请帮助。这段代码有什么错误？我想在数据库中检索文本（句子容器20个或更多单词）。我可以通过这个程序检索它吗？提前谢谢。
package com.apk.foodanalyzer.healthandnutrifactsanalyzer;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import com.apk.foodanalyzer.healthandnutrifactsanalyzer.goactivity.DatabaseHelper;
import com.apk.foodanalyzer.healthandnutrifactsanalyzer.goactivity.DoBackEnd;
import com.apk.foodanalyzer.healthandnutrifactsanalyzer.goactivity.GoItemContent;
import com.apk.foodanalyzer.healthandnutrifactsanalyzer.growactivity.GrowBackEnd;
import com.apk.foodanalyzer.healthandnutrifactsanalyzer.growactivity.GrowItemContent;
/**
* Created by Pavilion on 12/1/2015.
*/
public class GrowValueActivityContent extends AppCompatActivity{
private TextView FoodDescription, Scientificname, AlternateName,EdiblePortion,
Water,Energy,Protein,Fat,Carbohydrate,Crudefiber,Ash,Calcium,Phosphorus,Iron,Retinol,
Carotene,VitA,Thiamin,Riboflavin,Niacin,AscorbicAcid, Postip,Negatip;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gocontent_layout);
Intent intent = getIntent();
Bundle bundle = intent.getExtras();
int dictionaryId = bundle.getInt("RowId");
int search = dictionaryId + 1;
FoodDescription = (TextView)findViewById(R.id.go_conent_fooddescription);
Scientificname = (TextView)findViewById(R.id.go_conent_scientificname);
AlternateName = (TextView)findViewById(R.id.go_content_alternatename);
EdiblePortion = (TextView)findViewById(R.id.goedibleportion_value);
Water = (TextView)findViewById(R.id.water_value);
Energy = (TextView)findViewById(R.id.energy_value);
Protein = (TextView)findViewById(R.id.protein_value);
Fat = (TextView)findViewById(R.id.fat_value);
Carbohydrate = (TextView)findViewById(R.id.carbohydrate_value);
Crudefiber = (TextView)findViewById(R.id.crudefiber_value);
Ash = (TextView)findViewById(R.id.ash_value);
Calcium = (TextView)findViewById(R.id.calcium_value);
Phosphorus = (TextView)findViewById(R.id.phosphorus_value);
Iron = (TextView)findViewById(R.id.iron_value);
Retinol = (TextView)findViewById(R.id.retinol_value);
Carotene = (TextView)findViewById(R.id.carotene_value);
VitA = (TextView)findViewById(R.id.vitamina_value);
Thiamin = (TextView)findViewById(R.id.thiamin_value);
Riboflavin = (TextView)findViewById(R.id.riboflavin_value);
Niacin = (TextView)findViewById(R.id.niacin_value);
AscorbicAcid = (TextView)findViewById(R.id.ascorbicacid_value);
Postip = (TextView) findViewById(R.id.txtvx_tippos);
Negatip = (TextView)findViewById(R.id.txtvx_tipneg);
GrowBackEnd dbBackend = new GrowBackEnd(GrowValueActivityContent.this);
GrowItemContent allQuizQuestions = dbBackend.getQuizById(search);
FoodDescription.setText(allQuizQuestions.getFoodDescription());
Scientificname.setText(allQuizQuestions.getScientificName());
AlternateName.setText(allQuizQuestions.getAlternateName());
EdiblePortion.setText(String.valueOf(allQuizQuestions.getEdiblePortion()) + " g");
Water.setText(String.valueOf(allQuizQuestions.getWater()) + " g");
Energy.setText(String.valueOf(allQuizQuestions.getEnergy()) + " kcal");
Protein.setText(String.valueOf(allQuizQuestions.getProtein()) + " g");
Fat.setText(String.valueOf(allQuizQuestions.getFat()) + " g");
Carbohydrate.setText(String.valueOf(allQuizQuestions.getCarbohydrate()) + " g");
Crudefiber.setText(String.valueOf(allQuizQuestions.getCrudefiber()) + " g");
Ash.setText(String.valueOf(allQuizQuestions.getAsh()) + " g");
Calcium.setText(String.valueOf(allQuizQuestions.getCalcium()) + " mg");
Phosphorus.setText(String.valueOf(allQuizQuestions.getPhosphorus()) + " mg");
Iron.setText(String.valueOf(allQuizQuestions.getIron()) + " mg");
Retinol.setText(String.valueOf(allQuizQuestions.getRetinol()) + " ");
Carotene.setText(String.valueOf(allQuizQuestions.getCarotene()));
VitA.setText(String.valueOf(allQuizQuestions.getVitA()));
Thiamin.setText(String.valueOf(allQuizQuestions.getThiamin()) + " mg");
Riboflavin.setText(String.valueOf(allQuizQuestions.getRiboflavin()) + " mg");
Niacin.setText(String.valueOf(allQuizQuestions.getNiacin()) + " mg");
AscorbicAcid.setText(String.valueOf(allQuizQuestions.getAscorbicAcid()) + " mg");
Postip.setText(String.valueOf(allQuizQuestions.getPositiveTip()));
//Negatip.setText(allQuizQuestions.getNegativeTip());
}
}
这是LOGCAT显示的。 ：（
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: FATAL EXCEPTION: main
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: Process: com.apk.foodanalyzer.healthandnutrifactsanalyzer, PID: 26713
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.apk.foodanalyzer.healthandnutrifactsanalyzer/com.apk.foodanalyzer.healthandnutrifactsanalyzer.GrowValueActivityContent}: java.lang.NullPointerException
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2386)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2438)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.access$800(ActivityThread.java:160)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:110)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.os.Looper.loop(Looper.java:193)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5368)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:515)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: Caused by: java.lang.NullPointerException
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at com.apk.foodanalyzer.healthandnutrifactsanalyzer.GrowValueActivityContent.onCreate(GrowValueActivityContent.java:83)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.Activity.performCreate(Activity.java:5369)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1088)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2340)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2438)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.access$800(ActivityThread.java:160)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:110)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.os.Looper.loop(Looper.java:193)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5368)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:515)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
12-05 16:38:33.602 26713-26713/com.apk.foodanalyzer.healthandnutrifactsanalyzer E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
这是什么意思造成的：java.lang.NullPointerException？