我知道，这个问题被问过很多次，但在阅读了一些答案后我完全迷失了。我是 Android 开发的新手。我已经创建了一个 fragment 并从该 fragment 初始化并设置了适配器
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = ViewModelProviders.of(this).get(ConfigDataloggerViewModel.class);
dataLoggerList = getResources().getStringArray(R.array.DataLoggerStringArray);
// TODO: Use the ViewModel
//for (int j=0; j< dataLoggerList.length; j++){ DummyArrayList.add(dataLoggerList[j]);}
RecyclerView recyclerView = getView().findViewById(R.id.config_datalogger_recycle_view);
ConfigDataloggerAdapter configDataloggerAdapter = new ConfigDataloggerAdapter(dataLoggerList, getActivity());
recyclerView.setAdapter(configDataloggerAdapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
我的 fragment 中有 EditText 列表，我在适配器中设置这些 EditText，我还将 EditTexts 中的值保存到适配器本身定义的数组中。
public class ConfigDataloggerAdapter extends RecyclerView.Adapter<ConfigDataloggerAdapter.ViewHolder>{
//private ArrayList<RFIDReader> readers = new ArrayList<>();
private String [] mDummyList ;
// private ArrayList<String> mDummyArrayList = new ArrayList<>();
public String [] mDummyArrayList;
//public ArrayList<String> mConfigDataloggerData ;
public String[] mConfigDataloggerData;
// private ConfigDataloggerViewModel mConfigDataModel;
public Map<String, String> tempDataModel = new HashMap<>();
private Context mContext;
public ConfigDataloggerAdapter( String [] mDummyArrayList, Context mContext) {
this.mDummyArrayList = mDummyArrayList;
this.mContext = mContext;
mConfigDataloggerData = new String[mDummyArrayList.length];
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.config_datalogger_list,viewGroup,false);
ConfigDataloggerAdapter.ViewHolder holder = new ConfigDataloggerAdapter.ViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(@NonNull ConfigDataloggerAdapter.ViewHolder holder, int i) {
String [] mConfigDataloggerText = null;
// for (int j=0; j< mDummyList.length; j++){ mDummyArrayList.add(mDummyList[j]);}
//ReaderDevice readerDevice = mDummyArrayList.get(i);
String temp = mDummyArrayList[i];
holder.mConfigDataloggerListText.setText(temp);
// tempDataModel.put(temp,mConfigDataloggerData.get(i) );
// mConfigDataModel.setConfigDataloggerVMData(tempDataModel);
//holder.reader_checkedTextView.setText(readerDevice.getName() );
}
@Override
public int getItemCount() {
return mDummyArrayList.length;
}
public class ViewHolder extends RecyclerView.ViewHolder{
public TextView mConfigDataloggerListText;
public EditText mConfigDataloggarListEditText;
public LinearLayout configDataloggerLayout;
public ViewHolder(@NonNull View itemView) {
super(itemView);
mConfigDataloggerListText = itemView.findViewById(R.id.textView_config_datalogger);
mConfigDataloggarListEditText = itemView.findViewById(R.id.editText_config_datalogger);
mConfigDataloggarListEditText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
mConfigDataloggerData[getAdapterPosition()] =
mConfigDataloggarListEditText.getText().toString();
//here I am storing data from editText to the array
}
@Override
public void afterTextChanged(Editable s) {
}
});
configDataloggerLayout = itemView.findViewById(R.id.config_datalogger_list_layout);
}
}
}
我有两个问题，1) 如何从 fragment 中的适配器访问 mConfigDataloggerData？ 2)我在同一个 fragment 中有一个按钮。当我按下按钮时，其他 fragment 开始。现在，我想在按下按钮时将数据从 mConfigDataloggerData 保存到 ViewModel。那么我到底在哪里写 mViewModel = ViewModelProviders.of(this).get(xxxx.class); ？
供您引用，下面的代码是我的 fragment 所附加的 Activity 。
public class defaultActivity extends AppCompatActivity {
private String TAG = "default activity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.datalogger_activity);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ConfigDataloggerFragment configDataloggerFragment = new ConfigDataloggerFragment();
// getSupportFragmentManager().beginTransaction().add(R.id.default_datalogger_activity, datalogger).commit();
getSupportFragmentManager().beginTransaction().add(R.id.default_datalogger_activity, configDataloggerFragment).commit();
}
public void StartorStopInventory(View view) {
Button button = (Button) view;
if (application.mConnectedReader.isConnected()){
if (application.mIsInventoryRunning ){
application.mIsInventoryRunning = true;
button.setText("STOP");
try{
TriggerInfo triggerInfo = new TriggerInfo();
Log.d(TAG, "Start trigger setting when button is pressed" + triggerInfo.StartTrigger.getTriggerType());
Log.d(TAG, "Stop trigger setting when button is pressed" + triggerInfo.StartTrigger.getTriggerType());
application.mConnectedReader.Actions.Inventory.perform();
}catch (InvalidUsageException e){
Log.d(TAG, "StartorStopInventory: Inventory perform fail " + e);
} catch (final OperationFailureException op) {
op.printStackTrace();
Log.d(TAG, "StartorStopInventory: Operational failure " + op.getResults() + " " + op.getVendorMessage());
Toast.makeText(view.getContext(), op.getVendorMessage(), Toast.LENGTH_LONG);
}
}
}
}
public void start_data_logging_click(View view) {
Datalogger datalogger = new Datalogger();
// getSupportFragmentManager().beginTransaction().replace(R.id.default_datalogger_activity, datalogger);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.default_datalogger_activity, datalogger);
transaction.addToBackStack(null);
transaction.commit();
}
}
最佳答案
1) 在 Adapter 中为您的字段创建 getter，例如
public String[] getConfigDataloggerData(){
return mConfigDataloggerData;
}
...
全局声明适配器；
public class YourFragment {
ConfigDataloggerAdapter configDataloggerAdapter,
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = ViewModelProviders.of(this).get(ConfigDataloggerViewModel.class);
dataLoggerList = getResources().getStringArray(R.array.DataLoggerStringArray);
// TODO: Use the ViewModel
//for (int j=0; j< dataLoggerList.length; j++){ DummyArrayList.add(dataLoggerList[j]);}
RecyclerView recyclerView = getView().findViewById(R.id.config_datalogger_recycle_view);
configDataloggerAdapter = new ConfigDataloggerAdapter(dataLoggerList, getActivity());
recyclerView.setAdapter(configDataloggerAdapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
}
}
然后在您的 Fragment 中调用 configDataloggerAdapter.getConfigDataloggerData()，您将获得数据。其他领域同理
2)我还不明白那部分
关于android - 如何从 Fragment 访问 RecyclerView 中的数据？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54312361/