我正在编写一个 Android 应用程序，我正在使用主屏幕上的按钮将用户带到其他屏幕。目前我所有的按钮都可以工作，只有一个。在我的主屏幕中，我试图将用户带到 DBUse 类的业务屏幕。单击此按钮后，我收到一条错误消息，并且不确定如何修复它，因为我是 android 新手。任何帮助将不胜感激。
创建所有内容的 MainActivity:
package com.think_bloomington;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends Activity {
private SQLiteDatabase mDB;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/** Called when the user clicks the Map button */
public void viewMap(View view) {
// Do something in response to button
Intent intent = new Intent(this, MapActivity.class);
startActivity(intent);
}
/** Called when the user clicks the Business button */
public void viewBusiness(View view) {
// Do something in response to button
Intent intent = new Intent(this, DBUse.class);
startActivity(intent);
}
/** Called when the user clicks the Events button */
public void viewEvents(View view) {
// Do something in response to button
Intent intent = new Intent(this, EventActivity.class);
startActivity(intent);
}
/** Called when the user clicks the Facebook button */
public void viewFacebook(View view) {
// Do something in response to button
Intent intent = new Intent(this, FacebookActivity.class);
startActivity(intent);
}
public Cursor getBusinessInfo(String business) throws SQLException {
// TODO Auto-generated method stub
return mDB.rawQuery("SELECT business,address,phone,hours,website,type FROM Business where business like ? Limit 5", new String[]{"%"+business+"%"});
}
public Cursor getBusinessType(String type)throws SQLException {
// TODO Auto-generated method stub
return mDB.rawQuery("SELECT business,address,phone,hours,website,type FROM Business where type like ? Limit 5", new String[]{"%"+type+"%"});
}
}
DBUse 按钮试图带走用户的类:
package com.think_bloomington;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class DBUse extends Activity {
EditText dEdit;
DBAdapter data;
long id;
public static final String KEY_ROWID = "_id";
public static final String KEY_BUSINESS = "business";
public static final String KEY_ADDRESS = "address";
public static final String KEY_PHONE = "phone";
public static final String KEY_HOURS = "hours";
public static final String KEY_WEB = "website";
public static final String KEY_TYPE = "type";
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
data = new DBAdapter(this);
Button buttonName =(Button)findViewById(R.id.buttonName);
buttonName.setOnClickListener(startName);
Button buttonType =(Button)findViewById(R.id.buttonType);
buttonType.setOnClickListener(startType);
dEdit =(EditText)findViewById(R.id.textView1);
data.open();
id =data.insertTitle("BloomingFoods","419 E. Kirkwood Ave. Bloomington, IN", "812-336-5300", "M-Sat:8AM-9PM Sun:9AM-8PM","http://www.bloomingfoods.coop","Grocery");
id=data.insertTitle("BloomingFoods","316 W. 6th Street Bloomington, IN", "812-333-5300", "M-Sat:7AM-10PM Sun:9AM-9PM","http://www.bloomingfoods.coop","Grocery");
id=data.insertTitle("BloomingFoods","3220 E. 3rd Street Bloomington, IN", "812-336-5300", "M-Sun:8AM-10PM","http://www.bloomingfoods.coop","Grocery");
id=data.insertTitle("The Uptown Cafe","102 E. Kirkwood Ave. Bloomington, IN", "812-339-0900", "M-Sat:8AM-9PM Sun:9AM-8PM", "http://www.the-uptown.com/","Cajun-Creole");
id=data.insertTitle("Crazy Horse","214 W. Kirkwood Ave. Bloomington, IN", "812-336-8877", "M-Sat:11AM-2AM Sun:Noon-Midnight", "http://www.crazyhorseindiana.com/","Restaurant & Live Music");
id=data.insertTitle("FARMbloomington","108 E. Kirkwood Ave. Bloomington, IN", "812-323-0002", "Tue.-Thurs.:8AM-10PM F:8AM-1AM Sat: 10AM-3AM Sun: 10AM-10PM","http://www.farm-bloomington.com","Grocery");
id=data.insertTitle("Laughing Planet","322 E. Kirkwood Ave. Bloomington, IN", "812-323-2233", "M-Sun:11AM-9PM","http://www.facebook.com/laughingplanetbtown","Burritos & Salads");
id=data.insertTitle("Soma Coffeehouse","322 E. Kirkwood Bloomington, IN", "812-331-2770", "M-Sat:7AM-11PM Sun:8AM-11PM","http://www.iheartsoma.com","Coffee House");
id=data.insertTitle("Upland Brewing Company","350 W. 11th St. Bloomington, IN", "812-336-2337", "M-Thurs:11AM-Midnight F-Sat:11AM-1AM Sun: Noon-Midnight","http://www.uplandataeer.com","Brewery & Restaraunt");
id=data.insertTitle("Nick's English Hut","423 E. Kirkwood Bloomington, IN", "812-332-4040", "M-Sat:11AM-2AM Sun: Noon-Midnight","http://www.nicksenglishhut.com","Bar & Restaraunt");
id=data.insertTitle("The Village Deli","409 E. Kirkwood Ave. Bloomington, IN", "812-336-2303", "M-F:7AM-8PM Sat-Sun 8AM-8PM","http://www.villagedeli.biz","Breakfast,Lunch,Dinner");
id=data.insertTitle("Rachael's Cafe","300 E. 3rd St. Bloomington, IN", "812-330-1882", "M-F:8AM-9PM Sat-Sun 9AM-9PM","http://www.rachaelscafe.com","Coffee House & Live Music");
id=data.insertTitle("Happy Pig","1604 W. 7th St. Bloomington, IN", "None", "W:Sample Gates Noon-3PM Thurs:Sample Gates Noon-3PM F:Atlas Bar 11:30PM-3:30AM Sat:Courthouse Square 11:30PM-3:30AM","http://www.happypigbloomington.com","BBQ Streetfood");
id=data.insertTitle("Lennie's Restaurant and Brewpub","1795 E. 10th St. Bloomington, IN", "812-323-2112", "Sun-Th:11AM-11PM F-Sat 11AM-Midnight","http://www.lenniesgourmetpizza.com","Bar & Restaurant");
id=data.insertTitle("Pizza X","1791 E. 10th St. Bloomington, IN", "812-339-7737", "Sun-Tues:11AM-2AM Wed-Thur: 11AM-3AM F-Sat:11AM-4AM","http://www.pizzaxbloomington.com","Pizza");
id=data.insertTitle("Pizza X","1610 W. 3rd St. Bloomington, IN", "812-332-2522", "Sun-Wed:4PM-Midnight Thur: 4PM-3AM F-Sat:4PM-4AM","http://www.pizzaxbloomington.com","Pizza");
id=data.insertTitle("Pizza X","877 S. College Mall Rd. Bloomington, IN", "812-355-5000", "Sun-Wed:4PM-Midnight Thur: 4PM-3AM F-Sat:4PM-4AM","http://www.pizzaxbloomington.com","Pizza");
id=data.insertTitle("Pizza X","2443 S. Walnut St. Pk. Bloomington, IN", "812-332-8500", "Sun-Wed:4PM-Midnight Thur: 4PM-3AM F-Sat:4PM-4AM","http://www.pizzaxbloomington.com","Pizza");
id=data.insertTitle("The Atlas Bar","209 S. College Ave. Bloomington, IN", "812-334-4435", "M-F:5PM-3AM Sat-Sun:7PM-3AM","http://www.atlasballroom.com","Bar");
id=data.insertTitle("The Bishop","123 S. Walnut St. Bloomington, IN", "812-333-4700", "Mon-Sat:7PM-3AM","http://www.thebishopbar.com","Bar & Live Music");
id=data.insertTitle("Oliver Winery","8024 N. State Road 37 Bloomington, IN", "812-876-5800", "Mon-Sat:10AM-6PM Sun: 12PM-6PM Tours:F-Sat Noon-4:30PM Sun:1PM-4:30PM","http://www.oliverwinery.com","Winery");
id=data.insertTitle("Revolution Bike and Bean","401 E. 10th St. Bloomington, IN", "812-336-0241", "Mon-Fri:10AM-6PM Sat: 10AM-5PM","http://www.revolutionbikeandataean.com","Coffee House & Bike Repair Shop");
id=data.insertTitle("Mother Hubbard's Cupboard","1010 S. Walnut Bloomington, IN", "812-355-6843", "Mon-Fri:4PM-6PM","http://www.mhcfoodpantry.org","Food Pantry Service & Non-Profit");
id=data.insertTitle("Patricia's Wellness Arts Cafe and Quilter's Comfort Teas","725 W. Kirkwood Ave. Bloomington, IN", "812-331-0886", "Mon-Sat:11AM-5PM First Friday: 11AM-8PM","http://www.hartrock.net/cafe.htm","Tea House & Holistic and Naturopathic & Reiki & Counseling");
id=data.insertTitle("One World Catering and Events","2234 W. Industrial Pk. Dr. Bloomington, IN", "812-334-3663", "","http://www.oneworldcateringandevents.com","Catering");
id=data.insertTitle("Nelson's Furniture Restoration","6573 S. Old State Road 37 Bloomington, IN", "812-824-7769", "M-F:10AM-6PM","http://www.nelsonrestoration.com","Furniture Restoration");
id=data.insertTitle("NR Hiller Design, Inc","3450 S. Garrison Chapel. Rd. Bloomington, IN", "812-825-5872", "Hours By Appointment","http://www.nrhillerdesign.com","Furniture Design & Furniture Building & Cabinet-Making & Furniture");
id=data.insertTitle("Showers Inn Bed and Breakfast","430 N. Washington St. Bloomington, IN", "812-334-9000", "Hours By Appointment","http://www.showersinn.com","Bed and Breakfast");
id=data.insertTitle("Monroe County History Center","202 E. 6th St. Bloomington, IN", "812-332-2517", "Tues-Sat:10AM-4PM","http://www.monroehistory.org","Museum");
id=data.insertTitle("WFHB","108 W. 4th St. Bloomington, IN", "812-323-0320", "Hours By Appointment","http://www.wfhb.org","Radio Station & Non-Profit");
id=data.insertTitle("Brinegar Eye Care","4001 E. 3rd St. Suite 8 Bloomington, IN", "812-339-7995", "Mon-F:9AM-5PM","http://www.brinegareyecare.com","Optometrist");
id=data.insertTitle("Sole Sensations","414 S. College Ave. Bloomington, IN", "812-331-1962", "Mon:10AM-6PM Tues:10AM-8PM Wed:10AM-6PM Thurs:10AM-8PM Sat:10AM-5PM","http://www.solesensations.com/Soul-Inspirations.html","Orthotics & Shoes");
id=data.insertTitle("Bloomignton Area Birth Services (BABS)","2458 S. Walnut St. Bloomington, IN", "812-337-8121", "Mon-Fri:10AM-5PM Sat:10AM-2PM" ,"http://www.bloomingtonbirth.org","Holistic and Naturopathic & Non-Profit & Gifts & Toys & Books & Maternity/Nursing Wear & Prenatal and Postnatal Yoga & Childatairth Classes & Breastfeeding Classes and Consultation");
id=data.insertTitle("Karen Knight, LMHC Counseling Services","115 N. College Ave Suite 214 Bloomington, IN", "812-361-3601", "Mon-Fri:9AM-8PM By Appointment" ,"http://www.karenknight.net","Mental Health & Counseling");
id=data.insertTitle("Mister Buck's Genuinely Good Pet Food Compnay","319 S. Mitchell Bloomington, IN", "812-384-3853", "24hr Internet Access" ,"http://www.mrbuckspetfood.com","Pet Care");
id=data.insertTitle("Center for Sustainable Living","323 S. Walnut St. Bloomington, IN", "812-332-8796", "24hr Internet Access" ,"http://www.simplycsl.org","Non-Profit");
id=data.insertTitle("Friends of Art Bookshop","1201 E. 7th St. (Fine Arts Building, Indiana University) Bloomington, IN", "812-855-7498","M-Thurs:9AM-6PM Sat-Sun:1PM-5PM" ,"http://www.fa.indiana.edu/foart/","Non-Profit & Books & Art Books & Textbooks");
id=data.insertTitle("Cardinal Stage Company","900 S. Walnut St. Bloomington, IN", "812-323-3020", "24hr Internet Access" ,"http://www.cardinalstage.org","Non-Profit & Theater");
id=data.insertTitle("Bloomington Playwrights Project","107 W. 9th St. Bloomington, IN", "812-334-1188", "Mon-Fri:9AM-5PM" ,"http://www.newplays.org","Non-Profit");
id=data.insertTitle("Boxcar Books","408 E. 6th St. Bloomington, IN", "812-339-8710", "Mon-Fri: 11AM-9PM Sat:10AM-9PM Sun:10AM-5PM" ,"http://www.boxcarbooks.org","Non-Profit & Books & Textbooks");
id=data.insertTitle("Community Foundation of Bloomington and Monroe County,Inc.","101 W. Kirkwood Ave. Suite 321 Bloomington, IN", "812-333-9016", "Mon-Fri:8:30AM-5PM" ,"http://www.cfbmc.org","Non-Profit");
id=data.insertTitle("Windfall Dancers","1101 N. Dunn St. Bloomington, IN", "812-334-0506", "24hr Internet Access" ,"http://www.windfalldancers.org","Non-Profit & Modern Dance & Dance");
id=data.insertTitle("The Updraft Supplementary Scholarship Project, Inc. (USSP)","403 E. 6th St. Bloomington, IN", "812-961-3553 Toll Free:877-451-8535", "Mon-Fri:9AM-5PM" ,"http://www.usspkids.org","Non-Profit");
id=data.insertTitle("Story Insights","P.O. Box 2264. Bloomington, IN 47402", "812-340-0479", "24hrs" ,"http://storyinsights.com","Non-Profit & Story Development & Project Management & Web Design");
id=data.insertTitle("Middle Way House","P.O. Box 95 Bloomington, IN 47402", "Administration:812-333-7404 Crisis Line:812-336-9063", "24hr Internet Access" ,"http://www.middlewayhouse.org","Non-Profit");
id=data.insertTitle("Baugh Enterprises, Inc","1611 S Rogers St. Bloomington, IN", "812-334-8189", "Mon-Fri:8:30AM-5PM" ,"http://www.baughenterprises.com","Printing Service & Printwork Design");
id=data.insertTitle("White Rabbit","118 W. 6th St. Bloomington, IN", "812-339-5020 Fax:812-339-7847", "Mon-Fri:8:30AM-5PM" ,"http://www.whiterabbitcopyservice.com","Printing Service");
id=data.insertTitle("Mr. Copy","501 E. 10th St. Bloomington, IN", "812-334-2679", "Mon-Fri:9AM-6PM Sat: Noon-5PM" ,"http://www.copysales.com","Printing Service & Graphic Design");
id=data.insertTitle("Rosenplot Design","P.O Box 1083 Bloomington, IN 47402", "812-822-2077 Fax:812-822-2077", "Mon-Fri:8:30AM-5PM" ,"http://www.rosenplotdesign.com","Graphic Design");
id=data.insertTitle("Patrick Siney Art Direction and Design","1303 S. Stull Ave. Bloomington, IN", "812-334-0019", "Mon-Fri:8:30AM-5PM" ,"http://www.patricksiney.com","Graphic Design & Web Design");
id=data.insertTitle("Bloomington Cooking School","115 N. College Ave. Suite 014 Bloomington, IN ", "812-333-7100", "Mon-Fri:8:30AM-5PM" ,"http://www.bloomingtoncookingschool.com","Cooking Class");
id=data.insertTitle("Bloomington Pedal Power","", "812-325-2777", "Mon-Wed:8AM-5PM Thurs-Sat:8AM-2AM" ,"http://www.bloomingtonpedalpower.com","Delivery Service");
id=data.insertTitle("Backyard Classrooms LLC","Elletsville,IN", "812-844-5826", "Mon-Sun:8AM-8PM" ,"http://www.backyardclassroms.com","Education & Group Events & Agritourism");
id=data.insertTitle("Kemp & Associates","403 E. 6th St. Bloomington,IN", "812-961-3533 Fax:812-961-2072 Toll Free:877-451-8535", "By Appointment Mon-Fri:9AM-5PM" ,"http://www.kempandassociates.com","Financial Retirement Planning & Estate Planning & Life and Health Insurance Planning & Family Office Services");
id=data.insertTitle("ISU The May Agency","1327 N. Walnut St. Bloomington, IN", "812-334-2400", "Mon-Fri:9AM-5PM" ,"http://www.MayAgency.com","Life and Health Insurance Planning");
id=data.insertTitle("LNoggleDesigns","", "812-320-5865", "Flexible" ,"http://www.lnoggledesigns.com","Illustration & Architectural Design & Creative Consultation & Architecture");
id=data.insertTitle("Sustainability Dashboard Tools LLC","300 W. Hillside Dr. Bloomington, IN", "812-269-2805", "Mon-Fri:9AM-5PM" ,"http://www.green2sustainable.com","Sustainability Services");
id=data.insertTitle("PrimeSource Office Products, Inc","5015 N. Capitol Ave. Bloomington, IN", "812-876-1143", "Mon-Fri:8AM-5PM" ,"http://www.primesourceop.com","Office Supply");
id=data.insertTitle("The Dog Knows Detection","P.O. Box 3122 Bloomington, IN 47401", "812-334-7959", "By Appointment" ,"http://www.thedogknowsdetection.com","Pest Control");
id=data.insertTitle("Easy Go Lawn Care","5929 W. Koontz Rd. Bloomington, IN", "812-320-2844", "By Appointment" ,"http://locallawncareservice.com","Lawn Care & Gutter Cleaning & Snow Removal");
id=data.insertTitle("Clutter Wrangler","", "812-334-2400", "By Appointment" ,"http://www.clutterwrangler.com","Professional Organizer");
id=data.insertTitle("Ann Schertz Photography","P.O. Box 1403 Bloomington, IN 47402", "812-327-3402", "By Appointment" ,"http://www.annschertz.com","Photography");
id=data.insertTitle("The Ryder Magazine and Film Series","Bloomington, IN", "812-339-2002", "" ,"http://www.theryder.com","Magazine & Film Showings");
id=data.insertTitle("Bloom Magazine","P.O. Box 1204 Bloomington, IN 47402", "812-323-8959", "" ,"http://www.magbloom.com","Magazine");
id=data.insertTitle("Gallagher Properties","107 N. College Ave. Bloomington, IN", "812-333-5252", "By Appointment" ,"http://www.homefinder.org/findrealtor/findRealtor-AgentSearch.asp?mode=Office_Clicked&BrokerID=175","Housing & Property Management & Commercial Real Estate");
id=data.insertTitle("Jeanne Walters Real Estate","107 E. 6th St. Bloomington, IN", "866-877-6677", "By Appointment" ,"http://www.jeannewalters.com","Housing");
id=data.insertTitle("Olympus Properties","2620 N. Walnut St. Bloomington, IN", "812-334-8200", "Mon-Fri:8:30AM-4:30PM" ,"http://www.olympusproperties.com","Housing & Property Management");
id=data.insertTitle("Blue Studio Gallery","116.5 S. College Ave. Upstairs#10 Bloomington, IN", "812-361-7504", "Mon/Wed/Thurs:Noon-6PM F-Sat:3PM-6PM By Appointment" ,"http://www.bluestudiogallery.com","Art & Gallery");
id=data.insertTitle("A.Z. Vintage","236 N. Morton St. Bloomington, IN", "812-333-1960", "Mon:By Appointment Tues-Sat:10AM-7PM Sun:Noon-5PM" ,"http://www.azvintagebloomington.com","Art & Gifts & Shoes & Furniture & Handmade Art & Jewelry & Clothing & Vintage");
id=data.insertTitle("Sweany Artworks-Wandering Turtle On-Line","P.O. Box 1476 Bloomington, IN 47402", "812-219-2992", "By Appointment" ,"http://www.wanderingturtle.com","Art & Gifts & Online Art Gallery");
id=data.insertTitle("Paper Crane Gallery and Studio","116 S. Grant St. Bloomington, IN", "", "Wed-Fri:2PM-8PM Sat:10AM-4PM Sun:Noon-5PM" ,"http://www.papercranegallery.org","Art & Gifts & Illustration");
id=data.insertTitle("Conduit Press","Online Store", "", "24hr Web" ,"http://conduit-press.com","Art & Gifts & Books & Art Books");
id=data.insertTitle("Sadly Harmless","Online Store", "", "24hr Web" ,"http://www.sadlyharmless.com","Art & Illustration");
id=data.insertTitle("Opportunity House", "907 W. 11th St. Bloomington,IN","812-336-2443","Donate:8:30AM-3PM Shop:9AM-2PM", "http://www.mcum.org/opportunity_house.html", "Gifts & Toys & Books & Shoes & Window Treatment & Furniture & Jewelry & Clothing & Vintage & Reasle");
id=data.insertTitle("Moda Industria", "2120 W. Industrial Park Dr. Bloomington,IN","812-606-7185","24hr Web Studio by appointment", "http://www.modaindustry.com", "Gifts & Furniture & Handmade Art & Jewelry & Art");
id=data.insertTitle("Athena", "116 N. Walnut Ave. Bloomington,IN","812-339-0734","Mon-Thur:10:30AM-7PM Fri-Sat:10:30AM-8:30PM Sun:Noon-5:00PM", "http://www.btownboutiques.com/accessories/athena.com", "Gifts");
id=data.insertTitle("Green Nursery", "509 E. Hillside Dr. Suite B104 Bloomington,IN","812-339-5090","Mon-Fri:10AM-5:30PM Sat:10AM-5PM", "http://www.thegreennursery.com", "Gifts & Toys & Online Option & Cloth Diapers & Baby Carriers& Baby Items");
id=data.insertTitle("Melody Music Shop LLC", "402 W. 6th St. Bloomington,IN","812-336-6319","Mon-Thurs:11:30AM-7:30PM Fri-Sat:11:30AM-5PM", "http://www.melodymusicshop.com", "Music & Musical Instruments");
id=data.insertTitle("Landlocked", "202 N. Walnut St. Bloomington,IN","812-339-2574","Mon-Sat:11:30AM-7:30PM Sun:Noon-5PM", "http://www.landlockedmusic.com", "Music");
id=data.insertTitle("Nature's Crossroads Seed Company", "230 W. Church Lane Bloomington,IN","Customer Service:812-327-9612 Office&Fax:812-824-3727","By Appointment", "http://www.naturescrossroads.com", "Seeds & Gardening Supplies & Certified Organic Farm");
id=data.insertTitle("Discount Blinds & Verticals Inc.", "3910 S. Walnut St. Bloomington,IN","812-333-8412","By Appointment", "http://www.blindsandverticals.com", "Window Treatment");
id=data.insertTitle("American Futons", "105 S. Walnut St. Bloomington,IN","812-333-1305","Wed-Fri:Noon-6PM Sat-Sun Noon-4PM", "http://www.bloomington.in.us/~futons/futons.html", "Furniture & Futons");
id=data.insertTitle("Creating Harmony LLC", "Online Store","888-325-1963","24hr Web Service", "http://www.CreatingHarmonyLLC.com", "Baby Items & Bath and Body & Skincare & Spiritual Development & Meditation");
id=data.insertTitle("Soapy Soap Company", "2786 E. Bressingham Way Bloomington,IN","812-269-8812","By Appointment", "http://www.soapysoapcompany.com", "Bath and Body & Personal Care Products");
id=data.insertTitle("Full Moon Milk Soaps", "Online Store","","24hr Web Service", "http://www.fullmoonmilksoaps.com", "Bath and Body");
id=data.insertTitle("Know Yoga Know Peace", "234 N. Morton Street Bloomington, IN","812-822-1101","View Website for Hours", "http://www.knowyogakowpeace.org", "Hatha Yoga & Hot Yoga");
id=data.insertTitle("La Rua Enamels", "Bloomington, IN","Online Store","View Website for Hours", "http://www.laruaenamels.net", "Functional Art & Art");
id=data.insertTitle("By Hand Gallery", "101 W. Kirkwood Suite 109 Bloomington, IN","812-334-3255","Mon-Sat: 10AM-5:30PM First Friday & December:10AM-7:30PM", "http://www.bloomington.in.us/~byhand/", "Gallery");
id=data.insertTitle("Panache School of Ballroom and Social Dance", "325 E. Winslow Rd. Bloomington, IN","812-822-0050","Mon-Fri: 3PM-10PM Sat:10AM-2PM", "http://www.panachedance.com", "Ballroom and Social Dance Lessons & Dance");
id=data.insertTitle("Studio Cypher", "115 N. College Ave. Bloomington, IN","812-392-4263","Mon-Fri: 8Am-5PM", "http://www.studiocypher.com", "Game Design & Web Design");
id=data.insertTitle("David Martin Design", "2112 S. Susie St. Bloomington, IN","812-650-4405","By Appointment", "http://www.davidmartindesign.com", "Web Design");
id=data.insertTitle("My Edible Eden LLC", "P.O. Box 613 Bloomington, IN 47402","812-202-6830","By Appointment", "http://www.myedibleeden.com", "Certified Permaculture Designer & Urban Farm Consultant");
id=data.insertTitle("T.A. Fuller Homes Inc", "Bloomington,IN","812-824-3300","By Appointment", "http://www.tafullerhomes.com/index.html", "Architecture & Home Building");
id=data.insertTitle("Amity Montessori School LLC", "401 E. Allen St. Bloomington, IN","Contact Via Website","By Appointment: 8:30AM-4:30PM", "http://www.amitymontessorischool.com", "Montessori & Preschool-Kindergarten");
id=data.insertTitle("Free University of Monroe County", "P.O. Box 5152 Bloomington, IN 47407","freeumc@gmail.com","By Appointment", "http://www.facebook.com/freeumc", "Adult Personal Enrichment");
id=data.insertTitle("BCT Box Office", "114 E. Kirkwood Ave. Bloomington, IN ","812-333-3020","Available By Website", "http://www.buskirkchumley.org", "Live Music & Theater & Tickets");
id=data.insertTitle("The Comedy Attic", "123 S. Walnut St. Bloomington, IN ","812-336-5233","Wed-Sat 8PM-Close Fri/Sat 8PM-Close", "http://www.comedyattic.com", "Comedy");
}
//displays the data
public void DisplayTitle(Cursor c) {
Toast.makeText(this,
"Name: " + c.getString(1)+"\n"+
"Address:" + c.getString(2)+"\n"+
"Phone:" + c.getString(3)+"\n"+
"Hours:" + c.getString(4)+"\n"+
"Website"+ c.getShort(5)+
"Type" + c.getShort(6),
Toast.LENGTH_LONG).show();
}
//Informs the user what is being searched
private OnClickListener startName=new OnClickListener(){
public void onClick (View v) {
Cursor cur=data.getBusinessInfo(dEdit.getText().toString());
String result="";
int iName=cur.getColumnIndex(KEY_BUSINESS);
int iAddress=cur.getColumnIndex(KEY_ADDRESS);
int iPhone=cur.getColumnIndex(KEY_PHONE);
int iHours=cur.getColumnIndex(KEY_HOURS);
int iWebsite=cur.getColumnIndex(KEY_WEB);
int iType=cur.getColumnIndex(KEY_TYPE);
Toast.makeText(DBUse.this, "Searching by Name", Toast.LENGTH_LONG).show();
// log.d("result",DBUse.getString(0));
for(cur.moveToFirst(); !cur.isAfterLast(); cur.moveToNext()){
result=result
+cur.getString(iName) + " "
+cur.getString(iAddress) + " "
+cur.getString(iPhone) + " "
+cur.getString(iHours) + " "
+cur.getString(iWebsite) + " "
+cur.getString(iType) + " " + " ";
Toast.makeText(DBUse.this, result, Toast.LENGTH_LONG).show();
};
return;
}
};
//Informs the user what is being searched
private OnClickListener startType=new OnClickListener(){
public void onClick (View v){
// TODO Auto-generated method stub
Cursor cur=data.getBusinessType(dEdit.getText().toString());
String result="";
int iName=cur.getColumnIndex(KEY_BUSINESS);
int iAddress=cur.getColumnIndex(KEY_ADDRESS);
int iPhone=cur.getColumnIndex(KEY_PHONE);
int iHours=cur.getColumnIndex(KEY_HOURS);
int iWebsite=cur.getColumnIndex(KEY_WEB);
int iType=cur.getColumnIndex(KEY_TYPE);
Toast.makeText(DBUse.this, "Searching by Type", Toast.LENGTH_LONG).show();
// log.d("result",DBUse.getString(0));
for(cur.moveToFirst(); !cur.isAfterLast(); cur.moveToNext()){
result=result
+cur.getString(iName) + " "
+cur.getString(iAddress) + " "
+cur.getString(iPhone) + " "
+cur.getString(iHours) + " "
+cur.getString(iWebsite) + " "
+cur.getString(iType) + " " + "\n";
Toast.makeText(DBUse.this, result, 30).show();
};
return;
}
};
};
日志:
04-29 11:27:43.029: D/dalvikvm(8175): GC_FOR_ALLOC freed 177K, 12% free 2484K/2796K, paused 265ms, total 269ms
04-29 11:27:43.069: I/dalvikvm-heap(8175): Grow heap (frag case) to 3.138MB for 614416-byte allocation
04-29 11:27:43.209: D/dalvikvm(8175): GC_FOR_ALLOC freed 2K, 10% free 3082K/3400K, paused 140ms, total 140ms
04-29 11:27:43.451: D/dalvikvm(8175): GC_CONCURRENT freed <1K, 10% free 3082K/3400K, paused 5ms+99ms, total 243ms
04-29 11:27:44.099: D/dalvikvm(8175): GC_FOR_ALLOC freed <1K, 10% free 3081K/3400K, paused 30ms, total 30ms
04-29 11:27:44.119: I/dalvikvm-heap(8175): Grow heap (frag case) to 3.597MB for 483952-byte allocation
04-29 11:27:44.199: D/dalvikvm(8175): GC_CONCURRENT freed 0K, 9% free 3554K/3876K, paused 17ms+6ms, total 84ms
04-29 11:27:44.210: D/dalvikvm(8175): WAIT_FOR_CONCURRENT_GC blocked 7ms
04-29 11:27:44.639: D/gralloc_goldfish(8175): Emulator without GPU emulation detected.
04-29 11:27:48.739: D/AndroidRuntime(8175): Shutting down VM
04-29 11:27:48.739: W/dalvikvm(8175): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
04-29 11:27:48.790: E/AndroidRuntime(8175): FATAL EXCEPTION: main
04-29 11:27:48.790: E/AndroidRuntime(8175): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.think_bloomington/com.think_bloomington.DBUse}: java.lang.NullPointerException
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.os.Handler.dispatchMessage(Handler.java:99)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.os.Looper.loop(Looper.java:137)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.ActivityThread.main(ActivityThread.java:5041)
04-29 11:27:48.790: E/AndroidRuntime(8175): at java.lang.reflect.Method.invokeNative(Native Method)
04-29 11:27:48.790: E/AndroidRuntime(8175): at java.lang.reflect.Method.invoke(Method.java:511)
04-29 11:27:48.790: E/AndroidRuntime(8175): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-29 11:27:48.790: E/AndroidRuntime(8175): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-29 11:27:48.790: E/AndroidRuntime(8175): at dalvik.system.NativeStart.main(Native Method)
04-29 11:27:48.790: E/AndroidRuntime(8175): Caused by: java.lang.NullPointerException
04-29 11:27:48.790: E/AndroidRuntime(8175): at com.think_bloomington.DBUse.onCreate(DBUse.java:41)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.Activity.performCreate(Activity.java:5104)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-29 11:27:48.790: E/AndroidRuntime(8175): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-29 11:27:48.790: E/AndroidRuntime(8175): ... 11 more
最佳答案
生成 NPE 是因为您的 Activity 不包含您指向的指定按钮，这是因为您可能指向了不正确的 Activity 。
将您的 Activity 指向正确的布局文件，使用
setContentView(R.layout.activity_youractivity);
关于android - android应用程序中的按钮导致空指针错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16277543/