получение исключения nullpointer при нажатии на кнопку

Question

Я использую кнопку, и когда вы нажимаете эту кнопку, текстовое поле автоматически создается, а состояние кнопки автоматически отключается, но если вы нажмете на кнопку отключения текстового поля, то автоматически удалите и статус кнопки изменится для того, чтобы разрешить этот процесс.

public class ConfigurationScreen extends MainScreen implements FieldChangeListener{ 
    TextField tf_text; 
    tf_text = new TextField(TextField.TYPE_PLAIN,img_text[1],img_text[0],TextField.FIELD_HCENTER); 
    tf_text.setWidth(Display.getWidth()/2+20); 

    ImageButton btn_en; 
    btn_en = new ImageButton(imgs_tmintrvl1,"enable",ImageButton.FIELD_HCENTER); 

    ImageButton btn_dis; 
    btn_dis=new ImageButton(imgs_tmintrvl1,"Disable",ImageButton.FIELD_HCENTER); 

    add(btn_en); 

    btn_en.setChangeListener(this); 

    public void fieldChanged(Field field, int context) { 
     if(field==btn_en) 
     { 
      delete(btn_en); 
      insert(btn_dis, 4); 
      insert(tf_text, 5); 

      System.out.println(ex); 
     }else if (field == btn_dis){ 
      delete(btn_dis); 
      delete(tf_text); 
      insert(btn_en, 4); 

      System.out.println("Disable Button="+ex); 
     } 
    }  

Но когда я запускаю этот код, я получаю исключение null pointerr, пожалуйста, помогите мне, где я делаю ошибку.

Answer 1

package org.maxmobility.wmp.beta; 

import com.maxmobility.customfield.H_FieldManager; 
import com.maxmobility.customfield.ImageButton; 
import com.maxmobility.customfield.LabelField; 
import com.maxmobility.customfield.PillButtonField; 
import com.maxmobility.customfield.PillButtonSet; 
import com.maxmobility.customfield.TextArea; 
import com.maxmobility.customfield.TextField; 
import com.maxmobility.util.AppColors; 

import net.rim.device.api.collection.List; 
import net.rim.device.api.system.Bitmap; 
import net.rim.device.api.system.Display; 
import net.rim.device.api.system.EncodedImage; 
import net.rim.device.api.ui.Color; 
import net.rim.device.api.ui.Field; 
import net.rim.device.api.ui.FieldChangeListener; 
import net.rim.device.api.ui.FocusChangeListener; 
import net.rim.device.api.ui.Font; 
import net.rim.device.api.ui.Manager; 
import net.rim.device.api.ui.UiApplication; 
import net.rim.device.api.ui.container.HorizontalFieldManager; 
import net.rim.device.api.ui.container.MainScreen; 
import net.rim.device.api.ui.container.VerticalFieldManager; 
import net.rim.device.api.ui.decor.Background; 
import net.rim.device.api.ui.decor.BackgroundFactory; 

public class ConfigurationScreen extends MainScreen implements FieldChangeListener{ 

    TextField tf_phn1; 
    TextField tf_phn2; 
    TextField tf_msg; 
    TextArea ta_msg; 
    ImageButton btn_add; 
    ImageButton btn_subtract; 
    ImageButton btn_en; 
    ImageButton btn_dis; 
    ImageButton btn_time1, btn_time2, btn_time3; 
    LabelField lf_msg; 
    LabelField lf_time; 
    LabelField lf1,lf2,lf3,lf4; 
    private Bitmap[] imgs_addbtn; 
    private Bitmap[] imgs_subbtn; 
    private Bitmap[] imgs_tmintrvl1; 
    private Bitmap[] imgs_tmintrvl2; 
    private Bitmap[] imgs_tmintrvl3; 
    private EncodedImage[] img_text; 
    private H_FieldManager hfm1 , hfm2; 
    private HorizontalFieldManager hfm3,hfm4; 
    private VerticalFieldManager vfm; 
    private boolean show = false; 
    PillButtonField pbf1; 
    PillButtonField pbf2; 
    PillButtonField pbf3; 
    PillButtonSet pbf_set; 

    public ConfigurationScreen(){ 
     super(USE_ALL_HEIGHT | USE_ALL_WIDTH); 
     Background background = BackgroundFactory 
       .createSolidBackground(AppColors.APP_BG); 
     this.getMainManager().setBackground(background); 

     LabelField lf = new LabelField("Configuration Screen", LabelField.FIELD_HCENTER | LabelField.USE_ALL_WIDTH); 
     lf.setColor(Color.RED); 
     setTitle(lf); 

     img_text = new EncodedImage[2]; 
     img_text[0] = EncodedImage.getEncodedImageResource("edittext_selected.png"); 
     img_text[1] = EncodedImage.getEncodedImageResource("edittext.png"); 

     imgs_addbtn = new Bitmap[3]; 
     imgs_addbtn[0] = Bitmap.getBitmapResource("btn_add_sub.png"); 
     imgs_addbtn[1] = Bitmap.getBitmapResource("btn_add_subfocused.png"); 
     imgs_addbtn[2] = Bitmap.getBitmapResource("btn_add_subfocused.png"); 

     imgs_subbtn = new Bitmap[3]; 
     imgs_subbtn[0] = Bitmap.getBitmapResource("btn_add_sub.png"); 
     imgs_subbtn[1] = Bitmap.getBitmapResource("btn_add_subfocused.png"); 
     imgs_subbtn[2] = Bitmap.getBitmapResource("btn_add_subfocused.png"); 

     imgs_tmintrvl1 = new Bitmap[3]; 
     imgs_tmintrvl1[0] = Bitmap.getBitmapResource("default_btn_Unfocused.png"); 
     imgs_tmintrvl1[1] = Bitmap.getBitmapResource("default_btn_focused.png"); 
     imgs_tmintrvl1[2] = Bitmap.getBitmapResource("default_btn_focused.png"); 

//  imgs_tmintrvl2 = new Bitmap[3]; 
//  imgs_tmintrvl2[0] = Bitmap.getBitmapResource("default_btn_Unfocused.png"); 
//  imgs_tmintrvl2[1] = Bitmap.getBitmapResource("default_btn_focused.png"); 
//  imgs_tmintrvl2[2] = Bitmap.getBitmapResource("default_btn_focused.png"); 
//   
//  imgs_tmintrvl3 = new Bitmap[3]; 
//  imgs_tmintrvl3[0] = Bitmap.getBitmapResource("default_btn_Unfocused.png"); 
//  imgs_tmintrvl3[1] = Bitmap.getBitmapResource("default_btn_focused.png"); 
//  imgs_tmintrvl3[2] = Bitmap.getBitmapResource("default_btn_focused.png"); 
//   
     tf_phn1 = new TextField(TextField.TYPE_PHONE,img_text[1],img_text[0],TextField.FIELD_LEFT); 
     tf_phn2 = new TextField(TextField.TYPE_PHONE,img_text[1],img_text[0],TextField.FIELD_LEFT); 
     tf_msg = new TextField(TextField.TYPE_PLAIN,img_text[1],img_text[0],TextField.FIELD_HCENTER); 
     tf_phn1.setWidth(Display.getWidth()/2+50); 
     tf_phn2.setWidth(Display.getWidth()/2+50); 
     tf_msg.setWidth(Display.getWidth()/2+95); 

     ta_msg = new TextArea(Display.getWidth()/2+130, 100,TextArea.FIELD_HCENTER); 

     btn_add = new ImageButton(imgs_addbtn," +",ImageButton.FIELD_HCENTER); 
     btn_subtract = new ImageButton(imgs_subbtn," -",ImageButton.FIELD_RIGHT); 
     btn_en = new ImageButton(imgs_tmintrvl1,"Enable",ImageButton.FIELD_HCENTER); 
     btn_dis = new ImageButton(imgs_tmintrvl1,"Disable",ImageButton.FIELD_HCENTER); 
//  btn_time1 = new ImageButton(imgs_tmintrvl1, "15 min",ImageButton.FIELD_LEFT); 
//  btn_time2 = new ImageButton(imgs_tmintrvl1, "30 min",ImageButton.FIELD_HCENTER); 
//  btn_time3 = new ImageButton(imgs_tmintrvl1, "45 min",ImageButton.FIELD_RIGHT); 
//  btn_time1.set_Margin(35,0, 0,0); 
//  btn_time2.set_Margin(0,0, 0,0); 
//  btn_time3.set_Margin(0,0, 0,0); 
     //btn_add.set_Margin(0,0, 8,8); 
     LabelField lf1 = new LabelField("",Display.getWidth(),45,LabelField.FIELD_LEFT); 
     LabelField lf2 = new LabelField("",Display.getWidth(),45,LabelField.FIELD_LEFT); 
     LabelField lf3 = new LabelField("",Display.getWidth(),45,LabelField.FIELD_LEFT); 
     LabelField lf4 = new LabelField("",Display.getWidth(),45,LabelField.FIELD_LEFT); 
     lf_msg = new LabelField("Alert Message",LabelField.FIELD_LEFT); 
     lf_msg.set_pos(35,0); 
     lf_time = new LabelField("Select Time Interval",LabelField.FIELD_LEFT); 
     lf_time.set_pos(35,20); 

     pbf1 = new PillButtonField("15 min"); 
     pbf2 = new PillButtonField("30 min"); 
     pbf3 = new PillButtonField("45 min"); 
     pbf_set = new PillButtonSet(300,40); 
     pbf_set.add(pbf1); 
     pbf_set.add(pbf2); 
     pbf_set.add(pbf3); 

     hfm1 = new H_FieldManager(tf_phn1, btn_add, true, H_FieldManager.FIELD_HCENTER); 
     hfm2 = new H_FieldManager(tf_phn2, btn_subtract, true, H_FieldManager.FIELD_HCENTER); 
     // hfm3 = new HorizontalFieldManager(HORIZONTAL_SCROLL_MASK); 
     hfm4 = new HorizontalFieldManager(pbf1.FIELD_HCENTER); 
//  hfm3.add(btn_time1); 
//  hfm3.add(btn_time2); 
//  hfm3.add(btn_time3); 
     hfm4.add(pbf_set); 
     vfm = new VerticalFieldManager(); 

     add(lf1); 
     add(hfm1); 
     add(lf_msg); 
     //add(tf_msg); 
     add(ta_msg); 
     add(btn_en); 
     add(lf_time); 
     //add(hfm3); 
     add(hfm4); 
     System.out.println(" insert label"); 


     btn_add.setChangeListener(this); 
     btn_subtract.setChangeListener(this); 
     btn_en.setChangeListener(this); 
     btn_dis.setChangeListener(this); 

    } 
    public void fieldChanged(Field field, int context) { 
     // TODO Auto-generated method stub 
     if(field == btn_add){ 
      insert(hfm2, 2); 

     }else if(field == btn_subtract){ 
      delete(hfm2); 
     //} 
      }else if(field == btn_en){ 
       replace(btn_en, btn_dis); 

       insert(tf_msg, 5); 

      }else if(field == btn_dis){ 
       replace(btn_dis, btn_en); 
       delete(tf_msg); 
      } 
    } 


} 

I hope your Problem will solve in this code.