There are two ways to define Button onclick, one of them is to create instance for BUTTON which defined in XML, then use setOnClickListener() to define private method to deal with What BUTTON was pressed. Another is declare OnClickListener method in XML.
I personal consider it is much easier way to declare onClickLstener method in XML. But I read first way in most of Android coding books.
what is the difference between them?
I thank you in advanced.
sincerely yours Tom
Related
Hi,
in my simple app i have an activity with some textviews and a single imageview.
I'm trying to understand how to dynamically change the content of the imageview in my linear layout. I have a linearlayout and i only need to change the image in it (based on the logic of the underlying application) and similarly the text of the textviews. The pictures are .png files that i have put in res/drawable.
It seems to me that the only way is to use an adapter (simpleadapter) but i struggle to find an example of source code as all the ones i found so far refer to more complex adapters (e.g. simplecursoradapter). Anyway i'm very new to these concepts (adapters, helpers, etc.).
Do i really need to define and use AdapterView (or a more specific subclass?) or if if i keep the image files in res/drawable there is a more straightforward way to dynamically change the ImageView?
Thanks in advance,
x70
ImageView iv = (ImageView)findViewById(R.id.myimageview);
iv.setImageResource(resId);
where resId = R.drawable.mypng
With the textviews is similar, just call setText.
Thanks a lot janfsd. That was really easy...
I did actually try before in that way but i thought i needed also to explicitly set the view (eg via setContentView) and it didnt work; i didn't realise that there is no need for that.
still its not clear to me when do i need to use setContentView, but i made good progress!
Cheers,
x70
setContentView is normally used to set the layout(View) of the activity. I have only used it once per activity. Unless you want to change all the Layout of the activity then don't use it more than once, only on the onCreate method after the super call.
So you should only need to use setSomething method which each view should have it.
Hi guys.
New to Android Development and was wondering if there was some way of taking the users input to create an activity? For example say the user is going through the process of setting up a profile of themself. One of the questions is "how many pets do you have?". The user inputs "4" and then clicks the 'Next' button (which opens the next activity).
How would I take the users input of "4" to create four editText objects in the next activity so that the user can now input the name's of his/her's pets?
I'm an ok-ish programmer (have never touched XML before) so you don't need to go into detail I just don't know how I would access this variable to create the four editText objects. From what I've found you can't add strings to the resources at runtime.
Don't bother replying, I've solved my problem. Just need to create a dynamic layout in JAVA
Could someone help me add a m player and a setonclicklistener in a fragment. I have a couple of sound bite apps and I am trying to put them together in a Viewpager. I have the layout all set up, but im not sure on how to have the m player to the fragment. Thanks.
Sent from my SCH-I535 using Tapatalk 2
Set an onClickListener by using the setOnClickListener() method in the onCreateView() method.
If you set the onClick attribute in the xml, it will look for the method in your Activity.
The MediaPlayer requires a Context, right? Pass your Activity which you can get by calling getActivity().
u can use fragmentpagerapteradapter
to assign fragment as viewpager child...
My app uses the ActionBarCompat and NavigationDrawer, which begs the question of how is one supposed to structure the navigation? I see two options:
1) Use a single Activity and swap out Fragments.
2) Use multiple Activities, and transition between them.
The latter seems to be the correct way, however this means that each Activity must get and build the ActionBar and NavigationDrawer when called from another Activity.
How will this affect my transition animations? If I have a left-to-right transition effect when a navigation item is clicked, will it transition the entire Activity or everything below the ActionBar?
The former seems fraught with issues. A single .java class file could get really heavy and difficult to manage.
But while we're on the subject of Fragments, please consider this situation and school me on proper Fragment management:
A blank Activity with just a LinearLayout attaches a new Fragment to it that contains a Button. Inside the Fragment class, this button gets an onClickListener and when the button is clicked, another of the same kind of Fragment should be attached to the LinearLayout inside the Activity.
A) Should the Fragment class communicate to the Activity that a new Fragment should be attached? This could be done with a custom public interface and the callback being executed within the onClickListener in the Fragment class.
B) Or, should the Fragment handle attaching the new instance inside the onClickListener, making the Activity work less? By simply bridging the clicked Button and calling .getParent() until the LinearLayout is reached, then attaching it there.
The correct way is the former. You should use fragments with the navigation drawer. If you use activities you are going to setup the navigation drawer every new activity. You should open other fragments from the activity and not from the fragment itself. I believe their is a tutorial on the android developer site that explains this in depth. A quick Google search for "android fragment to fragment communication" or something like that should get you to it. I'll try and find a link later when I am on my computer if you don't find anything
Sent from my Nexus 7 using XDA Premium HD app
[Q] Beginner: Issues with canvas bitmaps, buttons, and layouts
Hi, I'm hoping people might help me with this more open-ended question. I'm fairly new to programming with little scripting experience.
My problem is that I'm cobbling code together from various separate examples, but trying to implement them into my tests, they don't seem to work together.
Let me show you what my goals are for this experiment:
1) Create Button
2) Generate Images with Button click
3) Drag Images around
So far, I've been able to do create images with drawing bitmaps using canvas and create a working button with the easy drag and drop.
My specific problem is that I can't use the Design tool to create buttons if I use the canvas method of drawing bitmaps because setContentView() needs to be on the canvas.
Here's my onCreate():
Code:
GenerateItem ourView;
Button genButton;
LinearLayout myLinearLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ourView = new GenerateItem(this);
setContentView(ourView);
myLinearLayout = (LinearLayout)findViewById(R.id.linearLayout1);
genButton = new Button(this);
genButton.setText("Generate");
myLinearLayout.addView(genButton);
}
And related XML code from my AndroidManifest:
Code:
<LinearLayout xmlns:android="somelink"
android:id="@+id/linearLayout1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</LinearLayout>
Now I have two questions:
1) Am I going about this problem the correct way using a mix of Design layout tools and code created images (canvas bitmaps)?
2) Can I use canvas bitmaps with an onTouchListener as a button?
Whoaness said:
2) Can I use canvas bitmaps with an onTouchListener as a button?
Click to expand...
Click to collapse
You should use an ImageView instead. Canvas aren't Views, so they aren't managed by the Android System when an event occurs. Canvas are used, for example, to draw anything in a low-level-way (custom views, for example).
I didn't understand the first question..
Sent from my Vodafone 875
Andre1299 said:
You should use an ImageView instead. Canvas aren't Views, so they aren't managed by the Android System when an event occurs. Canvas are used, for example, to draw anything in a low-level-way (custom views, for example).
I didn't understand the first question..
Sent from my Vodafone 875
Click to expand...
Click to collapse
You might have answered my first question. I'm not sure.
I was asking whether I should stick with canvas methods and, from my limited scripting knowledge, draw a hitbox for the onTouch method to detect so I can redraw the object to the fingers position.
I can easily drag imageviews/imagebuttons around. I guess I have to figure out how to create Imageviews, though I think I seen a way to cast bitmaps into an imageview, but it never worked out for me.
Whoaness said:
You might have answered my first question. I'm not sure.
I was asking whether I should stick with canvas methods and, from my limited scripting knowledge, draw a hitbox for the onTouch method to detect so I can redraw the object to the fingers position.
I can easily drag imageviews/imagebuttons around. I guess I have to figure out how to create Imageviews, though I think I seen a way to cast bitmaps into an imageview, but it never worked out for me.
Click to expand...
Click to collapse
Uhm... so, let me know wheter I understood.
In your project you have a button that renders an image (a bitmap) wich is drawn with a canvas. But you want that this image is draggable.
Am I right?
Andre1299 said:
Uhm... so, let me know wheter I understood.
In your project you have a button that renders an image (a bitmap) wich is drawn with a canvas. But you want that this image is draggable.
Am I right?
Click to expand...
Click to collapse
Yes, draggable image button. Although I'm not sure if it needs to be a button, but I thought button properties would be appropriate for touch and dragging.
Sorry for the late reply. I was on a hiatus.