In the code below, the first TextView symbol cannot be resolved, and the findById method cannot be resolved. Can someone explain to me what the problem is and how I can fix it?
final TextView factLabel = (TextView) findViewById(R.id.factTextView);
Button showFactButton = (Button) findById(R.id.showFactButton);
View.OnClickListener listener = new View.OnClickListener() {
#Override
public void onClick(View v) {
String fact = "";
// Randomly select a fact.
// Update the label with our dynamic fact
factLabel.setText(fact);
}
};
You need to give more background. Are you in a fragment, or an activity? How was the layout set? I'm guessing the answer is that you need to be calling findViewById() on the View of your layout - e.g. view.findViewById() but it depends on how your layout was set.
If you're in an activity, calling findViewById() on the Activity object will only work if the current Activity layout is set by setContentView. If your layout was set a different way, then you need to get the View object of the layout and call findViewById() on it. If you're in a fragment, and you're in onCreateView() then the view has been passed in for you and you just need to call view.findViewById()
I am asuming that you want some text to set on text view on click of button try this
final TextView factLabel = (TextView)findViewById(R.id.factTextView);
Button showFactButton = (Button)findViewById(R.id.showFactButton);
showFactButton.setOnClickListener(new View.onClickListener()
{
#Override
public void onClick(View v) {
String fact = "Your Text Here";
// Randomly select a fact.
// Update the label with our dynamic fact
factLabel.setText(fact);
});
Make sure you are importing all the packages you need. Also make sure all the dependancies are working. Lastly make sure that there is a text view in the XML for the activity. Hooe some of this is helpful.
Related
I know where my problem exactly is, I just don't know how to fix it. I'm trying to change the value of a TextView and with my code, the app just crashes and I get the error in the title.
My code:
#Override
protected void onStart() {
super.onStart();
if(authenticate() == true) {
displayUserDetails();
} else {
startActivity(new Intent(MainActivity.this, Login.class));
}
}
private boolean authenticate() {
return userLocalStore.getUserStatus();
}
private void displayUserDetails() {
User user = userLocalStore.getLoggedInUser();
final TextView userName = (TextView) findViewById(R.id.userName);
userName.setText(user.name);
final TextView userEmail = (TextView) findViewById(R.id.userEmail);
userEmail.setText(user.email);
}
There you have a snippet of my code, if you need the whole class I'd be happy to provide. Thank you in advance.
UPDATE:
The issue was the content view as it was set to activity_main and since i couldn't switch to another I just did this:
private void displayUserDetails() {
User user = userLocalStore.getLoggedInUser();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
View header=navigationView.getHeaderView(0);
final TextView userName = (TextView) header.findViewById(R.id.userName);
userName.setText(user.name);
final TextView userEmail = (TextView) header.findViewById(R.id.userEmail);
userEmail.setText(user.email);
}
It may be the problem that when the function is invoked initially user.email value remains empty.
Your code looks correct, the problem is that findViewById() returns null.
There could be a lot of causes of the problem.
Check that your .xml file have views with id userName and userName.
Check that this .xml is accessible by all devices, i.e. it is present in all layout folders, for all screen sizes, densities, languages and so on.
Try to comment out one of the .setText()'s and see if other one is working. If it is just make sure that not working one is exactly the same.
If you are using an activity make sure that you call .setContentView() with correct layout file.
If you are using a fragment make sure that you return a view constructed put of a correct layout file from onCreateView.
I have a GridView in my activity. I am having 2 elements in the GridView. One is an ImageView and the other is a TextView.
I want to perform an action when clicking the ImageView only, but I want this to happen in the activity and not in the GridView adapter.
I handle the ImageView click in the getView() of my adapter, but I do not want it that way. I want to handle it in the activity when calling:
GridView gridview = (GridView) findViewById(R.id.gridview);
gridview.setAdapter(new ImageAdapter(this, items));
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
//THIS WORKS FINE
String string = ((TextView) v.findViewById(R.id.text)).getText().toString();
Log.d("string",string);
//THE PROBLEM OCCURS HERE
ImageView capture = (ImageView) v.findViewById(R.id.capture);
capture.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
}
});
}
});
//THE PROBLEM OCCURS HERE
The action is supposed to happen the first time I click the ImageView, but it only happens on the second click and further.
This is where I am stuck with the issue. I want this action to occur on the first click and not on the second click.
You can see the code block-
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
String string = ((TextView) v.findViewById(R.id.text)).getText().toString();
Log.d("string",string);
//THE PROBLEM OCCURS HERE
ImageView capture = (ImageView) v.findViewById(R.id.capture);
capture.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
}
});
}
Your imageview capture is adding any action after gridview is being clicked. So, after clicking first time it is executing and then setting click listener to imageview and then next click its executing its onClick block. So better, handle imageview click event inside adapter.
You can call method inside your activity from adapter class but you should implement setOnClickListener inside your adapter class.
with the help of interface, you can do that do one thing create an interface and implement it on your activity and get imageview click on the adapter and here initiate the interface and you will get the click inside the activity
I think the problem is that on the first click you just set OnClickListener on your imageView, and so its onClick() method is not getting called. On the second click though, as the listener is already set, onClick() is invoked.
Instead of setting new Listener to your imageView each time an item in the grid clicked (which does not make any sense by the way), you should do either of these:
If imageView in each item has to be handled the same way, set OnClickListener to the imageView in the adapter, when creating a view.
If not, pass the interface for handling imageView clicks to the constructor of the adapter, and then, in the activity, implement this interface when creating an adapter.
Create a method in you activity.
Now, in adapter, onClick call that method using
((Activityname)context).methodname(parameters);
I have a ListView in my app.
Its items have a Button and an invisible text field; I want to make the text field visible when the Button is pressed.
How can I do it from the onClick(View v) method of OnClickListener's object?
Maybe it's something like "getParent().findViewById()", but getParent() doesn't return a View..
You could set the tag of the button view to the TextView.
Then you can use v.getTag() to get it back, then do what you want with it.
Otherwise, make the TextView final in your adapter getView method after finding it , then simply use it within the click event
If you want to visible the textView
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.btn:
yourtextView.setVisibility(View.VISIBLE);
break;
}
}
try this
View view = listview.getAdapter().getView(0,null,null);
TextView textView = view.findViewById(R.id.textView);
I've created a method which adds a number of TextViews to a LinearLayout in a while loop. I'm having trouble identifying those TextViews by click. If I click on them, it prints out that they are the ID of my linear layout. Is there any way I can access them?
while(i.hasNext()){
TextView x = new TextView(this);
linearLayout.addView(x);
}
EDIT:
I understand this was an absurdly dumb question.
This...
x.setOnClickListener(this);
...did the trick.
Simple, you will get the reference of clicked view in OnClickListener() callback. type cast that view into textview and call getText() method of textview.
Here is sample code:
while(i.hasNext()) {
TextView x = new TextView(this);
linearLayout.addView(x);
x.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
TextView tv = (TextView) v;
v.getText();
}
});
}
if you'd be using a for loop you could do something like this x.setId(i+30); any number in place of 30. In while you can still take a variable i and do something like x.setId(x++ +30); . now if you want to access them from a loop its simple findViewById(i+30); or else findViewById(31);
I just started learning android programming and can't seem to work out how to permit the user to create a selected number (n) of EditText fields by clicking a button n times such that each would be uniquely identified, namely 1,2,3...,n as well as accessible programatically, from a different method (invoked by a different button click). I hope the question is clear enough as I don't really have that much code to provide.
Do something like this
// A list to keep reference to your created edit texts
List<EditText> mEditTexts = new ArrayList<EditText>();
// Get root view of your activity
ViewGroup viewGroup = (ViewGroup) ((ViewGroup)
findViewById(android.R.id.content)).getChildAt(0);
// Get the button and set a click listener to it
Button mButton = (Button) findViewById(R.id.button_id);
mButton.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
// Build edit text
EditText mEditText = new EditText(v.getContext());
// Pass two args (arg1/arg2); must be LayoutParams.MATCH_PARENT,
// LayoutParams.WRAP_CONTENT, or an integer pixel value.
mEditText.setLayoutParams(new LayoutParams(arg1, arg2));
// Add the edit text to your list
mEditTexts.add(mEditText);
// Add edit text to your root view
viewGroup.addView(mEditText);
}
}
To check your edit text fields you can then access them from the list
for(EditText editText : mEditTexts){
Log.d(TAG, editText.getEditableText().toString());
}
or explicitly
int specificPosition = (SOME_INT);
EditText specificEditText = mEditTexts.get(specificPosition);
Haven't been able to test it so it might need some modifying but it should be something along those lines. You can also use your layout directly if you don't want to use the viewGroup. Modify it to something like
LinearLayout mLayout = (LinearLayout) findViewById(R.id.layout_id);
....
mLayout.addView(mEditText);