I am trying to add multiple relative layouts to a Linear layout. I am using the following lines of code.
LayoutInflater inflator = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout item = (LinearLayout)findViewById(R.id.reviews);
for(int i=0 ; i<2 ; i++){
View child = inflator.inflate(R.layout.review_item, null);
child.setId(i);
child.setTag(i);
item.addView(child);
}
But I can only see one child view. Can anyone tell me where I am going wrong.
Declare the LinearLayout item outside of the for loop.
The way you're doing it the variables value will be overwritten each time you run through the for loop. So your method should look like this:
public void somemethod(){
LayoutInflater inflator = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout item = (LinearLayout)findViewById(R.id.reviews);
for(int i=0 ; i<2 ; i++)
{
View child = inflator.inflate(R.layout.review_item, null);
child.setId(i);
child.setTag(i);
item.addView(child);
}
}
You need to take the first two lines outside of the for loop. You're inflating the LinearLayout twice, which overrides the first layout you inflate, rather than adding to it. By putting those two lines before the for loop starts, you'll add both child views to a single LinearLayout.
Related
I have an Activity and its layout. Now I need to add a LinearLayout from another layout, menu_layout.xml.
LayoutInflater inflater;
inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout layout = (LinearLayout) inflater.inflate(R.layout.menu_layout, null);
After this, findViewById() returns null. Is there is any solution for that?
Note: I can't put both XML in one place, and using <include> also is not working.
Explanation
When you inflate a layout, the layout is not in the UI yet, meaning the user will not be able to see it until it's been added. To do this, you must get a hold of a ViewGroup (LinearLayout,RelativeLayout,etc) and add the inflated View to it. Once they're added, you can work on them as you would with any other views including the findViewById method, adding listeners, changing properties, etc
Code
//Inside onCreate for example
setContentView(R.layout.main); //Sets the content of your activity
View otherLayout = LayoutInflater.from(this).inflate(R.layout.other,null);
//You can access them here, before adding `otherLayout` to your activity
TextView example = (TextView) otherLayout.findViewById(R.id.exampleTextView);
//This container needs to be inside main.xml
LinearLayout container = (LinearLayout)findViewById(R.id.container);
//Add the inflated view to the container
container.addView(otherLayout);
//Or access them once they're added
TextView example2 = (TextView) findViewById(R.id.exampleTextView);
//For example, adding a listener to the new layout
otherLayout.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//Your thing
}
});
Assuming
main.xml contains a LinearLayout with the id container
other.xml is a layout file in your project
other.xml contains a TextView with the id exampleTextView
Try using
layoutObject.findViewById();
The following piece of code is inflating the same view for 20 times. Since inflating is costly. I want to inflate it only one, and use the same view for 20 items, i just want to change the visible data in the UI.
LinearLayout ll = new LinearLayout(context);
for (int i = 0; i < 20; ++i) {
View itemView = inflater.inflate(getLayoutId(), parent, false);
itemView.setText(data.getName(i);
ll.add(itemView);
}
I want something like this.
LinearLayout ll = new LinearLayout(context);
View itemView = inflater.inflate(getLayoutId(), parent, false);
for (int i = 0; i < 20; ++i) {
itemView.setText(data.getName(i);
ll.add(itemView);
}
But am not able to use the itemView obj this way.
Can anyone tell me how to use the view many times once it inflated.
You cannot do that. If you think its costly then find another way to create your layout.
But consider gridViews for example. They create a ton of views and show them and that works great.
You cannot add the same object of a view 2 times to a layout. Every object has its own state which in your case in a way says that you will share the state between all your 20 views which doesn't make sense to do, meaning changing the text on one textView will change it on all the rest...
Just inflate 20 seperate views and fill them appropriately.
Also consider using ListView or GridView if you actually have the exact same view it can offer some nice features like view recycling.
You should use ViewHolder patern:
http://developer.android.com/training/improving-layouts/smooth-scrolling.html#ViewHolder
it should do all things You want
Say I have a LinearLayout with some elements in it as an .xml file.
In Java, I need to somehow "clone" it a few times into an array, edit some of its children, and then loop through the array, adding each LinearLayout to my main view.
What do you think would be the correct way to "clone" this layout from an xml file into an array element in java?
Thanks!
LayoutInflater vi = (LayoutInflater) myContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.yourLayoutId, null);
you can do some thing like this to inflate the view, and then modify the element iside the view using the findViewById method. Hope this will help
Something like this:
....
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout layout = null;
for(....) {
layout = (LinearLayout) inflater.inflate(R.layout.YOUR_LAYOUT_ID, null);
someList.add(layout);
}
.....
Try getting the layout in a variable:
for (int c=0; c < count; c++)
{
LinearLayout layout = (LinearLayout) findViewById(R.id.yourmainlayout);
// do something with layout
// assign layout to a variable or add it on another layout
}
I have the same View inflated (from XML) multiple times. When I call findViewById(R.id.my_layout).setVisibility(View.GONE) I want to apply it on all such views.
How do I do that?
There isn't a version of findViewById() that returns all matches; it just returns the first one. You have a few options:
Give them different ids so that you can find them all.
When you inflate them, store the reference in an ArrayList, like this:
ArrayList<View> mViews = new ArrayList<View>();
Then when you inflate:
LayoutInflater inflater = getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mViews.add(inflater.inflate(R.layout.your_layout, root));
Then when you want to hide them:
for (View v : mViews) { v.setVisibility(View.GONE); }
Depending on what you're doing with these Views, the parent layout may have a way of accessing them. E.g., if you're putting them in a ListView or some such. If you know the parent element you can iterate through the children:
ViewGroup parent = getParentSomehow();
for (int i = 0; i < parent.getChildCount(); ++i) {
View v = parent.getChildAt(i);
if (v.getId() == R.id.my_layout) {
v.setVisibility(View.GONE);
}
}
If the above options don't work for you, please elaborate on why you're doing this.
Modify on the View that holds the inflated layout.
E.g:
If you have
View v = inflater.inflate(.... );
you change the visibility onto this view. v.setVisibility(View.GONE);
I have a LinearLayout with vertical orientation as parent, I want to add some view programmatically multiple times to this parent. Right now I am inflating the child every time getting new references to every UI element before adding to parent. This doesn't seem to be very efficient, is there any better way of doing this.
Current code I am using is below, If I inflate only once before for loop I get runtime error "he specified child already has a parent. You must call removeView() on the child's parent first."
LayoutInflater inflator = LayoutInflater.from(getBaseContext());
LinearLayout parentPanel = findViewById(R.id.parent_pannel);
ArrayList<String> myList = getData();
for(String data : myList) {
// inflate child
View item = inflator.inflate(R.layout.list_item, null);
// initialize review UI
TextView dataText = (TextView) item.findViewById(R.id.data);
// set data
dataText.setText(data);
// add child
parentPanel.addView(item);
}
Did you actually check if inflate is slow? As far as I know, inflating view is very fast (almost as fast as creating views manually).
It might be surprising for you to hear but inflate in fact does not parse the XMLs at all. XMLs for layout are parsed and pre-processed at compile time - they are stored in a binary form which makes view inflation very efficient (that's why you cannot inflate a view from an XML generated at runtime).
I'm not sure what your view is but have you creating it manually over inflating the XML:
ArrayList<String> myList = getData();
for(String data : myList) {
LinearLayout layout = new LinearLayout(this);
layout.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
TextView textView = new TextView(this);
textView.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
textView.setText(data);
layout.addChild(textView);
parentPanel.addView(layout);
}
But yeah your clearly attempting something that has been done for you with Simple ListView & API
You can't, even if you try to create a new view from the old view object the object will be passed by reference not value, and hence you will got an Exception as the childAlreadyHasParent, and so, the only way is to put the view into a for loop with the number of times you want it to be inflated, and this loop must contain the creating process from beginning not only the inflating lines.
Inflating multiple times cannot be done the same way doing it in single shot. Hope this works
LayoutInflater inflator = (LayoutInflater).getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout parentPanel = findViewById(R.id.parent_pannel);
ArrayList<String> myList = getData();
for(String data : myList) {
// inflate child
View item = inflator.inflate(R.layout.list_item, null);
// initialize review UI
TextView dataText = (TextView) item.findViewById(R.id.data);
// set data
dataText.setText(data);
// add child
parentPanel.addView(item);
}
This will work, at the least worked me