Java 实现接口的空类变量
我还没有发现类似的问题，所以我正在写一个新的。 我正在开发一个小的Android应用程序，我的界面有一些问题。该应用程序由3个片段和一个Java 实现接口的空类变量,java,android,android-fragments,android-alertdialog,Java,Android,Android Fragments,Android Alertdialog,我还没有发现类似的问题，所以我正在写一个新的。 我正在开发一个小的Android应用程序，我的界面有一些问题。该应用程序由3个片段和一个ViewPager组成。单击一个按钮，我将显示一个自定义对话框（扩展了AlertDialog.Builder类）。为了从目标片段检索数据，我在片段中实现了一个接口 一切似乎都正常，但当我试图访问重写方法中的片段类变量时，它们是空的！类变量在onCreateViewfragment方法中初始化。 谢谢 这有点混乱，因为我在尝试一些东西： public class
ViewPagerAlertDialog.BuilderonCreateViewpublic class EditBandDialog extends AlertDialog.Builder {
private final Band band;
private Spinner listColor;
private EditText inputName;
private DatabaseHelper dbHelper;
private BandDialogInterface bandDialogInterface;
public EditBandDialog(Context context, final Band band){
super(context);
this.band = band;
try{
bandDialogInterface = ((MercenAppActivity)context).getBandsFragment();
Log.d("CONTEXT", ((MercenAppActivity)context).getBandsFragment().toString());
}catch (Exception e){
e.printStackTrace();
}
View dialogView = ((Activity)context).getLayoutInflater().inflate(R.layout.dialog_edit_band, null);
setView(dialogView);
setCancelable(false);
dbHelper = new DatabaseHelper(context);
listColor = (Spinner)dialogView.findViewById(R.id.dialog_edit_band_color);
inputName = (EditText)dialogView.findViewById(R.id.dialog_edit_band_name);
BandColorAdapter adapter = new BandColorAdapter(context);
listColor.setAdapter(adapter);
if(isNewBand()) {
setTitle(R.string.title_new_band);
setPositiveButton("Crea", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//bandAdapter.insert(new Band(-1, inputName.getText().toString(), ((MyColor) listColor.getSelectedItem())));
//Toast.makeText(getContext(), R.string.toast_band_added, Toast.LENGTH_SHORT).show();
bandDialogInterface.onActionCreate(dialog, inputName.getText().toString(), (MyColor)listColor.getSelectedItem());
}
});
}else{
setTitle(R.string.title_edit_band);
inputName.setText(band.getName());
int pos = 0;
while(((MyColor)listColor.getAdapter().getItem(pos)).getColor() != band.getColor())
pos++;
listColor.setSelection(pos);
setPositiveButton("Modifica", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//dbHelper.updateBand(dbHelper.getWritableDatabase(), band.getId(), inputName.getText().toString(), ((MyColor) listColor.getSelectedItem()).getColor());
//bandAdapter.update(new Band(band.getId(), inputName.getText().toString(), ((MyColor) listColor.getSelectedItem())));
//Toast.makeText(getContext(), R.string.toast_band_edited, Toast.LENGTH_SHORT).show();
bandDialogInterface.onActionEdit(dialog, band.getId(), inputName.getText().toString(), (MyColor)listColor.getSelectedItem());
}
});
}
setNegativeButton("Annulla", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
}
private boolean isNewBand(){
return band == null;
}
}
class MyColor{
int color;
public MyColor(int color){
this.color = color;
}
public static MyColor fromString(String s){
return new MyColor(Color.parseColor(s));
}
public int getColor(){
return color;
}
}
class BandColorAdapter extends ArrayAdapter<MyColor> implements SpinnerAdapter {
private static final MyColor[] colors = {MyColor.fromString("#D60000"), //ROSSO
MyColor.fromString("#0080FF"), //AZZURRO
MyColor.fromString("#00AD37"), //VERDE
MyColor.fromString("#FFF700"), //GIALLO
MyColor.fromString("#FF8400"), //ARANCIO
MyColor.fromString("#10009C")}; //BLU
public BandColorAdapter(Context context) {
super(context, R.layout.row_band_color, colors);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_band_color, parent, false);
}
View bandColor = convertView.findViewById(R.id.band_color_item);
bandColor.setBackgroundColor(getItem(position).getColor());
return convertView;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
{
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_band_color, parent, false);
}
View bandColor = convertView.findViewById(R.id.band_color_item);
bandColor.setBackgroundColor(getItem(position).getColor());
return convertView;
}
}
public class BandsFragment extends Fragment implements BandDialogInterface{
private static final String TAG = "BandsFragment";
private static final boolean D = true;
private DatabaseHelper dbHelper;
private BandAdapter bandAdapter;
private String s;
public BandsFragment(){
}
@Override
public void onActionCreate(DialogInterface dialog, String name, MyColor color) {
//Toast.makeText(getActivity(), "CREATE", Toast.LENGTH_SHORT).show();
//bandAdapter.insert(new Band(0, name, color));
Log.d("CREATE", s);
}
@Override
public void onActionEdit(DialogInterface dialog, int id, String name, MyColor color) {
Toast.makeText(getActivity(), "EDITED", Toast.LENGTH_SHORT).show();
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static BandsFragment newInstance() {
BandsFragment fragment = new BandsFragment();
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_bands, container, false);
if (D) Log.d(TAG, "--- onCreateView ---");
dbHelper = new DatabaseHelper(getActivity());
ListView listBands = (ListView)rootView.findViewById(R.id.list_bands);
TextView noBands = (TextView)rootView.findViewById(R.id.no_bands);
bandAdapter = new BandAdapter(getActivity(), noBands);
listBands.setAdapter(bandAdapter);
// if(dbList.size() == 0){
// noBands.setVisibility(View.VISIBLE);
// }else{
// noBands.setVisibility(View.GONE);
// }
listBands.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//TODO something
}
});
registerForContextMenu(listBands);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (D) Log.d(TAG, "--- onAttach ---");
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (D) Log.d(TAG, "--- onCreate ---");
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (D) Log.d(TAG, "--- onViewCreated ---");
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (D) Log.d(TAG, "--- onActivityCreated ---");
}
@Override
public void onStart() {
super.onStart();
if (D) Log.d(TAG, "--- onStart ---");
}
@Override
public void onResume() {
super.onResume();
if (D) Log.d(TAG, "--- onResume ---");
}
@Override
public void onPause() {
super.onPause();
if (D) Log.d(TAG, "--- onPause ---");
}
@Override
public void onStop() {
super.onStop();
if (D) Log.d(TAG, "--- onStop ---");
}
@Override
public void onDestroyView() {
super.onDestroyView();
if (D) Log.d(TAG, "--- onDestroyView ---");
}
@Override
public void onDestroy() {
super.onDestroy();
if (D) Log.d(TAG, "--- onDestroy ---");
}
@Override
public void onDetach() {
super.onDetach();
if (D) Log.d(TAG, "--- onDetach ---");
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)menuInfo;
menu.setHeaderTitle(bandAdapter.getItem(info.position).getName());
getActivity().getMenuInflater().inflate(R.menu.context_band, menu);
MenuItem.OnMenuItemClickListener l = new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
onContextItemSelected(item);
return true;
}
};
for(int i = 0; i < menu.size(); ++i){
menu.getItem(i).setOnMenuItemClickListener(l);
}
}
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
switch (item.getItemId()){
case R.id.context_band_edit:
new EditBandDialog(getActivity(), bandAdapter.getItem(info.position)).show();
//Log.d("D",bandAdapter.getItem(info.position).getName());
break;
case R.id.context_band_delete:
/*dbHelper.deleteBand(dbHelper.getWritableDatabase(), bandAdapter.getItem(info.position).getId());
bandAdapter.remove(bandAdapter.getItem(info.position));
bandAdapter.notifyDataSetChanged();*/
bandAdapter.delete(bandAdapter.getItem(info.position));
Toast.makeText(getActivity(), R.string.toast_band_deleted, Toast.LENGTH_SHORT).show();
break;
}
return true;
}
}
class BandAdapter extends ArrayAdapter<Band> implements SpinnerAdapter{
private DatabaseHelper dbHelper;
private TextView noBands;
public BandAdapter(Context context, TextView noBands) {
super(context, R.layout.row_band);
this.noBands = noBands;
dbHelper = new DatabaseHelper(context);
updateAdapter();
}
private void updateAdapter(){
clear();
addAll(dbHelper.getAllBands());
if(noBands != null) {
if (isEmpty()) {
noBands.setVisibility(View.VISIBLE);
} else {
noBands.setVisibility(View.GONE);
}
}
notifyDataSetChanged();
}
public void insert(Band band){
//dbHelper.insertBand(dbHelper.getWritableDatabase(), band.getName(), band.getColor());
Toast.makeText(getContext(), "ADDED", Toast.LENGTH_SHORT).show();
updateAdapter();
}
public void update(Band band){
dbHelper.updateBand(dbHelper.getWritableDatabase(), band.getId(), band.getName(), band.getColor());
updateAdapter();
}
public void delete(Band band){
dbHelper.deleteBand(dbHelper.getWritableDatabase(), band.getId());
updateAdapter();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
Band band = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_band, parent, false);
}
// Lookup view for data population
TextView bandName = (TextView) convertView.findViewById(R.id.band_name);
View bandColor = (View) convertView.findViewById(R.id.band_color);
bandColor.setBackgroundColor(band.getColor());
// Populate the data into the template view using the data object
bandName.setText(band.getName());
// Return the completed view to render on screen
return convertView;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
{
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_band, parent, false);
}
Band band = getItem(position);
TextView bandName = (TextView) convertView.findViewById(R.id.band_name);
View bandColor = (View) convertView.findViewById(R.id.band_color);
bandColor.setBackgroundColor(band.getColor());
// Populate the data into the template view using the data object
bandName.setText(band.getName());
return convertView;
}
}
公共类BandsFragment扩展片段实现BandDialogInterface{
私有静态最终字符串标记=“BandsFragment”；
私有静态最终布尔值D=true；
私有数据库助手dbHelper；
二等兵
public class BandsFragment extends Fragment implements BandDialogInterface{
private static final String TAG = "BandsFragment";
private static final boolean D = true;
private DatabaseHelper dbHelper;
private BandAdapter bandAdapter;
private String s;
public BandsFragment(){
}
@Override
public void onActionCreate(DialogInterface dialog, String name, MyColor color) {
//Toast.makeText(getActivity(), "CREATE", Toast.LENGTH_SHORT).show();
//bandAdapter.insert(new Band(0, name, color));
Log.d("CREATE", s);
}
@Override
public void onActionEdit(DialogInterface dialog, int id, String name, MyColor color) {
Toast.makeText(getActivity(), "EDITED", Toast.LENGTH_SHORT).show();
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static BandsFragment newInstance() {
BandsFragment fragment = new BandsFragment();
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_bands, container, false);
if (D) Log.d(TAG, "--- onCreateView ---");
dbHelper = new DatabaseHelper(getActivity());
ListView listBands = (ListView)rootView.findViewById(R.id.list_bands);
TextView noBands = (TextView)rootView.findViewById(R.id.no_bands);
bandAdapter = new BandAdapter(getActivity(), noBands);
listBands.setAdapter(bandAdapter);
// if(dbList.size() == 0){
// noBands.setVisibility(View.VISIBLE);
// }else{
// noBands.setVisibility(View.GONE);
// }
listBands.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//TODO something
}
});
registerForContextMenu(listBands);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (D) Log.d(TAG, "--- onAttach ---");
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (D) Log.d(TAG, "--- onCreate ---");
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (D) Log.d(TAG, "--- onViewCreated ---");
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (D) Log.d(TAG, "--- onActivityCreated ---");
}
@Override
public void onStart() {
super.onStart();
if (D) Log.d(TAG, "--- onStart ---");
}
@Override
public void onResume() {
super.onResume();
if (D) Log.d(TAG, "--- onResume ---");
}
@Override
public void onPause() {
super.onPause();
if (D) Log.d(TAG, "--- onPause ---");
}
@Override
public void onStop() {
super.onStop();
if (D) Log.d(TAG, "--- onStop ---");
}
@Override
public void onDestroyView() {
super.onDestroyView();
if (D) Log.d(TAG, "--- onDestroyView ---");
}
@Override
public void onDestroy() {
super.onDestroy();
if (D) Log.d(TAG, "--- onDestroy ---");
}
@Override
public void onDetach() {
super.onDetach();
if (D) Log.d(TAG, "--- onDetach ---");
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)menuInfo;
menu.setHeaderTitle(bandAdapter.getItem(info.position).getName());
getActivity().getMenuInflater().inflate(R.menu.context_band, menu);
MenuItem.OnMenuItemClickListener l = new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
onContextItemSelected(item);
return true;
}
};
for(int i = 0; i < menu.size(); ++i){
menu.getItem(i).setOnMenuItemClickListener(l);
}
}
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
switch (item.getItemId()){
case R.id.context_band_edit:
new EditBandDialog(getActivity(), bandAdapter.getItem(info.position)).show();
//Log.d("D",bandAdapter.getItem(info.position).getName());
break;
case R.id.context_band_delete:
/*dbHelper.deleteBand(dbHelper.getWritableDatabase(), bandAdapter.getItem(info.position).getId());
bandAdapter.remove(bandAdapter.getItem(info.position));
bandAdapter.notifyDataSetChanged();*/
bandAdapter.delete(bandAdapter.getItem(info.position));
Toast.makeText(getActivity(), R.string.toast_band_deleted, Toast.LENGTH_SHORT).show();
break;
}
return true;
}
}
class BandAdapter extends ArrayAdapter<Band> implements SpinnerAdapter{
private DatabaseHelper dbHelper;
private TextView noBands;
public BandAdapter(Context context, TextView noBands) {
super(context, R.layout.row_band);
this.noBands = noBands;
dbHelper = new DatabaseHelper(context);
updateAdapter();
}
private void updateAdapter(){
clear();
addAll(dbHelper.getAllBands());
if(noBands != null) {
if (isEmpty()) {
noBands.setVisibility(View.VISIBLE);
} else {
noBands.setVisibility(View.GONE);
}
}
notifyDataSetChanged();
}
public void insert(Band band){
//dbHelper.insertBand(dbHelper.getWritableDatabase(), band.getName(), band.getColor());
Toast.makeText(getContext(), "ADDED", Toast.LENGTH_SHORT).show();
updateAdapter();
}
public void update(Band band){
dbHelper.updateBand(dbHelper.getWritableDatabase(), band.getId(), band.getName(), band.getColor());
updateAdapter();
}
public void delete(Band band){
dbHelper.deleteBand(dbHelper.getWritableDatabase(), band.getId());
updateAdapter();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
Band band = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_band, parent, false);
}
// Lookup view for data population
TextView bandName = (TextView) convertView.findViewById(R.id.band_name);
View bandColor = (View) convertView.findViewById(R.id.band_color);
bandColor.setBackgroundColor(band.getColor());
// Populate the data into the template view using the data object
bandName.setText(band.getName());
// Return the completed view to render on screen
return convertView;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
{
convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_band, parent, false);
}
Band band = getItem(position);
TextView bandName = (TextView) convertView.findViewById(R.id.band_name);
View bandColor = (View) convertView.findViewById(R.id.band_color);
bandColor.setBackgroundColor(band.getColor());
// Populate the data into the template view using the data object
bandName.setText(band.getName());
return convertView;
}
}