New to Android here. I've made a new Fragments app, and I'm having trouble accessing the database from the Fragment.
Here's the class:
public class ShopListActivity extends FragmentActivity {
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
DatabaseHelper db;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_shoplist);
db = new DatabaseHelper(this); // tried getApplicationContext(), and getBaseContext() as well
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
}
public void onClickAddProduct(View view) {
TextView productName = (TextView) findViewById(R.id.add_product_text);
SQLiteDatabase dbWritable = db.getWritableDatabase(); // <-- crashes here
ContentValues values = new ContentValues();
values.put("Name", (String) productName.getText());
dbWritable.insert("Lists", "Name", values);
}
All the other solutions I found on SO didn't help.
DatabaseHelper is a very basic DB Helper class:
public DatabaseHelper(Context context) {
super(context, dbName, null, dbVersion);
}
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL_CREATE_TABLES);
db.execSQL("INSERT INTO Lists (Name) VALUES('Test')");
}
Here's the Logcat:
07-07 21:03:24.351 9641-9641/com.chas.shopforme E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3606)
at android.view.View.performClick(View.java:4211)
at android.view.View$PerformClick.run(View.java:17362)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5227)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at android.view.View$1.onClick(View.java:3601)
... 11 more
Caused by: java.lang.NullPointerException
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
at com.chas.shopforme.ShopListActivity.onClickAddProduct(ShopListActivity.java:69)
... 14 more
Note: I know there are more questions like this, but their solutions didn't work for me.
try this
db = new DatabaseHelper(this.getApplicationContext());
I tried adding this as a comment to your question, but nasty things happen to code in comments.
Assuming you've tried a) in the comment above, and it didn't work, an example of b) follows:
protected void onCreate(Bundle savedInstanceState) {
...
Handler hand = new Handler();
hand.post(new Runnable() {
public void run() {
dbInit();
}
});
}
public void dbInit() {
db = new DatabaseHelper(this);
}
This allows the fragment manager to finish setting up the fragment before you try to use it. What it is doing is sending a message to itself which is processed when the fragment's message handler loop is running.
Related
I am having an issue with my college project. I am trying to delete a row from my one of my tables using the following query.
//---deletes a particular match---
public boolean deleteMatch(String name) {
SQLiteDatabase sqLiteDatabase = getWritableDatabase();
return sqLiteDatabase.delete(TABLE_FIXTURES, MATCH_OPPONENT + " = " + name, null) > 0;
}
Here I am trying to delete a record based upon the match_opponent and passing the String value name.
I am then calling this method in my EditSchedule activity below:
public class EditSchedule extends AppCompatActivity {
public Button fixtureSearch;
public EditText opponentName;
public String searchTerm;
ListView editMatch;
DBHelper dbHelper = new DBHelper(this);
SQLiteDatabase sqLiteDatabase;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_editfixture);
editMatch = (ListView) findViewById(R.id.listViewEditMatch);
opponentName = (EditText) findViewById(R.id.fixtureOpponentDelete);
searchTerm = opponentName.getText().toString();
fixtureSearch = (Button) findViewById(R.id.fixtureSearchButton);
fixtureSearch.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
dbHelper.deleteMatch(searchTerm);
}
}
);
}
}
So when I test my application by typing in a name of an opponent that I have in the fixture table and clicking on the delete button, I get the following error:
01-06 07:49:42.476 25778-25778/com.example.myacer.clubhub E/AndroidRuntime﹕ FATAL EXCEPTION: main
android.database.sqlite.SQLiteException: near "=": syntax error (code 1): , while compiling: DELETE FROM fixtures WHERE match_opponent =
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.delete(SQLiteDatabase.java:1494)
at com.example.myacer.clubhub.database.DBHelper.deleteMatch(DBHelper.java:243)
at com.example.myacer.clubhub.manager.EditSchedule$1.onClick(EditSchedule.java:47)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Can anyone see where I am going wrong? All help greatly appreciated.
You are passing blank value in deleteMatch(), put searchTerm = opponentName.getText().toString(); inside onClick()
fixtureSearch.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
searchTerm = opponentName.getText().toString();
dbHelper.deleteMatch(searchTerm);
}
}
);
As well as change your deleteMatch() method
sqLiteDatabase.delete(TABLE_FIXTURES, MATCH_OPPONENT + " = ?",new String[]{name});
try this:
sqLiteDatabase.delete(TABLE_FIXTURES, MATCH_OPPONENT + " = ?", new String[]{name})
I wanted to test my code on another device than my physical one, so I launched the app in GenyMotion emulator with a Samsung Galaxy S3 (API 18), but it keeps throwing a NoClassDefFoundError Exception in my class "SlidingMenuUtil" (a customized drawer menu) which is called on startup by my MainActivity.
Here is code from my onCreate in MainActivity:
#Bind(R.id.viewContentFullScreen) RelativeLayout viewContentFullScreen;
#Bind(R.id.viewContentTopBar) RelativeLayout viewContentTopBar;
#Bind(R.id.topBarWrapper) RelativeLayout topbarView;
private ViewContainer viewContainer;
private SlidingMenuUtil leftMenu;
private Bundle bundle;
private MessageHandler messageHandler;
private GoBackFunction currentGoBackFunction;
private CallbackManager callbackManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
bundle = savedInstanceState;
setContentView(R.layout.activity_main);
leftMenu = new SlidingMenuUtil(this, SlidingMenuUtil.MenuType.LEFT, R.layout.drawer_menu, (int)(LayoutUtil.getScreenWidth(this) * 0.75), false);
populateMenu();
ButterKnife.bind(this);
messageHandler = new MessageHandler(this, findViewById(R.id.spinner));
FacebookSdk.sdkInitialize(getApplicationContext());
callbackManager = CallbackManager.Factory.create();
}
The problem occurs in the SlidingMenuUtil class on line: 67. Here is the constructor for the class:
public SlidingMenuUtil(Activity activity, MenuType menuType, int menuLayout, int shownMenuWidth, boolean fadeEffectOn) {
this.activity = activity;
this.menuType = menuType;
this.shownMenuWidth = shownMenuWidth;
this.fadeEffectOn = fadeEffectOn;
this.screenWidth = LayoutUtil.getScreenWidth(activity);
this.rootView = (ViewGroup)((ViewGroup)activity.findViewById(android.R.id.content)).getChildAt(0);
this.activityWrapper = new RelativeLayout(activity);
this.activityWrapper.setLayoutParams(this.rootView.getLayoutParams());
this.overlay = new RelativeLayout(activity);
this.overlay.setLayoutParams(new ViewGroup.LayoutParams(-1, -1));
this.overlay.setBackgroundColor(Color.parseColor("#000000"));
this.overlay.setAlpha(0.0F);
this.overlay.setVisibility(View.GONE);
this.overlay.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (menuOpen) {
toggle(new ToggleMenu() {
#Override
public void animationDone() {
}
});
}
}
});
this.rootView.addView(this.overlay);
this.menu = (LinearLayout)activity.getLayoutInflater().inflate(menuLayout, (ViewGroup) null, false);
this.menu.setLayoutParams(new ViewGroup.LayoutParams(shownMenuWidth, -1));
if (menuType == MenuType.LEFT) {
this.menu.setTranslationX((float)(-shownMenuWidth));
} else {
this.menu.setTranslationX((float)(screenWidth));
}
this.rootView.addView(this.menu);
this.menuOpen = false;
}
lin 67 is:
this.overlay.setOnClickListener(new View.OnClickListener() {
As mentioned before the problem only occurs in the emulator.
Here is the log:
812-812/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NoClassDefFoundError: nightout.dk.nightoutandroid.utils.SlidingMenuUtil$1
at nightout.dk.nightoutandroid.utils.SlidingMenuUtil.<init>(SlidingMenuUtil.java:67)
at nightout.dk.nightoutandroid.MainActivity.onCreate(MainActivity.java:40)
at android.app.Activity.performCreate(Activity.java:5133)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
I hope somone can help me out.
Any help will be gratly appreciated
I am having a few issues running my custom CursorAdapter in my application. According to my logcat, the error I get:
11-08 06:41:03.228 6109-6109/? W/System.err? java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.name/com.app.name.MyActivity}: java.lang.NullPointerException
11-08 06:41:03.229 6109-6109/? W/System.err? at com.app.name.MyActivity.onCreate(MyActivity.java:71)
11-08 06:41:03.231 6109-6109/? E/AndroidRuntime? FATAL EXCEPTION: main
occurs at line 71 which sets the adapter (obj.setAdapter(myAdapter)). Initially I thought my database data retrieve function (Cursor chatCursor = mydb.selectConversation(msgId);) did not return any data but after testing it with the chatCursor.getCount() function, I realized that was not the case. Kindly assist me in solving this issue. Below are the codes for my activity, adapter and logcat. Thanks in advance.
MyAdapter.java
public class MyAdapter extends CursorAdapter {
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
public MyAdapter(Context context, Cursor cursor) {
super(context, cursor, 0);
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
return LayoutInflater.from(context).inflate(R.layout.chat_left, parent, false);
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
TextView user = (TextView) view.findViewById(R.id.reply_user);
TextView msg = (TextView) view.findViewById(R.id.reply_msg);
String theTime = cursor.getString(cursor.getColumnIndexOrThrow("message_id"));
String theMessage = cursor.getString(cursor.getColumnIndexOrThrow("message"));
user.setText(theTime);
msg.setText(String.valueOf(theMessage));
}
}
MyActivity.java
public class MyActivity extends ListActivity {
//Utils Class
Utils util;
final Context context = this;
private ProgressBar dialog;
ListView obj;
DBHelper mydb;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view);
util = new Utils(this);
mydb = new DBHelper(this);
Bundle extras = getIntent().getExtras();
final Integer msgId = extras.getInt("id");
obj = (ListView) findViewById(R.id.list);
Cursor chatCursor = mydb.selectConversation(msgId);
MyAdapter myAdapter = new MyAdapter(this, chatCursor);
obj.setAdapter(myAdapter);
}
}
logcat
11-08 06:41:03.228 6109-6109/? W/System.err? java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.name/com.app.name.MyActivity}: java.lang.NullPointerException
11-08 06:41:03.229 6109-6109/? W/System.err? at com.app.name.MyActivity.onCreate(MyActivity.java:71)
11-08 06:41:03.231 6109-6109/? E/AndroidRuntime? FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.name/com.app.name.MyActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2351)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2403)
at android.app.ActivityThread.access$600(ActivityThread.java:165)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1373)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5370)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.app.name.MyActivity.onCreate(MyActivity.java:71)
at android.app.Activity.performCreate(Activity.java:5122)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1150)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2315)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2403)
at android.app.ActivityThread.access$600(ActivityThread.java:165)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1373)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5370)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
11-08 06:41:03.238 559-832/? W/ActivityManager? Force finishing activity com.app.name/.MyActivity
11-08 06:41:03.742 559-574/? W/ActivityManager? Activity pause timeout for ActivityRecord{42e71938 u0 com.app.name/.MyActivity}
Take a look to your activity_view.xml. Probably the listview ID isn't "list" as you state when you try to find it with findViewById(R.layout.list).
I want to know why my application is throwing a runtime exception when I run it? I used to the code in the following link for my application,
dynamically add and remove view to viewpager.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar ab=getActionBar();
pagerAdapter = new MainPagerAdapter();
pager = (ViewPager) findViewById (R.id.pager);
pager.setAdapter (pagerAdapter);
inflater = (LayoutInflater)getSystemService
(Context.LAYOUT_INFLATER_SERVICE);
v0 = (FrameLayout) inflater.inflate (R.layout.listlayout, null);
Button button=(Button)findViewById(R.id.button1);
button.setOnClickListener(this);
pagerAdapter.addView (v0, 0);
pagerAdapter.notifyDataSetChanged();
}
#Override
public void onClick(View v) {
if(v.getId()==R.id.button1)
{
pagerAdapter.addView (v0);
pagerAdapter.notifyDataSetChanged();
}
}
LogCat:
FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.todolistworkable/com.example.todolistworkable.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
at android.app.ActivityThread.access$600(ActivityThread.java:128)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4514)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
at dalvik.system.NativeStart.main(Native Method)Caused by: java.lang.NullPointerException
at com.example.todolistworkable.MainActivity.onCreate(MainActivity.java:43)
at android.app.Activity.performCreate(Activity.java:4465)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
the object on line 43 of your code within your onCreate method is null. Most likely the target of one of your findViewById calls is not returning what you expect it to.
See this for more info.
How to interpret Logcat
I want to refresh data in ListFragment from my custom adapter class, but got the error NullPointerException.
This is Adaper class method:
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
BasketFragment basketFragment = new BasketFragment();
basketFragment.getBsketList();
}
});
And when I call it in my Fragment class I get java.lang.NullPointerException at mDataBase = dbHelper.getWritableDatabase();
getBasketList():
public void refreshList() {
dbAdaper.setArrayMyData(selectAll());
dbAdaper.notifyDataSetChanged();
}
And here is the part where I got the error:
public ArrayList<BasketData> selectAll() {
Cursor mCursor = null;
dbHelper = new DBHelper(getActivity());
mDataBase = dbHelper.getWritableDatabase();//NullPointerException
mCursor = mDataBase.query("orderTable", null, null, null, null, null, null);
LogCat:
java.lang.NullPointerException
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
at com.epon.fragments.BasketFragment.selectAll(BasketFragment.java:100)
at com.epon.fragments.BasketFragment.getBsketList(BasketFragment.java:142)
at com.epon.adapters.DBBasketAdapter$2.onClick(DBBasketAdapter.java:177)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Have you set the context right?
Android: NullPointerException on getWritableDatabase()
NullPointerException on getWritableDatabase()
I think that his is your problem a problem.
Maybe if this is not helping posting the content of getActivity() might be helpful?
edit
Your logcat makes me keep thinking that its a context error!