This Java class compiles smoothly but when I click on this when using my android phone as ADB. It says the device has stopped working

Question

This is the class causing trouble because before writing this class, the program ran fine on the phone.
So I think the problem is with this class.
Please look in to find the problem.

JAVA CLASS:

package com.boston.ppp.boston;




import java.util.Random;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.text.InputType;
import android.view.Display; 
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.ToggleButton;

/**
* Created by ppp on 4/19/2015.
*/
public class TextPlay extends Activity implements View.OnClickListener {
 Button b;
ToggleButton tog;
EditText ed;
TextView tex;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.text);
    arnavbhai();
    tog.setOnClickListener(this);
    b.setOnClickListener(this);
}

private void arnavbhai() {
    b = (Button) findViewById(R.id.button1);
    tog = (ToggleButton) findViewById(R.id.togglebutton);
    ed = (EditText) findViewById(R.id.etcommand);
    tex = (TextView) findViewById(R.id.tvresults);

}

@Override
public void onClick(View v) {
    switch (v.getId()){
        case R.id.button1:
            String check = ed.getText().toString();
            tex.setText(check);
            if (check.contentEquals("left")) {
                tex.setGravity(Gravity.LEFT);
            }

            if (check.contentEquals("right")) {
                tex.setGravity(Gravity.RIGHT);
            }
            if (check.contentEquals("center")) {
                tex.setGravity(Gravity.CENTER);
            }
            if (check.contains("WTF")) {
                Random crazy = new Random();
                tex.setText("WTF");
                tex.setTextSize(crazy.nextInt(75));
                tex.setTextColor(Color.rgb(crazy.nextInt(265),crazy.nextInt(265),crazy.nextInt(265)));
                switch(crazy.nextInt(3))
                {
                    case 0:
                        tex.setGravity(Gravity.LEFT);
                        break;
                    case 1:
                        tex.setGravity(Gravity.RIGHT);

                        break;
                    case 2:
                        tex.setGravity(Gravity.CENTER);

                        break;
                }
            }
            else {
                tex.setText("invalid");
                tex.setGravity(Gravity.CENTER);
                tex.setTextColor(Color.WHITE);
            }
            break;
        case R.id.togglebutton:
            if (tog.isChecked()) {
                ed.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
            } else {
                ed.setInputType(InputType.TYPE_CLASS_TEXT);
            }
            break;
    }
}

}

ERROR SHOWN :

04-21 18:18:02.157    8024-8024/com.boston.ppp.boston W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41662d40)
04-21 18:18:02.161    8024-8024/com.boston.ppp.boston E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.boston.ppp.boston, PID: 8024
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.boston.ppp.boston/com.boston.ppp.boston.TextPlay}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
        at android.app.ActivityThread.access$800(ActivityThread.java:139)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5086)
        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 com.boston.ppp.boston.TextPlay.onCreate(TextPlay.java:32)
        at android.app.Activity.performCreate(Activity.java:5248)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
        at android.app.ActivityThread.access$800(ActivityThread.java:139)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5086)
        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)
04-21 18:20:23.527    8024-8024/com.boston.ppp.boston I/Process﹕ Sending signal. PID: 8024 SIG: 9

Answer 1

The error is in the line 32.

You have to find your UI elements and define them in your code. Something like:

b = (Button) findViewById(R.id.ID_OF_BUTTON);
tog = (ToggleButton) findViewById(R.id.ID);

Then, you can call the listenners.

Answer 2

you are accessing tog and b without initialization which is causing a NPE . add

tog = (ToggleButton) findViewById(R.id.idOfTOG);
b = (Button)  findViewById(R.id.idOfButton);

in onCreate before calling setOnClickListener

Answer 3

You have a NullPointerException being thrown from TextPlay.onCreate(), line 32. It's right there in the stack trace.

Now, you can either * Attach a debugger and step through the method, looking for null references, or * Trace the set-up of your class and see where the null reference could be coming from

Answer 4

well, based on your comment. I think the problems is because of this

Layout

<Button 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_weight="20" 
    android:text="New Button" 
    android:id="@+id/bresults" 
/> 
<ToggleButton 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_weight="80" 
    android:checked="true" 
    android:paddingBottom="10dp" 
    android:id="@+id/togglebutton"
/>

Code

Button b;
ToggleButton tog;

@Override
protected void onCreate(Bundle savedInstanceState) {
    arnavbhai();
    tog.setOnClickListener(this); 
    b.setOnClickListener(this);   <-- seems this part is throwing NPE
}

private void arnavbhai() {
    b = (Button) findViewById(R.id.button1); <-- shouldn't it be R.id.bresults ?
    tog = (ToggleButton) findViewById(R.id.togglebutton);
}