I'm trying to change my TextView text from the code.
This is what my xml looks like:
XML:
<TextView
android:id="#+id/textView1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical|center_horizontal" />
And the code:
TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");
setContentView(tv1);
I'm getting an error on my device and the application stops.
I tried to show a TextView (not connected to an XML TextView) and it worked.
Your approach is incorrect. I think it will be Null Pointer Exception (next time post log cat)
You need to specify the layout you are using first, before finding views.
Java:
// Specify the layout you are using.
setContentView(R.layout.yourlayout);
// Load and use views afterwards
TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");
Kotlin:
// Specify the layout you are using.
setContentView(R.layout.yourlayout)
// Load and use views afterwards
val tv1: TextView = findViewById(R.id.textView1)
tv1.text = "Hello"
Click Here to study exactly you want to know
remove this.. setContentView(tv1);
I got the same problem. My app was stopping too.
Actually, I was writing the code outside of the function/method. So to fix this problem, these lines
TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");
must be inside a function/method. (can be user defined)
(I am new to android studio so I don't know the reason behind the problem but I only know how to fix this. Maybe this helps new ones despite this question being 8 years old.)
Related
I am totally new at Android Studio.
I am trying to write simple application with 2 screens and passing info from screen 1 to screen 2.
This is the code of the Second activity.
public class SecondActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
if(getIntent().hasExtra("com.gmail.zionrevi.SOMETHING")) {
String text = getIntent().getExtras().get("com.gmail.zionrevi.SOMETHING").toString();
TextView tv = (TextView)findViewById(R.id.textview);
tv.setText(text);
}
}
}
when i am running it i am getting the following Run Time exception:
E/AndroidRuntime: FATAL EXCEPTION: main
android.support.constraint.ConstraintLayout cannot be cast to android.widget.TextView
on the following line
TextView tv = (TextView)findViewById(R.id.textview);
What i am doing wrong?
can someone help me please?
You are trying to cast ConstraintLayout into TextView which cannot succeed. They are two completly different view.
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:id="#+id/textView"
android:layout_height="match_parent">
You need to set TextView in you xml layout or change ConstraintLayout id to some other id and set TextView id to textView
Part of learning Android is understanding the errors. When you're told that typeX cannot be cast to typeY it almost always means you're attempting to cast something to the wrong type.
In this case, it appears to be occurring here TextView tv = (TextView)findViewById(R.id.textview);. When you do something such as (TextView)findViewById(R.id.textview), you're casting whatever is returned by findViewById(...) to a TextView. If that ID you pass to the function is not a TextView, you will get a ClassCastException
In your case, very likely, you have a ConstrainLayout in your .xml file for this activity that has an ID of textview.
welcome at android programming ..
i think that your R.id.textview refers to [ConstraintLayout]
you should set your [textview] id to be [#+id/textview] and of course clear it from yourConstraintLayout .. and it will be
solved :)
happy programming
This code is within a method in a class (not main):
TextView moodouttw = (TextView) findViewById(R.id.moodouttw);
The textview seemes not to be recognized in this part: R.id.moodouttw
The textview moodouttw is located within a layout xml.
Can someone please helpout with code to correctly format the code above?
(I've tried to minimize code at first if it could be solved with any further info)
LOGCAT: 940Kb cant post
is not iR.d is just R.id
the proper way will be
findViewById(R.id.moodouttw);
this is the complete correct sentence
TextView moodouttw = (TextView) findViewById(R.id.moodouttw);
ok as you stated at your xml file, the problem is that your TextView id is moodtw and you are doing R.id.moodouttw;
so you need to do this
TextView moodouttw = (TextView) findViewById(R.id.moodtw);
I have just tried to display the value of the variable but is showing some kind of exception
that is FORCE CLOSE.
the code i have tried is
TextView myTextView = (TextView) findViewById(R.id.result9);
myTextView.setText("your score is " +count);
considered count=0 intially.
Can any one suggest me for this problem
thanks in advance
if myTexyView is in dialog you have to do this:
myTextView = (TextView) dialog.findViewById();
anyway do clean project...this happens sometimes:
in eclipse: project->clean->your project
Seems findViewById() returns null. It means that either there's no widget with id result9 in current layout or your forgot to setContentView().
can please check your xml which one you have set, setContainView() it mast have TextView with "result9" this id.
I'm having issues with understanding how I should organize my user interface in Android. My original plan was to create TextViews and ListViews programatically and change them when buttons are clicked, etc.
Here's my first simple attempt. viewFriends is a method within my Activity class. It's called when a menu button is pressed.
private void viewFriends()
{
mText = new TextView(this);
mText.setText("Gathering information...");
setContentView(mText);
...irrelevant code follows
Why doesn't this seemingly simple example work? How should I logically organize and manage my user interface objects (TextViews, ListViews, Buttons, etc).
Thanks.
The best work would be having those listviews and textviews in your XML files and give them a suitable ID like following:
<ListView
android:id="#+id/myList"
android:layout_width="wrap_content"
android:layout_weight="1"
/>
Just like above have your text view too in XML file an add the android:id attribute.
Once you define this way in your java file have references to them:
ListView myListObj = (ListView)findViewById(R.id.myList);
Now you have an object called myListObj in your java file and now you can do whatever you want to do with it.
:)
Let me if you find any issue in this so that I can update the answer to meet your specific need.
Don`t use setContentView in your method. Usually it should only be called once in the onCreate method of your activity.
Best predefine your bottons/TextViews in xml, get a handle for them (findViewbyId...)
and modify them that way.
If you create them programaticly, just add them to a view containter from your xml.
Like :
setContentView(R.layout.main);
Lets say in main.xml there is a LinearLayout with the id: root.
// get accces to that layout:
LinearLayout rootLayout = (LinearLayout) findViewById (R.id.root);
// create a new TextView
TextView tv1 = new TextView (this);
tv.setText("Hello!");
// add it to your base layout
rootLayout.addView(tv1);
// done! :)
Make a double check on what you are getting in "this".
change it to your java file name.this
You have to reload/refresh your activity once you change it.
Try this
#Override
protected void onResume() {
if(param.equalsIgnoreCase("gr"))
{
finish();
Intent myIntent = new Intent(yourActivity.this, yourActivity.class);
startActivity(myIntent);
}
This should be simple, but driving my crazy.
I have the following in my layout, not problems.
<TextView
android:id="#+id/birdinfo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#00009c"
android:text="The Robin is a popular bird"
/>
Then I have these arrays which are set up with the list of string resources I have
private Integer[] DetailIds = {
R.string.barnaclegoose,
R.string.barnowl,
R.string.bewicksswan,
R.string.blackbird,
R.string.blackcap_male};
So I simply want to do this!
TextView detail = (TextView)findViewById(R.id.birdinfo);
detail.setText(DetailIds[0]);
setContentView(R.layout.main);
But this causes a force close error.
The string resource looks like this ( without header and footer info of course
<string name="barnaclegoose">What a wonderful goose!</string>
Added to this problem is if I use the resource directly to the resource
detail.setText(R.string.barnaclegoose);
For example, I still get a null exception! I'm sure I've done this before, but maybe I'm missing the obvious???
Any ideas appreciated.
( Eclipse, Android 1.5, Emulator with 1.5 )
I realize this is very old, but it came up in a search... Anyways, you need to call setContentView() before findViewById() etc:
setContentView(R.layout.main);
TextView detail = (TextView)findViewById(R.id.birdinfo);
detail.setText(DetailIds[0]);
your problem is for this line setContentView(R.layout.main);
at first you must define this this line then setText your textView
Thanks for the answer. but if you mean R.string.barnaclegoose for example, this is an integer value for the ID pointing to the string itself in the resource.
Anyway, I finally got it working by just creating the view inline instead of using an resource view.
For example
TextView t= new TextView(ctx);
t.setId(2);
t.setTextColor(Color.BLACK);
t.setText(DetailIds[bird]);
mLinearLayout.addView(t,params);
mLinearLayout.setBackgroundColor(Color.WHITE);
setContentView(mLinearLayout);
And that works perfectly.