I am trying to set some things to the action bar but i get the same errors on any method i use for it (e.g actionBar.setTitle("my title"); or actionBar.setBackgroundDrawable(R.drawable.actionbar_draw);)
i cant even use the get methods for it...
they all give this error:
required android.support.v7.app.ActionBar but found android.app.ActionBar
i am using minimum sdk 15 and this is my code:
package com.tos.test.testactionbarapp;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar actionBar = getActionBar();
actionBar.setTitle("my title");
}
}
problem is, my app crashes whenever i start it because of this code and i get:
---
------ beginning of crash
05-28 15:32:00.403 11476-11476/ccom.tos.test.testactionbarapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.tos.test.testactionbarapp, PID: 11476
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tos.test.testactionbarapp/com.tos.test.testactionbarapp.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.app.ActionBar.getTitle()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.app.ActionBar.getTitle()' on a null object reference
at com.tos.test.testactionbarapp.MainActivity.onCreate(MainActivity.java:21)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
you have to import android.support.v7.app.ActionBar and use getSupportActionBar() method od activity.
Change
getActionBar();
to
getSupportActionBar();
Try it!!
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar actionBar = getSupportActionBar();
actionBar.setTitle("my title");
}
Just Do this
ActionBar actionBar = getSupportActionBar();
instead of
ActionBar actionBar = getActionBar();
Related
This question already has answers here:
NavigationView get/find header layout
(9 answers)
Closed 5 years ago.
I'm working with firebase auth authentication and with the navigation drawer layout, what I need is to set the user email on the header of my navigation, the thing is as I got, is that it can't find the related textView on my layout, because the main activity is associated with my main layout and not the navigation itself, I did a test to see if the user retrieved from the database, and I got the email, but when I do this:
auth = FirebaseAuth.getInstance();
String email = auth.getCurrentUser().getEmail();
Log.d("email",email);
if (auth.getCurrentUser() != null) {
userTxt.setText(email);
}
I get a NullPointerException, that I think is related to the userTxt, so if anyone experienced it before can you guys give me a tip about how to solve this?
StackTrace
FATAL EXCEPTION: main
Process: com.esmad.pdm.friendlymanager, PID: 31473
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.esmad.pdm.friendlymanager/com.esmad.pdm.friendlymanager.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.esmad.pdm.friendlymanager.MainActivity.onCreate(MainActivity.java:42)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
From the Exception it is clear that your userTxt is null.
To access NavigationView Header -- you need to first get the Header view:
From Documentation
View getHeaderView (int index) Gets the header view at the specified
position.
NavigationView navigationView = (NavigationView) findViewById(R.id.navigation_view);
View header = navigationView.getHeaderView(0) ;
TextView userTxt = (TextView) header.findViewById(R.id.textView); //your ID
userTxt.setText(email);
I have no underlined code, but as soon as i start my app on emulator, i'm receiving these errors.
FATAL EXCEPTION: main
Process: com.milos.sportisa, PID: 2735
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.milos.sportisa/com.milos.sportisa.SplashActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setTypeface(android.graphics.Typeface)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setTypeface(android.graphics.Typeface)' on a null object reference
at com.milos.sportisa.SplashActivity.onCreate(SplashActivity.java:29)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
And this is my SplashActivity:
public class SplashActivity extends AppCompatActivity {
private TextView etSportisa;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
/* ButterKnife.inject(this);
mProgressBar.setIndeterminateDrawable(new foldingCirclesDrawable.Builder(this)
.build());
mProgressBar.setIndeterminateDrawable(new foldingCirclesDrawable.Builder(this)
.colors(getResources().getIntArray(R.array.colors) //Array of 4 colors
.build()); */
Typeface myTypeFace = Typeface.createFromAsset(getAssets(), "fonts/esp_ital.ttf");
etSportisa.setTypeface(myTypeFace);
etSportisa = (TextView) findViewById(R.id.tv_sportisa);
final ProgressDialog pd = new ProgressDialog(SplashActivity.this);
pd.setMessage("Učitavanje...");
pd.show();
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
// Actions to do after 10 seconds
pd.dismiss();
Intent i = new Intent(SplashActivity.this, MainActivity.class);
startActivity(i);
}
}, 2000);
}
}
Special font is added in assets\font folder. I also added an image for the loading screen but i think that the font is cousin those issues
Make the following changes to your code:
Typeface myTypeFace = Typeface.createFromAsset(getAssets(), "fonts/esp_ital.ttf");
etSportisa = (TextView) findViewById(R.id.tv_sportisa);
etSportisa.setTypeface(myTypeFace);
After initialization, you can do any operation with any layout.
The problem is here:
etSportisa is null
set it after you findViewByID
Typeface myTypeFace = Typeface.createFromAsset(getAssets(), "fonts/esp_ital.ttf");
etSportisa = (TextView) findViewById(R.id.tv_sportisa);
etSportisa.setTypeface(myTypeFace);
I am creating a restaurant app that requires an expandable listview to show a menu for the waiter to take a customer's menu. The app is crashing and I think it has something to do with the code below:
public class Menu extends AppCompatActivity {
HashMap < String, List < String >> Food_menu;
List < String > Food_list;
ExpandableListView Exp_list;
FoodMenuAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Exp_list = (ExpandableListView) findViewById(R.id.exp_list);
Food_menu = DataProvider.getInfo();
Food_list = new ArrayList < String > (Food_menu.keySet());
adapter = new FoodMenuAdapter(this, Food_menu, Food_list);
Exp_list.setAdapter(adapter);
}
}
When I debugged the app, it said that:
Exp_list
Food_menu
Food_list
were all coming back as null. I'm new to android studios and I'm not sure how to remedy the problem. Any help would be greatly appreciated, thanks.
Logcat:
04-11 22:05:53.841 1960-1960/com.example.ben.restaurantapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.ben.restaurantapp, PID: 1960
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ben.restaurantapp/com.example.ben.restaurantapp.Menu}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ExpandableListView.setAdapter(android.widget.ExpandableListAdapter)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ExpandableListView.setAdapter(android.widget.ExpandableListAdapter)' on a null object reference
at com.example.ben.restaurantapp.Menu.onCreate(Menu.java:38)
at android.app.Activity.performCreate(Activity.java:5937)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
I think the second parameter of your FoodMenuAdapter has to be a resource layout file.
For example:
Food Food_menu = DataProvider.getInfo();
adapter = new FoodMenuAdapter(this, R.layout.your_xml_layout_here, Food_list);
Exp_list = (ExapandableListView) findViewById(R.id.exp_list);
Exp_list.setAdapter(adapter);
Where your_xml_layout_here is the layout that all the information will be displayed on. Keep in mind that an adapter is the middleman of information and what you see on your application screen.
From your logcat you can see the exact problem:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ExpandableListView.setAdapter(android.widget.ExpandableListAdapter)' on a null object reference
which means that at the point you try to use setAdapter method on the Exp_List, the said variable is null.
What you can do from here on is to check if your layout activity_main actually contains an ExpandableListView with an id of exp_list (maybe post your layout?).
Your question should not be android studio null error as the null has nothing to do with Android Studio - it comes from the programming language, in this specific case - Java.
You can learn how to fix NullPointerExceptions here.
i am unable to debug this problem.i.e.when i am trying to change text name and put an icon for action bar its not supporting..i mean it is throwing an error like
02-06 11:43:39.964 9510-9510/com.example.brahmaiah.app1_menu E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.brahmaiah.app1_menu, PID: 9510
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.brahmaiah.app1_menu/com.example.brahmaiah.app1_menu.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setIcon(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.app.ActionBar.setIcon(int)' on a null object reference
at com.example.brahmaiah.app1_menu.MainActivity.onCreate(MainActivity.java:20)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
my MainActivity.java
#TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_main);
android.support.v7.app.ActionBar actionBar=getSupportActionBar();
actionBar.setIcon(R.drawable.ic_image3);
Toolbar toolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(toolbar);
and i had support of v 7 and v 4 libraries.i am also tried to get execution like this in my activityi.e.actionBar.getSupportActionBar();.
kindly help me in that to get out of it debug.
i think no need of manifest.xml..because i had tag correctly with minversion:7 and maxVersion17..thanks in advance!!
and app theme also like...light.noActionBar
You need to set Toolbar as actionbar first then use getSupportActionBar()
You need to change the below code
android.support.v7.app.ActionBar actionBar=getSupportActionBar();
actionBar.setIcon(R.drawable.ic_image3);
Toolbar toolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(toolbar);
to
Toolbar toolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(toolbar);
android.support.v7.app.ActionBar actionBar=getSupportActionBar();
actionBar.setIcon(R.drawable.ic_image3);
use AppCompatActivity
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
TRY this code :
final ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeAsUpIndicator(R.drawable.back_dark);
actionBar.setTitle(getResources().getString(R.string.title));
i have a problem with getActionBar(), this problem happens when i'm trying to change view of action bar , i'm getting this error:
java.lang.RuntimeException: Unable to start activity ComponentInfo{h.ui01/h.ui01.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setNavigationMode(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3119)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3218)
at android.app.ActivityThread.access$1000(ActivityThread.java:198)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1676)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6837)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setNavigationMode(int)' on a null object reference
at h.ui01.MainActivity.onCreate(MainActivity.java:28)
at android.app.Activity.performCreate(Activity.java:6500)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1120)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3072)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3218)
at android.app.ActivityThread.access$1000(ActivityThread.java:198)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1676)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6837)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
My code is here :
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.action_bar, null);
actionBar.setCustomView(view, new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
}
}
even when i try to hide action bar or change color of the action bar , i saw similar error.