我有一个＆＃34; app＆＃34;它有一个带有三个标签的标签布局：
在第一个尝试从SQLite数据库中检索某些行并在ListView中显示它们时。
处理标签布局的类称为PageFragment：
public class PageFragment extends Fragment {
public static final String ARG_PAGE = "ARG_PAGE";
private int mPage;
public MainActivity Main;
public static PageFragment newInstance(int page) {
Bundle args = new Bundle();
args.putInt(ARG_PAGE, page);
PageFragment fragment = new PageFragment();
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mPage = getArguments().getInt(ARG_PAGE);
}
ListView ItemsLst;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = null;
switch(mPage)
{
case 1:
view = inflater.inflate(R.layout.layout_schedule, container, false);
DatabaseHandler db = new DatabaseHandler(getActivity().getApplicationContext());
Medicine med = new Medicine("Cardioaspirina", "Pillola", 1, "2015-02-25", "12:00:00");
db.AddMedicine(med);
ScheduleList(view, db.GetAllMedicines());
return view;
case 2:
view = inflater.inflate(R.layout.layout_settings, container, false);
return view;
case 3:
view = inflater.inflate(R.layout.layout_info, container, false);
return view;
}
return view;
}
public void ScheduleList(View v, List<Medicine> medicines) {
ItemsLst = (ListView) v.findViewById(R.id.listview);
ArrayAdapter<Medicine> adapter = new ArrayAdapter<Medicine>(getActivity(), android.R.layout.simple_list_item_1, medicines);
ItemsLst.setAdapter(adapter);
}
}
如您所见，在onCreateView()方法中，我管理了标签布局。
为了从数据库中检索数据，我创建了一个名为DatabaseHandler的类，其中包含AddRecord，GetRecord，GetAllRecords等方法。
问题是DatabaseHandler构造函数需要Context变量，我尝试使用以下内容为其提供上下文：
DatabaseHandler db = new DatabaseHandler(getActivity().getApplicationContext());
我也尝试只使用getActivity()，但它会抛出NullPointerException。
如果有用，这里是DatabaseHandler构造函数：
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
所以任何人都知道如何从PageFragment类获取应用程序上下文？提前谢谢！
P.S。这是堆栈跟踪：
02-25 21:04:52.588 1947-1947/com.mms.dailypill I/art﹕ Not late-enabling -Xcheck:jni (already on)
02-25 21:04:53.092 1947-1959/com.mms.dailypill I/art﹕ Background sticky concurrent mark sweep GC freed 2943(255KB) AllocSpace objects, 0(0B) LOS objects, 29% free, 796KB/1135KB, paused 30.424ms total 49.618ms
02-25 21:04:53.093 1947-1972/com.mms.dailypill D/OpenGLRenderer﹕ Render dirty regions requested: true
02-25 21:04:53.094 1947-1947/com.mms.dailypill D/﹕ HostConnection::get() New Host Connection established 0xa6840570, tid 1947
02-25 21:04:53.106 1947-1947/com.mms.dailypill D/Atlas﹕ Validating map...
02-25 21:04:53.125 1947-1947/com.mms.dailypill E/SQLiteLog﹕ (1) near "TABLEDailyPill": syntax error
02-25 21:04:53.125 1947-1947/com.mms.dailypill D/AndroidRuntime﹕ Shutting down VM
02-25 21:04:53.183 1947-1947/com.mms.dailypill E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mms.dailypill, PID: 1947
android.database.sqlite.SQLiteException: near "TABLEDailyPill": syntax error (code 1): , while compiling: CREATE TABLEDailyPill(id INTEGER AUTOINCREMENT, name VARCHAR(50), format VARCHAR(15), amount INTEGER, exp_dateDATE, time HOUR, PRIMARY KEY(id));
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1674)
at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1605)
at com.mms.dailypill.DatabaseHandler.onCreate(DatabaseHandler.java:63)
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:251)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:163)
at com.mms.dailypill.DatabaseHandler.AddMedicine(DatabaseHandler.java:84)
at com.mms.dailypill.PageFragment.onCreateView(PageFragment.java:48)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:486)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1073)
at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
at android.view.View.measure(View.java:17430)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:875)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560)
at android.view.View.measure(View.java:17430)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Chor
02-25 21:04:55.795 1947-1947/com.mms.dailypill I/Process﹕ Sending signal. PID: 1947 SIG: 9
答案 0 :(得分：1)
首先不要使用 getApplicationContext（），因为这个帖子中的原因解释了：
When to call activity context OR application context?
关于如何获取片段中的上下文的问题，请创建一个全局变量：
private Context context;
//onCreate method
context = this;
在创建视图方法时使用此上下文。
最后一点是，我不认为您的问题与上下文有关，但是您的数据库创建是因为日志清除状态附近存在问题＆＃34; TABLEDailyPill＆＃34;：我认为您的查询需要修复。
答案 1 :(得分：0)
android.database.sqlite.SQLiteException: near "TABLEDailyPill": syntax error (code 1): , while compiling: CREATE TABLEDailyPill(id INTEGER AUTOINCREMENT, name VARCHAR(50), format VARCHAR(15), amount INTEGER, exp_dateDATE, time HOUR, PRIMARY KEY(id));
您在TABLE和DailyPill之间缺少空格，假设DailyPill应该是表名。