ProgressBar in fragment

Question

I have + and - buttons in fragment and by pressing them i need to change the progress of ProgressBar, but instead i get NullPointException

In MainActivity:

public void selectVentilatorFunction(View view) {

    prg = (ProgressBar)view.findViewById(R.id.ventilator_progress);
    int pressedbutton = view.getId();

    switch (pressedbutton){
     case R.id.increase:
         if(int_ventilator < 100) int_ventilator = int_ventilator + 10;
         break;
     case R.id.decrease:
         if(int_ventilator > 0) int_ventilator = int_ventilator - 10;
         break;
    }
    prg.setProgress(int_ventilator);
    Log.d(TAG,"Ventilator progresas " + int_ventilator);
}

Fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/black" >


<RelativeLayout
        android:id="@+id/buttonview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="45dp"
        android:layout_marginLeft="45dp"
        android:layout_marginRight="45dp">

      <ProgressBar
            android:id="@+id/ventilator_progress"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="match_parent"
            android:layout_height="100dp" 
            android:layout_marginTop="200dp"
            android:layout_alignParentTop="true"
            android:progress="50"/>

        <Button
            android:id="@+id/decrease"
            android:layout_width="250dp"
            android:layout_height="160dp"
            android:layout_marginBottom="625dp"
            android:background="@android:color/transparent"
            android:layout_alignParentBottom="true"
            android:layout_alignParentLeft="true"
            android:onClick="selectVentilatorFunction" />

        <Button
            android:id="@+id/increase"
            android:layout_width="250dp"
            android:layout_height="160dp"
            android:layout_marginBottom="625dp"
            android:background="@android:color/transparent"
            android:layout_alignParentBottom="true"
            android:layout_alignParentRight="true"
            android:onClick="selectVentilatorFunction" />          

        </RelativeLayout>

        <ImageView        
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:contentDescription="@string/background"
            android:background="@drawable/bg2"
            android:scaleType="fitXY" />
</FrameLayout>

LogCat if needed

11-10 13:53:52.870: E/AndroidRuntime(16452): FATAL EXCEPTION: main
11-10 13:53:52.870: E/AndroidRuntime(16452): Process: com.example.leftpanelmenutest, PID: 16452
11-10 13:53:52.870: E/AndroidRuntime(16452): java.lang.IllegalStateException: Could not execute method of the activity
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.view.View$1.onClick(View.java:3814)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.view.View.performClick(View.java:4424)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.view.View$PerformClick.run(View.java:18383)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.os.Handler.handleCallback(Handler.java:733)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.os.Handler.dispatchMessage(Handler.java:95)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.os.Looper.loop(Looper.java:137)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.app.ActivityThread.main(ActivityThread.java:4998)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at java.lang.reflect.Method.invokeNative(Native Method)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at java.lang.reflect.Method.invoke(Method.java:515)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:811)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:627)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at dalvik.system.NativeStart.main(Native Method)
11-10 13:53:52.870: E/AndroidRuntime(16452): Caused by: java.lang.reflect.InvocationTargetException
11-10 13:53:52.870: E/AndroidRuntime(16452):    at java.lang.reflect.Method.invokeNative(Native Method)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at java.lang.reflect.Method.invoke(Method.java:515)
11-10 13:53:52.870: E/AndroidRuntime(16452):    at android.view.View$1.onClick(View.java:3809)
11-10 13:53:52.870: E/AndroidRuntime(16452):    ... 11 more
11-10 13:53:52.870: E/AndroidRuntime(16452): Caused by: java.lang.NullPointerException
11-10 13:53:52.870: E/AndroidRuntime(16452):    at com.example.leftpanelmenutest.MainActivity.selectVentilatorFunction(MainActivity.java:76)
11-10 13:53:52.870: E/AndroidRuntime(16452):    ... 14 more

EDIT

Full code, there isn't much in it. In MainActivity i have 4 buttons and select the fragment.

public class MainActivity extends Activity {

    final protected static String TAG = "MainActivity";

    Fragment fr;
    FragmentManager fm;
    FragmentTransaction fragmentTransaction;
    boolean firsttime;
    byte[] myData = {10,20};
    public ProgressBar prg;
    int int_ventilator = 0, int_light = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        getWindow().getDecorView().setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
              | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
              | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
              | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
              | View.SYSTEM_UI_FLAG_FULLSCREEN
              | View.SYSTEM_UI_FLAG_IMMERSIVE);
        if(fr==null){
        fr =  new StartMenu();
        fm = getFragmentManager();
        fragmentTransaction = fm.beginTransaction();
        fragmentTransaction.setCustomAnimations(android.R.animator.fade_in, android.R.animator.fade_out);
        fragmentTransaction.add(R.id.fragment_place, fr);
        fragmentTransaction.commit();

        }

}

    public byte[] getMyData() {
        return myData;
    }
    public int getInt() {
        return int_ventilator;
    }

    public void selectMainFunction(View view) {

    }

    public void selectVentilatorFunction(View view) {
        int pressedbutton = view.getId();   
        prg = (ProgressBar)view.findViewById(R.id.ventilator_progress); 
        switch (pressedbutton){
         case R.id.increase:
             if(int_ventilator < 100) int_ventilator = int_ventilator + 10;
             break;
         case R.id.decrease:
             if(int_ventilator > 0) int_ventilator = int_ventilator - 10;
             break;
        }
        prg.setProgress(int_ventilator);
        Log.d(TAG,"Ventilator progresas " + int_ventilator);
    }

    public void selectIndoorLightFunction(View view) {
        int pressedbutton = view.getId();
        switch (pressedbutton){
         case R.id.increase:
             if(int_light < 100) int_light = int_light + 10;
             break;
         case R.id.decrease:
             if(int_light > 0) int_light = int_light - 10;
             break;
        }
        Log.d(TAG,"Light progresas " + int_light);
    }

public void selectOutdoorFunction(View view) {

    }

    public void selectMenu(View view) {
         int pressedbutton = view.getId();


         switch (pressedbutton){
         case R.id.startmenu:
             fr = new StartMenu();
             break;
        case R.id.ventilatormenu:
            fr = new VentilatorMenu();   
             break;
        case R.id.indoormenu:
            fr = new IndoorLightMenu();
             break;
        case R.id.outdoormenu:
            fr = new OutdoorLight();
             break;
         }
         fm = getFragmentManager();
         fragmentTransaction = fm.beginTransaction();
         fragmentTransaction.setCustomAnimations(android.R.animator.fade_in, android.R.animator.fade_out);
         fragmentTransaction.replace(R.id.fragment_place, fr);
         fragmentTransaction.commit();

    }
}

VentilatorFragment

public class VentilatorMenu extends Fragment{

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.e("Test", "VENTILATOR");
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        MainActivity activity = (MainActivity) getActivity();
        View view = inflater.inflate(R.layout.bg2layout, container, false);
        return view;
    }

}

You are applying a onClick listener by XML. On your code, with the line `prg = (ProgressBar)view.findViewById(R.id.ventilator_progress);`, you are causing a NPE, because view is your Button, not your fragment view. — joao2fast4u, Nov 10 '14 at 12:15
Just make `prg` a global variable, so you can change it from inside `selectVentilatorFunction(View view)` method , like you want. — joao2fast4u, Nov 10 '14 at 12:17
@Martynas Poople are asking for whole class code, paste it first. — Pratik Dasa, Nov 10 '14 at 12:18

Haresh Chhelana · Accepted Answer · 2014-11-10T12:56:04.610

Initialize ProgressBar using your layout view reference in onCreateView() instead of button click view reference and have to implement button click listener in fragment instead activity.

public class VentilatorMenu extends Fragment{

    private ProgressBar prg;
    private Button decrease;
    private Button increase;
    private int int_ventilator;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.e("Test", "VENTILATOR");
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.bg2layout, container, false);
        prg = (ProgressBar)view.findViewById(R.id.ventilator_progress);
        decrease = (ProgressBar)view.findViewById(R.id.decrease);
        increase = (ProgressBar)view.findViewById(R.id.increase);
        decrease.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(int_ventilator > 0){
                    int_ventilator = int_ventilator - 10;
                }
                prg.setProgress(int_ventilator);
                Log.d(TAG,"Ventilator progresas " + int_ventilator);
            }
        });
        increase.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(int_ventilator < 100) {
                    int_ventilator = int_ventilator + 10;
                }
                prg.setProgress(int_ventilator);
                Log.d(TAG,"Ventilator progresas " + int_ventilator);
            }
        });
        return view;
    }

}

I tried this, but it searches in MainActivity for a `selectVentilatorFunction` not in fragment class — Martynas, Nov 10 '14 at 12:20
@Martynas,In your posted xml Button as well as ProgressBar also there. — Haresh Chhelana, Nov 10 '14 at 12:24
Yes indeed it solved NPE error, but the view changes only after reloding it. I mean i have to open the fragment again — Martynas, Nov 10 '14 at 12:38
Yes it wasn't updating the progress bar on click. I did that with simple onClickListener. I will accept your answer and edit my question with correct answer — Martynas, Nov 10 '14 at 12:52

score 0 · Answer 2 · edited May 23 '17 at 12:08

0

First, declare your ProgressBar as a global variable:

private ProgressBar;

Then inside onCreateView(), do:

prg = (ProgressBar)view.findViewById(R.id.ventilator_progress);

Then, inside selectVentilatorFunction(View view):

int pressedbutton = view.getId();

switch (pressedbutton){
 case R.id.increase:
     if(int_ventilator < 100) int_ventilator = int_ventilator + 10;
     break;
 case R.id.decrease:
     if(int_ventilator > 0) int_ventilator = int_ventilator - 10;
     break;
}
prg.setProgress(int_ventilator);
Log.d(TAG,"Ventilator progresas " + int_ventilator);

This will solve your NPE problem.

About your onClick XML callback not getting to your fragment, you can see here for a solution.

edited May 23 '17 at 12:08

Community

1
1

answered Nov 10 '14 at 12:25

joao2fast4u

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`selectVentilatorFunction(View view):` is in `MainActivity` and declaration should be in fragment class? – Martynas Nov 10 '14 at 12:28
If you see the link's second answer, you'll know how to solve your second issue. Just make your fragment implement OnClickListener. – joao2fast4u Nov 10 '14 at 12:30

ProgressBar in fragment

2 Answers2