override
void onClick(View v){
if (img.getDrawable() == ResourcesCompat.getDrawable(getResources(),
R.drawable.dog, null)) {
img.setImageResource(R.drawable.goofyDog);
} else {
img.setImageResource(R.drawable.dog);
}
}
}));
If you want to learn more about using objects in If statement, you can learn more about instance of object here : https://en.wikipedia.org/wiki/Instance_(computer_science)
You can't compare images the way you are doing. If you want to toggle between two images using a button, you can simple do:
Image img = findViewById(R.id.image_view);
Button button = findViewById(R.id.button);
String current = "";
button.setOnClickListener(new View.OnClickListener( v-> {
#Override
void onClick(View v){
if (current = "Dog") {
img.setImageResource(R.drawable.dog);
current = "Dog";
} else {
img.setImageResource(R.drawable.goofydog);
current = "Goofy";
}
}
}));
I know that was already asked but it is outdated:
I have 2 buttons that represent 2 choices and if one is selected the background color gets changed to yellow. But if i want to change the choice i need to somehow reset the button:
I already try to set it back but some old design comes out. Can you provide me the id of the modern button style? And show me how to implement it?
int myChoice;
if (view == findViewById(R.id.choice1)){
myChoice = 1;
choice1.setBackgroundColor(getResources().getColor(R.color.highlightButton));
choice2.setBackgroundResource(android.R.drawable.btn_default);
}
else if (view == findViewById(R.id.choice2)){
myChoice = 2;
choice2.setBackgroundColor(getResources().getColor(R.color.highlightButton));
choice1.setBackgroundResource(android.R.drawable.btn_default);
}
}
Use Tags with getBackground(). This will assure you are always setting back to original.
Add following in beginning of function
if (v.getTag() == null)
v.setTag(v.getBackground());
Then instead of setBackgroundResource, use
v.setBackground(v.getTag());
Starting from here, you can store the default color of the button into a Drawable and grab the selection color (Yellow in your case) into anther Drawable, then toggle background colors of buttons with these Drawable variables
please check below demo
public class MainActivity extends AppCompatActivity {
private Drawable mDefaultButtonColor;
private Drawable mSelectedButtonColor;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Button btn1 = findViewById(R.id.btn1);
final Button btn2 = findViewById(R.id.btn2);
mDefaultButtonColor = (btn1.getBackground());
mSelectedButtonColor = ContextCompat.getDrawable(this, R.color.buttonSelected);
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
toggleButton(btn1, true);
toggleButton(btn2, false);
}
});
btn2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
toggleButton(btn1, false);
toggleButton(btn2, true);
}
});
}
private void toggleButton(Button button, boolean isSelected) {
button.setBackground(isSelected ? mSelectedButtonColor : mDefaultButtonColor);
}
}
The title may sound confusing I know, I 'm adding a view everytime I click on a button, composed by a textview and a button. I'm setting every added view an ID with simply view.setID(++i) and every added button (inside the views) an ID simply with button.setID(++n), n starting at 1000, since I won't have more than 1000 added views.
Here's what I got:
public class MainActivity extends AppCompatActivity {
GridLayout gridLayout;
static int i;
static int n = 1000;
private Button theButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
gridLayout = (GridLayout)findViewById(R.id.gamehistory);
Button b = (Button)findViewById(R.id.Button01);
b.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
theButton = new Button(MainActivity.this);
TextView theText = new TextView(MainActivity.this);
theText.setGravity(Gravity.CENTER_HORIZONTAL);
LinearLayout theLayout = new LinearLayout(MainActivity.this);
theLayout.setOrientation(LinearLayout.VERTICAL);
theLayout.setBackgroundColor(Color.parseColor("#8BAAC3"));
theLayout.setId(++i);
theButton.setId(++n);
theButton.setText(theButton.getId() + "");
theText.setText(theLayout.getId() + "");
theLayout.addView(theButton);
theLayout.addView(theText);
gridLayout.addView(theLayout);
GridLayout.LayoutParams lp = (GridLayout.LayoutParams) theLayout.getLayoutParams();
lp.setMargins(10, 10, 10, 10);
}
});
What I need is when I click on a button that was created, the correspondent view is destroyed, and the next views take one step back feeling the gap in the parent which is a GridLayout
Add this where you are adding views to GridLayout -
theLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
gridLayout.removeView(theLayout);
}
});
theButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
gridLayout.removeView(theLayout);
}
});
For this , you need to make theLayout final
final LinearLayout theLayout = new LinearLayout(LauncherActivity.this);
The simplest method would be.
View v = gridLayout.findViewById(<some id>);
gridLayout.removeView(v);
However it seems like you may want to consider using a RecyclerView. You can add/remove items from the Adapter and the views will be updated for you.
EDIT
When using A RecyclerView you have to specify two essential components.
RecyclerAdapter - This converts data into views (rows, cards, cells, ect.)
LayoutManger - Most common are LinearLayoutManger and GridLayoutManager which define how the views from the adapter are presented out in relation to one another, and handle scrolling.
There are a few more option additions you can can use if needed.
ItemDecoration - define backgrounds, or overlays for cells. (E.G. draw a gray background for every other view in a list)
ItemTouchHelper - does most of the heavy lifting for swipe (e.g. swipe to delete) and drag (e.g. drag to re-arrange) operations.
I would highly suggest getting familiar with the RecyclerView it should be your goto component when you need to display a list of items on the screen.
I'm looking to call a few buttons but seem to be getting a NULL when trying to findbyviewid. When I activate this activity, it crashes.
//CREATE INSTANCE OF GLOBAL - QUESTIONS/ANSWERS
Global global = Global.getInstance();
//CURRENT QUESTION
static int QQ = 0;
//CORRECT ANSWER COUNT
static int correctAnswers = 0;
//CREATE VARIABLE FOR TEXTVIEW/QUESTION
TextView textQuestion = (TextView) findViewById(R.id.textQuestion);
//CREATE VARIABLES FOR BUTTONS/ANSWERS
Button buttonOne = (Button) findViewById(R.id.answerOne);
Button buttonTwo = (Button) findViewById(R.id.answerTwo);
Button buttonThree = (Button) findViewById(R.id.answerThree);
Button buttonFour = (Button) findViewById(R.id.answerFour);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_practice_questions);
setButtons();
buttonOne.setOnClickListener(this);
buttonTwo.setOnClickListener(this);
buttonThree.setOnClickListener(this);
buttonFour.setOnClickListener(this);
}
public void setButtons()
{
//SET QUESTION STRING TO TEXTVIEW
textQuestion.setText(global.getQ(QQ));
//SET ANSWER STRINGS TO BUTTONS' TEXT
buttonOne.setText(global.getA(QQ, 0));
buttonTwo.setText(global.getA(QQ, 1));
buttonThree.setText(global.getA(QQ, 2));
buttonFour.setText(global.getA(QQ, 3));
}
#Override
public void onClick(View v)
{
switch(v.getId())
{
case R.id.answerOne:
checkAnswer(0, buttonOne);
break;
case R.id.answerTwo:
checkAnswer(1, buttonTwo);
break;
case R.id.answerThree:
checkAnswer(2, buttonThree);
break;
case R.id.answerFour:
checkAnswer(3, buttonFour);
break;
default:
break;
}
}
public void checkAnswer(int a, Button b){
//IF AN INCORRECT ANSWER WAS CHOSEN, MAKE THE BACKGROUND RED
if(!global.getS(QQ, a))
{
b.setBackgroundColor(Color.RED);
}
else
{
//INCREMENT THE CORRECT ANSWER COUNTER
correctAnswers++;
}
//SET BACKGROUND OF CORRECT BUTTON TO GREEN
if(global.getS(QQ, 0))
{
buttonOne.setBackgroundColor(Color.GREEN);
}
else if(global.getS(QQ, 1))
{
buttonTwo.setBackgroundColor(Color.GREEN);
}
else if(global.getS(QQ, 2))
{
buttonThree.setBackgroundColor(Color.GREEN);
}
else if(global.getS(QQ, 3))
{
buttonFour.setBackgroundColor(Color.GREEN);
}
else
{
//IF NO ANSWER IS CORRECT, SET ALL TO BLUE
buttonOne.setBackgroundColor(Color.BLUE);
buttonTwo.setBackgroundColor(Color.BLUE);
buttonThree.setBackgroundColor(Color.BLUE);
buttonFour.setBackgroundColor(Color.BLUE);
}
//MOVE TO NEXT QUESTION
}
I have 4 buttons in the XML file and want to be able to set the text to them, as well as run a listener for the set of buttons (answers to a question). When one of the buttons is clicked, it should determine if it's the correct answer by pulling the status (true/false) and highlighting it red if it's incorrect. It then highlights the correct answer green.
At least, some of this is in theory and I'm trying to test it out, but I can't start the activity without crashing.
I'm not 100% sure but I think you can't do the findViewById at the instance constructions. You need to those inside onCreate() (after you called setContentView)
Just how i said in comment, you should initialize it in OnCreate method, cause you set view layout for activity here. And before you do it, all findViewById returns null.
So, here your code:
Button buttonOne;
Button buttonTwo;
Button buttonThree;
Button buttonFour;
TextView textQuestion;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_practice_questions);
buttonOne = (Button) findViewById(R.id.answerOne);
buttonTwo = (Button) findViewById(R.id.answerTwo);
buttonThree = (Button) findViewById(R.id.answerThree);
buttonFour = (Button) findViewById(R.id.answerFour);
textQuestion = (TextView) findViewById(R.id.textQuestion);
[...]
}
I'm trying to implement a ExpandableListView in java that when click deployment space elements inside, not the typical wish list allows choosing an option. What I try to do is basically something like this
One can see that the spinner "wraps" to have items and does not have a list, Would I could help a little?
You can use ExpandableListView .. check this tutorial http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/
You can easily create one on your own. Just create a Button and assign a Layout below. When the Button gets clicked set the View of you Layout to Visible and otherwise to Invisible. Additionaly you can set up and down arrows to the right of your Button.
final Button button = (Button) findViewById(R.id.button);
final LinearLayout linearLayout= (LinearLayout) findViewById(R.id.linearLayout);
linearLayout.setVisibility(View.GONE);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (linearLayout.getVisibility() == View.VISIBLE) {
linearLayout.setVisibility(View.GONE);
button.setCompoundDrawablesWithIntrinsicBounds(0, 0, R.drawable.expand, 0);
} else {
linearLayout.setVisibility(View.VISIBLE);
button.setCompoundDrawablesWithIntrinsicBounds(0, 0, R.drawable.collapse, 0);
}
}
});