I'm new to android development, and haven't programmed GUI's in java yet so button work is all new to me.
I'm making a simple hello world app, has some buttons/radios/checkboxes etc. We have to figure out a way to make it nice, there is nothing specific in the brief. so I figured I'd get some buttons and show the different kinds of toast, maybe change the background etc.
so I implemented a toast based off a tutorial, but it works on all of the instantiated buttons instead of just the one I want. I would like the other button to do something else.
I think it has to do with the onClickListener, but beyond that I'm stuck.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btn1 = (Button) findViewById(R.id.button1);
btn1.setOnClickListener(this);
btn2 = (Button) findViewById(R.id.button2);
btn2.setOnClickListener(this);
cb=(CheckBox)findViewById(R.id.check);
cb.setOnCheckedChangeListener(this);
browser=(WebView)findViewById(R.id.webkit);
browser.loadUrl("http://www.google.com/search");
}
public void onClick(View v) {
new AlertDialog.Builder(this).setTitle("MessageDemo").setMessage(
"This is an Alert Dialogue Toast").setNeutralButton(
"Here, here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
Toast.makeText(HelloWorldActivity.this,
"<clink, clink>", Toast.LENGTH_SHORT).show();
}
}).show();
}
and here's the xml for the buttons
<Button android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Testa"
android:layout_weight="0.2"></Button>
You've added the same onClickListener to each button so they will have the same behavior. You can actually create the listener right inside the setOnClickListener call, like this:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btn1 = (Button) findViewById(R.id.button1);
btn1.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
new AlertDialog.Builder(this).setTitle("MessageDemo").setMessage(
"This is an Alert Dialogue Toast").setNeutralButton(
"Here, here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
Toast.makeText(HelloWorldActivity.this,
"<clink, clink>", Toast.LENGTH_SHORT).show();
}
}).show();
}
});
btn2 = (Button) findViewById(R.id.button2);
btn2.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
// Do something different here.
}
});
// The rest of onCreate
}
EDIT: I've updated the answer to make it clear which parts of your original code would go where, but I usually wouldn't stick a big chunk of code like that inside of the onClick as it's not very readable. I'd prefer something more like this:
public void onCreate(Bundle savedInstanceState) {
// other onCreate code
btn1 = (Button) findViewById(R.id.button1);
btn1.setOnClickListener( new OnClickListener() {
public void onClick(View v) {
showBtn1ClickedDialog();
}
});
// other onCreate code
}
private void showBtn1ClickedDialog() {
new AlertDialog.Builder(this).setTitle("MessageDemo").setMessage(
"This is an Alert Dialogue Toast").setNeutralButton(
"Here, here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
Toast.makeText(HelloWorldActivity.this,"<clink, clink>", Toast.LENGTH_SHORT).show();
}
}).show();
}
In addition to goto10's solution, if you're not interested in defining the listeners in-line, your existing click handler can check the ID of the view:
public void onClick(View view) {
switch (view.getId()) {
case R.id.about_button:
// handle about
break;
// etc.
I tend towards goto10's solution, or even inner classes, rather than a switch statement like this, but it's another option. That said, I'm voting up his/her answer, and not mine.
One reason to use a switch instead of inner classes is memory usage, although with modern devices, this might not be a huge issue--but each inner class does take more space, and if the handler is small, IMO is more efficient to do it this way.
Clicking on any button generates an event which is caught by the onClick eventListener. But it doesn't automatically distinguish between the events as to which click generated the event. The information is contained in the View v and by using a switch case on the view, we can have separate events for different clicks.
#Override
public void onClick(View v) {
switch(v.getId()){
case R.id.btn1:
//Do something here
break;
case R.id.btn2:
//Do something else here
break;
case R.id.btn3:
break;
}
}
A summary of how you can use Listeners in your application.
Related
If the showChatList() function is not being called in the code, and the dialog is displayed normally.
When the listView is called via showChatList() function, it does not work.
To the original custom dialog
Is it impossible to bring up the listView?
public void callFunction() {
final Dialog dlg = new Dialog(context);
dlg.setContentView(R.layout.room_list);
dlg.show();
final Button okButton = (Button) dlg.findViewById(R.id.okButton);
final Button backbtn = (Button) dlg.findViewById(R.id.backbtn);
**final ListView chat_list = (ListView) dlg.findViewById(R.di.chat_list);**
- or
**chat_list = dlg.findViewById(R.id.chat_list);**
backbtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dlg.dismiss();
}
});
okButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dlg.dismiss();
}
});
showChatList();
}
Your adapter depends on firebase.
It will wait until it gets data,
then I believe you need to call
adapter.notifyDataSetChanged();
after
adapter.add();
When dealing with views like dialogs, it is important to load all the views needed in the dialog before calling dialog.show().
Alternatively, I'll suggest the use of DialogFragment with this example: https://blog.mindorks.com/implementing-dialog-fragment-in-android.
DialogFragments allow you to manage your dialogs just like any other fragment.
Let me know which one you're able to use.
My app currently has 5 buttons (I'm going to add more later) and when each button is clicked, it'll assign a number to an item.
I'm wondering if there's a more efficient way of writing the setOnClickListner (it seems like I have to use that since I'm using this as a fragment. I found a way to do it if I was to assign an onClick in the xml but I can't apply that to this part of the code). I have it written out 5 times (and in the future it'll be more)
buttons[0] = (Button) view.findViewById(R.id.cut1Btn);
buttons[1] = (Button) view.findViewById(R.id.cut2Btn);
buttons[2] = (Button) view.findViewById(R.id.cut3Btn);
buttons[3] = (Button) view.findViewById(R.id.cut4Btn);
buttons[4] = (Button) view.findViewById(R.id.cut5Btn);
buttons[0].setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getActivity(), "TESTING BUTTON CLICK 1",Toast.LENGTH_SHORT).show();
data = 1;
}
});
buttons[1].setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getActivity(), "TESTING BUTTON CLICK 2",Toast.LENGTH_SHORT).show();
data = 2;
}
});
buttons[2].setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getActivity(), "TESTING BUTTON CLICK 3",Toast.LENGTH_SHORT).show();
data = 3;
}
});
buttons[3].setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getActivity(), "TESTING BUTTON CLICK 4",Toast.LENGTH_SHORT).show();
data = 4;
}
});
buttons[4].setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getActivity(), "TESTING BUTTON CLICK 5",Toast.LENGTH_SHORT).show();
data = 5;
}
});
Could I maybe do a switch or a loop? Like assign i = 0, i < 5, i++ for the button array and then for data make that data = i + 1 ? If so, any suggestions on how I can do that?
Thanks!
THe other answers here will work, but either use the tag (generally a bad idea and prevents any other use) and aren't really object oriented. Instead you should make a class an instantiate it.
private class MyClickListener {
private int data;
public MyClickListener(int data) {
this.data = data;
}
public void onClick(View view) {
Toast.makeText(getActivity(), "TESTING BUTTON CLICK" + data,Toast.LENGTH_SHORT).show();
}
}
...
int i=0;
for(Button button : buttons) {
button.setOnClickListener(new MyClickListener(i++));
}
You could use a common method and then implement a switch case based upon R.id of your button
An example would in like this.
in onCreate(--) method
cut1Btn = (Button) view.findViewById(R.id.cut1Btn);
cut2Btn = (Button) view.findViewById(R.id.cut2Btn);
cut3Btn = (Button) view.findViewById(R.id.cut3Btn);
cut4Btn = (Button) view.findViewById(R.id.cut4Btn);
cut5Btn = (Button) view.findViewById(R.id.cut5Btn);
cut1Btn.setOnClickListener(this);
cut2Btn.setOnClickListener(this);
cut3Btn.setOnClickListener(this);
cut4Btn.setOnClickListener(this);
cut5Btn.setOnClickListener(this);
Implement View.onClickListener in your activity and override this method in your activity
public void onClick(View v){
switch(v.getId()){
case R.id.cut1Btn:
//Put Your Code Here
break;
case R.id.cut2Btn:
//Put Your Code Here
break;
case R.id.cut3Btn:
//Put Your Code Here
break;
case R.id.cut4Btn:
//Put Your Code Here
break;
case R.id.cut5Btn:
//Put Your Code Here
break;
}
}
You can implement a switch to do this things:
Your class must implement OnClickListener and override function OnClick(View view).
Then just set OnClickListener(this) like this on onCreate method
buttons[1].setOnClickListener(this)
buttons[2].setOnClickListener(this)
buttons[3].setOnClickListener(this)
do a switch-case on override function
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button1:
// button 1 do
break;
case R.id.button2:
// button 2 do
break;
case R.id.button3:
// button 3 do
break;
}
}
Always in my apps I added buttons in void onCreate, but now I'm trying to do app with more buttons (about 10). I would like to all buttons active on start app.
In my opinion it is too much buttons to add in this onCreate and app will be starting to long.
I tried to put this:
myButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
myMethod();
}
})
out of onCreate
but AndroidStudio underlines setOnClickListener and view
I don't have ideas, how and where can i add button out of onCreate.
If you don't want to overcrowd your oncreate method, then create a clicklistener outside onCreate anywhere in activity and in onCreate just set it.
onCreate :
edit_a_member = (Button) findViewById(R.id.edit_member);
delete_a_member = (Button) findViewById(R.id.delete_member);
edit_a_member.setOnClickListener(handleClick);
delete_a_member.setOnClickListener(handleClick);
clickListener:
private View.OnClickListener handleClick = new View.OnClickListener() {
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.edit_member:
member_selected = EDIT_MEMBER_SELECTED;
callDialog();
break;
case R.id.delete_member:
callDeleteAlert();
break;
}
}
};
You can simply add a separate method for your buttons in the same class, e.g.:
public void onCreate(...){
//Standard setup of views or whatever you want to do here
this.addButtons();
}
private void addButtons(){
Button b1 = new Button("Hi");
b1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
myMethod();
}
});
Button b2 = new Button("Hi to you too");
b2.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
myMethod();
}
});
}
This is an example. You can do this in soooo many ways. I feel like you should thoroughly learn Java's fundamental Object Oriented programming, because that's really what your question suggests you don't understand. Go follow a youtube tutorial. I always like "The New Boston"'s Java tutorial series on youtube.
PS: You can make code like this beautiful under the 'Words of wisdom': Don't repeat yourself
If you have to do a lot of work in your onCreate but you are worried that the UI will take too long to load you can always post a delayed runnable to a handler so in the onCreate method put :
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
//add your code here
}
},10);
what this will do is your UI will load then the code in your Runnable will be executed 10 milliseconds after your UI loads thus your app will not take too long to load the UI, even though in your case I doubt it would be necessary.
If you are declaring the buttons in xml file :
Add these properties in each button Declaration in your Xml :
android:clickable="true"
android:onClick="onClick"
And now in Activity Class create a method like this :
public void onClick(View v){
switch(v.getId){
case R.id.{buttons_id_in_xml}
(Your Code)
break;
(Like for others)
}
}
If you want to add buttons dynamically :
Create a method to add the button like this:
void addButton(String buttonName, int button id){
Button button = new Button(this);
button.setText("Push Me");
(add it to parent Layout of xml)
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
switch(id){
case id1:
(handle )
break;
(like for others)
}
}
});
}
The best way to do this is:
add implements View.OnClickListener to
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
// declare variables
private Button mBtn1;
private Button mBtn2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_start);
// make an instance to the btns
mBtn1 = findViewById(R.id.btn1);
mBtn2 = findViewById(R.id.btn2);
// set onClickListener
mBtn1.setOnClickListener(this); // with "this" you are passing the view
mBtn2.setOnClickListener(this);
}
// implement onClick
#Override
public void onClick(View view) {
// check which btn was clicked by id
switch (view.getId()) {
case R.id.btn1:
btn1Clicked();
break;
case R.id.btn2:
btn2Clicked();
break;
}
}
private void btn1Clicked() {
// your code btn1 clicked
}
private void btn2Clicked() {
// your code btn2 clicked
}
Hope this helped. Cheers!
I am making a log-in system on Android. And I want the register Button to be unclickable when it has been clicked. I am using this code:
final Button register = (Button) findViewById(R.id.register);
register.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
register.setEnabled(false);
Intent register = new Intent(getApplicationContext(), register.class);
startActivity(register);
}
});
This is working great, but I want the Button to remain unclickable even when the application or phone has been restarted. Does anyone know a way to make the Button unclickable permanently even when the application has been shut down?
As I already said in the comments section something like this may work:
public class MyActivity extends Activity {
private static final String KEY_IS_BUTTON_CLICKABLE = "key_clickable";
#Override
public void onCreate(Bundle savedInstanceState) {
...
final Button register = (Button) findViewById(R.id.register);
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
boolean isClickable = sharedPreferences.getBoolean(KEY_IS_BUTTON_CLICKABLE, true);
register.setEnabled(isClickable);
if(isClickable) {
register.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
register.setEnabled(false);
PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).edit()
.putBoolean(KEY_IS_BUTTON_CLICKABLE, false);
Intent register = new Intent(getApplicationContext(), register.class);
startActivity(register);
}
});
}
}
...
}
In this case you could take a pessimistic approach and disable the button in the layout (by default) with android:clickable="false" and enable it in the condition where registration is required.
I'm creating a dialog box and using the (this) isnt working. Up until now its just been a button calling a dialogbox but now the button within the called dialogbox needs to call another dialog. The Dialog dialogdelcon is the one with problem.
Here is the code:
case R.id.delappt:
//rmvall();
final Dialog dialogdelsel = new Dialog(this);
dialogdelsel.setContentView(R.layout.delsel);
dialogdelsel.setTitle("What would you like to do?");
dialogdelsel.setCancelable(true);
Button btndelsel = (Button) dialogdelsel.findViewById(R.id.btndelsel);
btndelsel.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// delete selected code here.
}
});
Button btndelall = (Button) dialogdelsel.findViewById(R.id.btndelall);
btndelall.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// delete all code here.
final Dialog dialogdelcon = new Dialog();
dialogdelcon.setContentView(R.layout.delcon);
dialogdelcon.setTitle("Deletion Confirmation");
dialogdelcon.setCancelable(true);
Button buttoncnclok = (Button) dialogdelcon.findViewById(R.id.btndelcon);
buttoncnclok.setOnClickListener(new OnClickListener() {
// on click for cancel button
#Override
public void onClick(View v) {
dialogdelcon.dismiss();
}
});
dialogdelcon.show();
}
});
dialogdelsel.show();
break;
getApplicationContext() or use YourActictyName.this Because this refers the button click listner ,not your class Object
If this code is in the onCreate() method, or similiar, add getApplicationContext() instead of this and you should be fine. That's because this in a Button-context will refer to the button environment.
To improve the isolation between the two dialogs, it would be best to call showDialog(R.id.delapptcon) from the onClick handler. Then load the new dialog in the onCreateDialog of your activity. In this way, you can create more reusable dialogs and avoid the scoping issue you have now.