Develop Reference

Setting the text of a programatically created button

Basic question regarding setting the text of a programatically created button. As seen in my code below I've done the basics in terms of creating the button but my button appears as seen in my attached image. Basically the text in the button doesn't appear as expected. Any ideas why?
Note: I've declared button as a public instance variable right above my onCreate() and has been added correctly to my relative layout using addView();
// Create User button
btnUserAdmin = new Button(this);
// Customise the UserAdmin button
btnUserAdmin.setBackgroundColor(Color.BLUE);
btnUserAdmin.setTextSize(13.7f);
btnUserAdmin.setTextColor(Color.parseColor("#FFCC00"));
btnUserAdmin.setText("USER ADMINISTRATION");
btnUserAdmin.setGravity(Gravity.LEFT);
Thanks.

You should specify the dimensions of the button, otherwise the size could be unexpected. For instance
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.MATCH_PARENT );
btnUserAdmin.setLayoutParams(lp);
also, you can directly set them when you add the buttom
yourRelativeLatout.addView(btnUserAdmin, lp);
Also remember that numeric values for the dimensions (of the bottom or the layout) usually are evil. As you can, use only WRAP_CONTENT and MATCH_PARENT

Android add View

I have the following problem:
The code below successfully adds my TextView to my custom RelativeLayout:
RectF rectRecord = getItemRect(trCurrent);
TextView tv = new TextView(this.getContext());
tv.setLeft((int)rectRecord.left);
tv.setRight((int)rectRecord.right);
tv.setTop((int)rectRecord.top);
tv.setBottom((int)rect.bottom);
addView(tv);
Unfortunately the methods ("setLeft,setRight,setTop,setBottom") aren't available on Android older than 3.0.
So I tried to add my TextView the alternative way:
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
params.setMargins((int)rectRecord.left, (int)rectRecord.top, (int)rectRecord.right, (int)rectRecord.bottom);
//tv.setLayoutParams(tv);
addView(tv, params);
Doing it that way does not show a child control ...
I already tried to change the class my host control derives from ViewGroup to LinearLayout, RelativeLayout and the deprecated AbsoluteLayout but always the same.
Also removed my custom onDraw and onMeasure and "setWillNotDraw(false);" but that didn't solved my problem.
Snippet 1 is displaying my child views.
Snippet 2 does not show a child.
Can anyone point to the solution for this problem?

Your margins are set to 1234 - that's 1234 dip (density independent PIXELS) and that is huge. Your control doesn't show up on the screen because margins are too big, and your control has no place to show on the screen.

Adding a child view to a custom view within Android, programmatically

What I am trying to do is simply add an imageButton view as a child of a custom view, in the top right corner. My custom view extends Webview. I have had no problem adding the imageButton to my custom view, I just can't move it to the top right corner. I need to do this programmatically, not in xml. I would never think something this simple would require me to post on here, but I really can't figure it out.
Here is what I am using to add the imageButton to the custom view currently, but it's at the top left corner:
public class customView extends WebView {
private void imageButtonInit() {
ImageButton closeImageButton = new ImageButton(getContext());
Drawable image = getResources().getDrawable(com.package.image);
closeImageButton.setBackgroundDrawable(image);
closeImageButton.setLayoutParams(new RelativeLayout.LayoutParams(25, 25));
closeImageButton.bringToFront();
customView.this.addView(closeImageButton);
}
}
What I have tried in order to move it to the top right corner:
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(25, 25);
lp.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, -1);
closeImageButton.setLayoutParams(lp);
customView.this.addView(closeImageButton);
As well as:
FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(25, 25, Gravity.RIGHT|Gravity.TOP);
closeImageButton.setLayoutParams(lp);
customView.this.addView(closeImageButton);
All of which results in the imageButton being placed in the top left corner. This is my first post on this site so I hope the question is properly formatted. Please no xml solutions. Thanks everyone.

I think what you are doing in your other two methods is literally setting your CustomView to have those layout params. What you should try instead is set the layout params of your child using this method;
customView.this.addView(child, params);
where child is your image button and params is the layout params.

RelativeLayout add rule "RelativeLayout.LEFT_OF" not working

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.

Android button in arbitrary position over RelativeLayout

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.