I have a class Scores.java I need to know whats the correct way to create these. I get "The constructor Scores is not defined. Do I have to extend off everything in Android??
package com.threeuglymen.android.stuff;
import android.app.Application;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.preference.PreferenceManager;
import android.util.Log;
public class Scores {
private Context mycontext;
public Scores (Context context) {
// TODO Auto-generated method stub
this.mycontext = context;
}
public void resetScores(){
try {
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(mycontext);
Editor edit = pref.edit();
edit.putInt("correct", 0);
edit.putInt("incorrect", 0);
edit.commit();
} catch (Exception e) {
Log.d("Scores", "Exception:" + e.toString());
}
return;
}
}
Thx for any guidance
Eric
What you have currently should work. In your main activity, don't call
Scores score = new Scores();
instead call
Scores score = new Scores(getContext());
Let me know if this works.
You probably want:
public class ScoresSub extends Scores
{
public ScoresSub(Context context)
{
super(context);
}
}
Since you defined a constructor taking parameters in Scores, the compiler doesn't provide a no-arg one.
When you create a class you don't always new to extend from another, all clases extend from the class Object and if you extend another like in this case class Application it is because you want its function and you want to make a variation of it or override some method and i think in this case you don't even need to extend from Application, because your class is not intended to be an Application so:
public class Scores {
private Context mycontext;
public Scores () {
this.mycontext = null;
}
public Scores (Context context) {
// TODO Auto-generated method stub
this.mycontext = context;
}
public void resetScores(){
try {
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(mycontext);
Editor edit = pref.edit();
edit.putInt("correct", 0);
edit.putInt("incorrect", 0);
edit.commit();
} catch (Exception e) {
Log.d("Scores", "Exception:" + e.toString());
}
return;
}
}
and i don't think you should have a problem.
Related
This is my first question here on stack overflow, so please forgive me for any oversight or formatting errors. This issue seems simple enough, but I am not able to "put the pieces together" for some reason. I am also learning java and android studio as I go, so please forgive and educate on any bad code.
I need to gather data from my barcode scanning app, submit it to a variable, and then pass that variable through my database to fetch information based on the UPC code. I am using the ZXing library for the barcode scanner, with the handleResult method to capture the initial data.
I have the data collected within the SimpleScanner activity, but I can't figure out how to use that variable in a SQlite query. Below are the main classes I am using.
Any help would be appreciated. I can query the entire database just fine, but I need to look up the rows that match the actual item I am scanning. Thanks again!
SimpleScannerActivity.java
package com.example.android.dropr;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.database.Cursor;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.Toast;
import com.google.zxing.Result;
import java.util.ArrayList;
import java.util.List;
import me.dm7.barcodescanner.zxing.ZXingScannerView;
public class SimpleScannerActivity extends MainActivity implements ZXingScannerView.ResultHandler {
private ZXingScannerView mScannerView;
#Override
public void onCreate(Bundle state) {
super.onCreate(state);
mScannerView = new ZXingScannerView(this); // Programmatically initialize the scanner view
setContentView(mScannerView); // Set the scanner view as the content view
}
#Override
public void onResume() {
super.onResume();
mScannerView.setResultHandler(this); // Register ourselves as a handler for scan results.
mScannerView.startCamera(); // Start camera on resume
}
#Override
public void onPause () {
super.onPause();
mScannerView.stopCamera(); // Stop the camera on pause
}
#Override
public void handleResult(Result rawResult) {
String TAG = "Dropr";
/**
* Create Alert Dialog, so that user has time to read the information within.
*/
AlertDialog.Builder scanInfo = new AlertDialog.Builder(this);
String messageContent = "Content - " + rawResult.getText();
String messageFormat = "Format - " + rawResult.getBarcodeFormat().toString() + ".";
scanInfo.setTitle("Scan Information:");
scanInfo.setMessage(messageContent + "\n" + messageFormat);
scanInfo.setCancelable(true);
scanInfo.setPositiveButton(
"OK",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
// IF you would like to resume scanning, call this method below:
// Handle the data
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
mScannerView.resumeCameraPreview(SimpleScannerActivity.this);
}
}, 1000);
}
});
AlertDialog showInfo = scanInfo.create();
showInfo.show();
// Do something with the result here
Log.v(TAG, rawResult.getText());
Log.v(TAG, rawResult.getBarcodeFormat().toString());
}
}
DatabaseAccess.java
package com.example.android.dropr;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
public class DatabaseAccess {
private SQLiteOpenHelper openHelper;
private SQLiteDatabase database;
private static DatabaseAccess instance;
private SimpleScannerActivity scannerActivity = new SimpleScannerActivity();
/**
* Private constructor to avoid object creation from outside classes.
*
* #param context
*/
protected DatabaseAccess(Context context) {
this.openHelper = new DatabaseOpenHelper(context);
}
/**
* Return a singleton instance of DatabaseAccess.
*
* #param context
* #return the instance of DatabaseAccess
*/
public static DatabaseAccess getInstance(Context context) {
if (instance == null) {
instance = new DatabaseAccess(context);
}
return instance;
}
/**
* Open the database connection
*/
public void open() {
this.database = openHelper.getWritableDatabase();
}
/**
* Close the database connection
*/
public void close() {
if (database != null) {
this.database.close();
}
}
/**
* Read all quotes from the database.
*
* #return a list of quotes
*/
public List<String> getCodes() {
List<String> list = new ArrayList<>();
Cursor cursor = database.rawQuery("SELECT name, upc14 FROM Barcodes", null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
list.add(cursor.getString(0));
list.add(cursor.getString(1));
cursor.moveToNext();
}
cursor.close();
return list;
}
}
I finally came up with a solution, thanks to #muratgu! I created another method that creates and stores a variable for the scanned data, and passes the variable through a query.
/**
* read a single record from the database the matches the UPC-A code scanned.
* if there is no match, do nothing.
* #param rawContent
* #return a brand name based on the matching UPC-A code that was scanned.
*/
public String getInfo(String rawContent) {
String TAG = "Getinfo():";
String content = "00" + rawContent;
String brandName = "";
Cursor cursor = database.rawQuery("SELECT name, upc12 from Barcodes WHERE '" + content + "' = upc12", null);
if(cursor.getCount() > 0) {
cursor.moveToFirst();
brandName = cursor.getString(cursor.getColumnIndex("name"));
cursor.close();
} else {
Log.v(TAG, "uh oh, something went wrong in the if loop! ");
}
return brandName;
}
This method gets called in the SimpleScannerActivity.java file, where the scanned data can be passed through the variable. The method returns the name of the item, which is then placed in the dialog box. Exactly what I needed.
Thanks again, #muratgu! you gave me enough information that I could solve the problem myself. I just had to think on it for a bit!
I have search now for hours through the internet and have found nothing substantial so far. The thing that I want to do is a multi choice preference view, that disables the last item and reenables it, if it is not alone anymore.
I through so far about taking the super class force read the private variables in there to write my own onPrepareDialogBuilder(AlertDialog.Builder builder). Which is configuring its own OnMultiChoiceClickListener that jumps in, in the moment where has only one item left. The problem here is, that I use a bad practice force read of a private variable and that I have so far no idea how to get the checkbox item and how to disable it. But I think looking even deeper into the Android SDK will solve this problem.
At the end, if nothing works, solving the problem with doing an overwrite the OnPreferenceChangeListener to display a toast if the user has less than one item selected. But user friendliness is a high value, that needs to be earned and that often isn't easy.
Thx.
import android.content.Context;
import android.preference.MultiSelectListPreference;
import android.util.AttributeSet;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import georg.com.flironetest_01.Variables.Units;
/**
* Created by Georg on 16/03/16.
*/
public class UnitMultipleSelectorPreference extends MultiSelectListPreference {
public UnitMultipleSelectorPreference(Context context, AttributeSet attrs) {
super(context, attrs);
List<CharSequence> humanU = new ArrayList<>();
List<CharSequence> machineU = new ArrayList<>();
Units[] all = Units.values(); // Units is a enum with a rewriten to string statement.
for (Units elem : all) {
humanU.add(elem.toString());
machineU.add(elem.name());
}
setEntries(humanU.toArray(new CharSequence[humanU.size()]));
setEntryValues(machineU.toArray(new CharSequence[machineU.size()]));
Set<String> mU = new HashSet<>();
mU.add(Units.C.name());
mU.add(Units.K.name());
setDefaultValue(mU);
}
}
Okay. To answer my own question here after the motto "self is the man": I ended up with programming my own preference panel. Below is the code. If somebody likes to look over it and give some times how to make it even more stable: feel free.
But to sum up what I did: I created my own ArrayAdapter. But DialogPreference didn't allowed me to create my own multi selector. You need to change the final dialog fragment to create a working multi selector list (see here: https://stackoverflow.com/a/17907379/5759814). That is not an easy task if you work with the DialogPreferences. The reason is these few amounts of code:
/**
* Shows the dialog associated with this Preference. This is normally initiated
* automatically on clicking on the preference. Call this method if you need to
* show the dialog on some other event.
*
* #param state Optional instance state to restore on the dialog
*/
protected void showDialog(Bundle state) {
Context context = getContext();
mWhichButtonClicked = DialogInterface.BUTTON_NEGATIVE;
mBuilder = new AlertDialog.Builder(context)
.setTitle(mDialogTitle)
.setIcon(mDialogIcon)
.setPositiveButton(mPositiveButtonText, this)
.setNegativeButton(mNegativeButtonText, this);
View contentView = onCreateDialogView();
if (contentView != null) {
onBindDialogView(contentView);
mBuilder.setView(contentView);
} else {
mBuilder.setMessage(mDialogMessage);
}
onPrepareDialogBuilder(mBuilder);
getPreferenceManager().registerOnActivityDestroyListener(this);
// Create the dialog
final Dialog dialog = mDialog = mBuilder.create();
if (state != null) {
dialog.onRestoreInstanceState(state);
}
if (needInputMethod()) {
requestInputMethod(dialog);
}
dialog.setOnDismissListener(this);
dialog.show();
}
As you can see here is a method triggered to change my dialog builder with onPrepareDialogBuilder, but it doesn't seem like that there is any other function triggered afterwards, that would allow me to change the dialog directly after its creation. And the second idea of changing the onPrepareDialogBuilder so that I can init everything there, doesn't really help, because I end up with displayed dialog windows. That lead me to my decision of creating my completely own Preference class. With that decision I loose all those nice prepared functions like onRestoreInstanceState and Co, but I now have an application with a much more persistent flow, that doesn't do any stupid things when I select zero units for my thermal view.
Below the non commented code. I'm sorry, but I think its simple enough for everybody who landing here.
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.SharedPreferences;
import android.preference.Preference;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import georg.com.flironetest_01.Variables.Units;
/**
* Created by Georg on 16/03/16.
*/
public class UnitMultipleSelectorPreference extends Preference implements DialogInterface.OnClickListener, Preference.OnPreferenceClickListener {
String[] human_entries = null;
String[] machine_entries = null;
public SharedPreferences prev;
public UnitMultipleSelectorPreference(Context context, AttributeSet attrs) {
super(context, attrs);
prev = getSharedPreferences();
List<String> humanU = new ArrayList<>();
List<String> machineU = new ArrayList<>();
Units[] all = Units.values();
for (Units elem : all) {
humanU.add(elem.toString());
machineU.add(elem.name());
}
human_entries = humanU.toArray(new String[humanU.size()]);
machine_entries = machineU.toArray(new String[machineU.size()]);
Set<String> mU = new HashSet<>();
mU.add(Units.C.name());
mU.add(Units.K.name());
setDefaultValue(mU);
setOnPreferenceClickListener(this);
}
boolean[] selected = new boolean[0];
protected void onPrepareDialogBuilder(AlertDialog.Builder builder) {
if (prev == null)
return;
if (human_entries == null || machine_entries == null || human_entries.length != machine_entries.length ) {
throw new IllegalStateException(
"ListPreference requires an entries array and an entryValues array which are both the same length");
}
selected = new boolean[human_entries.length];
for (int i = 0; i < human_entries.length; i++)
selected[i] = prefSet.contains(machine_entries[i]);
String[] stringObj = new String[human_entries.length];
int i = 0;
for(CharSequence ch : human_entries)
stringObj[i++] = ch.toString();
builder.setAdapter(new MyAdapter(getContext(), android.R.layout.simple_list_item_multiple_choice, stringObj), new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
}
});
AlertDialog mDialog = builder.create();
mDialog.getListView().setChoiceMode(AbsListView.CHOICE_MODE_MULTIPLE);
mDialog.getListView().setItemsCanFocus(false);
mDialog.getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// Manage selected items here
ListView mParent = (ListView)parent;
if (mParent.getCheckedItemCount() >= 1)
selected[position] = mParent.isItemChecked(position);
if (mParent.getCheckedItemCount() == 0)
mParent.setItemChecked(position, true);
}
});
mDialog.show();
i = 0;
for (boolean select : selected)
mDialog.getListView().setItemChecked(i++, select);
}
#Override
public boolean onPreferenceClick(Preference preference) {
AlertDialog.Builder mBuilder = new AlertDialog.Builder(getContext());
mBuilder.setTitle(getTitle())
.setPositiveButton(android.R.string.ok, this)
.setNegativeButton(android.R.string.cancel, this);
onPrepareDialogBuilder(mBuilder);
return true;
}
#Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getContext(), "W:"+which + " | " + Arrays.toString(selected), Toast.LENGTH_SHORT).show();
switch (which) {
case -1:
if (isPersistent()) {
prefSet = new HashSet<>();
for (int i = 0; i < selected.length; i++) {
if (selected[i])
prefSet.add(machine_entries[i]);
}
getEditor().putStringSet(getKey(), prefSet).apply();
Toast.makeText(getContext(), "W:"+which + " | " + getSharedPreferences().getStringSet(getKey(),null).toString(), Toast.LENGTH_SHORT).show();
}
return;
}
}
public class MyAdapter extends ArrayAdapter<String> {
public MyAdapter(Context context, int textViewResourceId, String[] objects) {
super(context, textViewResourceId, objects);
}
#Override
public boolean isEnabled(int n) {
return true;
}
}
Set<String> prefSet;
#Override
protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
super.onSetInitialValue(restorePersistedValue, defaultValue);
prev = getSharedPreferences();
if(restorePersistedValue) {
prefSet = prev.getStringSet(getKey(), new HashSet<String>());
} else {
try {
prefSet = (Set<String>)defaultValue;
if(isPersistent())
getEditor().putStringSet(getKey(), prefSet);
} catch (ClassCastException e) {
Log.e("ERROR_CAST", "Error casting the default value to Set<String>.");
}
}
}
}
A really simple solution is to set a setOnPreferenceChangeListener and just return false if the new value would be empty.
All of the code is put into onCreatePreferences.
MultiSelectListPreference infoPreference = findPreference("information");
infoPreference.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
#Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
if (size(newValue) == 0){
return false;
}
return true;
}
});
I am relatively new to Java and working with the ArcGIS Runtime SDK for Android. I am making an app where the user selects the parcel id from spinner list. If the user clicks on a 'ZOOM' button the map should zoom to the parcel that was selected. Here is my code:
package gist8010.main;
import java.util.ArrayList;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import com.esri.android.map.MapView;
import com.esri.android.map.ags.ArcGISDynamicMapServiceLayer;
import com.esri.android.map.ags.ArcGISTiledMapServiceLayer;
import com.esri.core.geometry.Envelope;
import com.esri.core.geometry.Point;
import com.esri.core.map.Feature;
import com.esri.core.map.FeatureResult;
import com.esri.core.tasks.query.QueryParameters;
import com.esri.core.tasks.query.QueryTask;
public class Spinner_WalkActivity extends Activity {
MapView mMapView;
Button mBtnZoom;
ArcGISDynamicMapServiceLayer mDynamicLayer;
Spinner mSpnParcels;
String mMapServiceURL = "http://indy14.athena.bcit.ca:8080/"
+ "esri_rest/services/gist_8010_test_ms/MapServer";
int mLotLayerID = 0;
String mLotLayerURL = mMapServiceURL + "/" + mLotLayerID;
String mLotNumColName = "PARCELS_ID";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
/** Allow querying on main thread */
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new
StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
/** Create spinner and button */
setMapView();
this.mBtnZoom = (Button) findViewById(R.id.btnZoom);
mBtnZoom.setOnClickListener(new OnClickListener() {
/** Upon click of zoom button, invoke th zoomtoFeature Method */
public void onClick(View v) {
zoomToFeature(v);
}
});
this.mSpnParcels = (Spinner) findViewById(R.id.spnParcels);
/** Add Layer to map */
mDynamicLayer = new ArcGISDynamicMapServiceLayer(mMapServiceURL);
mMapView.addLayer(mDynamicLayer);
QueryParameters qryLotNums = new QueryParameters();
qryLotNums.setReturnGeometry(false);
qryLotNums.setOutFields(new String[] { mLotNumColName });
qryLotNums.setWhere(mLotNumColName + ">0");
com.esri.core.tasks.query.QueryTask qtask = new com.esri.core.tasks.query.QueryTask(
mLotLayerURL);
try {
FeatureResult fSet = qtask.execute(qryLotNums);
ArrayList<String> listOfLotsNums = new ArrayList<String>();
Feature tmpFeat;
for (Object featAsObj : fSet) {
tmpFeat = (Feature) featAsObj;
listOfLotsNums.add(tmpFeat.getAttributeValue(mLotNumColName)
.toString());
}
ArrayAdapter<String> adtTmp = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_dropdown_item,
listOfLotsNums);
mSpnParcels.setAdapter(adtTmp);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}// of catch
}
#Override
protected void onDestroy() {
super.onDestroy();
}
#Override
protected void onPause() {
super.onPause();
mMapView.pause();
}
#Override
protected void onResume() {
super.onResume();
mMapView.unpause();
}
// =============================================================================
// Zooms the map the the MBR of the feature selected in the spinner
// import android.view.View;
// =============================================================================
public void zoomToFeature(View v) {
QueryParameters zoomQuery = new QueryParameters();
zoomQuery.setReturnGeometry(true);
zoomQuery.setOutFields(new String[] { mLotNumColName });
zoomQuery.setWhere(mLotNumColName + "=" + mSpnParcels.getSelectedItem());
QueryTask qtask = new QueryTask(mLotLayerURL);
try {
FeatureResult fset = qtask.execute(zoomQuery);
Feature tmpFeat = (Feature) fset.iterator().next();
Envelope envelope = new Envelope();
envelope.queryEnvelope((Envelope) tmpFeat.getGeometry());
getMapView().setExtent(envelope);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// =============================================================================
// getter for the main map
// =============================================================================
private MapView getMapView() {
// =============================================================================
// if MapView is underlined in red, change the name to match your
// MapView
// =============================================================================
return mMapView;
}
// =============================================================================
// setter for the main map
// =============================================================================
private void setMapView() {
// ========================================================================
// if mapView is underlined in red then sync class-level var names
// if R.id.map is underlined in red ensure that you added the xml
// fragment
// such as "MapView Generic" to a layout
// ========================================================================
mMapView = (MapView) findViewById(R.id.map);
}
}
After attempting to debug, I think my issue is with the Envelope class. The queryEnvelope method accepts a Envelope argument. As you can see, I cast the geometry of the Feature tmpFeat from a geometry type into a Envelope type.
When I run the application on my phone I get an System.Err in my log Cat saying:
java.lang.ClassCastException: com.esri.core.geometry.Polygon cannnot be cast to com.esri.core.geometry.Envelope
Am I doing the casting incorrectly? I cannot think of another way of linking my Envelope instance with the geometry of the feature class i want to zoom to.
Envelop is a child class of com.esri.core.geometry.Geometry, not vice versa. I guess this is why you fail when do the cast.
https://developers.arcgis.com/android/api-reference/reference/com/esri/core/geometry/Envelope.html
As it to your question, I guess envelop is not necessary to zoom to a feature. MapView.zoomToResolution(Point centerPt, double res) or zoomTo(Point centerPt, float factor) may be a better choice. You may find these sample codes helpful:
https://developers.arcgis.com/android/sample-code/geocoding/
I'm doing basic calculator for Android in Java. My calculator worked but i had all code in one class. Then i wanted to make code more readable and i created another Calculation class and i put calculation code in there. And now for some reason my app crashes. LogCat says: NullPointerException. (My app starts fine and then when i choose desirable currency to convert and when i click on ImageButton(convert) then app crashes). Here is my code:
CroToEu class:
package com.eu.calculator;
import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageButton;
import android.widget.TextView;
public class CroToEur extends Activity {
TextView resultView;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.cro_to_eur);
final ImageButton convert = (ImageButton) findViewById(R.id.converButton);
convertButton(convert);
}
private void convertButton(final ImageButton convert) {
resultView = (TextView) findViewById(R.id.resultView);
convert.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
Calculate now = new Calculate();
now.croToEu();
if(event.getAction() == MotionEvent.ACTION_DOWN) {
convert.setImageResource(R.drawable.convert_button_ontouch);
checkForEmptyEntry();
} else if (event.getAction() == MotionEvent.ACTION_UP) {
convert.setImageResource(R.drawable.convert_button);
}
return false;
}
private void checkForEmptyEntry() {
if(Calculate.HRKfield.getText() == null || "".equals(Calculate.HRKfield.getText().toString())) {
resultView.setText("You left empty field");
} else {
resultView.setText(Calculate.HRKfield.getText()+" HRK = "+Calculate.fixDecimal+" EUR");
}
}
});
}
}
And my calculation class:
package com.eu.calculator;
import java.math.BigDecimal;
import android.app.Activity;
import android.widget.EditText;
public class Calculate extends Activity {
public static EditText HRKfield; //S tem dobimo vrednost iz polja edittext
public static double EUR = 0.133;//drži vrednost
public static Double HRK; // Možnost uporabe double za parsing
public static double result; // rezultat
public static BigDecimal fixDecimal; // rezultat pretvori na decimalko
public BigDecimal croToEu() {
HRKfield = (EditText) findViewById(R.id.enterField);
try {
HRK = Double.parseDouble(HRKfield.getText().toString()); //tukaj dobimo čisto številko, ki jo uporabnik vnese v polje
result = HRK * EUR;
fixDecimal = new BigDecimal(result);
fixDecimal = fixDecimal.setScale(2, BigDecimal.ROUND_HALF_UP);
} catch (NumberFormatException e) {
}
return fixDecimal;
}
}
Don' t extend Calculate class with Activity . Remove extends Activity in Calculate class
If you are trying to just create a helper class whcih does the calculation for you then don't extend Activity on your Calculate class. Instead get your croToEu method to return a variable and call this from the other class as follows.
Calculate now = new Calculate();
BigDecimal val = now.croToEu();
Id actually have the caluclate class as follows
public abstract class Calculate {
public static final double EUR = 0.133;//drži vrednost
public static BigDecimal croToEu(double hrkValue) {
BigDecimal fixDecimal = new BigDecimal(hrkValue * EUR);
fixDecimal = fixDecimal.setScale(2, BigDecimal.ROUND_HALF_UP);
return fixDecimal;
}
}
Then in your main activity class call
BigDecimal val = Calculate.croToEu(hrkValue);
if(Calculate.HRKfield.getText() == null || "
this is wrong to get the view of other activity .........
you are in CroToEur and your acessing the HRKfield of Calculate activity which will be null
So should pass the data from CroToEur activity to Calculate activity using intent and set that in HRKfield in onCreate of CroToEur
You are missing your onCreate() method and even setContentView in Calculate.class and so it cannot find your edittext HRKfield, and so it is throwing NullpointerException
Okay so my first app, I got an XML parser working. In the same class it works fine, but if i seperate it to a new class/java file, It doesnt work, compiles fine but wont load in AVD. Could someone please look at my classes, ill include im imports etc as well because i think it has something to do with the namespace...Any help much appreciated
package com.helloworld;
import android.app.Activity;
import java.io.IOException;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
//import android.app.Activity;
import android.content.res.Resources;
import android.content.res.XmlResourceParser;
import android.os.Bundle;
import android.widget.TextView;
// import com.helloworld.XMLParse;
//import android.widget.TextView;
public class HelloworldActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
XMLParse xml_parse = new XMLParse();
xml_parse.doXML();
}
}
And the main class to do the job in my package is,
package com.helloworld;
import java.io.IOException;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import android.app.Activity;
import android.content.res.Resources;
import android.content.res.XmlResourceParser;
import android.widget.TextView;
public class XMLParse extends Activity {
public void doXML() {
TextView myXmlContent = (TextView)findViewById(R.id.my_xml);
String stringXmlContent;
try {
stringXmlContent = getEventsFromAnXML(this);
myXmlContent.setText(stringXmlContent);
} catch (XmlPullParserException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private String getEventsFromAnXML(Activity activity)
throws XmlPullParserException, IOException
{
StringBuffer stringBuffer = new StringBuffer();
Resources res = activity.getResources();
XmlResourceParser xpp = res.getXml(R.xml.myxml);
xpp.next();
int eventType = xpp.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT)
{
if(eventType == XmlPullParser.START_DOCUMENT)
{
stringBuffer.append("--- Start XML ---");
}
else if(eventType == XmlPullParser.START_TAG)
{
stringBuffer.append("\nSTART_TAG: "+xpp.getName());
}
else if(eventType == XmlPullParser.END_TAG)
{
stringBuffer.append("\nEND_TAG: "+xpp.getName());
}
else if(eventType == XmlPullParser.TEXT)
{
stringBuffer.append("\nTEXT: "+xpp.getText());
}
eventType = xpp.next();
}
stringBuffer.append("\n--- End XML ---");
return stringBuffer.toString();
}
}
I don't know anything about android but it looks weird to me that your XMLParse is inheriting from Activity.
Maybe it shouldn't and you should pass in your HelloworldActiviy:
public void doXML(Activity activity) {
TextView myXmlContent = (TextView)activity.findViewById(R.id.my_xml);
String stringXmlContent;
try {
stringXmlContent = getEventsFromAnXML(activity);
myXmlContent.setText(stringXmlContent);
} catch (XmlPullParserException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
In android, Activities are displayable components for your app. You can't directly instantiate an Activity because it relies on a bunch of OS code to be created and maintained properly. There is a lot wrong here, but at a high level you really don't want the functionality of parsing XML to extend Activity. It doesn't seem to make sense to have a method called getEventsFromAnXML which takes an Activity as a parameter.