Develop Reference

switch case using variables, repetitive code

I have 50 Buttons. I use the switch statement as shown below. Each case has the same On-Click code. But I make many changes to the code for each Button, and it's really tedious work and very repetitive to change the code the same way 50 times. My code currently looks like this:
public void ButtonOnClick(View v) {
switch (v.getId()) {
case button1:
if(button_list.get(1).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(1).getText().toString());
is_clicked= (String)button_list.get(1).getTag();
if ("0".equals(is_clicked)){
button_list.get(1).setBackgroundResource(R.drawable.button_pressed);
button_list.get(1).setTag("1");
}else{
button_list.get(1).setBackgroundResource(R.drawable.button_normal);
button_list.get(1).setTag("0");
}
break;
case button2:
if(button_list.get(2).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(2).getText().toString());
is_clicked= (String)button_list.get(2).getTag();
if ("0".equals(is_clicked)){
button_list.get(2).setBackgroundResource(R.drawable.button_pressed);
button_list.get(2).setTag("1");
}else{
button_list.get(2).setBackgroundResource(R.drawable.button_normal);
button_list.get(2).setTag("0");
}
break;
case button3:
if(button_list.get(3).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(3).getText().toString());
is_clicked= (String)button_list.get(3).getTag();
if ("0".equals(is_clicked)){
button_list.get(3).setBackgroundResource(R.drawable.button_pressed);
button_list.get(3).setTag("1");
}else{
button_list.get(3).setBackgroundResource(R.drawable.button_normal);
button_list.get(3).setTag("0");
}
break;
case button4:
if(button_list.get(4).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(4).getText().toString());
is_clicked= (String)button_list.get(4).getTag();
if ("0".equals(is_clicked)){
button_list.get(4).setBackgroundResource(R.drawable.button_pressed);
button_list.get(4).setTag("1");
}else{
button_list.get(4).setBackgroundResource(R.drawable.button_normal);
button_list.get(4).setTag("0");
}
break;
case button5:
if(button_list.get(5).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(5).getText().toString());
is_clicked= (String)button_list.get(5).getTag();
if ("0".equals(is_clicked)){
button_list.get(5).setBackgroundResource(R.drawable.button_pressed);
button_list.get(5).setTag("1");
}else{
button_list.get(5).setBackgroundResource(R.drawable.button_normal);
button_list.get(5).setTag("0");
}
break;
case button6:
if(button_list.get(6).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(6).getText().toString());
is_clicked= (String)button_list.get(6).getTag();
if ("0".equals(is_clicked)){
button_list.get(6).setBackgroundResource(R.drawable.button_pressed);
button_list.get(6).setTag("1");
}else{
button_list.get(6).setBackgroundResource(R.drawable.button_normal);
button_list.get(6).setTag("0");
}
break;
case button7:
if(button_list.get(7).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(7).getText().toString());
is_clicked= (String)button_list.get(7).getTag();
if ("0".equals(is_clicked)){
button_list.get(7).setBackgroundResource(R.drawable.button_pressed);
button_list.get(7).setTag("1");
}else{
button_list.get(7).setBackgroundResource(R.drawable.button_normal);
button_list.get(7).setTag("0");
}
break;
case button8:
if(button_list.get(8).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(8).getText().toString());
is_clicked= (String)button_list.get(8).getTag();
if ("0".equals(is_clicked)){
button_list.get(8).setBackgroundResource(R.drawable.button_pressed);
button_list.get(8).setTag("1");
}else{
button_list.get(8).setBackgroundResource(R.drawable.button_normal);
button_list.get(8).setTag("0");
}
break;
case button9:
if(button_list.get(9).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(9).getText().toString());
is_clicked= (String)button_list.get(9).getTag();
if ("0".equals(is_clicked)){
button_list.get(9).setBackgroundResource(R.drawable.button_pressed);
button_list.get(9).setTag("1");
}else{
button_list.get(9).setBackgroundResource(R.drawable.button_normal);
button_list.get(9).setTag("0");
}
break;
case button10:
if(button_list.get(10).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(10).getText().toString());
is_clicked= (String)button_list.get(10).getTag();
if ("0".equals(is_clicked)){
button_list.get(10).setBackgroundResource(R.drawable.button_pressed);
button_list.get(10).setTag("1");
}else{
button_list.get(10).setBackgroundResource(R.drawable.button_normal);
button_list.get(10).setTag("0");
}
break;
Is there a way I can use a general variable to access each case so if I make a change I won't need to make it 50 times for each button? I thought about doing something like this:
public void ButtonOnClick(View v) {
switch (v.getId()) {
case button[i]
if(button_list.get(i).getTag().equals("0"))
enter_txt.setText(enter_txt.getText()+button_list.get(i).getText().toString());
is_clicked= (String)button_list.get(i).getTag();
if ("0".equals(is_clicked)){
button_list.get(i).setBackgroundResource(R.drawable.button_pressed);
button_list.get(i).setTag("1");
}else{
button_list.get(i).setBackgroundResource(R.drawable.button_normal);
button_list.get(i).setTag("0");
}
break;
Would this work? Or is there something else I need to do so I don't need to make 50 changes to my code every time I decide I want to change the OnClick method?

I'm going to assume that ButtonOnClick is the click handler for the buttons. I'm going to further assume that for any i, the contents of button_list.get(i) is the button. If that's right, then the argument v is the same Button object stored in the list. You can then reduce your entire handler to:
public void ButtonOnClick(View v) {
Button btn = (Button) v;
if (btn.getTag().equals("0")) {
enter_txt.setText(enter_txt.getText()+btn.getText().toString());
}
is_clicked= (String) btn.getTag();
if ("0".equals(is_clicked)){
btn.setBackgroundResource(R.drawable.button_pressed);
btn.setTag("1");
}else{
btn.setBackgroundResource(R.drawable.button_normal);
btn.setTag("0");
}
}
As an aside, you might consider using Boolean objects instead of String objects as the button tags.

First you should never copy paste code, try to extract your code in another method.
If you are using a arraylist where you store all your buttons, you can probably use the ArrayList.indexOf(Object o)
So just replace your ButtonOnClick method with this one, you can handle other buttons behavior easily too in the future :
public void ButtonOnClick(View v) {
if(button_list.contains(v))
{
setButtonBackground(button_list.indexOf(v));
}
}
private setButtonBackground(int buttonNumber)
{
Button myButton = (Button) button_list.get(buttonNumber);
if(myButton.getTag().equals("0"))
{
enter_txt.setText(enter_txt.getText()+myButton.getText().toString());
}
is_clicked = (String) myButton.getTag();
if ("0".equals(is_clicked))
{
myButton.setBackgroundResource(R.drawable.button_pressed);
myButton.setTag("1");
}
else
{
myButton.setBackgroundResource(R.drawable.button_normal);
myButton.setTag("0");
}
}
When you are developping instead of copy and paste code, just use the shortcut extract to a method so you will get something like this and will save yourself time.
[...]
case button1:
setButtonBackground(1);
break;
case button2:
setButtonBackground(2);
break;
[...]
Let me know if it works for you

onClick event buttons

I have 5 buttons,each of them open another activity. How to make clickeble only one of them at current moment?When i click 2 different buttons simultaneusly onClick event calls 2 times and 2 different activities opens. How can i resolve my problem. Thanks.My code
public void onClick(View v)
{
switch (v.getId())
{
case R.id.play_button:
onPlayClick();
setButtonsEnable(false);
break;
case R.id.difficalty_button:
onDifficultyClick();
setButtonsEnable(false);
break;
case R.id.hight_scores_button:
onHighScoresClick();
setButtonsEnable(false);
break;
case R.id.share_button:
setButtonsEnable(false);
break;
case R.id.turn_off_button:
onLeaderboardClick();
setButtonsEnable(false);
break;
default:
break;
}
}
After return to main activity i make my buttons clickable
protected void onResume() {
super.onResume();
setButtonsEnable(true);
}
public void setButtonsEnable(boolean config)
{
playBtn.setClickable(config);
difficultyBtn.setClickable(config);
hScoreBtn.setClickable(config);
shareBtn.setClickable(config);
turnOffButton.setClickable(config);
}

setOnClickListener(null)
would do the trick or you can make
setClickable(false)

Maybe what you really need is RadioGroup? It allows out of the box to select click/select only one button at the time.
Doc reference
Tutorial

Create a variable clicked in Activity:
boolean clicked=false;
Set this value in onClick code:
public void onClick(View v)
{
if(!clicked){
clicked=true;
switch (v.getId())
{
case R.id.play_button:
onPlayClick();
setButtonsEnable(false);
break;
case R.id.difficalty_button:
onDifficultyClick();
setButtonsEnable(false);
break;
case R.id.hight_scores_button:
onHighScoresClick();
setButtonsEnable(false);
break;
case R.id.share_button:
setButtonsEnable(false);
break;
case R.id.turn_off_button:
onLeaderboardClick();
setButtonsEnable(false);
break;
default:
break;
}}
}

If you want to open an activity on each click, use a onclicklistener for each button or add a method call in the xml layout via android:onClick="someMethod", when you click a button and call another activity the UI should block itself...have you tried it this way?

Changing button text and ID by clicking on it

In part of my program, I change the id and text of a button when it is clicked. When the button is clicked again, the id and text are reverted to the previous values. However, I am getting error. (I have added a comment to the line where I am getting the error).
I just need to change text by clicking a button. Then change it back to the old values by clicking it again. Does anyone have a solution or some better idea on how to accomplish this?
public void onClick(View v) {
switch(v.getId()){
case R.id.btn_start_again:
mPlayer.stop();
start.setText("Pause");
start.setId(R.id.pause);
break;
case R.id.pause:
start.setText("Pause"); //here it is not accepting pause
start.setId(R.id.btn_start_again);
break;
}
}

I don't think you want to change the id of the Button. What it looks like you are doing is having a Button that starts play then turns to pause while playing. Simply have the two Buttons in the same space in your xml. Start with the visibility of the pause Button as gone then check the visibility in the function.
Something like
public void onClick(View v) {
switch(v.getId()){
case R.id.btn_start_again:
mPlayer.stop();
btnPause.setVisibility(View.VISIBLE);
btnPlay.setVisibility(View.GONE);
break;
case R.id.pause:
btnPause.setVisibility(View.GONE);
btnPlay.setVisibility(View.VISIBLE);
break;
}
Button Docs

You don't need to change the ID of the button, use something like a boolean flag to keep track of the state of the button:
boolean isPlaying = false;
public void onClick(View v) {
switch(v.getId()){
case R.id.btn_start_again:
if(isPlaying){
mPlayer.stop();
start.setText("Play");
isPlaying = !isPlaying;
}else{
//mPlayer.start() <--- you don't start it anywhere?
start.setText("Pause");
isPlaying = !isPlaying;
}
break;
}
}

There a better way you can do it.
Set different tag to the button according to the status.

changing ID programmatically is a bad idea, better solution is to define a global boolean value:
private boolean isSelected = false;
and then in Your onClick:
public void onClick(View v) {
if(isSelected==false){
mPlayer.stop();
start.setText("Pause");
isSelected=true;
}else{
start.setText("Pause");
isSelected=false;
}

you could just have 1 button which can handle different events and change its behaviour based upon the current button text.
public void onClick(View v) {
switch(v.getText()){
case "Pause":
mPlayer.stop();
start.setText("Play");
break;
case "Play":
start.setText("Pause");
mPlayer.play();
break;
}
}
or you could have the button initally setup to fire 1 click event which once fired then sets the button click event to the second click event and vice versa
public void onClickOne()
{
// do stuff
btn.OnClick = onClickTwo();
}
public void onClickTwo()
{
// do stuff
btn.OnClick = onClickOne
}

I ended up doing it in this way:
String value=start.getText().toString();
if(value.equals("Start")){
start.setText("Pause");
}
else if(value.equals("Pause")){
start.setText("Start");
}

Droid: How to get button id from onClick method described in XML?

Following the dev guide, I can add a method to a button using in the XML. This calls the 'buttonPress' method in my activity. If I apply the same method to multiple buttons, how can I determine the identity of the button that has been clicked?

Use getId() method. It returnes the int id that you can compare to the id from resources.
It is very convenient to use switch statement like this:
public void buttonPress(View v) {
switch (v.getId()) {
case R.id.button_one:
// do something
break;
case R.id.button_two:
// do something else
break;
case R.id.button_three:
// i'm lazy, do nothing
break;
}
}

One method for several buttons?

Instead of have to call separate method for each button, would it be possible to just use one method and check which button it was that was clicked by it's id?
I'm using the simple way like android:onClick="activateButtons"
public void activateButtons(View v)
{
if(?? == btn_1)
{
Code for button with ID = btn_1
}
if(?? == btn_1)
{
Code for button with ID = btn_2
}
}

You can do that if you tag the buttons with an Id. Set the android:id="#+id/yourbuttonid" in the xml file. Then do if(v.getId() == R.id.yourbuttonid) in the onClick method.

Yes it is possible. You can assign specific ids(eg: button1) for buttons and then call v.getId() in activateButtons(onclick method) to check if it is equal to R.id.button1 and then do your operation there.
Cheers,
Richie

public void onClickKeyPad(View view)
{
EditText text = (EditText)findViewById(R.id.text_password);
switch(view.getId())
{
case R.id.button_0:
text.setText(text.getText() + "0");
break;
case R.id.button_1:
text.setText(text.getText() + "1");
break;
case R.id.button_cancel:
finish();
break;
default:
break;
}
}