我在 android 中开发了一个地图应用程序，它根据用户的搜索输入在数据库中搜索地点。我试图使用一个字段来查询 sqlite 数据库，该字段将在数据库中搜索并返回所有在数据库中的地方的纬度。该字段不是下面的主键是代码。请我需要帮助。用于创建和访问数据库的数据库类。
public class Places {
private Context context;
private DbHelper dataHelper;
private SQLiteDatabase database;
//columns for places table
public static final String ROW_ID="_id";
public static final String P_NAME="placename";
public static final String G_NAME="genericname";
public static final String LONGITUDE="longitude";
public static final String LATITUDE="latitude";
public static final String CONTACT="contactnumbers";
private static final String DB_NAME="MAP.db";
private static final String DB_TABLE_PLACES="places";
private static final String DB_TABLE_EXAMS="exam";
private static final String DB_TABLE_SMS="message";
private static final int DB_VERSION= 1;
// Places.java 的构造函数
public Places(Context c){
this.context = c;
}
//数据库助手类
private static class DbHelper extends SQLiteOpenHelper {
//constructor for DbHelper inner class
public DbHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
//creating table PLACES
db.execSQL("CREATE TABLE "+DB_TABLE_PLACES+"("+ROW_ID+" PRIMARY KEY, " +
""+P_NAME+" TEXT NOT NULL, " +
""+G_NAME+" TEXT NOT NULL, " +
""+LONGITUDE+" TEXT NOT NULL, " +
""+LATITUDE+" TEXT NOT NULL, " +
""+CONTACT+" TEXT );");
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+DB_TABLE_PLACES);
db.execSQL("DROP TABLE IF EXISTS "+DB_TABLE_EXAMS);
db.execSQL("DROP TABLE IF EXISTS "+DB_TABLE_SMS);
onCreate(db);
}
}
public Places openDatabase() throws SQLiteException{
dataHelper = new DbHelper(context);
database= dataHelper.getWritableDatabase();
return this;
}
public void closeDatabase(){
dataHelper.close();
database.close();
}
@SuppressWarnings("null")
public List<String> getPlaceLatitude(String string) {
// TODO Auto-generated method stub
List<String> latitudes = null;
String[] columns= new String[]{ROW_ID,P_NAME,LATITUDE,LONGITUDE,G_NAME,CONTACT};
Cursor c = database.query(DB_TABLE_PLACES, columns,G_NAME+" = "+string, null, null, null, null);
int iLatitude = c.getColumnIndex(LATITUDE);
if (c !=null){
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
latitudes.add(c.getString(iLatitude));
}
}
return latitudes;}
触发操作以查询数据库的方法。
public void searchDbAndOpenIntent(String search){
try{
Places placeDb = new Places(this);
placeDb.openDatabase();
List<String> longitude1= placeDb.getPlaceLongitude(search);
List<String> latitude1=placeDb.getPlaceLatitude(search);
placeDb.closeDatabase();
}
catch (Exception e) {
// TODO:handle exception Toast.makeText(getBaseContext(),e.toString(),Toast.LENGTH_LONG).show();
}
}
public void searchDbAndOpenIntent(String search){
try{
Places placeDb = new Places(this);
placeDb.openDatabase();
List<String> longitude1= placeDb.getPlaceLongitude(search);
List<String> latitude1=placeDb.getPlaceLatitude(search);
placeDb.closeDatabase();
}
catch (Exception e) {
// TODO: handle exception
Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG).show();
}
}
请我想根据地点的通用名称返回纬度，但是当我尝试查询 generic_name 列时，它返回 java.lang.NullPointerexception 。在它下面是当按下查询数据库的按钮时我得到的日志猫
05-14 20:52:37.202: D/ddm-heap(243): Got feature list request
05-14 20:52:41.123: E/ActivityThread(243): Failed to find provider info for com.google.settings
05-14 20:52:41.132: E/ActivityThread(243): Failed to find provider info for com.google.settings
05-14 20:52:41.172: E/ActivityThread(243): Failed to find provider info for com.google.settings
05-14 20:52:41.562: D/dalvikvm(243): GC freed 2007 objects / 134424 bytes in 125ms
05-14 20:52:41.802: D/LocationManager(243): Constructor: service = android.location.ILocationManager$Stub$Proxy@44e8c078
05-14 20:52:42.012: I/MapActivity(243): Handling network change notification:CONNECTED
05-14 20:52:42.012: E/MapActivity(243): Couldn't get connection factory client
05-14 20:52:42.453: D/dalvikvm(243): GC freed 4934 objects / 288736 bytes in 136ms
05-14 20:52:48.852: D/dalvikvm(243): GC freed 10599 objects / 817800 bytes in 137ms
05-14 20:53:56.712: W/KeyCharacterMap(243): No keyboard for id 0
05-14 20:53:56.723: W/KeyCharacterMap(243): Using default keymap: /system /usr/keychars/qwerty.kcm.bin
05-14 20:53:59.712: D/LocationManager(243): removeUpdates: listener = my.project.success.KnustP2PActivity@44e93c70
05-14 20:54:11.812: D/dalvikvm(243): GC freed 5940 objects / 725376 bytes in 98ms
05-14 20:54:11.812: I/dalvikvm(243): Uncaught exception thrown by finalizer (will be discarded):
05-14 20:54:11.812: I/dalvikvm(243): Ljava/lang/IllegalStateException;: Finalizing cursor android.database.sqlite.SQLiteCursor@44f31670 on places that has not been deactivated or closed
05-14 20:54:11.812: I/dalvikvm(243): at android.database.sqlite.SQLiteCursor.finalize(SQLiteCursor.java:596)
05-14 20:54:11.822: I/dalvikvm(243): at dalvik.system.NativeStart.run(Native Method)
05-14 20:54:11.872: E/Database(243): Leak found
05-14 20:54:11.872: E/Database(243): java.lang.IllegalStateException: /data/data/my.project.success/databases/MAP.db SQLiteDatabase created and never closed
05-14 20:54:11.872: E/Database(243): at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1694)
05-14 20:54:11.872: E/Database(243): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:738)
05-14 20:54:11.872: E/Database(243): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:760)
05-14 20:54:11.872: E/Database(243): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:753)
05-14 20:54:11.872: E/Database(243): at android.app.ApplicationContext.openOrCreateDatabase(ApplicationContext.java:473)
05-14 20:54:11.872: E/Database(243): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:193)
05-14 20:54:11.872: E/Database(243): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
05-14 20:54:11.872: E/Database(243): at my.project.success.Places.openDatabase(Places.java:201)
05-14 20:54:11.872: E/Database(243): at my.project.success.SearchActivity.searchDbAndOpenIntent(SearchActivity.java:217)
05-14 20:54:11.872: E/Database(243): at my.project.success.SearchActivity.onClick(SearchActivity.java:151)
05-14 20:54:11.872: E/Database(243): at android.view.View.performClick(View.java:2364)
05-14 20:54:11.872: E/Database(243): at android.view.View.onTouchEvent(View.java:4179)
05-14 20:54:11.872: E/Database(243): at android.widget.TextView.onTouchEvent(TextView.java:6540)
05-14 20:54:11.872: E/Database(243): at android.view.View.dispatchTouchEvent(View.java:3709)
05-14 20:54:11.872: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:11.872: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:11.872: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:11.872: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:11.872: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:11.872: E/Database(243): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
05-14 20:54:11.872: E/Database(243): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
05-14 20:54:11.872: E/Database(243): at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
05-14 20:54:11.872: E/Database(243): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
05-14 20:54:11.872: E/Database(243): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
05-14 20:54:11.872: E/Database(243): at android.os.Handler.dispatchMessage(Handler.java:99)
05-14 20:54:11.872: E/Database(243): at android.os.Looper.loop(Looper.java:123)
05-14 20:54:11.872: E/Database(243): at android.app.ActivityThread.main(ActivityThread.java:4363)
05-14 20:54:11.872: E/Database(243): at java.lang.reflect.Method.invokeNative(Native Method)
05-14 20:54:11.872: E/Database(243): at java.lang.reflect.Method.invoke(Method.java:521)
05-14 20:54:11.872: E/Database(243): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
05-14 20:54:11.872: E/Database(243): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
05-14 20:54:11.872: E/Database(243): at dalvik.system.NativeStart.main(Native Method)
05-14 20:54:12.014: I/dalvikvm(243): Uncaught exception thrown by finalizer (will be discarded):
05-14 20:54:12.022: I/dalvikvm(243): Ljava/lang/IllegalStateException;: Finalizing cursor android.database.sqlite.SQLiteCursor@44f2f0b0 on places that has not been deactivated or closed
05-14 20:54:12.022: I/dalvikvm(243): at android.database.sqlite.SQLiteCursor.finalize(SQLiteCursor.java:596)
05-14 20:54:12.032: I/dalvikvm(243): at dalvik.system.NativeStart.run(Native Method)
05-14 20:54:12.152: E/Database(243): Leak found
05-14 20:54:12.152: E/Database(243): java.lang.IllegalStateException: /data/data/my.project.success/databases/MAP.db SQLiteDatabase created and never closed
05-14 20:54:12.152: E/Database(243): at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1694)
05-14 20:54:12.152: E/Database(243): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:738)
05-14 20:54:12.152: E/Database(243): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:760)
05-14 20:54:12.152: E/Database(243): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:753)
05-14 20:54:12.152: E/Database(243): at android.app.ApplicationContext.openOrCreateDatabase(ApplicationContext.java:473)
05-14 20:54:12.152: E/Database(243): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:193)
05-14 20:54:12.152: E/Database(243): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
05-14 20:54:12.152: E/Database(243): at my.project.success.Places.openDatabase(Places.java:201)
05-14 20:54:12.152: E/Database(243): at my.project.success.SearchActivity.searchDbAndOpenIntent(SearchActivity.java:217)
05-14 20:54:12.152: E/Database(243): at my.project.success.SearchActivity.onClick(SearchActivity.java:79)
05-14 20:54:12.152: E/Database(243): at android.view.View.performClick(View.java:2364)
05-14 20:54:12.152: E/Database(243): at android.view.View.onTouchEvent(View.java:4179)
05-14 20:54:12.152: E/Database(243): at android.widget.TextView.onTouchEvent(TextView.java:6540)
05-14 20:54:12.152: E/Database(243): at android.view.View.dispatchTouchEvent(View.java:3709)
05-14 20:54:12.152: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:12.152: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:12.152: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:12.152: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:12.152: E/Database(243): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
05-14 20:54:12.152: E/Database(243): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
05-14 20:54:12.152: E/Database(243): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
05-14 20:54:12.152: E/Database(243): at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
05-14 20:54:12.152: E/Database(243): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
05-14 20:54:12.152: E/Database(243): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
05-14 20:54:12.152: E/Database(243): at android.os.Handler.dispatchMessage(Handler.java:99)
05-14 20:54:12.152: E/Database(243): at android.os.Looper.loop(Looper.java:123)
05-14 20:54:12.152: E/Database(243): at android.app.ActivityThread.main(ActivityThread.java:4363)
05-14 20:54:12.152: E/Database(243): at java.lang.reflect.Method.invokeNative(Native Method)
05-14 20:54:12.152: E/Database(243): at java.lang.reflect.Method.invoke(Method.java:521)
05-14 20:54:12.152: E/Database(243): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
05-14 20:54:12.152: E/Database(243): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
05-14 20:54:12.152: E/Database(243): at dalvik.system.NativeStart.main(Native Method)