I'm developing a simple application in which youb have different spots placed on google map.
When I click on a spot I get its details which are displayed in a GridViewPager.
For now my application is based on the GridViewPager sample available with the sdk.
Here is my layout for the spot details (nothing fancy)
<android.support.wearable.view.GridViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:keepScreenOn="true"/>
My problem now is that I'm not able to detect a Click event on a card.
I've tried this but it doesn't work.
public class DetailsActivity extends Activity implements GridViewPager.OnClickListener {
#Override
public void onClick(View v) {
}
I've also tried View.OnClickListener.
Have any idea ?
There are two issues here. First, if you really want to make the GridViewPager clickable, you need to tell it to listen for click events - just implementing the OnClickListener interface isn't sufficient. So you need to do something like this:
public class DetailsActivity ... {
#Override
public void onCreate(Bundle savedInstanceState) {
...
GridViewPager pager = (GridViewPager)findViewById(R.id.pager);
pager.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// put your onClick logic here
}
});
...
}
}
That being said, however, based on your description it sounds like what you actually want is to set up click handlers on individual pages within the grid, not on the entire grid. If so, then you'll need to do something similar but in each page's Fragment class. For example:
public class MyPageFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View result = inflater.inflate(...);
result.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// put your onClick logic here
}
});
...
return result;
}
}
Note: if you are using CardFragments in your GridViewPager, then you would probably set the OnClickListener in your onCreateContentView override. Otherwise, the above Fragment-based example should apply.
Related
I am making a keyboard app. For what I need to know if I can assign seperate onclicklistener to each button, ie around 70 onclicklisteners on a single activity.
Is it a right way to do it??
Implement View.OnClickListener in your activity.Give different id for the views.
public class KeyBoardActivity extends Activity implements View.OnClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
}
#Override
public void onClick(View v) {
//Write your code for the corresponding view ids
}
}
I have a class where I have a List with three WebView from different Activities
public class Class {
private List<WebView> webViews;
.
.
.
public void bindOnClickEvent(ActionMethod aMethod, View control){
control.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
//Here I need know which webview in webViews is in the same context that View control
//webView.loadUrl("javascript:myJSFunction(\'"+s+"\');");
}
});
}
}
I need use inside of the method onClick(View v) the webView (that i can found in the List "webViews") which is in the same context that the parameter View v.
Any idea?
Thanks!
View has a method getContext(). You should be able to compare the contexts to determine which Views belong to which Activitys.
So I've been looking around for android tutorials, help questions, etc.. I keep running into questions or tutorials hard for me to understand.
Here's my questions:
When I create an item in the visual designer, piece of code will be created in the .xml.
How can I get the ID of that item to use it in the .java file later?
How can I add callbacks when let's say a button gets clicked?
Here's what I have so far:
.java
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void Button_click_callback() // Where to add the callback in the .xml?
{
// How to get button ID and change the text of it?
//Knowing this will help me A LOT!
}
}
.xml
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="79dp"
android:layout_marginTop="32dp"
android:text="Button" />
When I create an item in the visual designer, piece of code will be created in the .xml. How can I get the ID of that item to use it in the .java file later?
Step #1: Ensure that you have assigned an ID for the widget in the designer (in your XML above, you will see this as android:id="#+id/button1)
Step #2: In Java, you can get at the Java object for that widget by calling findViewById(R.id.button1) at some appropriate time (e.g., from an Activity, sometime after you call setContentView()).
How can I add callbacks when let's say a button gets clicked?
Generally, there is a setter method for this, such as setOnClickListener() that you can call on the Button you retrieved by findViewById().
In the specific case of click events on widgets hosted by activities, there is also an android:onClick attribute you can have in the XML, which supplies the name of a method on your Activity that will get called when the widget is clicked, instead of your having to use the setter.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button1 = (Button)findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do something in response to button click
}
});
}
All of this is extensively documented on the Android Developer site. You should be looking their for this basic stuff.
http://developer.android.com/guide/topics/ui/controls/button.html
You can use findViewById to get view ids from XML in Java, Make sure that you should declare the ids in views, otherwise it might cause exception which results apps force close
If you want call back with xml rather than programatically
you can declare android:onClick attribute on that Views in layout XML
For example, in your case you need add android:onClick="Button_click_callback" in your
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="79dp"
android:layout_marginTop="32dp"
android:text="Button"
android:onClick="Button_click_callback"/>
then you can use Button_click_callback method for call back in your Activity
public void Button_click_callback()
{
}
if you want call back programatically with java,
first you have get the view with findViewById and then you can add click listener to that view
You need to use the onClickListener and override the onClick method.
btn.setOnClickListener.(new View.OnClickListener(){
#Override
public void onClick(View v) {
//TO DO
}
});
OnClickListener is an interface. And thats why you need to override the OnClick method.
//in oncreate method of activity
//take button id like that
Button button1 = (Button)findViewById(R.id.button1);
//then implement on click listener for performing action on button
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do something in response to button click
}
});
}
//you can also implements onclicklistener in activity.its interface;
public class MainActivity extends Activity implements View.OnClickListener
//then generate method
public void onClick(View view) {
}
public class MainActivity extends Activity {
private Button button1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = findViewById(R.id.button1);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void Button_click_callback() {
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do something in response to button click
Log.e("click", "-------------button click");
}
});
}
}
Those two code snippets are equal, just implemented in two different ways.
Code Implementation
Button btn = (Button) findViewById(R.id.mybutton);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myFancyMethod(v);
}
});
// some more code
public void myFancyMethod(View v) {
// does something very interesting
}
Above is a code implementation of an OnClickListener. And this is the XML implementation.
XML Implementation
<?xml version="1.0" encoding="utf-8"?>
<!-- layout elements -->
<Button android:id="#+id/mybutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click me!"
android:onClick="myFancyMethod" />
1) First Look at your XML file.In code it shows
android:id="#+id/button1.
You can edit it on your own name.Same thing you can do to change it though the GUI appear at right side of your design.
You can get your ID using findViewById(R.id.your id name); function.
For an Example:
My button id is btn1.In my code I can use that button by getting it's Id as follows:
Button btn1=findViewById(R.id.btn1);
2)You can callback after creating your Button which you have created Before as follows;
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Create your code
}
});
}
For the call backs - The android component needs to be registered in the calling device . The id of the components has to be unique in the xmls.
Using the unique id the components can be dynamically altered or the call backs can be used.
I'm trying to make multiple OnClickListener methods for 5 buttons in my program, and I've been able to declare them, and I made a switch using the xml id of what was clicked, but I need a parameter for the setOnClickListener method when I call it, and all that will work is null. I have also tried passing in this, so the method has context.
Here's some of the code:
add.setOnClickListener(null);
sub.setOnClickListener(null);
mult.setOnClickListener(null);
div.setOnClickListener(null);
equal.setOnClickListener(null);
The parameter has to be an instance of some object that implements the OnClickListener interface. One way to do it is to use an anonymous inner class:
add.setOnClickListener(new OnClickListener{
public void onClick(View view){
//your event handler code here
}
});
another way is to make your class implement OnClickListener --do that by changing your declaration to look like:
public class MyActivity extends Activity implements OnClickListener{
then define an implementation for the onClick method:
public void onClick(View view){
if(view == add){
//handle add button click
}else if (view == sub){
//handle sub button click
}
//etc
}
then to install the listener you could do:
add.setOnClickListener(this);
You are supposed to pass View.OnClickListener to this function, which is a listener that will get called once the button is clicked.
To do that, you can either:
Declare this listener in the layout XML, with the button, as specified in Button 4 in this site.
Create an instance of View.OnClickListener and pass it to setOnClickListener method as in the example below (Taken from android site which is a great source):
// Create an anonymous implementation of OnClickListener
private OnClickListener mCorkyListener = new OnClickListener() {
public void onClick(View v) {
// do something when the button is clicked
}
};
protected void onCreate(Bundle savedValues) {
...
// Capture our button from layout
Button button = (Button)findViewById(R.id.corky);
// Register the onClick listener with the implementation above
button.setOnClickListener(mCorkyListener);
...
}
Since View.OnClickListener is an interface, your activity may implement it as well, and be itself the listener, in this case, you will pass the activity instance(this) to the setOnClickListener method, but this is just one option, and not that recommended IMHO.
Coming from a .NET background, I struggled with the same thing at first. It's just a different syntax than .NET as java doesn't support properties, or events like I was used to. Here's a simple example of how to do this using a class level click listener variable...
#Override
private void onCreate(Bundle bundle) {
myButton.setOnClickListener(this.genericButtonListener);
}
private OnClickListener genericButtonListener = new OnClickListener() {
#Override
public void onClick(View v) {
//v represents your button
}
};
You need a concrete class here. For example:
imageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// your code here
}
});
If you look at documentation, you will notice it takes View.OnClickListener as parameter. If you need five separate listeners, which you are not going to use anywhere else, you can pass an anonymous class implementing onClick(View v), like this
add.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
//do required actions here
}
});
I have a custom TextView which is clickable. It defines its own onClick handler in order to change its appearance based on clicks. However if I then define a second onClick handler in my activity in order to do something based on the button being clicked, only one of the onClick functions is called. onClick is a void function - is there any way to say I didn't process this click, please pass it on to other onClick handlers?
To be more clear here is the code:
Inside MyCheckButton which extends TextView I have:
setOnClickListener( mClickListener );
private OnClickListener mClickListener = new OnClickListener() {
public void onClick(View v) {
toggle();
}
};
However I include MyCheckButton into my Activity, and of course I need to do something when its clicked so I attach another OnClickListener to it:
MyCheckButton button= (MyCheckButtonButton) findViewById(R.id.cb);
button.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
// do something in the app
}
});
By calling setOnClickListener twice it appears that I am replacing the original listener so toggle() which changes the appearance is never called. How can I do something in my activity when this button is clicked if it is already using the onClick handler to change its appearance? I thought I would simply see both OnClickListeners getting called.
This is a bit dirty, but the way I would do this if you need multiple listeners is to register one that knows about the other. The first one (the one that's actually registered) will then need to know when to delegate to the other listener based on the conditions of the event. Actually, in reality, there's no real need to have two OnClickListener classes. The second class can implement whatever interface you want. Additionally, there's no need to create a special interface for what you need.
public class MyClickListener implements OnClickListener{
private SomeCustomClass mSecondListener = new SomeCustomClass();
public void onClick(View v){
if (needToForward){
mSecondListener.handleClick(v);
}else{
//handle the click
}
}
}
Then, in your code for your activity, you would do this
MyClickListener lstn = new MyClickListener();
mCheckBox.setOnClickListener(lstn);
Is there a reason this wouldn't work for you?
Alternatively, if you wanted, the second class could also implement the OnClickListener interface.
Additionally, if you need true bubbling, you could define your own interface that supports adding multiple click listeners to an intermediate class that happens to implement the OnClickListener interface. From there, in that class's onClick() method, you would iterate through the registered listeners calling the appropriate method.
A cleaner approach would be to use the CompositeListener pattern.
Taken from:
how can I set up multiple listeners for one event?
You'd have to add this class in your project:
/**
* Aux class to collect multiple click listeners.
*/
class CompositeListener implements OnClickListener {
private List<OnClickListener> registeredListeners = new ArrayList<OnClickListener>();
public void registerListener (OnClickListener listener) {
registeredListeners.add(listener);
}
#Override
public void onClick(View v) {
for(OnClickListener listener:registeredListeners) {
listener.onClick(View v);
}
}
}
Then add this on your MyCheckButton
private CompositeListener clickListener = new CompositeListener();
public MyCheckButton()
{
super.setOnClickListener(clickListener); //multi event listener initialization
}
#Override
public void setOnClickListener(OnClickListener l) {
clickListener.registerListener(l);
}
Both your calls to setOnClickListener would go through this override, get added to the list and get called when the event is fired. Hope it helps.
Since it appears I can only have one onClickListener per View. What I think I have to do is define an interface:
public interface MyOnClickListener {
public void onMyClick(View v);
}
Implement it from my activity and override the onMyClick function to do whatever I want and in the MyCheckButton class I'll need to pass a MyOnClickListener in the constructor save it and call listener.onMyClick inside the onClick handler.
Let me know if theres a better way. I considered using the onTouch handler in either the activity or the MyCheckButton class, but later if I add onTouch or onClick to either one I will get a difficult to notice bug.
My idea doesn't work because I don't know how to get a reference to the activity from my constructor:
public class TVCheckButton extends TextView {
private MyOnClickListener mListener;
public TVCheckButton(Context context, AttributeSet attrs) {
super(context, attrs);
mListener = ???;
}
}
Since only one OnclickListener works on Android 2.1 [I don't know about later versions) make the view private and static and create a static function that can change it e.g.
public class ExampleActivity extends Activity{
private SomeOtherclass someOtherClass;
private static Button b_replay;
public void onCreate(Bundle savedInstanceState){
someOtherClass = new SomeOtherclass();
b_replay = (Button) findViewById(R.id.b_replay);
b_replay.setOnClickListener(someOtherClass);
}
public static void changeReplayText(String text){
b_replay.setText(text);
}
}
A nice generic approach is to use a list of listeners, such as ListenerList and WeakListenerList from the Beryl library.
For some reason I could not use the answers above so here is an alternative:
//I had all of this in one method where I had two buttons, and based on external factors one would be visible and other would not aka 'gone'. So, I had that checked out! Hope it helps someone!!
Button b = (Button) findViewById(R.id.b_reset);
Button breakk = (Button) findViewById(R.id.b_break);
if ((findViewById(R.id.b_reset)).getVisibility() == View.VISIBLE) {
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//some code and methods...
}
});
} else if ((findViewById(R.id.b_break)).getVisibility() == View.VISIBLE) {
breakk.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//some code and methods...
}
});
}
In the first class, define a virtual button:
private static Button myVirtualButton = new Button(context);
... and a public method to register it:
public static void registerMyVirtualButton(Button b) { myVirtualButton = b;}
In the OnClickListener do whatever action is desired, and in the end, softclick the virtual button:
if (myVirtualButton!=null) { myVirtualButton.callOnClick(); }
In the second class, define a button and its OnClickListener with whatever action is additionally desired.
Transmit the button to the first class via registerMyVirtualButton.
Upon clicking the object of the first class, both actions will be executed.
You can attach an OnClick listener to the button in the following way :
Button button= (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
// do something
}
});
Similarily, your TextView should have it's on OnClick listener.