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>
It was my own stupidity:
java.text.DateFormat dateFormat = android.text.format.DateFormat.getDateFormat(getApplicationContext());
Putting this inside onCreate()
method fixed my problem.
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);
}
<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>
where is your dot before MyBookActivity?
I had the same issue, I cleaned and rebuilt the project and it worked.
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>
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