我不明白为什么会这样
我在代码中提到了/错误，所以您可以很容易地找到
你知道怎么解决这个问题吗？有时它正常工作，没有任何错误，但有时它抛出nullpointerexception
错误日志

java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null object reference
        at com.app.android.Provider.PrefManager.<init>(PrefManager.java:34)
        at com.app.android.ui.fragement.PlayerFragment.addView(PlayerFragment.java:1901)
        at com.app.android.ui.fragement.PlayerFragment$25.onPlayerStateChanged(PlayerFragment.java:993)

prefmanager.java文件

public class PrefManager {

    SharedPreferences pref;
    SharedPreferences.Editor editor;
    Context _context;

    // shared pref mode
    int PRIVATE_MODE = 0;

    // Shared preferences file name
    private static final String PREF_NAME = "status_app";

    private static final String IS_FIRST_TIME_LAUNCH = "IsFirstTimeLaunch";

    public PrefManager(Context context) {
        this._context = context;
         pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);//Error Here
         editor = pref.edit();
         editor.apply();

    }

    public void setBoolean(String PREF_NAME,Boolean val) {
        editor.putBoolean(PREF_NAME, val);
        editor.commit();
    }
    public void setString(String PREF_NAME,String VAL) {
        editor.putString(PREF_NAME, VAL);
        editor.commit();
    }
    public void setInt(String PREF_NAME,int VAL) {
        editor.putInt(PREF_NAME, VAL);
        editor.commit();
    }
    public boolean getBoolean(String PREF_NAME) {
        return pref.getBoolean(PREF_NAME,true);
    }
    public void remove(String PREF_NAME){
        if(pref.contains(PREF_NAME)){
            editor.remove(PREF_NAME);
            editor.commit();
        }
    }
    public String getString(String PREF_NAME) {
        if(pref.contains(PREF_NAME)){
            return pref.getString(PREF_NAME,null);
        }
        if (PREF_NAME.equals("LANGUAGE_DEFAULT")){
            return "0";
        }
        if(PREF_NAME.equals("ORDER_DEFAULT_IMAGE")){
            return "created";
        }
        if(PREF_NAME.equals("ORDER_DEFAULT_GIF")){
            return "created";
        }
        if(PREF_NAME.equals("ORDER_DEFAULT_VIDEO")){
            return "created";
        }
        if(PREF_NAME.equals("ORDER_DEFAULT_JOKE")){
            return "created";
        }
        if(PREF_NAME.equals("ORDER_DEFAULT_STATUS")){
            return "created";
        }
        return  "";
    }

    public int getInt(String key) {
        return pref.getInt(key,0);
    }
}

playerfragment.java文件

final PrefManager prefManager = new PrefManager(getActivity()); //Error Here
Integer id_user = 0;
String key_user= "";
if (prefManager.getString("LOGGED").toString().equals("TRUE")) {
    id_user=  Integer.parseInt(prefManager.getString("ID_USER"));
    key_user=  prefManager.getString("TOKEN_USER");
}

playerfragment.java文件

public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
    if (playbackState == ExoPlayer.STATE_READY) {
        simple_arc_loader_exo.setVisibility(View.GONE);
        exo_pause.setVisibility(View.GONE);
        exo_play.setVisibility(View.GONE);
        playing = true;
        exo_play.setColorFilter(Color.WHITE, android.graphics.PorterDuff.Mode.SRC_IN);
        addView();// Error Here
    }
    if (playbackState == ExoPlayer.STATE_BUFFERING) {
        simple_arc_loader_exo.setVisibility(View.VISIBLE);
        exo_pause.setVisibility(View.GONE);
        exo_play.setVisibility(View.GONE);

    }
}