[Android Studio] plopmenz:
Hello,

i am trying to launch my app on a samsung galaxy s3, but the activity doesn't launch :(

can someone help me?

error:

06-14 08:36:58.720 24601-24601/plopmenzinc.nsapp E/AndroidRuntime: FATAL EXCEPTION: main

Process: plopmenzinc.nsapp, PID: 24601

java.lang.RuntimeException: Unable to start activity ComponentInfo{plopmenzinc.nsapp/plopmenzinc.nsapp.Start}: java.lang.NullPointerException

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2436)

at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2495)

at android.app.ActivityThread.access$900(ActivityThread.java:170)

at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)

at android.os.Handler.dispatchMessage(Handler.java:102)

at android.os.Looper.loop(Looper.java:146)

at android.app.ActivityThread.main(ActivityThread.java:5635)

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:1291)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)

at dalvik.system.NativeStart.main(Native Method)

Caused by: java.lang.NullPointerException

at plopmenzinc.nsapp.Start.onCreate(Start.java:37)

at android.app.Activity.performCreate(Activity.java:5580)

at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2400)

at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2495)*

at android.app.ActivityThread.access$900(ActivityThread.java:170)*

at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)*

at android.os.Handler.dispatchMessage(Handler.java:102)*

at android.os.Looper.loop(Looper.java:146)*

at android.app.ActivityThread.main(ActivityThread.java:5635)*

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:1291)*

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)*

at dalvik.system.NativeStart.main(Native Method)*

start.java:

package plopmenzinc.nsapp;

import android.app.Activity;

import android.app.PendingIntent;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.content.SharedPreferences;

import android.nfc.NfcAdapter;

import android.os.CountDownTimer;

import android.preference.PreferenceManager;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.ImageSwitcher;

import android.widget.TextView;

import android.widget.Toast;

public class Start extends AppCompatActivity {

int number = 0;

private ImageSwitcher sw;

public static final String MIME_TEXT_PLAIN = "text/plain";

public static final String TAG = "NfcDemo";

private TextView mTextView;

private NfcAdapter mNfcAdapter;

[MENTION=439709]override[/MENTION]

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_start);

mNfcAdapter = NfcAdapter.getDefaultAdapter(this);

sw.setImageResource(R.drawable.reclame);

if (mNfcAdapter == null) {

// Stop here, we definitely need NFC

Toast.makeText(this, "U kunt deze functie helaas niet gebruiken, omdat uw toestel geen NFC heeft.", Toast.LENGTH_LONG).show();

finish();

return;

}

if (!mNfcAdapter.isEnabled()) {

mTextView.setText("Om deze functie te gebruiken moet u NFC aanzetten.");

}

handleIntent(getIntent());

}

[MENTION=439709]override[/MENTION]

protected void onResume() {

super.onResume();

/**

* It's important, that the activity is in the foreground (resumed). Otherwise

* an IllegalStateException is thrown.

*/

setupForegroundDispatch(this, mNfcAdapter);

}

[MENTION=439709]override[/MENTION]

protected void onPause() {

/**

* Call this before onPause, otherwise an IllegalArgumentException is thrown as well.

*/

stopForegroundDispatch(this, mNfcAdapter);

super.onPause();

}

[MENTION=439709]override[/MENTION]

protected void onNewIntent(Intent intent) {

/**

* This method gets called, when a new Intent gets associated with the current activity instance.

* Instead of creating a new activity, onNewIntent will be called. For more information have a look

* at the documentation.

*

* In our case this method gets called, when the user attaches a Tag to the device.

*/

handleIntent(intent);

}

private void handleIntent(Intent intent) {

TextView var = (TextView) findViewById(R.id.score);

number++;

String disp = Integer.toString(number);

var.setText(disp);

final TextView CountDown = (TextView) findViewById(R.id.textView3);

new CountDownTimer(300000, 1000) {

public void onTick(long millisUntilFinished) {

CountDown.setText(millisUntilFinished / 1000 + " sec");

}

public void onFinish() {

CountDown.setText("0 sec");

}

}.start();

}

/**

* [MENTION=955119]param[/MENTION] activity The corresponding {@link Activity} requesting the foreground dispatch.

* [MENTION=955119]param[/MENTION] adapter The {@link NfcAdapter} used for the foreground dispatch.

*/

public void setupForegroundDispatch(final Activity activity, NfcAdapter adapter) {

final Intent intent = new Intent(activity.getApplicationContext(), activity.getClass());

intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

final PendingIntent pendingIntent = PendingIntent.getActivity(activity.getApplicationContext(), 0, intent, 0);

IntentFilter[] filters = new IntentFilter[1];

String[][] techList = new String[][]{};

// Notice that this is the same filter as in our manifest.

filters[0] = new IntentFilter();

filters[0].addAction(NfcAdapter.ACTION_NDEF_DISCOVERED);

filters[0].addCategory(Intent.CATEGORY_DEFAULT);

try {

filters[0].addDataType(MIME_TEXT_PLAIN);

} catch (IntentFilter.MalformedMimeTypeException e) {

throw new RuntimeException("Check your mime type.");

}

adapter.enableForegroundDispatch(activity, pendingIntent, filters, techList);

}

public void stopForegroundDispatch(final Activity activity, NfcAdapter adapter) {

adapter.disableForegroundDispatch(activity);

}

public void image_next(){

sw.setImageResource(R.drawable.reclame);

}

public void image_prev(){

sw.setImageResource(R.drawable.reclame2);

}

}

activity:

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="(link)"

xmlns:tools="(link)"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="plopmenzinc.nsapp.Start"

android:saveEnabled="true">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Uw aantal punten:"

android:id="@+id/textView"

android:layout_alignParentTop="true"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_marginTop="50dp"

android:singleLine="true"

android:textColor="#FF2646B0"

android:textSize="22sp" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/disp"

android:id="@+id/score"

android:layout_alignBottom="@+id/textView"

android:layout_toRightOf="@+id/textView"

android:layout_toEndOf="@+id/textView"

android:textSize="22sp" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Tijd tot U weer kunt scannen:"

android:id="@+id/textView2"

android:layout_below="@+id/textView"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_marginTop="34dp"

android:singleLine="true"

android:textColor="#FF2646B0"

android:textSize="22sp"/>

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="0 sec"

android:id="@+id/textView3"

android:singleLine="true"

android:textSize="22sp"

android:layout_alignTop="@+id/textView2"

android:layout_toRightOf="@+id/textView2"

android:layout_toEndOf="@+id/textView2" />

<ImageSwitcher

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/imageSwitcher"

android:layout_below="@+id/textView"

android:layout_centerHorizontal="true"

android:layout_marginTop="275dp" />

<Button

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="prev"

android:id="@+id/button"

android:layout_alignTop="@+id/button2"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_marginLeft="54dp"

android:layout_marginStart="54dp"

android:onClick="image_prev" />

<Button

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="next"

android:id="@+id/button2"

android:layout_alignParentBottom="true"

android:layout_alignRight="@+id/textView3"

android:layout_alignEnd="@+id/textView3"

android:onClick="image_next" />

</RelativeLayout>

Manifest:

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="(link)"

package="plopmenzinc.nsapp">

<application

android:allowBackup="true"

android:icon="@mipmap/ic_launcher"

android:label="@string/app_name"

android:supportsRtl="true"

android:theme="@style/AppTheme">

<activity android:name=".Start">

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

</application>

<uses-permission android:name="android.permission.NFC" />

<uses-feature

android:name="android.hardware.nfc"

android:required="true" />

<activity

android:name="net.vrallev.android.nfc.demo.MainActivity"

android:label="@string/app_name" >

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

<intent-filter>

<action android:name="android.nfc.action.TECH_DISCOVERED" />

</intent-filter>

<meta-data

android:name="android.nfc.action.TECH_DISCOVERED"

android:resource="@xml/nfc_tech_filter" />

</activity>

</manifest>

need to get this finished before thursday, so please help me