Collectives™ on Stack Overflow
Find centralized, trusted content and collaborate around the technologies you use most.
Learn more about Collectives
Teams
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
Learn more about Teams
I know this error appeared on forum million of times, but please help me find what I missed.
I'm trying to do simple tab orientated application,I don't have much (except errors)
1) my main activity is based on tablayout tutorial what I found
public class MainTabPanel extends TabActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mainlayout);
Resources res = getResources();
TabHost tabHost = getTabHost();
TabHost.TabSpec spec;
Intent intent;
intent = new Intent().setClass(this, MyBookActivity.class);
spec = tabHost.newTabSpec("main")
.setIndicator("Main", res.getDrawable(R.drawable.ic_mybook))
.setContent(intent);
tabHost.addTab(spec);
tabHost.setCurrentTab(0);
2) mainlayout.xml
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp">
<TabWidget
android:id="@android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp" />
</LinearLayout></TabHost>
3) my second activity is basically almost empty, it;s just display current date and time, worked before I tried to add tab panel
4) my manifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.th.mybook"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainTabPanel"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="MyBookActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.ALTERNATIVE" />
</intent-filter>
</activity>
</application>
</manifest>
5 log cat error
02-10 21:04:45.203: E/AndroidRuntime(1107): FATAL EXCEPTION: main
02-10 21:04:45.203: E/AndroidRuntime(1107): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.th.mybook/org.th.mybook.MainTabPanel}: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{org.th.mybook/org.th.mybook.MyBookActivity}: java.lang.NullPointerException
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.os.Handler.dispatchMessage(Handler.java:99)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.os.Looper.loop(Looper.java:123)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.main(ActivityThread.java:4627)
02-10 21:04:45.203: E/AndroidRuntime(1107): at java.lang.reflect.Method.invokeNative(Native Method)
02-10 21:04:45.203: E/AndroidRuntime(1107): at java.lang.reflect.Method.invoke(Method.java:521)
02-10 21:04:45.203: E/AndroidRuntime(1107): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-10 21:04:45.203: E/AndroidRuntime(1107): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-10 21:04:45.203: E/AndroidRuntime(1107): at dalvik.system.NativeStart.main(Native Method)
02-10 21:04:45.203: E/AndroidRuntime(1107): Caused by: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{org.th.mybook/org.th.mybook.MyBookActivity}: java.lang.NullPointerException
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.startActivityNow(ActivityThread.java:2503)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:651)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.widget.TabHost.setCurrentTab(TabHost.java:323)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.widget.TabHost.addTab(TabHost.java:213)
02-10 21:04:45.203: E/AndroidRuntime(1107): at org.th.mybook.MainTabPanel.onCreate(MainTabPanel.java:30)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-10 21:04:45.203: E/AndroidRuntime(1107): ... 11 more
02-10 21:04:45.203: E/AndroidRuntime(1107): Caused by: java.lang.NullPointerException
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:100)
02-10 21:04:45.203: E/AndroidRuntime(1107): at org.th.mybook.MyBookActivity.<init>(MyBookActivity.java:16)
02-10 21:04:45.203: E/AndroidRuntime(1107): at java.lang.Class.newInstanceImpl(Native Method)
02-10 21:04:45.203: E/AndroidRuntime(1107): at java.lang.Class.newInstance(Class.java:1429)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
02-10 21:04:45.203: E/AndroidRuntime(1107): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
02-10 21:04:45.203: E/AndroidRuntime(1107): ... 20 more
please help me, and tell me what i missed, im comparing this code with my old one and i can't find anything
regards
6) my book activity
public class MyBookActivity extends Activity {
java.text.DateFormat dateFormat = android.text.format.DateFormat.getDateFormat(getApplicationContext());
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DigitalClock clock = (DigitalClock) findViewById(R.id.digitalClock1);
final TextView date = (TextView) findViewById(R.id.textView1);
date.setText(dateFormat.format(new Date()));
TextWatcher watcher = new TextWatcher() {
@Override
public void afterTextChanged(Editable s) {
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
@Override
public void onTextChanged(CharSequence s, int start, int before,
int count) {
if (s.toString().startsWith("00:00:00")
|| s.toString().startsWith("12:00:00")) {
date.setText(dateFormat.format(new Date()));
clock.addTextChangedListener(watcher);
7) main.xml layout -> for my book activity
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="right"
android:orientation="horizontal" >
<LinearLayout
android:id="@+id/DatePanel1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginRight="@dimen/space"
android:layout_weight="1"
android:text="TextView" />
<DigitalClock
android:id="@+id/digitalClock1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="DigitalClock" />
</LinearLayout>
</LinearLayout>
–
–
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.ALTERNATIVE" />
</intent-filter>
</activity>
where is your dot before MyBookActivity?
–
It was my own stupidity:
java.text.DateFormat dateFormat = android.text.format.DateFormat.getDateFormat(getApplicationContext());
Putting this inside onCreate() method fixed my problem.
Your Manifest Must Change like this Activity name must Specified like ".YourActivityname"
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.th.mybook"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8" android:targetSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainTabPanel"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MyBookActivity" >
</activity>
</application>
I encountered a similar error in one of my app recently, when I checked Android Vitals. So, I'm writing this.
This is the error.
java.lang.RuntimeException: Unable to start activity ComponentInfo{my.package.name/my.package.name.activity.MainActivity}: android.view.InflateException: Binary XML file line #30: Binary XML file line #30: Error inflating class fragment
After checking my Binary XML file on line #30, I found out that this my navGraph was on line #30. app:navGraph="@navigation/mobile_navigation"
Then, I realized that I was inflating the fragment wrongly.
I came across Get started with the Navigation component which clearly states that:
When creating the NavHostFragment using FragmentContainerView or if
manually adding the NavHostFragment to your activity via a
FragmentTransaction, attempting to retrieve the NavController in
onCreate() of an Activity via Navigation.findNavController(Activity,
@IdRes int) will fail. You should retrieve the NavController directly
from the NavHostFragment instead.
This is the correct way of Inflating the NavHostFragment:
NavHostFragment navHostFragment =
(NavHostFragment) supportFragmentManager.findFragmentById(R.id.nav_host_fragment);
NavController navController = navHostFragment.getNavController();
Earlier, I was trying to inflate like this:
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
NavigationUI.setupWithNavController(navigationView, navController);
So, my new code becomes:
NavHostFragment navHostFragment = (NavHostFragment) getSupportFragmentManager().findFragmentById(R.id.nav_host_fragment);
NavController navController = null;
if (navHostFragment != null) {
navController = navHostFragment.getNavController();
if (navController != null) {
NavigationUI.setupActionBarWithNavController(MainActivity.this, navController, mAppBarConfiguration);
NavigationUI.setupWithNavController(navigationView, navController);
My problem looked similar, after some hours I found that not all of my project was converted to androidx, so I changed:
<android.support.constraint.ConstraintLayout
<androidx.constraintlayout.widget.ConstraintLayout
then androidStudio still complaints, but the problem solver can add constraintlayout to your libraries or so.
Now it starts again! It's funny that past 8 years many similar problems appear with a different solution.
Dear You have used two Intent launcher in your Manifest. Make only one Activity as launcher:
Your manifest activity is :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.th.mybook"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainTabPanel"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="MyBookActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.ALTERNATIVE" />
</intent-filter>
</activity>
</application>
</manifest>
now write code will be ( i have made your 'MyActivityBook' your default activity launcher. Copy and paste it on your manifest.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.th.mybook"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".MainTabPanel"
android:label="@string/app_name" >
</activity>
<activity
android:name="MyBookActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
and Second error may be if you copy paste old code then please update com.example.packagename.FILE_NAME
hope this will work !
This might be of use to someone, even though we are in an 11-year-old thread.
I was going through Google's Basic Android Kotlin Training, particularly the "unscramble" app codelabs, and that is where the problem hit.
On the first screenshot is the traceback of the error that occurred.
On the second is the simple tip from the same exact codelab which I'd completely missed.
It turned out that my package statement was missing from both of the Kotlin source files, even though it was also absent in the codelab's solution code written by Google themselves.
After the simple addition of the package line at the start of the source files, the problem was resolved.
package com.example.android.unscramble.ui.game
After trying few answers they are either not related to my project or , I have tried cleaning and rebuilding (https://stackoverflow.com/a/48760966/8463813). But it didn't work for me directly. I have compared it with older version of code, in which i observed some library files(jars and aars in External Libraries directory) are missing. Tried Invalidate Cache and Restart worked, which created all the libraries and working fine.
If you are using ViewModel and passing any argument but not using the ViewModelFacoty to implement this... then this issue might occur
Solution: Use ViewModelFactory to pass any argument in ViewModel class.
