Develop Reference

Add a dynamic button to the view and save it permanently

I have a fragment with this view:
XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:tag="general"
android:id="#+id/root"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#343535"
android:orientation="vertical"
tools:context=".fragments.GeneralFragment">
<Button
android:id="#+id/hello"
android:layout_width="match_parent"
android:layout_height="60dp"
android:gravity="center_vertical"
android:onClick="onClick"
android:text="#string/hello" />
<Button
android:id="#+id/observed"
android:layout_width="match_parent"
android:layout_height="60dp"
android:gravity="center_vertical"
android:onClick="onClick"
android:text="#string/observed" />
<Button
android:id="#+id/thanks"
android:layout_width="match_parent"
android:layout_height="60dp"
android:gravity="center_vertical"
android:onClick="onClick"
android:text="#string/thanks" />
</LinearLayout>
There are 3 buttons. Whenever you click on one of them, its text will be displayed.
Now I would like to add another button but dynamically. It should be added before #+id/hello.
I have tried it with
LinearLayout root = (LinearLayout) view.findViewById(R.id.root);
root.addView();
but it looks completely wrong since some parameters are missing.
For instance, the new button should be like:
XML:
<Button
android:layout_width="match_parent"
android:layout_height="60dp"
android:gravity="center_vertical"
android:onClick="onClick"
android:text="I am a dynamic text" />
This button should be saved permanently in the app. How can I do this?
Update
I am using a dialog, so this is the class:
#SuppressLint("ValidFragment")
public class Dialog extends DialogFragment {
private final int _layout;
private TextInputEditText _customTextField;
#SuppressLint("ValidFragment")
public Dialog(int layout) {
_layout = layout;
}
public interface ICustomTts {
void customTts(String input, Activity activity);
}
public ICustomTts iCustomTts;
public interface ITarget {
void getTarget(String input);
}
public ITarget iTarget;
#RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(_layout, container, false);
// Display fragment_custom
if (_layout == R.layout.fragment_custom) {
_customTextField = view.findViewById(R.id.customTextField);
Button _customBtn = view.findViewById(R.id.customCta);
_customBtn.setOnClickListener(new View.OnClickListener() {
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
public void onClick(View view) {
Log.d(TAG, "onClick: Clicked on CTA of custom");
String input = _customTextField.getText().toString();
if (!input.equals("")) {
iCustomTts.customTts(input, getActivity());
_dismiss();
}
}
});
MaterialCheckBox customeSave = view.findViewById(R.id.customSave);
customeSave.setOnClickListener(new View.OnClickListener() {
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
public void onClick(View v) {
Log.d(TAG, "customeSave was clicked!");
LinearLayout root = view.findViewById(R.id.root);
Button button = new Button(getContext());
float heightInPixel = 60 * getResources().getDisplayMetrics().density;
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, (int) heightInPixel);
params.gravity = Gravity.CENTER;
button.setText("I am a dynamic text");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do the stuff on the click
}
});
root.addView(button, 0);
}
});
}
// Display fragment_target
if (_layout == R.layout.fragment_target) {
_customTextField = view.findViewById(R.id.targetTextField);
Button _customBtn = view.findViewById(R.id.targetCta);
_customBtn.setOnClickListener(new View.OnClickListener() {
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
public void onClick(View view) {
Log.d(TAG, "onClick: Clicked on CTA of target");
String input = _customTextField.getText().toString();
if (!input.equals("")) {
iTarget.getTarget(input);
_dismiss();
}
}
});
}
return view;
}
/**
* Dismissing the dialog
*/
private void _dismiss() {
this.dismiss();
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
try {
if (_layout == R.layout.fragment_custom) {
iCustomTts = (ICustomTts) getActivity();
}
else if (_layout == R.layout.fragment_target) {
iTarget = (ITarget) getActivity();
}
}
catch (ClassCastException e) {
Log.e(TAG, "onAttach: ClassCastException: " + e.getMessage());
}
}
}

You need to use the two-argument version of addView() to determine the order (index) of the button inside the LinearLayout:
LinearLayout root = view.findViewById(R.id.root);
Button button = new Button(requireContext());
float heightInPixel = 60 * getResources().getDisplayMetrics().density;
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, (int) heightInPixel);
params.gravity = Gravity.CENTER;
button.setText("I am a dynamic text");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Do the stuff on the click
}
});
root.addView(button, 0);

Method tabLayout.setupWithViewPager(viewPager) causes app crashes

Recently I changed from andoroid to androidx. After that, my app crash after successfully sign in. The following quotes are the errors:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.material.tabs.TabLayout.setupWithViewPager(androidx.viewpager.widget.ViewPager)' on a null object reference
After a lot of research, some suggest that use finishUpdate method but my app still crashes.
#Override public void finishUpdate(ViewGroup container) {
try{
super.finishUpdate(container);
}
catch (NullPointerException nullPointerException){
System.out.println("Catch the NullPointerException in MainActivityFragmentsAdapter.finishUpdate");
}
}
I also have tried to replace code tabLayout.setupWithViewPager(viewPager); to codes below but same error
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
//tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(viewPager));
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
The codes below are my MainActivity class
public class MainActivity extends BaseActivity {
MainActivityFragmentsAdapter mainActivityFragmentsAdapter;
ViewPager viewPager;
String SAVE_INSTANCE_STATE_KEY = "MainActivityFragmentConfig";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainActivityFragmentsAdapter = new MainActivityFragmentsAdapter(getSupportFragmentManager());
viewPager = findViewById(R.id.main_view_pager);
viewPager.setAdapter(mainActivityFragmentsAdapter);
if(savedInstanceState != null ) {
position = savedInstanceState.getInt(SAVE_INSTANCE_STATE_KEY);
viewPager.setCurrentItem(position);
}
final TabLayout tabLayout = findViewById(R.id.main_tab_layout);
tabLayout.setupWithViewPager(viewPager); // This is the ERROR LINE
viewPager.setOffscreenPageLimit(4);
setTabIcons(tabLayout);
ActivityCompat.requestPermissions(MainActivity.this, new String[]
{android.Manifest.permission.ACCESS_FINE_LOCATION, android.Manifest.permission.ACCESS_COARSE_LOCATION}, 100);
}
#Override
public void onRestoreInstanceState(Bundle savedInstanceState, PersistableBundle persistentState) {
super.onRestoreInstanceState(savedInstanceState, persistentState);
if(savedInstanceState != null ) {
int position = savedInstanceState.getInt(SAVE_INSTANCE_STATE_KEY);
viewPager.setCurrentItem(position);
}
}
#Override
public void onStart() {
super.onStart();
}
int position;
#Override
protected void onPause() {
super.onPause();
position = viewPager.getCurrentItem();
}
#Override
protected void onResume() {
super.onResume();
viewPager.setCurrentItem(position);
}
public void setTabIcons(TabLayout tabLayout) {
int icons[]= {
R.drawable.ic_calendar,
R.drawable.ic_task_complete,
R.drawable.ic_alarm_clock,
R.drawable.ic_man_user
};
for(int i = 0; i < icons.length; i++) {
tabLayout.getTabAt(i).setIcon(icons[i]);
}
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Log.d("MAIN ACTIVITY", "Saving instance state");
outState.putInt(SAVE_INSTANCE_STATE_KEY, viewPager.getCurrentItem());
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.fyp.selfzenapp.MainActivity">
<androidx.viewpager.widget.ViewPager
android:id="#+id/main_view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="60dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<include
android:id="#+id/main_tab_layout_include"
layout="#layout/main_tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

How Do I Remove Selected Item From ArrayList and ArrayAdapter On Button Click?

I have ListView with a custom list layout. I am using an ArrayList and ArrayAdapter for this. I am having a difficult time removing selected items from the arraylist. I am not sure want I am doing wrong. Here's an example of a arraylist that I have:
Item A
Item B
Item C
Item D
Let's say that I selected Item C next on button clicked labeled "Remove" I want Item C removed from the list. How do I accomplish this? Currently my code only removes the item on index 0. I want selected item index to be removed.
Here's my codes...
Java Class:
public class MainActivity extends AppCompatActivity {
ListView lstVw;
Button addBtn, removeBtn, clearListBtn;
ArrayList<String> arrayList;
ArrayAdapter<String> adapter;
int getPosition = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lstVw = findViewById(R.id.lstView);
addBtn = findViewById(R.id.add_item_btn);
removeBtn = findViewById(R.id.remove_item_btn);
clearListBtn = findViewById(R.id.clear_list_btn);
arrayList = new ArrayList<>();
adapter = new ArrayAdapter<>(getApplicationContext(), R.layout.item_list, R.id.item_tv, arrayList);
lstVw.setAdapter(adapter);
lstVw.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String getItem = adapter.getItem(position);
getPosition = Integer.parseInt(getItem);
}
});
addBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
adb.setTitle("Enter Item Name");
final EditText itemTxt = new EditText(MainActivity.this);
itemTxt.setText(getString(R.string.default_item_name_value));
itemTxt.setInputType(InputType.TYPE_CLASS_TEXT);
adb.setView(itemTxt);
adb.setPositiveButton("Add", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
String getItem = itemTxt.getText().toString();
Set<String> s = new LinkedHashSet<>(arrayList);
if (s.contains(getItem)) {
arrayList.clear();
arrayList.addAll(s);
Toast.makeText(getApplicationContext(), getItem + " already exists in the list!", Toast.LENGTH_LONG).show();
} else {
arrayList.add(getItem);
adapter.notifyDataSetChanged();
}
}
});
adb.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
}
});
adb.create();
adb.show();
}
});
clearListBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (!arrayList.isEmpty()) {
arrayList.clear();
adapter.notifyDataSetChanged();
}
}
});
removeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String getItem = arrayList.get(getPosition);
arrayList.remove(getItem);
adapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(), getItem + " is removed!", Toast.LENGTH_LONG).show();
}
});
}
}
Main XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/rl"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ScrollView
android:layout_width="match_parent"
android:layout_height="650dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="650dp">
<ListView
android:id="#+id/lstView"
android:layout_width="match_parent"
android:layout_height="650dp"
tools:ignore="NestedScrolling" />
</RelativeLayout>
</ScrollView>
<include layout="#layout/action_buttons"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"/>
Action Buttons XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_gravity="center|top">
<Button
android:id="#+id/add_item_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:textAllCaps="false"
android:text="#string/add_item_text"
android:textSize="14sp"
android:textStyle="bold"
android:textColor="#android:color/black"/>
<Button
android:id="#+id/remove_item_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_toEndOf="#id/add_item_btn"
android:textAllCaps="false"
android:text="Remove Item"
android:textColor="#android:color/black"
android:textSize="14sp"
android:textStyle="bold"/>
<Button
android:id="#+id/clear_list_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_toEndOf="#id/remove_item_btn"
android:textAllCaps="false"
android:text="#string/clear_list_text"
android:textSize="14sp"
android:textStyle="bold"
android:textColor="#android:color/black"/>
My Custom List Layout XML:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/item_tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textStyle="bold"
android:textSize="20sp"
android:textColor="#android:color/black"/>
</ScrollView>
I appreciate the help! Thanks!

removeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String getItem = arrayList.get(getPosition);
arrayList.remove(getItem);
adapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(), getItem + " is removed!", Toast.LENGTH_LONG).show();
}
});
From where are you getting this getPosition?

It looks to me like your int getPosition = 0; variable is not getting updated with your new position. On your click listener you are trying to parse the value of your selected item to an Integer, maybe you could try simply updating with the current position instead?
lstVw.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
getPosition = position;
}
});
Edit:
You could go with something like this:
Create an interface that your activity will implement and will be used by your adapter to notify a position change:
public interface PositionChangeListener {
void onPositionChanged(int newPosition);
}
Create a custom adapter:
public class CustomAdapterView extends BaseAdapter {
private Context context;
private PositionChangeListener listener;
private ArrayList<String> items;
public CustomAdapterView(Context context, ArrayList<String> items, PositionChangeListener listener) {
this.context = context;
this.items = items;
this.listener = listener;
}
#Override
public int getCount() {
return items.size();
}
#Override
public Object getItem(int position) {
return items.get(position);
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder = null;
if (convertView == null) {
convertView = LayoutInflater.from(context).inflate( R.layout.item_list, null);
viewHolder = new ViewHolder();
viewHolder.txt = convertView.findViewById(R.id.item_tv);
viewHolder.txt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
listener.onPositionChanged(position);
}
});
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.txt.setText(items.get(position));
return convertView;
}
private class ViewHolder {
TextView txt;
}
}
And now in your activity:
public class MainActivity extends AppCompatActivity implements PositionChangeListener{
ListView lstVw;
Button addBtn, removeBtn, clearListBtn;
ArrayList<String> arrayList;
BaseAdapter adapter;
int getPosition = 0;
#Override
public void onPositionChanged(int newPosition) {
getPosition = newPosition;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lstVw = findViewById(R.id.lstView);
addBtn = findViewById(R.id.add_item_btn);
removeBtn = findViewById(R.id.remove_item_btn);
clearListBtn = findViewById(R.id.clear_list_btn);
arrayList = new ArrayList<>();
adapter = new CustomAdapterView(this, arrayList, this);
lstVw.setAdapter(adapter);
addBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
adb.setTitle("Enter Item Name");
final EditText itemTxt = new EditText(MainActivity.this);
itemTxt.setText("default item name");
itemTxt.setInputType(InputType.TYPE_CLASS_TEXT);
adb.setView(itemTxt);
adb.setPositiveButton("Add", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
String getItem = itemTxt.getText().toString();
Set<String> s = new LinkedHashSet<>(arrayList);
if (s.contains(getItem)) {
arrayList.clear();
arrayList.addAll(s);
Toast.makeText(getApplicationContext(), getItem + " already exists in the list!", Toast.LENGTH_LONG).show();
} else {
arrayList.add(getItem);
adapter.notifyDataSetChanged();
}
}
});
adb.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
}
});
adb.create();
adb.show();
}
});
clearListBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (!arrayList.isEmpty()) {
arrayList.clear();
adapter.notifyDataSetChanged();
}
}
});
removeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String getItem = arrayList.get(getPosition);
arrayList.remove(getItem);
adapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(), getItem + " is removed!", Toast.LENGTH_LONG).show();
}
});
}
}

Android piechart in custom fragment

I want to display pie-chart in a fragment dialog box..
This is the code:--
MainActivity.java
public class MainActivity extends Activity implements
MyDialogFragment.Communicator {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#SuppressLint("NewApi")
public void showDialog(View view) {
FragmentManager manager = getFragmentManager();
MyDialogFragment1 mydialog = new MyDialogFragment1();
mydialog.show(manager, "mydialog");
}
#Override
public void message(String data) {
Toast.makeText(getApplicationContext(), data + " button clicked",
Toast.LENGTH_SHORT).show();
}
}
and the MyDialogFragment1.java
#SuppressLint({ "NewApi", "InflateParams" })
public class MyDialogFragment1 extends DialogFragment implements OnClickListener {
Button no_button;
Context context;
private static int[] COLORS = new int[] { Color.MAGENTA, Color.CYAN };
private static String[] NAME_LIST = new String[] { "A", "B" };
private CategorySeries mSeries = new CategorySeries("");
private DefaultRenderer mRenderer = new DefaultRenderer();
private GraphicalView mChartView;
private int[] VALUES = { 40, 60 };
Communicator communicator;
#SuppressLint("NewApi")
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (activity instanceof Communicator) {
communicator = (Communicator) getActivity();
} else {
throw new ClassCastException(activity.toString()
+ " must implemenet MyListFragment.communicator");
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setCancelable(false);
getDialog().setTitle("Title");
// View view = inflater.inflate(R.layout.main, null, false);
View view = (LinearLayout) inflater.inflate(R.layout.main,container, false);
mRenderer.setApplyBackgroundColor(true);
mRenderer.setBackgroundColor(Color.argb(100, 50, 50, 50));
mRenderer.setChartTitleTextSize(20);
mRenderer.setLabelsTextSize(15);
mRenderer.setLegendTextSize(15);
mRenderer.setMargins(new int[] { 20, 30, 15, 0 });
mRenderer.setZoomButtonsVisible(true);
mRenderer.setStartAngle(90);
for (int i = 0; i < VALUES.length; i++) {
//mSeries.add(NAME_LIST[i] + " " + VALUES[i], VALUES[i]);
mSeries.add(NAME_LIST[i] + "(" + VALUES[i]+"%)", VALUES[i]);
SimpleSeriesRenderer renderer = new SimpleSeriesRenderer();
renderer.setColor(COLORS[(mSeries.getItemCount() - 1) % COLORS.length]);
mRenderer.addSeriesRenderer(renderer);
}
if (mChartView != null) {
mChartView.repaint();
}
//yes_button = (Button) view.findViewById(R.id.yesbtn);
no_button = (Button) view.findViewById(R.id.nobtn);
// setting onclick listener for buttons
// yes_button.setOnClickListener(this);
no_button.setOnClickListener(this);
return view;
}
#SuppressLint("ShowToast")
#Override
public void onResume() {
super.onResume();
if (mChartView == null) {
LinearLayout layout = (LinearLayout) findViewById(R.id.chart);
mChartView = ChartFactory.getPieChartView(context, mSeries, mRenderer ) ;
mRenderer.setClickEnabled(true);
mRenderer.setSelectableBuffer(10);
mChartView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SeriesSelection seriesSelection = mChartView.getCurrentSeriesAndPoint();
}
});
mChartView.setOnLongClickListener(new View.OnLongClickListener() {
#SuppressLint("ShowToast")
#Override
public boolean onLongClick(View v) {
SeriesSelection seriesSelection = mChartView.getCurrentSeriesAndPoint();
return false;
}
});
layout.addView(mChartView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
}
else {
mChartView.repaint();
}
}
private LinearLayout findViewById(int chart) {
// TODO Auto-generated method stub
return null;
}
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.nobtn :
dismiss();
communicator.message("Dialog No btn clicked");
break;
}
}
public interface Communicator {
public void message(String data);
}
}
and the xml files are:--
activity_main.xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp" >
<Button
android:id="#+id/button1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="showDialog"
android:text="Show Dialog" />
</LinearLayout>
and main.xml is :--
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/chart"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal" >
</LinearLayout>
<Button
android:id="#+id/nobtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/yesbtn"
android:layout_alignBottom="#+id/yesbtn"
android:layout_alignRight="#+id/textView1"
android:layout_marginRight="38dp"
android:text="No" />
</LinearLayout>
Now, When I run this program it shows the button,when I click the button it stops...
and showing the following error:--
FATAL EXCEPTION: main
Process: com.emple.dialog_android_example, PID: 21181
java.lang.ClassCastException: com.emple.dialog_android_example.MainActivity#41ef95b0 must implemenet MyListFragment.communicator
at com.emple.dialog_android_example.MyDialogFragment1.onAttach(MyDialogFragment1.java:64)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:849)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
at android.app.BackStackRecord.run(BackStackRecord.java:698)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5324)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
where is the problem????

I think your activity is not a instance of Communicator
Check here :
#SuppressLint("NewApi")
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (activity instanceof Communicator) {
communicator = (Communicator) getActivity();
} else {
throw new ClassCastException(activity.toString()
+ " must implemenet MyListFragment.communicator");
}
}

how to call a function that's in a custom View from an activity

Using the button in MainActivity how can i call sprite.move("left") (which will move the sprite left twice a second) that has to be run in GView?
MainActivity.java
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.button);
button.setOnTouchListener(new View.OnTouchListener() {
private Handler mHandler;
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (mHandler != null)
return true;
mHandler = new Handler();
mHandler.postDelayed(mAction, 0);
break;
case MotionEvent.ACTION_UP:
if (mHandler == null)
return true;
mHandler.removeCallbacks(mAction);
mHandler = null;
break;
}
return false;
}
Runnable mAction = new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(), "Performing action...", Toast.LENGTH_LONG).show();
mHandler.postDelayed(this, 500);
}
};
});
}
}
main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${packageName}.${activityClass}" >
<com.viracide.depth.GView
android:id="#+id/gview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginBottom="180dp"
android:layout_marginLeft="40dp"
android:layout_marginTop="40dp"
android:layout_marginRight="40dp">
</com.viracide.depth.GView>
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/gview"
android:layout_alignParentBottom="true"
android:layout_marginBottom="73dp"
android:text="Button" />
</RelativeLayout>
GView.java
public class GView extends View {
private Bitmap bmp;
sprite sprite; //sprite image
public GView(Context context) {
super(context);
bmp = BitmapFactory.decodeResource(getResources(), R.drawable.bit);
}
public void draw(Canvas canvas) {
canvas.drawColor(Color.WHITE);
canvas.drawBitmap(bmp, 10 , 10, null);
}
}

public class MainActivity extends Activity {
GView mGView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
// initialize here
mGView = (GView)findViewById(R.id.gview);
// put this anywhere and make sure you do not violate UI thread constraint for making any UI changes
mGview.<yourmethod>()
...