Develop Reference

Use addView instead of a listView

I'm trying to implement a code where there are multiple items.
I am able to populate the ListView and display all these items but I want to inflate a view onItemClick. Unfortunately, AdapterView does not support addView().
So now I want to use addView() to dynamically add items by traversing an ArrayList<>().
How do I do it?
Basically, I want to display a Custom Keypad layout next to a TextView inside the ListView and update the Value of the TextView
This is what I'm trying to do now.
public class OrderSummary extends Activity {
LinearLayout linearLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_order_summary);
linearLayout = new LinearLayout(this);
View view = View.inflate(this, R.layout.top_bar_layout, null);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
linearLayout.addView(view, params);
view.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(OrderSummary.this, "Clicked", Toast.LENGTH_SHORT).show();
}
});
}
}

What you can do is take a LinearLayout(with orientation set to vertical) instead of a ListView. Then make a custom view for each row, traverse the ArrayList, and then inflate the views and keep adding them to the LinearLayout with addView().
P.S. without the actual code , I cannot tell you how to correct your code.

In your code there is issue where are you adding linearLayout into main container ?

Having problems setting up button of another layout

The problem is MainActivity starts with a setContentView with a layout.xml. We can add buttons or anything to the layout and code in in the MainActivity class but when I try to code the buttons of another layout in the same Activity the app forces stop . Whats wrong ?
Ok I found out that is because of the context.
When you try to change other activity you have to use layoutinflater. Example below
LayoutInflater inflater = getLayoutInflater();
View myLayout = inflater.inflate(R.layout.my_layout, null);
To work with widgets inside it like buttons or anything .
Button b = mylayout.findViewById(R.id.button);
b.setText("Successfully changed");
Now you can use myLayout as your changed layout.

Please sent me your Activities
What the text of problem ?
You may write next code to go to another activity
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(),nameActivity.class));
}
});
Where button is name of your button
See that you xml-file doesnt have any mistakes

You are getting a crash because you are trying to access the layout when it is not inflated. In other words, you must call setContentView() on an Activity, or inflater.inflate() on a Fragment to instantiate the view and make the elements accessible for manipulation. So if you want to add buttons to another Activity, you would need to call its onCreate() and setContentView() before you can add buttons to it.
EDIT: In response to comments...
In order to access/manipulate/modify elements in a layout at runtime, they must first be instantiated, which happens when the view is inflated. So to add a button to an Activity at runtime, you would do it in the onCreate() method after calling setContentView() like this:
Keep in mind this is the onCreate() of your SECOND activity...not your main Activity. So your main activity would start this Activity, then the button would get created during the setup of the second Activity.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.your_second_activity;
Button button = new Button(this);
button.setText("Your New Button");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d("NEW BUTTON", "I just clicked my new button!");
}
});
RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.layout_in_your_second_activity);
relativeLayout.addView(button);
}
If you are using a Fragment to display your UI, you can't access your UI elements until you have inflated your layout, which happens in the onCreateView() method. So you would do something like this in your Fragment code:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.your_fragment_layout, container, false);
RelativeLayout relativeLayout = (RelativeLayout) view.findViewById(R.id.container_layout_that_holds_button);
//You would get your context from an onAttach() Override
Button button = new Button(context);
button.setText("Your New Button");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d("NEW BUTTON", "I just clicked my new button!");
}
});
relativeLayout.addView(button);
return view;
}
You're likely getting a NullPointerException when you try to manipulate your layouts before they are created. Keep in mind that even if you have an XML file with layouts specified within, the actual objects for those elements won't be created until the system decides it needs them, which happens when you actually try to display the view.

Dynamically Add and Remove Views from Layout

I'm working on one demo project in that I had create one XML file containing some views like ImageView, EditText. I'm loading this XML file on FrameLayout at runtime. At one point I want to remove all that views and again want to display them, I used removeView() method on button click but it does not work for me,,Please tell me the right way to do it..
public class Demo extends Fragment implements OnClickListener, OnTouchListener{
//Declaration of framelayout
FrameLayout f;
//Declaration of imageview
ImageView imageview;
View view, framelayoutview;
File file;
EditText etcardname, EditTextUserName,EditTextUsesrMobNumber,EditTextUsesrEmailID,EditTextUsesrAddress;
TextView dialogtesting;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.activity_modify_card ,container, false);
framelayoutview = inflater.inflate(R.layout.frame_layout_data ,container, false);
captureImageInitialization();
Initialize();
return view;
}
// Initialization of all views components
private void Initialize() {
f=(FrameLayout)view.findViewById(R.id.framelayout);
Button btneditcardreset=(Button)view.findViewById(R.id.buttonresetcard);
btneditcardreset.setOnClickListener(this);
Bundle bundle = this.getArguments();
int myInt;
myInt = bundle.getInt("position");
imageview=(ImageView)framelayoutview.findViewById(R.id.imageViewicon);
EditTextUserName=(EditText)framelayoutview.findViewById(R.id.modifycardeditTextusername);
EditTextUsesrMobNumber=(EditText)framelayoutview.findViewById(R.id.editTextmobilesnumber);
EditTextUsesrEmailID=(EditText)framelayoutview.findViewById(R.id.editTextemailid);
EditTextUsesrAddress=(EditText)framelayoutview.findViewById(R.id.editTextaddress);
imageview.setOnTouchListener(this);
EditTextUserName.setOnTouchListener(this);
EditTextUsesrMobNumber.setOnTouchListener(this);
EditTextUsesrEmailID.setOnTouchListener(this);
EditTextUsesrAddress.setOnTouchListener(this);
f.addView(framelayoutview);
}
#Override
public void onClick(View v){
if(v.getId()==R.id.buttonresetcard){
if(framelayoutview.getParent()!=null){
f.removeAllViews();
}
f.addView(framelayoutview);
}
}
Sorry to all I forgot to tell that I provided OnTouchListener so that I can move the views anywhere in Layout. So when I press reset button all Views should get move back to their original location means where they were at on first load..

you can use
imageview.setVisibility(View.GONE);
And
imageview.setVisibility(View.VISIBLE);
on particular event

If you had added your views dynamically to your FrameLayout then you can remove them.
Otherwise, if you showing your views from XML which are exist inside the frameLayout XML then you can't remove them but you can hide them from showing by setting setVisibility(View.GONE) or setVisibility(View.INVISIBLE).

Try this-
#Override
public void onClick(View v){
if(v.getId()==R.id.buttonresetcard){
if(framelayoutview.getParent()!=null){
f.setVisibility(View.GONE);
}
f.addView(framelayoutview);
}
}

Android: Load Layout-File dynamically

I have a question about Android.
Assume we have our main xml layout file, and defining there a place holder by using (for example) a FrameLayout. Also assume we have 2 other xml layout files displaying any content.
So what I want to do is inject dynamically and programmtically one of the two layouts into the place holder. I know there exists the concept of Activitis, Fragments, ViewFlipper etc. But I find it comfortable to do things like this:
public class MainActivity extends Activity {
private FrameLayout placeHolder;
private View view1;
private View view2;
private RelativeLayout canvasPlaceHolder;
private PuzzleCanvas canvas;
private TextView infoLabel;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// init gui
setContentView(R.layout.activity_main);
// Load layouts from xml
LayoutInflater factory = getLayoutInflater();
view1 = factory.inflate(R.layout.view1, null);
view2 = factory.inflate(R.layout.view2, null);
}
}
with for example a Button on screen that does something like this:
#Override
public void onClick(View v) {
placeHolder.removeView(view1);
placeHolder.addView(view2);
}
For example to show a loadingAnimation (view2) instead of the normal content (view1) and so I can define both views comfortable and independent in xml.
Is the use of LayoutInflater commendable? What about the performance and memory management? What do you think about this? Is that a common way in Android?

Use 'include ' tag on the xml's frame layout to include both your xml's in the main xml. All you have to do is switch their ' VISIBILITY' through java according to ur app logic.
eg: on a listener, set :
public void onClick(View v) {
innerView1.setVisibilty(View.INVISIBLE);
innerView2. setVisibilty(View.VISIBLE);
}

// Load layouts from xml
LayoutInflater factory = getLayoutInflater();
view1 = factory.inflate(R.layout.view1, null);
view2 = factory.inflate(R.layout.view2, null);
Using LayoutInflater is ok, but I suggest not directly do this action in onCreate, if your layout is very complex, it might cause ANR (draw layout over 5 secs). Since these two views only appears after user reaction, I prefer to do with sendEmptyMessage with handler.
onCreate(...){
handler.sendEmptyMessage(1);
}
private Handler handler = new Handler(){
#Override
public void handleMessage(final Message msgs) {
if(msgs.what == 1){
view1 = factory.inflate(R.layout.view1, null);
view2 = factory.inflate(R.layout.view2, null);
}
}
}

Access custom view properties after inflation in Android

I have an activity with a LinearLayout which I want to add multiple buttons to. These buttons are Custom Views which I inflate. I need to add these custom buttons to my Linear Layout in code. All of this works.
What I cant get to work is to use findViewById in my custom button after I have inflated it so I can set its properties. findViewById returns null.
Activity Code:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.levelbrowser);
LinearLayout uttonLayout = (LinearLayout)findViewById(R.id.ButtonLayout);
LevelBrowserButton button1 = new LevelBrowserButton(this, "Level 1");
ButtonLayout.addView(button1);
}
Custom Button Code:
public LevelBrowserButton(Context context, String name)
{
super(context);
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.levelbrowser_button, this);
TextView nameTextView = (TextView) layout.findViewById(R.id.NameTextView);
// nameTextView = null!
NameTextView.setText("test"); // This will throw an exception
}
I have read through many posts on the internet and still cant get this to work. I have also tried "Clean..." in Eclipse on my project.