The application works but when i added the buttonclick the application gives no errors but on emulator it just crashes without starting.
This is the expected result:
https://imgur.com/a/QyKG1
Here is the entire file:
https://pastebin.com/e6Q5ViuS
Here is the code that contains the error:
public class MainActivity extends AppCompatActivity {
ArrayList<Product> arrayList;
ListView lv;
EditText txtUrl;
Button btnSubmit;
String EditTextValue;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
arrayList = new ArrayList<>();
lv = (ListView) findViewById(R.id.listView);
btnSubmit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
EditTextValue = txtUrl.getText().toString();
runOnUiThread(new Runnable() {
#Override
public void run() {
new ReadJSON().execute(EditTextValue);
}
});
}
});
}
You need to initialize this way :
btnSubmit = (Button) findViewById(R.id.[your id]);
BEFORE you use it to set the onClick listener...
You have not initialized button before adding click listener
That's why your app crashes
Related
I am trying to pass some data from one activity to another and I have made a toast in the other activity to see if data is being passed.When the toast shows up it is blank.I have done everything right and tried many different times with different methods I have also created another app but the problem still stays.It gives me null.
My java code in the first activity
public class titleandcuisine extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
public static final String TITLE_GET = "title";
public static final String CUISINE_GET = "cuisine";
ImageView imageView;
Button button;
Spinner spinner;
EditText dish;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_titleandcuisine);
dish = findViewById(R.id.editText);
spinner = findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,R.array.cuisines,android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(this);
button = findViewById(R.id.next);
imageView = findViewById(R.id.close);
imageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(), homepage.class));
}
});
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String text = dish.getText().toString();
String text2 = spinner.getSelectedItem().toString();
Intent data = new Intent(getBaseContext(),imagepost.class);
data.putExtra(TITLE_GET,text);
data.putExtra(CUISINE_GET,text2);
startActivity(data);
}
});
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
}
Second activity java code
public class reviewactivity extends AppCompatActivity {
TextView cuisine,title;
ImageView displayimage,back;
Uri myUri;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_reviewactivity);
Intent intent = getIntent();
String titleget = intent.getStringExtra(titleandcuisine.TITLE_GET);
String cuisineget = intent.getStringExtra(titleandcuisine.CUISINE_GET);
Toast.makeText(this, titleget + cuisineget, Toast.LENGTH_SHORT).show();
cuisine = findViewById(R.id.reviewcuisine);
title = findViewById(R.id.reviewtitle);
back = findViewById(R.id.backtopostvideo);
displayimage = findViewById(R.id.reviewdisplaimage);
// cuisine.setText(cuisineget);
// title.setText(titleget);
// myUri = Uri.parse(uri);
displayimage.setImageURI(myUri);
back.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(getApplicationContext(),videopost.class));
}
});
}
}
You need to read the text from the EditText when the button is clicked. Something like:
title = dish.getText().toString(); // Add this
Intent data = new Intent(getBaseContext(),imagepost.class);
data.putExtra(Intent.EXTRA_TEXT, title);
...
One more thing: You are trying to read the Intent.EXTRA_TEXT at the reviewactivity activity. However, nothing is starting that activity (at least within the piece of code that you shared).
I am having one Array list in Class-A and two textfields one from Class-A and other from Class-B,
While adding values to Array List through Class-A textfield it works fine for me,
and when trying to add from Class-B textfield, it gets added to Array list but does not display the updated list in the listview(Blank)
Below is the code i have tried till now
Class-A :-
public static ArrayList<String> arrayList = new ArrayList<>();
ArrayAdapter<String> arrayAdapter;
ListView listView;
EditText quickTask;
Button addButton;
Button moreButton;
public static ArrayList<String> addToList( String i ) {
arrayList.add(i);
return arrayList;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
quickTask = (EditText) findViewById(R.id.quicktaskeditText);
listView = (ListView) findViewById(R.id.TasksListView);
arrayAdapter = new ArrayAdapter<String>(ClassA.this, android.R.layout.simple_list_item_1,arrayList);
addButton = (Button) findViewById(R.id.Addbutton);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String task = quickTask.getText().toString();
arrayList.add(task);
listView.setAdapter(arrayAdapter);
arrayAdapter.notifyDataSetChanged();
}
});
moreButton = (Button) findViewById(R.id.moreButton);
moreButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent secondActIntent = new Intent(getApplicationContext(),ClassB.class);
startActivity(secondActIntent);
}
});
}
Class-B :-
EditText Title;
Button AddButton;
ArrayList<String> alist;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Title = (EditText) findViewById(R.id.Title);
AddButton = (Button) findViewById(R.id.secondAddButton);
AddButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String task = Title.getText().toString();
//Adding text to Class-A arraylist
alist = ClassA.addToList(task);
Intent startIntent = new Intent(getApplicationContext(),ClassA.class);
startActivity(startIntent);
}
});
}
Because you don't notify ListView that contents of ArrayList changed.
You have notifyDataSetChanged only in button listener. You need to add it in Class-A#onResume or in addTolist.
I am semi-ok with the understanding of how you store and retrieve data through intents, what I am not sure about however is the code implementation. What I want to accomplish is to pass stored data (name/value pairs and a bundle object) to my ThirdActivity class from MainActivity class. Here is a snippet what i have attempted thus far (which when the user clicks on the a3button it just displays a blank page with no string):
MainActivity from which I want to store data to send to ThirdActivity:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button a2_button = (Button) findViewById(R.id.a2_button);
a2_button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent a2intent = new Intent("com.tester.lab.x");
startActivityForResult(a2intent, 1);
}
});
Button a3_button = (Button) findViewById(R.id.a3_button);
a3_button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent a3intent = new Intent(v.getContext(), ThirdActivity.class);
a3intent.putExtra("greeting","my Name");
startActivity(a3intent);
}
});
}
}
ThirdActivity:
public class ThirdActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_third);
getIntent().getStringExtra("greeting");
}
}
How would I display the string "my Name" once the user clicks ThirdActivity button? Any help is wonderful, thanks!
Everything is good, just add String type for value that you are getting and use this String as you want (to show in TextView else..):
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_third);
EditText text = (EditText) findViewById(R.id.your_textView_id);
String value = getIntent().getStringExtra("greeting");
text.setText(value);
}
Or by using Button:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_third);
EditText text = (EditText) findViewById(R.id.your_textView_id);
Button three = (Button) findViewById(R.id.your_button_id);
three.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String value = getIntent().getStringExtra("greeting");
text.setText(value);
}
});
}
so im a beginner in android/java programming and im trying to do the following: the selected item from my spinner should go in a listview when I click a button.So far I did this,eclipse doesnt show any errors or warnings,but my app crash when I try to launch it:
public class MainActivity extends ActionBarActivity {
Button button3;
Button button2;
Button button4;
ListView listView1;
Spinner s1;
String text;
ArrayAdapter<String> adapter;
ArrayList<String> list;
int itemPos;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button3 = (Button) findViewById(R.id.button3);
button4 = (Button) findViewById(R.id.button4);
button2 = (Button) findViewById(R.id.button2);
s1 = (Spinner) findViewById(R.id.spinner1);
listView1 = (ListView) findViewById(R.id.listView1);
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_single_choice, list); //this part here might not be correct
listView1.setAdapter(adapter);
button3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String text = s1.getSelectedItem().toString();
adapter.add(text);
}});
listView1.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
itemPos = position;
}
});}}
I dont get why it crash, how to fix that?
thank you!
Declare,
ArrayList<String> list = new ArrayList<String>();
Now, you can not text in ArrayAdapter directly, for that we have created ArrayList.
So do like this way,
button3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String text = s1.getSelectedItem().toString();
list.add(text);
// To notify adapter after that changes in data
adapter.notifyDataSetChanged();
}
});
Let's if that's the problem.
In the android sdk, I have programmed 2 buttons to bring me to 2 different layouts. However, only the first one I have programmed will work, while the second one will do completely nothing. I will provide the code if you can catch any things I missed, please tell me what you think. This is one of my first applications to run on android, so try to explain your suggestion as simple as you could.
Code:
public class MainActivity extends Activity {
private final String T = "Settings";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
settingsButton();
}
private final String T2 = "ManualAdd";
protected void onCreate1(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
feederButton();
}
private void settingsButton() {
Button messageButton = (Button) findViewById(R.id.Settings);
View.OnClickListener myListener = new View.OnClickListener() {#
Override
public void onClick(View v) {
Log.i(T, "You clicked the settings button!");
startActivity(new Intent(MainActivity.this, SettingsActivity.class));
}
};
messageButton.setOnClickListener(myListener);
}
private void feederButton() {
Button feedButton = (Button) findViewById(R.id.AddFeeder);
View.OnClickListener my2ndListener = new View.OnClickListener() {
public void onClick(View v) {
Log.i(T2, "You clicked the add button!");
startActivity(new Intent(MainActivity.this, ManualAdd.class));
}
};
feedButton.setOnClickListener(my2ndListener);
}
}
You cannot make a different onCreate() method for every button you have. The reason why only one of your Buttons work is because only the onCreate() method is only called. The system has no idea about onCreate1(). To get both of your buttons working change
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
settingsButton();
}
to
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
settingsButton();
feederButton();
}
You can completely delete onCreate1() from your source code, it is now obsolete.
It would also be a good idea to follow the official Android "First App" tutorial instead.
Try this code
public class MainActivity extends Activity {
Button Your_Button_Name;
Button Your_Button_Name;
Activity activity;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.Your_Layout_Name);
//In (R.id.Your_Btn_Name) that's the name that you gave your button in the XML
activity = this;
Your_Button_Name = (Button) findViewById(R.id.Your_Btn_Name);
Your_Button_Name = (Button) findViewById(R.id.Your_Btn_Name);
Your_Button_Name.setOnClickListener(listener);
Your_Button_Name.setOnClickListener(listener);
}
private View.OnClickListener listener = new View.OnClickListener() {
public void onClick(View v) {
switch (v.getId()) {
case (R.id.Your_Btn_Name):
startActivity(new Intent(MainActivity.this, Your_Layout_Name.class));
break;
case (R.id.Your_Btn_Name):
startActivity(new Intent(MainActivity.this, Your_Layout_Name.class));
break;
}
}
};
}