in the last few days I tried to develop android applications with no success, for some reason my application keep crashing.
the application keeps throwing few exceptions that I didn't succeeded to handle with.
MainActivity.java :
package com.mobIce.digicoin.digitalcoin;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends ActionBarActivity {
private List<Coin> coins;
public MainActivity(){
coins = new ArrayList<Coin>();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
populateCoins();
populateListView();
}
}
private void populateCoins() {
coins.add(new Coin("Bitcoin", "650", "4", "http://coinmarketcap.com/img/Bitcoin.png"));
coins.add(new Coin("Dogecoin", "100", "400", "http://coinmarketcap.com/img/Bitcoin.png"));
coins.add(new Coin("fafaf", "8065", "400", "http://coinmarketcap.com/img/Bitcoin.png"));
}
private void populateListView() {
ArrayAdapter<Coin> adapter = new MyListAdapter();
ListView list = (ListView) findViewById(R.id.coinsListView);
list.setAdapter(adapter);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
private class MyListAdapter extends ArrayAdapter<Coin> {
public MyListAdapter()
{
super(MainActivity.this, R.layout.coin_layout, coins);
}
#Override
public View getView(int position, View convertView, ViewGroup parent){
View itemView = convertView;
if(itemView == null)
itemView = getLayoutInflater().inflate(R.layout.coin_layout, parent, false);
//find the coin to work with.
Coin currentCoin = coins.get(position);
//fill the view
try{
TextView coinName = (TextView) itemView.findViewById(R.id.coinName);
coinName.setText(currentCoin.getName());
TextView coinPrice = (TextView) itemView.findViewById(R.id.coinPrice);
coinPrice.setText(currentCoin.getPrice());
TextView coinPercentage = (TextView) itemView.findViewById(R.id.coinPercentage);
coinPercentage.setText(currentCoin.getPercentage());
}
catch (NullPointerException e){ }
return itemView;
}
}
}
activity_main.xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mobIce.digicoin.digitalcoin.MainActivity"
tools:ignore="MergeRootFrame" />
fragment_main.xml:
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/coinsListView"
android:paddingLeft="30dp" />
</LinearLayout>
coin_layout.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:padding="8dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="coinName"
android:id="#+id/coinName"
android:layout_alignParentTop="true"
android:layout_toRightOf="#+id/coinIcon"
android:layout_marginTop="35dp"
android:layout_marginLeft="20dp" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/coinIcon"
android:maxHeight="80dp"
android:maxWidth="80dp"
android:minHeight="80dp"
android:minWidth="80dp"
android:src="#drawable/dogecoin"
android:longClickable="false"
android:focusable="false"
android:focusableInTouchMode="false"
android:baselineAlignBottom="false"
android:clickable="false"
android:adjustViewBounds="true"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Large Text"
android:id="#+id/coinPrice"
android:layout_marginLeft="35dp"
android:layout_alignTop="#+id/coinIcon"
android:layout_toRightOf="#+id/coinName"
android:layout_marginTop="25dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Medium Text"
android:id="#+id/coinPercentage"
android:layout_below="#+id/coinPrice"
android:layout_alignLeft="#+id/coinPrice"
android:layout_alignStart="#+id/coinPrice" />
</RelativeLayout>
logcat trace:
03-17 08:59:33.977 1107-1107/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 08:59:33.977 1107-1107/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 08:59:33.987 1107-1107/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1107
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:47)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:36)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:04:09.857 1149-1149/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:04:09.857 1149-1149/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:04:09.867 1149-1149/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1149
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:39)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:06:36.697 1192-1192/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:06:36.697 1192-1192/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:06:36.717 1192-1192/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1192
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:39)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:13:38.647 1239-1239/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:13:38.647 1239-1239/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:13:38.747 1239-1239/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1239
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:37)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:13:45.127 1239-1239/com.mobIce.digicoin.digitalcoin I/Process﹕ Sending signal. PID: 1239 SIG: 9
03-17 09:19:34.847 1285-1285/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:19:34.847 1285-1285/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:19:34.857 1285-1285/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1285
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:37)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:20:11.987 1285-1285/com.mobIce.digicoin.digitalcoin I/Process﹕ Sending signal. PID: 1285 SIG: 9
Your coinsListView is in the fragment layout and not in activity layout. You cannot access it with findViewById() in populateListView() called from activity onCreate(). Instead, move the list view population to the fragment's onCreateView() after the inflation, calling findViewById() on the rootView layout you just inflated.
Related
Other stuck posts unfortunately couldn't help me.
When I clicked button while easy radiobutton is checked, the app stops working. I couldn't go and see another activity.
Sender Side:
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(radiobutton_arm_triceps_easy.isChecked()) {
String dene = "my example test";
int myValue=2;
Intent intent = new Intent(getApplicationContext(), exercise_arm_triceps_execute.class);
intent.putExtra("attempt1", myValue );
startActivity(intent);
}
}
});
Receiver Side:
int receiveValue=getIntent().getIntExtra("attempt1",0);
textshow.setText(receiveValue);
LOGCAT
04-26 16:52:06.320 31527-31527/com.example.kerem.tutorial_project E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.kerem.tutorial_project, PID: 31527
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.kerem.tutorial_project/com.example.kerem.tutorial_project.exercise_arm_triceps_execute}: android.content.res.Resources$NotFoundException: String resource ID #0x2
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x2
at android.content.res.Resources.getText(Resources.java:244)
at android.support.v7.widget.ResourcesWrapper.getText(ResourcesWrapper.java:52)
at android.widget.TextView.setText(TextView.java:3888)
at com.example.kerem.tutorial_project.exercise_arm_triceps_execute.onCreate(exercise_arm_triceps_execute.java:28)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Use
textshow.setText(String.valueOf(receiveValue));
I'm receiving an error when executing this code.
When connected to wifi, the function should display MAC address, otherwise "---"
private void DisplayWifiStatus() {
ConnectivityManager conMgr = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = conMgr.getActiveNetworkInfo();
wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo info = wifi.getConnectionInfo();
if (networkInfo.isConnected()) {
textMac.setText(info.getMacAddress());
}else {
textMac.setText("-----");
}
}
Logcat/Stacktrace:
03-11 21:32:07.532 3348-3348/com.light87sakurahimegmail.wifiscanner E/dalvikvm﹕ >>>>> Normal User
03-11 21:32:07.532 3348-3348/com.light87sakurahimegmail.wifiscanner E/dalvikvm﹕ >>>>> com.light87sakurahimegmail.wifiscanner [ userId:0 | appId:10337 ]
03-11 21:32:07.782 3348-3348/com.light87sakurahimegmail.wifiscanner E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.light87sakurahimegmail.wifiscanner, PID: 3348
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.light87sakurahimegmail.wifiscanner/com.light87sakurahimegmail.wifiscanner.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2350)
at android.app.ActivityThread.access$800(ActivityThread.java:163)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1257)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5335)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.light87sakurahimegmail.wifiscanner.MainActivity.DisplayWifiStatus(MainActivity.java:79)
at com.light87sakurahimegmail.wifiscanner.MainActivity.onCreate(MainActivity.java:43)
at android.app.Activity.performCreate(Activity.java:5389)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2256)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2350)
at android.app.ActivityThread.access$800(ActivityThread.java:163)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1257)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5335)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
at dalvik.system.NativeStart.main(Native Method)
I have created a custom View which draws a line:
public class DrawView extends View {
Paint paint = new Paint();
public DrawView(Context context) {
super(context);
paint.setColor(Color.BLACK);
}
#Override
public void onDraw(Canvas canvas) {
canvas.drawLine(0, 0, 100, 100, paint);
}
}
I have a MainActivity class and activity_main layout where my layout contains an image and several buttons. I want to put the custom view that I created to my XML file(activity_main) where a line would be drawn on top of the image.
I tried adding it:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
//imageview and buttons here
<com.myapp.alphasickbro.myapplication2.DrawView
android:id="#+id/paintView"
android:layout_width="100dp"
android:layout_height="100dp"
/>
</RelativeLayout>
Here is my MainActivity:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
But when I run it, the app unfortunately stops. Did I miss something? What lines of code should I add?
Any answer would be appreciated
EDIT:
04-18 15:24:47.517 26732-26732/com.myapp.alphasickbro.myapplication2 E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.myapp.alphasickbro.myapplication2, PID: 26732
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.alphasickbro.myapplication2/com.myapp.alphasickbro.myapplication2.MainActivity}: android.view.InflateException: Binary XML file line #6: Error inflating class com.myapp.alphasickbro.myapplication2.DrawView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2318)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:149)
at android.app.ActivityThread.main(ActivityThread.java:5268)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #6: Error inflating class com.myapp.alphasickbro.myapplication2.DrawView
at android.view.LayoutInflater.createView(LayoutInflater.java:620)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:696)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
at android.app.Activity.setContentView(Activity.java:2002)
at com.myapp.alphasickbro.myapplication2.MainActivity.onCreate(MainActivity.java:15)
at android.app.Activity.performCreate(Activity.java:5411)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:149)
at android.app.ActivityThread.main(ActivityThread.java:5268)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at android.view.LayoutInflater.createView(LayoutInflater.java:594)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:696)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
at android.app.Activity.setContentView(Activity.java:2002)
at com.myapp.alphasickbro.myapplication2.MainActivity.onCreate(MainActivity.java:15)
at android.app.Activity.performCreate(Activity.java:5411)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:149)
at android.app.ActivityThread.main(ActivityThread.java:5268)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.myapp.alphasickbro.myapplication2.DrawView.<init>(DrawView.java:27)
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at android.view.LayoutInflater.createView(LayoutInflater.java:594)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:696)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
at android.app.Activity.setContentView(Activity.java:2002)
at com.myapp.alphasickbro.myapplication2.MainActivity.onCreate(MainActivity.java:15)
at android.app.Activity.performCreate(Activity.java:5411)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:149)
at android.app.ActivityThread.main(ActivityThread.java:5268)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
at dalvik.system.NativeStart.main(Native Method)
I think you need to add the missing constructors. Clean your project.
public class DrawView extends View {
Paint paint;
public DrawView(Context context) {
super(context);
init();
}
public DrawView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public DrawView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
paint = new Paint();
paint.setColor(Color.BLACK);
}
}
I feel bad for asking about this but for 2 hours now I can't find any way to solve this:
**The Problem: ** I have set up a canvas area(where i plot a drawable figure) and a button below the canvas area.
In my AnimatedView class I want find the button and give it an onClickListener, but it returns a NullPointerException.
my activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:orientation="vertical"
android:background="#000000">
<com.example.julle.bounce.AnimatedView
android:id="#+id/anim_view"
android:layout_height="300dp"
android:layout_width="fill_parent"/>
<Button
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/anim_view"
android:id="#+id/button_jump"
android:clickable="true"
android:text="Jump"/>
my code for AnimatedView.java:
package com.example.julle.bounce;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.BitmapDrawable;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class AnimatedView extends ImageView{
private Context mContext;
int x = -1;
int y = -1;
private int xVelocity = 10;
private int yVelocity = 5;
private Handler h;
private final int FRAME_RATE = 30;
boolean jump=false;
public AnimatedView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
final Button button = (Button) findViewById(R.id.button_jump);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
jump=true;
}
});
h = new Handler();
}
private Runnable r = new Runnable() {
#Override
public void run() {
invalidate();
}
};
protected void onDraw(Canvas c) {
BitmapDrawable ball = (BitmapDrawable) mContext.getResources().getDrawable(R.drawable.ball);
if(jump==true) {
if (y < 0) {
y = this.getHeight() / 2;
} else {
y += yVelocity;
}
jump=false;
}else{
y= this.getHeight()/2;
}
c.drawBitmap(ball.getBitmap(), x, y, null);
h.postDelayed(r, FRAME_RATE);
}
}
and my MainActivity:
package com.example.julle.bounce;
import ...
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
I believe I've realised the problem: the buttons are existent in the MainActivity class but not in my AnimatedView class. Allthou it might be very simple, I'm not sure how to solve that.
Thank you for all replies!
Sorry, totally forgot that I changed the code. AnimatedView is updated:
The line that gives NullPointException is line 26 in AnimatedView: button.setOnClickListener...
logcat:
02-24 14:47:32.005 31934-31934/com.example.julle.bounce E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.julle.bounce/com.example.julle.bounce.MainActivity}: android.view.InflateException: Binary XML file line #13: Error inflating class com.example.julle.bounce.AnimatedView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class com.example.julle.bounce.AnimatedView
at android.view.LayoutInflater.createView(LayoutInflater.java:613)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
at com.example.julle.bounce.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:5206)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at android.view.LayoutInflater.createView(LayoutInflater.java:587)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
at com.example.julle.bounce.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:5206)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.julle.bounce.AnimatedView.<init>(AnimatedView.java:26)
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at android.view.LayoutInflater.createView(LayoutInflater.java:587)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:228)
at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
at com.example.julle.bounce.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:5206)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
at dalvik.system.NativeStart.main(Native Method)
You can pass a reference to your button from main activity to AnimatedView class.
package com.example.julle.bounce;
import ...
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button)findViewByID(R.id.button_jump);
AnimatedView av = (AnimatedView)findViewByID(R.id.anm_view);
av.setJumpButton(btn);
}
}
You will need to add the setJumpButton method in your AnimatedView class.
i am try to implement a numberPicker to select minute values.
But i am getting a NullPointer Exception at this line:
minutePicker = (NumberPicker) findViewById(R.id.minuten_picker);
Following Code:
public class MainActivity extends Activity {
NumberPicker minutePicker;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Auswahl Minuten zum starten / Stoppen aller
minutePicker = new NumberPicker(MainActivity.this);
minutePicker = (NumberPicker) findViewById(R.id.minuten_picker);
minutePicker.setMaxValue(30);
minutePicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
#Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
abschaltzeit = minutePicker.getValue();
}
});
minutePicker.setValue(0);
minutePicker.setWrapSelectorWheel(false);
}
}
XML:
<NumberPicker
android:id="#+id/minuten_picker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_row="6"
android:layout_column="0"
android:paddingLeft="20dp" />
Log:
09-25 11:00:09.749 10687-10687/de.carsten.awesome.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: de.carsten.awesome.app, PID: 10687
java.lang.RuntimeException: Unable to start activity ComponentInfo{de.carsten.awesome.app/de.carsten.awesome.app.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at de.carsten.awesome.app.MainActivity.onCreate(MainActivity.java:83)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
minutePicker = new NumberPicker(MainActivity.this);
minutePicker = (NumberPicker) findViewById(R.id.minuten_picker);
You're creating a NumberPicker programmatically and then overwriting the reference with whatever findViewById() returns. It returns null if your activity_main layout does not contain a minuten_picker.
Choose only the other: either create it prorgrammatically or find it from a view hierarchy you inflated.
If you choose the programmatic way new NumberPicker(), remember to add it to some layout in your activity view hierarchy, e.g. with setContentView()
If you choose the inflation way, make sure you have the view in your XML layout file.
I'm guessing the NPE you're seeing is actually on the following line where you're trying to invoke a method on the minutePicker and it's null.
I apologize.
I moved the Code from the MainActivity in the creating Fragment and it works with rootView.findView.
Sorry but i am new with the Fragement Konzept.
Thanks a lot for your help !