I am trying to initialize all the navigation bar buttons and assign Black background color, when user clicks on one of the button, that one should change color and all other should remain Black.
But i get the following error:
Attempt to invoke virtual method 'android.view.View android.widget.LinearLayout.getChildAt(int)' on a null object
reference
public void bottomNavIcons(View view){
for(int i=0;i<Constants.bottom_nav_icon.length;i++) {
LinearLayout linearLayout = (LinearLayout) view.findViewById(R.id.bottom_nav_bar);
ImageButton imageButton = new ImageButton(getActivity());
imageButton.setClickable(true);
imageButton.setOnClickListener(onClickListener);
imageButton.setImageResource(Constants.bottom_nav_icon[i]);
imageButton.setBackgroundColor(Color.BLACK);
imageButton.setPadding(70, 0, 70, 0);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
linearLayout.addView(imageButton, layoutParams);
}
}
View.OnClickListener onClickListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
LinearLayout linearLayout = (LinearLayout) v.findViewById(R.id.bottom_nav_bar);
for(int i=0;i<Constants.bottom_nav_icon.length;i++) {
ImageView imageButton = (ImageView) linearLayout.getChildAt(i);
imageButton.setBackgroundColor(Color.BLACK);
}
v.setBackgroundColor(Color.BLUE);
}
};
I think this is the problem:
LinearLayout linearLayout = (LinearLayout) v.findViewById(R.id.bottom_nav_bar);
You are assuming the LinearLayout is inside the view which is clicked - my best guess is this is not true (you probably want to get the clicked view's parent, not child).
You have 2 options:
Start iterating the view hierarchy to the top (i.e. call v.getParent()) until you reach the LinearLayout.
Call findViewById on the containing activity (or fragment's root view) instead of the v object.
Related
I have created multiple button in a layout dynamically.Now,how can i remove this layout after used.
for example:-
LinearLayout parent = new LinearLayout(this);
parent.setLayoutParams(new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT));
parent.setOrientation(LinearLayout.HORIZONTAL);
for (int i = 0; i < 10; i++) {
Button b = new Button(this);
b.setText("Primary");
Drawable image = ContextCompat.getDrawable(
getApplicationContext(),
R.drawable.your_image);
image.setBounds(0, 0, 60, 60);
b.setCompoundDrawables(null, null, image, null);
parent.addView(b);
}
If you still have the instance of the linear layout, just call removeView(...) as you did for the addView(...).
you can set visibility of linearLayout to gone by parent.setVisibility(View.GONE);
or remove all the views from the linearLayout by parent.removeAllViews().
You'll have to use removeView(View) or removeViewAt(position) from the parent, depending on if you keep track of the indexes or the objects.
parent.removeView(button);
parent.removeViewAt(buttonIndex);
get the parent of the view and remove that view from its parent
((ViewGroup) parent.getParent()).removeView(parent);
Try this:
View button = view.findViewById(R.id.buttonid);
((ViewGroup) button.getParent()).removeView(button);
I had removed ParentView from its child (Textview's) click.
tvClose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (llContainer.getChildCount() > 1) {
((LinearLayout) view.getParent()).removeView(view);
}
}
});
I want to parse text, and create for each word - button, but i don't know how to arrange them one after the other
String s = "Alice was beginning to get very tired of sitting";
String[] q = s.split(" ");
for (int i = 0; i < q.length; i++) {
Button myButton = new Button(this);
myButton.setText(q[i]);
RelativeLayout layout = (RelativeLayout) findViewById(R.id.layout1);
layout.addView(myButton, params);
}
See this custom library: FlowLayout
While you're adding views inside FlowLayout, it automatically wraps when there is no space for the next item.
There's not much wrong about your approach, it's only that relative layout as name suggests requires child views to have some parameters to align the views relative to them e.g. above, below etc. As a result you are getting views overlapping each other and hence only the last added view is visible being on top.
Use FlowLayout instead and you'll be fine.
You need to define RelativeLayout parameters as in example below
Heres an example to get you started, fill in the rest as applicable:
TextView tv = new TextView(mContext);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.ALIGN_PARENT_LEFT, RelativeLayout.TRUE);
params.leftMargin = 107
...
mRelativeLayout.addView(tv, params);
The docs for RelativeLayout.LayoutParams and the constructors are
here
From: How to add a view programmattically to RelativeLayout?
Check the link below to get more useful informations.
Hope it will help
In the following code, you should change the upper limits of the for, to a variable.
public class MainActivity
extends Activity
implements View.OnClickListener {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TableLayout layout = new TableLayout (this);
layout.setLayoutParams( new TableLayout.LayoutParams(4,5) );
layout.setPadding(1,1,1,1);
for (int f=0; f<=13; f++) {
TableRow tr = new TableRow(this);
for (int c=0; c<=9; c++) {
Button b = new Button (this);
b.setText(""+f+c);
b.setTextSize(10.0f);
b.setTextColor(Color.rgb( 100, 200, 200));
b.setOnClickListener(this);
tr.addView(b, 30,30);
} // for
layout.addView(tr);
} // for
super.setContentView(layout);
} // ()
public void onClick(View view) {
((Button) view).setText("*");
((Button) view).setEnabled(false);
}
} // class
I had to implement the expand/collapse(show/hide) a particular view on click of a some other view..Finally got it working but with a small problem.
I have a relative layout with two children: first is the textview and second is a linear layout.
On the click event of the textview i set the visibility(VISIBLE or GONE) of the following linear layout.
Now the problem is that after the linear layout is visible it somehow manages to hide the textview..
I tried textview.bringToFront() but it just makes the textview overlap the first row of the linearlayout ie the textview comes on top of the linear layout content.
I tried putting the textview in a linearlayout, but it makes no difference.
I tried setting the linear layout as BELOW. All in vain..
I know the textview exists because when i click the first row(which is overlapping the textview) the click event gets fired..
All i want is that no matter what my textview should be visible and the linear layout must take its position below the textview if it is visible..
EDIT
RelativeLayout wrapperlayout = new RelativeLayout(getActivity());
//wrapperlayout.setLayoutParams(new android.widget.RelativeLayout.LayoutParams(android.widget.RelativeLayout.LayoutParams.MATCH_PARENT, android.widget.RelativeLayout.LayoutParams.WRAP_CONTENT));
//-------------HANDLE---------------------------
TextView txtHeader = new TextView(getActivity());
txtHeader.setOnClickListener(new OnClickListener() {
#SuppressLint("NewApi")
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
TextView tv = (TextView) v;
RelativeLayout rParent = (RelativeLayout) tv.getParent();
LinearLayout lInner = (LinearLayout) rParent.getChildAt(1);
if(lInner.isShown())
{
tv.setCompoundDrawablesWithIntrinsicBounds(R.drawable.expand, 0, 0, 0);
//tv.bringToFront();
lInner.setVisibility(View.GONE);
//lInner.startAnimation(AnimationUtils.loadAnimation(getActivity(), R.anim.slide_up));
}
else{
tv.setCompoundDrawablesWithIntrinsicBounds(R.drawable.collapse, 0, 0, 0);
//tv.bringToFront();
lInner.setVisibility(View.VISIBLE);
lInner.setTop(tv.getBottom());
//lInner.startAnimation(AnimationUtils.loadAnimation(getActivity(), R.anim.slide_down));
}
}
});
txtHeader.setText("Header");
txtHeader.setCompoundDrawablesWithIntrinsicBounds(R.drawable.expand, 0, 0, 0);
txtHeader.setLayoutParams(new android.widget.LinearLayout.LayoutParams(android.widget.LinearLayout.LayoutParams.MATCH_PARENT, android.widget.LinearLayout.LayoutParams.WRAP_CONTENT));
//--------------CONTENT-------------------------
LinearLayout lContent = new LinearLayout(getActivity());
lContent.setLayoutParams(new android.widget.LinearLayout.LayoutParams(android.widget.LinearLayout.LayoutParams.MATCH_PARENT, android.widget.LinearLayout.LayoutParams.WRAP_CONTENT));
lContent.setOrientation(LinearLayout.VERTICAL);
HashMap<String, String> MySet = new HashMap<String, String>();
MySet = getData();
Iterator<String>RowItr = MySet.keySet().iterator();
int rowcnt = 0;
while (RowItr.hasNext()) {
LinearLayout lRow = new LinearLayout(getActivity());
LinearLayout.LayoutParams lparams1 = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
lRow.setLayoutParams(lparams1);
lRow.setOrientation(LinearLayout.HORIZONTAL);
TextView txtLbl = new TextView(getActivity());
txtLbl.setLayoutParams(new LinearLayout.LayoutParams(0, android.view.ViewGroup.LayoutParams.WRAP_CONTENT, 1));
TextView txtVal = new TextView(getActivity());
txtVal.setLayoutParams(new LinearLayout.LayoutParams(0, android.view.ViewGroup.LayoutParams.WRAP_CONTENT, 1));
String Lbl = RowItr.next();
txtLbl.setText(Lbl);
if(rowcnt % 2 != 0)
lRow.setBackgroundColor(Color.parseColor("#dbe4f0"));
else
lRow.setBackgroundColor(Color.parseColor("#ffffff"));
txtVal.setText(MySet.get(Lbl));
lRow.addView(txtLbl);
lRow.addView(txtVal);
lRow.setPadding(10, 10, 10, 10);
lContent.addView(lRow);
rowcnt++;
}
lContent.setVisibility(View.GONE);
wrapperlayout.addView(txtHeader);
wrapperlayout.addView(lContent);
RelativeLayout.LayoutParams rPARAMS = new RelativeLayout.LayoutParams(android.widget.RelativeLayout.LayoutParams.MATCH_PARENT, android.widget.RelativeLayout.LayoutParams.WRAP_CONTENT);
//rPARAMS.addRule(RelativeLayout.ABOVE, txtHeader.getId());
//rPARAMS.addRule(RelativeLayout.BELOW, lContent.getId());
wrapperlayout.setLayoutParams(rPARAMS);
well you can store your LinearLayout as an instance variable, and simply call layout.setvisibility(View.GONE); in your onClick method. Doubt theres any other solution unless you want to save the parent(the layout that both of your views are attached to) and perform findViewById inside onClick or call getChildAt(1) orso
Got a solution.. i tried setting margins..and it all worked out well.. te handle and content both are visible without hiding any other views..
I have a question regarding Android Activitys:
An Activity has the Method addContentView(View) while a ViewGroup has a (similar?) addView(View) Method.
Unfortunately its undocumented where the View from addContentView is placed. Is it like a LinearLayout just adding the View to the bottom, or is it more like a FrameLayout, which adds its Views "onTop" ? Does it depend on the ViewGroup set by setContentView?
If I dive into the sources I see that addContentView will call Window's abstract Method addContentView. Unfortunately I cannot see which class is implementing this Method. So whats the behaviour of Activitys addContentView exactly?
The base layout of every activity is a FrameLayout. This means the layout you usually set via setContentView() is a child of this layout. addContentView() adds just another child, therefore it behaves like a FrameLayout (which means it adds new UI elements above existing ones).
You can check this by using a tool called hierachyviewer from your ANDROID_SDK\tools folder. Here are two screenshots:
This is the layout before calling addContentView(), my activity consists of the default FrameLayout, holding a LinearLayout with a Button (my layout here). This is reflected in the bottom row here, the other elements above are the title/statusbar.
After adding a TextView via addContentView() it looks like this. You can see that the base FrameLayout got a new child.
public void addContentView(View view,
LayoutParams params) {
mActivity.addContentView(view, params);
}
//
public static void SetActivityRoot(Activity c) {
View v = ((ViewGroup)c.findViewById(android.R.id.content)).getChildAt(0);
ScrollView sv = new ScrollView(c);
LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
sv.setLayoutParams(lp);
((ViewGroup) v.getParent()).removeAllViews();
sv.addView((View) v);
c.addContentView(sv, lp);
}
//
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout mainLayout =
(LinearLayout)findViewById(R.id.mainlayout);
//newButton added to the existing layout
Button newButton = new Button(this);
newButton.setText("Hello");
mainLayout.addView(newButton);
//anotherLayout and anotherButton added
//using addContentView()
LinearLayout anotherLayout = new LinearLayout(this);
LinearLayout.LayoutParams linearLayoutParams =
new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
Button anotherButton = new Button(this);
anotherButton.setText("I'm another button");
anotherLayout.addView(anotherButton);
addContentView(anotherLayout, linearLayoutParams);
}
}
Alright. So I start my activity in Main, grab the FragmentManager and instantiate a Fragment which needs to return a View. OK. So I extended a LinearLayout in order to have something to return. My Activity and Fragment are happy but I am not.
Three LinearLayouts which I create in the parent ViewGroup are there (code below). I have verified this by counting children and by setting the background colors to contrast one another. The parent also changes size depending on how tall I make the children (when I don't declare any LayoutParams on the parent).
public class Mainmenu extends LinearLayout {
private ArrayList<LinearLayout> panes = new ArrayList<LinearLayout>();
private Context context;
private final int
LEFT = 0, CENTER = 1, RIGHT = 2;
public Mainmenu(Context c) {
super(c);
context = c;
setBackgroundColor(Color.WHITE);
setOrientation(HORIZONTAL);
setLayoutParams(
new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.FILL_PARENT,
LinearLayout.LayoutParams.FILL_PARENT));
for(int i=0;i<=RIGHT;i++){ //Create the (3) Panes
LinearLayout ll = new LinearLayout(context);
ll.setLayoutParams(
new LinearLayout.LayoutParams(300,
LinearLayout.LayoutParams.FILL_PARENT));
switch(i){
case LEFT | RIGHT:
ll.setBackgroundColor(Color.DKGRAY);
default:
ll.setBackgroundColor(Color.BLACK);
}
ll.setOrientation(LinearLayout.VERTICAL);
ll.setVisibility(VISIBLE);
ll.setWillNotDraw(false);
panes.add(i, ll);
addView(ll);
}
LinearLayout.LayoutParams buttons =
new LinearLayout.LayoutParams(100, 50);
buttons.setMargins(15, 5, 5, 0);
TextView tv1 = new TextView(context);
tv1.setText("hello");
tv1.setTextColor(Color.RED);
panes.get(LEFT).addView(tv1, buttons);
Button button = new Button(context);
button.setText("Launch Editor");
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
}
});
panes.get(CENTER).addView(button);
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// TODO Auto-generated method stub
}
}
Nothing is null, all my elements (3 ViewGroups and 2 Views) are present in the tree but not visible. I've tried bringing children to the front through the parent and the children, creating them in different super.methods and invalidating the view in a similarly shotgunned fashion. What's going on? Is it as simple as not having any idea what I'm doing?
The problem is simply because you are overriding onLayout and doing nothing with it. You only need to override this if you want to layout the children yourself (ie, you were designing some unique custom layout). In this case just remove that method, or call super.onLayout.