I am beginner in android studio and When i click on button to transfer my activity from one to another then i am getting error:App is not responding? What's wrong with my code?
Here is first activity which is initial destination
Here is my Second Activity which is final destination
Your button b variable it is bad instantiated, you should declared as follows:
b = (Button) findViewById(R.id.simpleProgramDisplayDate);
Related
I created an android app and i want to start my app at the MainActivity every time my app is launched? That is if my app is at activity B and the user press the home key, then when the app is launched again, it starts at MainActivity instead of activity B? how i can do that ?
There is a flag for exactly this purpose. In the <activity> declaration for your MainActivity add:
android:clearTaskOnLaunch="true"
This will cause the app to start at MainActivity whenever it is relaunched.
There are few ways to do this -
In your activity B override the 'onPause' method and add 'finish()'
In your manifest file where you have added <activity> tag for your activity B, you can add 'android:noHistory=true'. Check this link to understand more - https://developer.android.com/guide/topics/manifest/activity-element
I hope this will solve your issue.
I am trying to change photos in android studio by clicking on my button.
When I put code for changing the photo in my MainActivity.java I keep getting this type of error messages and it says :
Cannot resolve symbol "image"
image.setImageResource(R.drawable.xxx);
I am watching Udemy course for android development and I have done everything same like the professor on that video.
I have tried to restart android studio.
I have tried to make new project.
I have tried to clear invalidate caches and restart.
public void changeImage(View view)
{
ImageView bitcoin = findViewById(R.id.bitcoin);
image.setImageResource(R.drawable.xxx);
}
I hope there is actual error with android studio,because code is clone of the video that I am watching.
You are binding your layout's ImageView in Java file with bitcoin variable and you are trying to set an image on an unknown variable 'image'(maybe it's not defined in the class). So you have to set as below.
ImageView bitcoin = findViewById(R.id.bitcoin);
bitcoin.setImageResource(R.drawable.xxx);
Set Your Code Like this
ImageView image = findViewById(R.id.bitcoin);
image.setImageResource(R.drawable.xxx);
change your this line
image.setImageResource(R.drawable.xxx)
to this one:
bitcoin.setImageResource(R.drawable.xxx)
I am trying to get text from textview which is located in class 2 to use it in class 1 by pressing a button. I do this by sending an Intent, but i got the error of my content. That is what i am trying to send (from class 2 to class 1):
public static void intent_send(){
Intent i = new Intent();
i.putExtra("number",Integer.parseInt(text_view_current_page.getText().toString()));
class2.startActivity(i);
}
text_view_current_page is a static TextView, otherwise it has an error in this void. I call this void by pressing a button in class 1:
Class2.intent_send();
Intent i = getIntent();
Bundle b = i.getExtras();
PagerNumber = b.getInt("number");
I have an error in the line of the content definition:
i.putExtra("number",Integer.parseInt(text_view_current_page.getText().toString()));
What should i do with this textView to be able get it's text from another class by pressing a button? Should it be static or should i declare it in that class which receives an intent?
In Android activities are fully separated components and hence those cannot access each other's stuff directly. Those have their own window and view hierarchy which are private only to the owner activity itself.
Nevertheless there are a couple of ways for activities to interact with each other.
Sending data when you are starting second activity via Intent.
Utilizing Application object as a share object among all app's components.
Registering in-activity broadcast receivers by which you can send signals between activities.
My Recommendation for your case:
If in your case, the second activity should have a very close relation with the first one (e.g. accessing its view hierarchy), you could implement the second activity as a dialog or fragment not an activity.
In my android app, if I have an activity called Home.java, how could I get the string "Home" on the oncreate event of that activity?
Thanks.
this.getClass().getSimpleName()
I am new to Android Development and I have a simple list app which I have been asked to create.I have had no problems having the app as activity based however I have to extend the functionality and use fragments for a 'universal' app. My main activity is:
I was able to successfully compile your code by taking the following steps:
It looks like this line is the problem (inside Main.java):
contactCursor = contactDBAdapter.getAllContactsCursor();
I looked at how your contactDBAdapter gets initialized and it turns out you initialize it after you setContentView for your activity. However, your view involves calls to contactDBAdapter. So in Main.java you need to move the following two lines to the TOP of the onCreate window:
public void onCreate(Bundle savedInstanceState)
{
contactDBAdapter = new ContactDBAdapter(this);
contactDBAdapter.open();
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
....
}
Furthermore, the following line in Main.java needs to be removed (or commented out):
contact.clear();
Also, I had to make two further changes to how you call ListView
In list_view.xml, the way you identify a ListView for Android is :
android:id="#+id/android:list"
In ContactListFragment.java, then call the ListView this way :
parent.myListView = (ListView)v.findViewById(android.R.id.list);
have you not just tried using the Eclipse Template which set up everything for you just copy in your existing code?
File>New>Android Application Project then under the Create Activity Step select
Your Fragment class needs an empty default constructor. See Android Reference