Develop Reference

How do I detect more than single tap?

I would like to detect single taps several times. I have an activity where the user can tap on an image, they should receive the Toast message, and the program should change the image to another one, and whenever the user taps on this image, there's should be another Toast message. To be more specific, I'll try to provide an example:
Let's say we have two images:
1 - straight line
2 - circle
when the user will enter the specified activity, should see one of those images in the toolbar (let's say that first of them are straight line). When the user will click on this image, the app should display Toast, and then change the straight line to a circle.
*By changing images I mean setting method like
circle.setVisibility(View.VISIBLE); // circle.setVisibility(View.GONE);
Unfortunately, my switch case doesn't work as I intended. Whenever a user clicks on the first image, it's changing the visibility of those two, but look's like the OnClick method doesn't recognize another tap. Here's the code
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.line: {
Toast.makeText(TAG.this, "line", Toast.LENGTH_SHORT).show();
test = 2;
break;
}
case R.id.circle: {
Toast.makeText(TAG.this, "circle", Toast.LENGTH_SHORT).show();
break;
}
}
switchImages();
}
private void switchImages(){
switch (test){
case 1:
line.setVisibility(View.GONE);
circle.setVisibility(View.VISIBLE);
break;
case 2:{
line.setVisibility(View.VISIBLE);
circle.setVisibility(View.GONE);
break;
}
}
}

You missed something.. ;)
public void onClick(View v) {
switch (v.getId()) {
case R.id.line: {
Toast.makeText(TAG.this, "line", Toast.LENGTH_SHORT).show();
test = 2;
break;
}
case R.id.circle: {
Toast.makeText(TAG.this, "circle", Toast.LENGTH_SHORT).show();
break;
}
}
switchImages();
}
In the first case you are assigning test = 2 but in the second one you don't do anything with that variable, so method switchImages() won't really do anything, since it depends on test which is 2 all the time (images will not switch accordingly)

You are initializing test in first case as test = 2 but forget to initialize it in second case
So just change the code :
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.line: {
Toast.makeText(TAG.this, "line", Toast.LENGTH_SHORT).show();
test = 2;
break;
}
case R.id.circle: {
Toast.makeText(TAG.this, "circle", Toast.LENGTH_SHORT).show();
test = 1;
break;
}
}
switchImages();
}

I would have changed only onClick(View v) and removed switchImages();
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.line: {
Toast.makeText(TAG.this, "line", Toast.LENGTH_SHORT).show();
line.setVisibility(View.GONE);
circle.setVisibility(View.VISIBLE);
break;
}
case R.id.circle: {
Toast.makeText(TAG.this, "circle", Toast.LENGTH_SHORT).show();
line.setVisibility(View.VISIBLE);
circle.setVisibility(View.GONE);
break;
}
}
}
As per your question, if you click line, it will toast and make visible circle and hide line and vice-versa

Button long click does not work

I'm working on a soundboard and I want to implement a long click to share the sound.
I am working with a switch Case for each button
public void MainMMP(View view){
switch (view.getId()) {
case R.id.button1:
MainMMP.release();
MainMMP = MediaPlayer.create(this, R.raw.xxx1);
MainMMP.start();
break;
case R.id.button2:
MainMMP.release();
MainMMP = MediaPlayer.create(this, R.raw.xxx2);
MainMMP.start();
break;
case R.id.button3:
MainMMP.release();
MainMMP = MediaPlayer.create(this, R.raw.xxx3);
MainMMP.start();
break;
And now I want to implement the long click. I tried a lot of different code here but it is not working for me.
I do not know where to put the onLongClick statement and how.
Can somebody show me a working method and in case of long click it should just send me a Toast that I know the method works?

You could add the OnLongClickListener where you want, in the onCreate method for example.
Try to use the following code:
Button button = (Button)findViewById(R.id.button);
button.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
//Your code
return false; // True if you want to execute simple click code too
}
});

You can use this
private View.OnLongClickListener listener = new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
switch (view.getId())
case R.id.button1:
// Do something...
break;
case R.id.button2:
// Do something else...
break;
// If you still want to get normal click callbacks return true,
// if you do not then return false.
return true;
}
}
Somewhere in your code
Button button1 = (Button)findViewById(R.id.button1);
Button button2 = (Button)findViewById(R.id.button2);
button1.setOnLongClickListener(listener);
button2.setOnLongClickListener(listener);
Or better this
One common recommended way to get onClick/onLongClick/whatever callbacks is to make the Activity implement the callback interfaces.
class YourActivity extend Activity implements View.OnLongClickListener {
#Override
public boolean onCreate(/* ... */) {
// ...
button1.setOnLongClickListener(this);
button2.setOnLongClickListener(this);
}
#Override
public boolean onLongClick(View view) {
// Same code as the one above
}
}

AlertDialog box Repeats four times

OK my question is a lot bigger than the Title. But can't describe everything in a Title. So here we go.
I am writing an App that when a NFC cards get detected by Phone, it will be able to WRITE and READ a NDEF message on / from it.
I use two buttons READ and WRITE to trigger these events. Everything works fine, just the thing that EVERYTHING REPEATS ITSELF FOUR (4x) TIMES!
Only the TAG "UltraLightCard Detected" and "Connected" pops once.
Everything else that you see in code in "ShowMessage" will pop out 4x times also the AlertDialog box gets triggered 4x times and you have to write the text 4 times.
If you wrote it only once and then clicked "Save" 3x times just to close it, it wont store the string.
Here's my code:
protected void ultralightCardLogic() {
final Button b_write = (Button)findViewById(R.id.b_write);
final Button b_read = (Button)findViewById(R.id.b_read);
b_write.setId(1);
b_read.setId(2);
//showImageSnap(R.drawable.ultralight);
ShowMessage("UltraLight Card Detected :" + mifareUL.getTagName(), 'a');
try {
mifareUL.connect();
mifareUL.formatT2T();
ShowMessage("Connected!" , 'd');
b_write.setOnTouchListener(new MyTouchListener());
b_read.setOnTouchListener(new MyTouchListener());
} catch (IOException e) {
e.printStackTrace();
}
}
Here is MyTouchListener:
public class MyTouchListener implements OnTouchListener{
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stu
int id = v.getId();
switch(id){
case 1:
onCreateDialog();
break;
case 2:
readNDEFmsg();
break;
case 3:
break;
}
return false;
}
}
Here is the OnCreateDialog:
final View v = getLayoutInflater().inflate(R.layout.dia_box,null);
AlertDialog.Builder builder = new AlertDialog.Builder(this)
.setView(v)
.setPositiveButton("SAVE", new DialogInterface.OnClickListener(){
#Override
public void onClick(DialogInterface dialog, int id) {
// TODO Auto-generated method stub
final EditText mEdit=(EditText)v.findViewById(R.id.et_dia);
String str = mEdit.getText().toString();
writeNDEFmsg(str);
dialog.dismiss();
}
});
AlertDialog alert = builder.create();
alert.show();
If you guys need some more of the code, I can add it then. Don't want to write too much code, because my experience tells me that then noone will try to help me out.
Please, help me out

Thanks to your help I figured out my issue.
I used onTouchListener, which triggers more than once, since it has more MotionEvents available.
After I changed on to OnClickListener everything works smoothly!
Just be sure to implement View.OnClickListener
if you are doing it like I do in my public class MyClickListener.
Then Eclipse will auto-generate your necessary code. Extract the id of your buttons and do the switch statement (again, if you`re doing it this way):
public class MyClickListener implements android.view.View.OnClickListener{
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
int id = v.getId();
switch(id){
case 1:
onCreateDialog();
break;
case 2:
readNDEFmsg();
break;
case 3:
break;
}
}
Thanks again for the help! Hope it will help someone else too.

How to Modularize Long Code

I have over 900 lines in my MainActivity because I can't figure out how to make other classes work.
It works but it makes it hard to read and tedious to update.
I will give an example of what I would want to separate to another class.
I would like to call this from the main activity.
MainActivity:
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.apm:
apm();
return true;
}
}
public void apm() {
AlertDialog levelDialog;
final CharSequence[] items = {" Reboot ", " Reboot Recovery ", " Hot Reboot "};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("What do you want to do?");
builder.setCancelable(true);
builder.setSingleChoiceItems(items, -1, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
switch (item) {
case 0:
rooted();
reboot();
break;
case 1:
rooted();
recovery();
break;
case 2:
rooted();
softreboot();
break;
//case 3:
//shutdown();
//break;
}
}
});
levelDialog = builder.create();
levelDialog.show();
}

Create a new class called Util (for example) in a new file, Util.java.
In this class put:
public static void apm(MainActivity activity){
//Put the code from your old apm method here.
//Whenever you need to call a method that is part of MainActivity
//just prepend activity. in front of the method call.
}
Then in MainActivity, call Util.apm(this);.
EDIT:
Here's more detail. Put the following in Util.java and call Util.apm(this); in your MainActivity.
public static void apm(MainActivity activity) {
AlertDialog levelDialog;
final CharSequence[] items = {" Reboot ", " Reboot Recovery ", " Hot Reboot "};
AlertDialog.Builder builder = new AlertDialog.Builder(activity);
builder.setTitle("What do you want to do?");
builder.setCancelable(true);
builder.setSingleChoiceItems(items, -1, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
switch (item) {
case 0:
activity.rooted();
activity.reboot();
break;
case 1:
activity.rooted();
activity.recovery();
break;
case 2:
activity.rooted();
activity.softreboot();
break;
//case 3:
//activity.shutdown();
//break;
}
}
});
levelDialog = builder.create();
levelDialog.show();
}

you can write your apm method in another class. From your mainActivity, you can instanciate that class and pass the context of the activity to the constructor of the class.
then from mainActivity, just call the methods of that class using the class instance.
I hope you understand what I try to say. In your new class, you can access mainActivity components using the context you received in constructor.

android : what's the procedure to write functions for alertdialog item?

I'm going to write some function in AlertDialog's item : - Code is : -
final CharSequence[] items = {"Now", "Later", "Cancel"};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("When you need to Take BackUp?");
builder.setSingleChoiceItems(items, -1, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item)
{
// Toast.makeText(getApplicationContext(),items[item],Toast.LENGTH_SHORT).show();
items[0].notify();
items[1].charAt(2);
}
});
builder.show();
This item will enable some function, how can i declare and define that.

The item that is selected will be passed into the onClick method, the int item in the method's signature.
public void onClick(DialogInterface dialog, int item) {
switch(item) {
case 0: // the first item in the CharSequence[]
callUserClickedNow();
break;
case 1: // the second item in the CharSequence[]
callUserClickedLater();
break;
case 2: // the thirditem in the CharSequence[]
callUserClickedCancel();
break;
}
dialog.dismiss();
}
Then outside of the method where you create the AlertDialog:
private void callUserClickedNow() {
// do stuff
}
etc...