There are plenty of similar questions asked in SO, but then also, please take time to read my question.
I need to create a UI programmatically that would have multiple ImageView, all positioned at different location of the screen and having their associated click events (its a game app). I found that FrameLayout is appropriate choice, where I can set margins on my own and have it positioned at desired location.
Now, I'm confused whether to have FrameLayout for every single ImageView I create, or to keep single FrameLayout and add all ImageViews within it, but set each imageview at different position.
In either of the case, how can I add FrameLayout, and ImageView within it, programmatically and also set its margin such that it can be placed anywhere on the screen.
Note that my main canvas, which will carry all these ImageViews has background, and the canvas is a LinearLayout set via XML, so my onCreate() already has setContentView(R.layout.game_canvas);, and I'd be using addContentView() to add additional views, but this method too accepts LayoutParams object as it second parameter, so what exactly should I set for this, when I add my FrameLayouts using this method?
My question might be confusing itself, so please let me know if I need to elaborate.
FrameLayouts are designed to only hold one View, so this isn't really the appropriate choice.
Use a RelativeLayout to hold all of your ImageViews. You can position each ImageView by setting the margins in their LayoutParams.
E.g. The following code would place an ImageView at coordinates 50,50:
RelativeLayout imgLayout = new RelativeLayout(this);
ImageView iv = new ImageView(this);
iv.setImageResource(R.drawable.an_image);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
lp.setMargins(50, 50, 0, 0);
lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
lp.addRule(RelativeLayout.ALIGN_PARENT_TOP);
imgLayout.addView(iv, lp);
You can then add this RelativeLayout to your main LinearLayout using its addView() method.
Related
I want to create this sort of a view where the cross should be separate image view as I want it to be clickable. How can I achieve this ?
It would be great If I can create this view programatically as I am a dynamic list of images and I am programatically creating the image Views. All I need now is to add the overlapping imageview as well.
Thanks in advance
Use FrameLayout and you can overlay views on top of each other
Ex:
FrameLayout frame = (FrameLayout) findViewById(R.id.frame);
ImageView image = new ImageView(this);
iv.setImageResource(R.drawable.image);
ImageView cross = new ImageView(this);
i.setImageResource(R.drawable.cross);
FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
layoutParams.gravity = Gravity.RIGHT | Gravity.TOP;
i.setLayoutParams(layoutParams);
frame.addView(image);
frame.addView(cross);
Create a RelativeLayout programmatically, which contains two ImageViews. Place your image in the first one, and your second image in the second one. Adjust the margins accordingly to place it in the top right corner.
First create a completely new layout to use as an placeholder for example "partial_layout.xml". Then in your code first make a LayoutInflater with something like this:
LayoutInflater mInflater = (LayoutInflater) this.getSystemService(this.LAYOUT_INFLATER_SERVICE);
then try to get a fresh copy of this layout with something like this:
View convertView = mInflater.inflate(R.layout.partial_layout, null);
now put your current data to this view, and finally add this view to your content view.
If you create a list of views, you can still use XML by inflating it only when needed - just watch the lecture "the world of listView" in order to do it correctly. Using ListView is much more efficient than creating as many views as the number of items to show (for example, if there are 100 images to show, only those that are on screen need to be created).
Anyway, the xml can contain either FrameLayout or RelativeLayout as the root view, and you just put the 2 imageViews according to the right position you wish to have. You can use the UI designer for this, or edit the XML itself by adding margin-top for the larger image. also, make sure the larger image is written there before the small one.
as for the clicking, you can use setOnClickListener on the small imaveView.
BTW, if it's just images, you should probably use GridView instead of ListView.
How can I retain attributes of the children in a RelativeLayout when dynamically adding ImageViews?
I have a custom ImageView I want to add at runtime to an empty RelativeLayout (nothing inside in XML), I can add the first, then move, scale and rotate them, it works fine.
When I add another ImageView all previously added instances loose their position and their size, but when I touch them they get back just their size, not the position.
In my ImageView I'm overriding onDraw and onTouch, do I need to override something else?
Maybe I have to write my own RelativeLayout implementation? I wouldn't!
This is the pseudocode for adding new ImageView:
create new instance of ImageView
set bitmap
set scaletype
add imageview to the RelativeLayout container
I even tried to set a standard layout parameter for the brand new added ImageView with the same result.
I tried to get the margins for every children, based on its position, and the re set the layout with ImgeView.setLayout(l, t, r, b);
no success...
Here's the XML RelativeLayout container, pretty simple, maybe too much?
<RelativeLayout
android:id="#+id/face_container"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
</RelativeLayout>
Do you need more details to help me? Please ask, I can post the code too, but I have to clean it up a bit before, I can do it tomorrow, in the meantime please give me some advice.
In a RelativeLayout all view positions are related to the others views. So, as you do in xml, you should provide for each view the relative parameters.
Before add imageView to the RelativeLayout call setLayoutParams(layoutParams):
// Create a new RelativeLayout.LayoutParams instance
RelativeLayout.LayoutParams layoutParams =
new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
// add roules
layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);
layoutParams.addRule(.........
layoutParams.addRule(.........
//add params to view
imageView.setLayoutParams(layoutParams);
//add imageview to the RelativeLayout container
yourRelativeLayout.addView(imageView);
Look here for all rules.
I have a relativeLayout like below:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:id="#+id/parent" >
<ListView
android:layout_width="360dp"
android:layout_height="600dp"
android:id="#+id/list"
android:inputType="text"
android:maxLines="1"
android:layout_margin="50dp"
android:layout_alignParentRight="true"
/>
</RelativeLayout>
In the java code, I want to add a view to the left of the listview, but it didn't worked:
m_relativeLayout = (RelativeLayout)findViewById(R.id.parent);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
layoutParams.addRule(RelativeLayout.LEFT_OF, m_listView.getId());
Button button2 = new Button(this);
button2.setText("I am button 2");
m_relativeLayout.addView(button2, layoutParams);
only if I set the listview to alignParentRight, it will work. Is this an android bug or I'm missing something?
I always try addView(View child, int index, LayoutParams params), but it might only work in the linearlayout. So is there an normal solution to make the RelativeLayout.LEFT_OF work?
EDIT
I have tried RelativeLayout.BELOW and RelativeLayout.RIGHT_OF, and they worked perfectly, so it means I don't have enough place to get the button? I tried to give more space, but it still not work.
I use Toshiba AT100 (1280*800) and landscape, so the space is enough. Test below and right just same as the left. I think If i put an control A in the relativelayout, then I add control B and decalare it's on the left of the control A, the result should be the control B will push the control A to its right, right?
I think If i put an control A in the relativelayout, then i add control B and declare it's on the left of the control A, the result should be the control B will push the control A to its right, right?
Your assumption is incorrect, the control A will not be pushed to the right unless you specified this with a RelativeLayout.LayoutParams rule. RelativeLayout places its children one one top of each other starting at the top-left corner of the screen if you don't specify placement rules for them. When you add the View A to the RelativeLayout without any rules(like layout_alignParentRight) it will be placed starting from the top-left corner of the screen. Then, when you add the View B, the rule to_leftOf will apply to this View position but this rule doesn't mean anything for the View A who will maintain its position on the screen. This will make View B to be place to the left of View A but outside of the screen as View A bounds start from the left border of the screen.
The Button will be placed to the left of the ListView when you use layout_alignParentRight="true" because there is now space to actually see the Button(it's not outside anymore). addView(View child, int index, LayoutParams params) works in a LinearLayout because the LinearLayout arranges its children in a row or column(depending on orientation) so when you add a View at a specific position, it will push the other Views after it to the right or below(depending on orientation)(there is no relative positioning of the views in a LinearLayout, the only rule is that the children come one after the other).
Starting with the ListView without any rules set on it, here is an example on how to make the Button to appear on the left of the ListView:
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
Button button2 = new Button(this);
button2.setText("I am button 2");
button2.setId(1000);
m_relativeLayout.addView(button2, layoutParams);
RelativeLayout.LayoutParams rlp = (RelativeLayout.LayoutParams) m_listView
.getLayoutParams();
rlp.addRule(RelativeLayout.RIGHT_OF, button2.getId());
The Button will be added as normal to the screen and it will appear starting from the top-left corner of the screen. Without the two lines from the code above the Button and ListView will overlap as this is the normal behavior of RelativeLayout for children without any rules on them. We then explicitly modify the position of the ListView to move it to the right(with the last two line from the code above).
If your variable names are indicative, it's because you are adding the widget to a LinearLayout, so tags for a RelativeLayout get ignored.
This line is the one I'm talking about:
m_linearLayout.addView(button2, layoutParams);
EDIT
You say alignParentRight works... the only difference there is that ot doesn't take an anchor parameter. Perhaps m_listView.getId() isn't returning the proper id. You could step through with the debugger and see if it's returning a proper value.
Maybe you could try calling the id specifically...
layoutParams.addRule(RelativeLayout.LEFT_OF, R.id.list);
To perform it, use predefined view ID or declare one. In values folder create ids.xml then add a Item like this:
<item name="imageViewID" type="id"/>
use this id in your code where you are creating new Instance of view like this:
RelativeLayout layout=new RelativeLayout(context);
ImageView imageView = new ImageView(context);
imageView.setId(R.id.imageViewID);
RelativeLayout.LayoutParams layoutParams = new LayoutParams(50, 50);
layoutParams.addRule(RelativeLayout.CENTER_HORIZONTAL);
layout.addView(imageView, layoutParams);
TextView textView = new TextView(context);
RelativeLayout.LayoutParams textViewParams= new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
textViewParams.addRule(RelativeLayout.CENTER_HORIZONTAL);
textViewParams.addRule(RelativeLayout.BELOW, imageView.getId());
layout.addView(nameView, nameLayoutParams);
or we can directly use this function View.generateViewId() to perform the same. Like this:
imageView.setId(View.generateViewId());
I think you might have forgotten to add m_listView to the RelativeLayout or m_listView's visibility would be GONE.
Can you please check for that?
setId before align is called, especially for the new object view.
If you are using a custom id and not a regular generated Android id (eg. R.id.my_id), make sure that the id is not equal to 0 (or negative), otherwise the rule will be ignored.
I do a constructer and set some view inside programmatically and add some rule. so When i call constructer i see default view.
Now i want to reach someof this view and change set margin.It is basic i know but i dosent work for me.
Can anybody help?
Part of my constructer:
_photoImgVw = new ImageView(getContext());
_photoImgVw.setImageResource(R.drawable.pic);
_photoImgVw.setAdjustViewBounds(true);
_photoImgVw.setMaxWidth(100);
_photoImgVw.setId(2);
lp2=new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
lp2.setMargins(0,0,0,0);
addView(_photoImgVw,lp2);
LayoutParams lp3=new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
lp3.addRule(RelativeLayout.RIGHT_OF,_photoImgVw.getId());
lp3.setMargins(0,0,0,0);
addView(_nameTxt,lp3);
Call in the activity for change:
facebookPersonView.lp2.setMargins(10,300,100,20);
Make sure that the layout params lp2 are an instance of the class RelativeLayout.LayoutParams instead of MarginLayoutParams, or any other subclass of it named LayoutParams (there are quite a few, see the top of the documentation).
If the params are an instance of the latter, they won't contain any rules for the RelativeLayout. Which means the parent layout doesn't know where to place the view¹ and therefore can't make any sense out of the margins.
It's best to declare that explicitly in a way like this:
RelativeLayout.LayoutParams lp2
= new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
lp2.setMargins(0,0,0,0);
addView(_photoImgVw,lp2);
¹ It will still make it visible in the top-left corner, but it's kind of an undefined state.
I'm trying to build an android application that features a graphical display drawn within a RelativeLayout. I want to place "+" and "-" buttons next to several of the parameters, which are drawn at various points on the canvas. The positions are free-form don't seem to conform to any of the standard XML layouts.
I know how to create the buttons programmatically, but I don't know how to place them over the canvas where I need them to be. I'm assuming that this would be done in the view thread's doDraw() method, after all the graphics have been drawn, but how?
I struggled with the same problem, and found out great solution.
RelativeLayout rules like "leftOf" or "rightOf" can be implemented programmatically like this:
RelativeLayout container = new RelativeLayout(getApplicationContext());
Button weight = new Button(getApplicationContext());
final int WEIGHT_ID = 0;
weight.setId(WEIGHT_ID);
weight.setText("0.0");
LayoutParams wrapBoth =
new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
container.addView(weight, wrapBoth);
Button increaseWeight = new Button(getApplicationContext());
increaseWeight.setText("+");
// Note the difference: RelativeLayout.LayoutParams in spite of LayoutParams
RelativeLayout.LayoutParams toBeRightOfWeight =
new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
container.addView(parameter,wrapBoth);
// Sweet part
clearAirParams.addRule(RelativeLayout.RIGHT_OF, WEIGHT_ID);
container.addView(increaseWeight, toBeRightOfWeight);
So, in code you can create a 'container' RelativeLayout, then add several Views with unique ID's and, finally, create RelativeLayout.LayoutParams object to achieve sweet-like-sugar methods for alignment, like in XML.