我正在处理两个片段，一个称为图，另一个称为函数。 在图形中，用户可以使用节点和边来绘制图形。 在“功能”中，用户可以选择算法或图论功能。
当我在Fragment函数中时，我试图从Fragment Graph中获取数据，但这返回了null错误，并且“ Fragment未连接到上下文” 已经尝试使用bundle和interface。
创建边缘，我能够在界面中使用捆绑包，并将数据传递给对话框，用户可以在其中选择节点并创建边缘。
这是我的标签页：
public class Tab extends AppCompatActivity implements FragmentGrafo.TexteData {
private Toolbar toolbar;
private boolean orientado;
private TabLayout tabLayout;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tab);
Bundle bundle = this.getIntent().getExtras();
if (bundle != null){
orientado = Objects.requireNonNull(getIntent().getExtras()).getBoolean("orientado");
}
toolbar = findViewById(R.id.toolbar_tab);
tabLayout = findViewById(R.id.tabLayout);
viewPager = findViewById(R.id.viewPager);
if (orientado){
this.toolbar.setTitle(getString(R.string.txt_toolbar_tab_orientado));
} else {
toolbar.setTitle(R.string.txt_toolbar_tab_nao_orientado);
}
setSupportActionBar(toolbar);
Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
if (orientado) {
adapter.AddFragment(new FragmentGrafoOrientado(), getString(R.string.txt_tab_grafo));
adapter.AddFragment(new FragmentFuncoes(), getString(R.string.txt_tab_funcoes));
} else {
adapter.AddFragment(new FragmentGrafo(), getString(R.string.txt_tab_grafo));
adapter.AddFragment(new FragmentFuncoes(), getString(R.string.txt_tab_funcoes));
}
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home){
finish();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void Data(String s) {
FragmentFuncoes f = new FragmentFuncoes();
Bundle b = new Bundle();
b.putString("key", s);
f.setArguments(b);
}
}
这是我的FragmentGrafo：
public class FragmentGrafo extends Fragment implements DialogAddAresta.HelperAddAresta, DialogDeletar.HelperDeletar {
private TexteData mListener;
private BottomNavigationView bottomNavigationView;
private Graph graph;
private DefaultFragment fragment;
private String[] alfabeto = new String[]{"A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V","X","W","Y","Z"};
private int alfaPos = 0;
private float x = 0.0f, y = 0.0f;
private List<String> listNos = new ArrayList<>();
private List<String> listArestas = new ArrayList<>();
private String styleSheet = "graph { fill-color: #CDCDCD; }" +
"node { size: 100px; text-size: 30px; fill-color: white; stroke-mode: plain; }" +
"node:clicked { fill-color: #007FFF; }" ;
public FragmentGrafo() {}
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.activity_fragment_grafo, container, false);
bottomNavigationView = view.findViewById(R.id.bottomNavView);
bottomNavigationView.setOnNavigationItemSelectedListener(selectedListener);
return view;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
graph = new SingleGraph("AthenaGraph");
graph.setAttribute("ui.stylesheet", styleSheet);
graph.setAttribute("ui.antialias");
display(savedInstanceState, graph, false);
}
private BottomNavigationView.OnNavigationItemSelectedListener selectedListener
= menuItem -> {
switch (menuItem.getItemId()){
case R.id.add_no:
addNo();
return true;
case R.id.add_aresta:
openDialogAddAresta();
return true;
case R.id.deletar:
openDialogDeletar();
return true;
}
return false;
};
public void display(Bundle savedInstanceState, Graph graph, boolean autoLayout) {
if (savedInstanceState == null) {
FragmentManager fm = Objects.requireNonNull(getActivity()).getFragmentManager();
fragment = (DefaultFragment) fm.findFragmentByTag("fragment_tag");
if (null == fragment) {
fragment = new DefaultFragment();
fragment.init(graph, autoLayout);
}
FragmentTransaction ft = fm.beginTransaction() ;
ft.add(R.id.frameLayout, fragment).commit();
}
}
public void addNo(){
if (alfaPos < alfabeto.length){
String aux = alfabeto[alfaPos];
graph.addNode(aux);
graph.getNode(aux).setAttribute("ui.label", aux);
graph.getNode(aux).setAttribute("xyz", x, y, 0);
listNos.add(aux);
alfaPos++;
x += 0.5f;
y += 0.5f;
} else {
Toast.makeText(getActivity(), getResources().getString(R.string.txt_no_maximo), Toast.LENGTH_SHORT).show();
}
}
private void openDialogAddAresta() {
DialogAddAresta dialogAddAresta = new DialogAddAresta();
Bundle bundle = new Bundle();
bundle.putStringArrayList("listNos", (ArrayList<String>) listNos);
dialogAddAresta.setTargetFragment(FragmentGrafo.this, 1);
dialogAddAresta.setArguments(bundle);
dialogAddAresta.show(Objects.requireNonNull(getActivity()).getSupportFragmentManager(), getString(R.string.txt_add_aresta));
}
@Override
public void applyAddAresta(String noFrom, String noTo, String peso) {
String nomeAresta = noFrom + noTo;
String nomeArestaInvertido = noTo + noFrom;
int tam = graph.getEdgeCount(), count = 0;
// Se tam for == 0 nao tem aresta entao cria uma direto.
if (tam == 0){
if (peso.equals("")) {
peso = "1";
graph.addEdge(nomeAresta, noFrom, noTo, false)
.setAttribute("length", peso);
listArestas.add(nomeAresta);
} else {
graph.addEdge(nomeAresta, noFrom, noTo, false)
.setAttribute("length", peso);
graph.getEdge(nomeAresta).setAttribute("ui.label", peso);
listArestas.add(nomeAresta);
}
}
if (tam != 0){
for (int i = 0; i < tam; i++){
String compara = graph.getEdge(i).getId();
if (compara.equals(nomeAresta) || compara.equals(nomeArestaInvertido)){
count = 1;
}
}
}
if (count == 1){
Toast.makeText(getActivity(), R.string.txt_aresta_existente, Toast.LENGTH_SHORT).show();
} else if (tam >= 1){
if (peso.equals("")) {
peso = "1";
graph.addEdge(nomeAresta, noFrom, noTo, false)
.setAttribute("length", peso);
listArestas.add(nomeAresta);
} else {
graph.addEdge(nomeAresta, noFrom, noTo, false)
.setAttribute("length", peso);
graph.getEdge(nomeAresta).setAttribute("ui.label", peso);
listArestas.add(nomeAresta);
}
}
}
private void openDialogDeletar(){
DialogDeletar dialogDeletar = new DialogDeletar();
Bundle bundle = new Bundle();
bundle.putStringArrayList("listNos", (ArrayList<String>) listNos);
bundle.putStringArrayList("listArestas", (ArrayList<String>) listArestas);
dialogDeletar.setTargetFragment(FragmentGrafo.this, 1);
dialogDeletar.setArguments(bundle);
dialogDeletar.show(Objects.requireNonNull(getActivity()).getSupportFragmentManager(), getString(R.string.txt_deletar));
}
@Override
public void applyDeletar(String deletaNo, String deletaAresta, boolean controle) {
if (controle){
graph.removeNode(deletaNo);
listNos.remove(deletaNo);
atualizaListas(deletaNo);
} else {
graph.removeNode(deletaAresta);
listArestas.remove(deletaAresta);
}
}
private void atualizaListas(String item){
int tam = graph.getEdgeCount();
listArestas.clear();
for (int i = 0; i < tam; i++){
listArestas.add(graph.getEdge(i).getId());
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof TexteData) {
mListener = (TexteData) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
//this was just a test to see if the Toast works
public void vamos(){
Toast.makeText(getActivity(), getResources().getString(R.string.txt_no_maximo), Toast.LENGTH_SHORT).show();
}
public interface TexteData{
void Data(String s);
}
}
这是我的FragmentFuncoes：
public class FragmentFuncoes extends Fragment {
private Spinner spinner;
private ImageButton btnRun, btnExecurar;
private TextView tvResp;
private String item;
private boolean run = true;
public FragmentFuncoes() {}
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.activity_fragment_funcoes, container, false);
spinner = view.findViewById(R.id.spFuncoes);
btnRun = view.findViewById(R.id.btnRun);
btnExecurar = view.findViewById(R.id.btnExecutar);
tvResp = view.findViewById(R.id.tvLinha2);
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(Objects.requireNonNull(getContext()),
android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.funcoes));
arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(arrayAdapter);
spinner.setOnItemSelectedListener(spinnerSelected);
btnRun.setOnClickListener(btnRunClicked);
btnExecurar.setOnClickListener(btnExecutarClicked);
return view;
}
private Spinner.OnItemSelectedListener spinnerSelected =
new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
item = spinner.getSelectedItem().toString();
switch (item){
case "***":
tvResp.setText("Escolha um funcionalidade");
break;
case "Informações Gerais":
tvResp.setText("Execute para ver as informacoes do grafo.");
break;
case "Dijkstra":
Toast.makeText(getContext(),"teste selecionou Dijkstra",Toast.LENGTH_SHORT).show();
break;
case "Coloração":
Toast.makeText(getContext(),"teste selecionou Coloração",Toast.LENGTH_SHORT).show();
break;
}
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
};
private ImageButton.OnClickListener btnExecutarClicked =
v -> {
switch (item){
case "***":
Toast.makeText(getContext(),"teste selecionou *** - executar",Toast.LENGTH_SHORT).show();
break;
case "Informações Gerais":
getInformacoesGerais();
break;
case "Dijkstra":
Toast.makeText(getContext(),"teste selecionou Dijkstra - executar",Toast.LENGTH_SHORT).show();
break;
case "Coloração":
Toast.makeText(getContext(),"teste selecionou Coloração - executar",Toast.LENGTH_SHORT).show();
break;
}
};
private ImageButton.OnClickListener btnRunClicked =
v -> {
if (run){
btnRun.setImageResource(R.drawable.ic_slow_run);
Toast.makeText(getContext(), getResources().getString(R.string.btn_run_slow), Toast.LENGTH_SHORT).show();
run = false;
} else {
btnRun.setImageResource(R.drawable.ic_fast_run);
Toast.makeText(getContext(), getResources().getString(R.string.btn_run_fast), Toast.LENGTH_SHORT).show();
run = true;
}
};
private void getInformacoesGerais(){
FragmentGrafo fragmentGrafo = new FragmentGrafo();
fragmentGrafo.vamos();
}
}
我该在哪里弄错数据？
答案 0 :(得分：0)
我这样做是这样的：-
YourSecondFragment fragment = new YourSecondFragment ();
Bundle args = new Bundle();
args.putString("YourKey", "YourValue");
fragment .setArguments(args);
getFragmentManager().beginTransaction().add(R.id.container, fragment ).commit();
在YourSecondFragment的onCreateView中：
String value = getArguments().getString("YourKey");