如何恢复片段状态onTouchEvent

Question

我有一个片段（ItemFragment），带有一堆EditText，一个微调器和一个日期选择器。用户输入将保存在SQL数据库中。然后，用户输入使用RecyclerView显示在列表片段（ListFragment）中。当用户单击列表中的项目时，它将转到ItemFragment并恢复用户输入。我在ItemFragment中添加了onSaveInstanceState。我对Android很陌生，所以请耐心等待。那么如何在RecylerView的onTouchEvent中恢复ItemFragment状态呢？

ItemFragment.java （不确定这是否是正确的方法？）

@Override
public void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putString("title", title);
    outState.putString("quantity", quantity);
    outState.putString("unit", unit);
    outState.putString("date", date);
    outState.putString("note", Note);
}

ListFragment.java

mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
        @Override
        public boolean onInterceptTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
            View child = recyclerView.findChildViewUnder(motionEvent.getX(), motionEvent.getY());

            if (child != null && mGestureDetector.onTouchEvent(motionEvent)) {
                int position = recyclerView.getChildLayoutPosition(child);
                Item selectedItem = mItems.get(position);
                //How do I restore ItemFragment here???

            return true;
            }
            return false;
        }

已编辑添加了Item.java和ItemFragment.java的完整代码

Item.java

public class Item {
private Long id;
private String title;
private String quantity;
private String unit;
private String date;
private String Note;

    public String getNote() {
        return Note;
    }

    public void setNote(String Note) {
        this.Note = Note;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public String getUnit() {
        return unit;
    }

    public void setUnit(String unit) {
        this.unit = unit;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getQuantity() {
        return quantity;
    }

    public void setQuantity(String quantity) {
        this.quantity = quantity;
    }




    public static Item getItemfromCursor(Cursor cursor){
        Item item = new Item();
        item.setId(cursor.getLong(cursor.getColumnIndex(Constants.COLUMN_ID)));
        item.setTitle(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_TITLE)));
        item.setQuantity(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_QUANTITY)));
        item.setUnit(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_UNIT)));
        item.setNote(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_NOTE)));
        item.setDate(cursor.getString(cursor.getColumnIndex(Constants.COLUMN_DATE)));


        return item;
    }
}

ItemFragment.java

public class ItemFragment extends DialogFragment {


private View mRootView;
private Item currentItem = null;
private Toolbar mToolbar;
private String date;
private String Note;
private String title;
private String quantity;
private TextView dateText;
private TextView unitError;
private EditText itemEditText;
private EditText quantityEditText;
private EditText noteEditText;
private Spinner remSpinner;
private Spinner spinner;
private String unit;
private String reminder;
private int spinnerCount=0;
private int spinnerInitializedCount=0;
private int remSpinnerCount=0;
private int remSpinnerInitializedCount=0;


public ItemFragment() {

}

//create an instance of the fragment
public static ItemFragment newInstance(long id) {
    ItemFragment fragment = new ItemFragment();

    if (id > 0) {
        Bundle bundle = new Bundle();
        bundle.putLong("id", id);
        fragment.setArguments(bundle);
    }
    return fragment;
}

//get id of an item
public void getCurrentItem() {
    Bundle args = getArguments();
    if (args != null && args.containsKey("id")) {
        long id = args.getLong("id", 0);
        if (id > 0) {
            currentItem = ItemManager.newInstance(getActivity()).getItem(id);
        }
    }
}

//notify Activity that the fragment wants to place an item in the menu
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
    getCurrentItem();

}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    mRootView = inflater.inflate(R.layout.add_item, container, false);
    itemEditText=(EditText)mRootView.findViewById((R.id.add_item));
    quantityEditText=(EditText)mRootView.findViewById(R.id.amount);
    unitError = (TextView)mRootView.findViewById(R.id.unit_error);
    noteEditText = (EditText)mRootView.findViewById(R.id.add_notes);
    dateText = (TextView)mRootView.findViewById(R.id.date_selected);

    //unit spinner code here
    //reminder spinner here

    spinner.setOnItemSelectedListener(spinnerListener);
    remSpinner.setOnItemSelectedListener(spinnerListener);
    spinnerCount=1;
    remSpinnerCount=1;

    return mRootView;
}


//spinner listener
AdapterView.OnItemSelectedListener spinnerListener = new AdapterView.OnItemSelectedListener() {

    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

        switch (parent.getId()) {

            case R.id.units:
                //set spinner text appearance
                ((TextView)parent.getChildAt(0)).setTextSize(13);
                ((TextView)parent.getChildAt(0)).setTextColor(Color.DKGRAY);

                if(spinnerInitializedCount<spinnerCount){
                    spinnerInitializedCount++;
                } else {
                    //get selected unit
                    unit = parent.getItemAtPosition(position).toString();
                }
                break;

            case R.id.reminder_list:
                //set spinner text appearance
                ((TextView)parent.getChildAt(0)).setTextSize(13);
                ((TextView)parent.getChildAt(0)).setTextColor(Color.DKGRAY);

                //get selected reminder
                reminder = parent.getItemAtPosition(position).toString();
                break;
                }
        }}


    public void onNothingSelected(AdapterView<?> parent) {
    }
};

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater){
    super.onCreateOptionsMenu(menu, inflater);
    menu.clear();
    inflater.inflate(R.menu.menu_add_item, menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item){
    switch (item.getItemId()){
        case R.id.delete:
            if(currentItem != null){
                promptForDelete();
            }
            else{
                makeToast("Cannot delete item that has not been saved");
            }
            break;
        case R.id.save:
            if(saveItem()){
                makeToast(currentItem != null ? "Item updated" : "Item saved");
            }
            break;
    }
    return super.onOptionsItemSelected(item);
}

private void makeToast(String message){
    Toast.makeText(getActivity(), message, Toast.LENGTH_SHORT).show();
}


private boolean saveItem(){

    Note = noteEditText.getText().toString();
    date = dateText.getText().toString();

    title = itemEditText.getText().toString();
    if(TextUtils.isEmpty(title)){
        itemEditText.setError("Item is required");
        return false;
    }

    quantity = quantityEditText.getText().toString();
    if(TextUtils.isEmpty(quantity)){
        quantityEditText.setError("Quantity is required");
        return false;
    }

    if(unit.equals("None")){
        unitError = (TextView)spinner.getSelectedView();
        unitError.setError("");
        unitError.setTextColor(Color.RED);
        unitError.setTextSize(R.dimen.text_size_normal);
        unitError.setText("Select a unit!");
        return false;
    }

    if(currentItem != null){
        currentItem.setTitle(title);
        currentItem.setQuantity(quantity);
        currentItem.setUnit(unit);
        currentItem.setDate(date);
        currentItem.setNote(Note);
        ItemManager.newInstance(getActivity()).update(currentItem);
    }

    else {
        Item item = new Item();
        item.setTitle(title);
        item.setQuantity(quantity);
        item.setUnit(unit);
        item.setDate(date);
        item.setNote(Note);
        ItemManager.newInstance(getActivity()).create(item);
    }
    return true;
}

private void populateFields(){
    itemEditText.setText(currentItem.getTitle());
    quantityEditText.setText(currentItem.getQuantity());
    noteEditText.setText(currentItem.getNote());
    dateText.setText(currentItem.getDate());
}

@Override
public void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putString("title", title);
    outState.putString("quantity", quantity);
    outState.putString("selunit", unit);
    outState.putString("seldate", date);
    outState.putString("note", Note);
}


public void promptForDelete(){
    final String itemToBeDeleted = currentItem.getTitle();
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(getActivity());
    alertDialog.setTitle("Delete" + itemToBeDeleted + "?");
    alertDialog.setMessage("Are you sure you want to delete " + itemToBeDeleted + "?");
    alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            ItemManager.newInstance(getActivity()).delete(currentItem);
            makeToast(itemToBeDeleted + "deleted");
            startActivity(new Intent(getActivity(), MainActivity.class));
        }
    });
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });
    alertDialog.show();
}

}

已编辑 - 添加了ItemListAdapter.java＆amp; ItemManager.java

ItemListAdapter.java

public class ItemListAdapter extends RecyclerView.Adapter<ItemListAdapter.ViewHolder> {

private List<Item> mItems;
private Context mContext;

public ItemListAdapter(List<Item> items, Context context){
    mItems = items;
    mContext = context;

}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_item_list, parent, false);
    ViewHolder viewHolder = new ViewHolder(rowView);
    return viewHolder;
}

@Override
public void onBindViewHolder(final ViewHolder holder, int position) {

    holder.itemx.setText(mItems.get(position).getTitle());
    holder.quantity.setText(String.valueOf(mItems.get(position).getQuantity()));
    holder.unit.setText(mItems.get(position).getUnit());
    holder.note.setText(mItems.get(position).getNote());
    holder.expDate.setText(mItems.get(position).getDate());
}

@Override
public int getItemCount() {

    return mItems.size();
}


public static class ViewHolder extends RecyclerView.ViewHolder {
    public final TextView itemx;
    public final TextView quantity;
    public final TextView unit;
    public final TextView note;
    public final TextView expDate;


    public ViewHolder(View itemView) {
        super(itemView);

        itemx = (TextView)itemView.findViewById(R.id.tv_item);
        quantity = (TextView)itemView.findViewById(R.id.tv_quantity);
        unit = (TextView)itemView.findViewById(R.id.tv_unit);
        note = (TextView)itemView.findViewById(R.id.tv_note);
        expDate = (TextView)itemView.findViewById(R.id.tv_exp_date);
    }


}


public void promptForDelete(final int position){
    String fieldToBeDeleted = mItems.get(position).getTitle();
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
    alertDialog.setTitle("Delete " + fieldToBeDeleted + " ?");
    alertDialog.setMessage("Are you sure you want to delete the item " + fieldToBeDeleted + "?");
    alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            mItems.remove(position);
            notifyItemRemoved(position);
        }
    });
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });
    alertDialog.show();
}
}

ItemManager.java

public class ItemManager{

    private Context mContext;
    private static ItemManager itemManagerInstance = null;

    public static ItemManager newInstance(Context context){
        if (itemManagerInstance == null){
            itemManagerInstance = new ItemManager(context.getApplicationContext());
        }
        return itemManagerInstance;
    }

    private ItemManager(Context context){
        this.mContext = context.getApplicationContext();
    }

    public long create(Item item){ 
        ContentValues values = new ContentValues(); 
        values.put(Constants.COLUMN_TITLE, item.getTitle());
        values.put(Constants.COLUMN_QUANTITY, item.getQuantity());
        values.put(Constants.COLUMN_UNIT, item.getUnit());
        values.put(Constants.COLUMN_EXPIRY_DATE, item.getDate());
        values.put(Constants.COLUMN_NOTE, item.getNote());

        Uri result = mContext.getContentResolver().insert(XContentProvider.ITEM_URI, values);

        long id = Long.parseLong(result.getLastPathSegment());
        return id;
    }

    public void update(Item item){
        ContentValues values = new ContentValues();
        values.put(Constants.COLUMN_TITLE, item.getTitle());
        values.put(Constants.COLUMN_QUANTITY, item.getQuantity());
        values.put(Constants.COLUMN_UNIT, item.getUnit());
        values.put(Constants.COLUMN_EXPIRY_DATE, item.getDate());
        values.put(Constants.COLUMN_NOTE, item.getNote());
        mContext.getContentResolver().update(XContentProvider.ITEM_URI, values, Constants.COLUMN_ID + " = " + item.getId(), null);
    }

    public void delete(Item item){
        mContext.getContentResolver().delete(XContentProvider.ITEM_URI, Constants.COLUMN_ID + " = " + item.getId(), null);
    }

    public List<Item> getAllItems(){
        List<Item> items = new ArrayList<Item>();
        Cursor cursor = mContext.getContentResolver().query(XContentProvider.ITEM_URI, Constants.COLUMNS, null, null, null);
        if (cursor != null){
            cursor.moveToFirst();
            while (!cursor.isAfterLast()){
                items.add(Item.getItemfromCursor(cursor));
                cursor.moveToNext();
            }
            cursor.close();
        }
        return items;
    }

    public Item getItem(Long id){
        Item item;
        Cursor cursor = mContext.getContentResolver().query(XContentProvider.ITEM_URI, Constants.COLUMNS, Constants.COLUMN_ID + " = " + id, null, null);
        if (cursor != null){
            cursor.moveToFirst();
            item = Item.getItemfromCursor(cursor);
            return item;
        }
        return null;
    }
}

Answer 1

您可能需要使用SharedPreferences或SQL database来保存数据。onSaveInstanceState用于在片段可能被销毁时保存状态。

只需将项目ID传递给ItemFragment并在其中显示数据。

openFragment(new ItemFragment(item.getId()), "Add Item")

package com.airi.vcare;

import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;

public class ItemFragment extends DialogFragment {


private View mRootView;
private Item currentItem = null;
private Toolbar mToolbar;
private String date;
private String Note;
private String title;
private String quantity;
private TextView dateText;
private TextView unitError;
private EditText itemEditText;
private EditText quantityEditText;
private EditText noteEditText;
private Spinner remSpinner;
private Spinner spinner;
private String unit;
private String reminder;
private int spinnerCount=0;
private int spinnerInitializedCount=0;
private int remSpinnerCount=0;
private int remSpinnerInitializedCount=0;


public ItemFragment() {

}

//create an instance of the fragment
public static ItemFragment newInstance(long id) {
    ItemFragment fragment = new ItemFragment();

    if (id > 0) {
        Bundle bundle = new Bundle();
        bundle.putLong("id", id);
        fragment.setArguments(bundle);
    }
    return fragment;
}

//get id of an item
public void getCurrentItem() {
    Bundle args = getArguments();
    if (args != null && args.containsKey("id")) {
        long id = args.getLong("id", 0);
        if (id > 0) {
            currentItem = ItemManager.newInstance(getActivity()).getItem(id);
        }
    }
}

//notify Activity that the fragment wants to place an item in the menu
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
    getCurrentItem();

}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    mRootView = inflater.inflate(R.layout.add_item, container, false);
    itemEditText=(EditText)mRootView.findViewById((R.id.add_item));
    quantityEditText=(EditText)mRootView.findViewById(R.id.amount);
    unitError = (TextView)mRootView.findViewById(R.id.unit_error);
    noteEditText = (EditText)mRootView.findViewById(R.id.add_notes);
    dateText = (TextView)mRootView.findViewById(R.id.date_selected);

    //unit spinner code here
    //reminder spinner here

    spinner.setOnItemSelectedListener(spinnerListener);
    remSpinner.setOnItemSelectedListener(spinnerListener);
    spinnerCount=1;
    remSpinnerCount=1;
    //just display fields .
    populateFields();
    return mRootView;
}


//spinner listener
AdapterView.OnItemSelectedListener spinnerListener = new AdapterView.OnItemSelectedListener() {

    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

        switch (parent.getId()) {

            case R.id.units:
                //set spinner text appearance
                ((TextView)parent.getChildAt(0)).setTextSize(13);
                ((TextView)parent.getChildAt(0)).setTextColor(Color.DKGRAY);

                if(spinnerInitializedCount<spinnerCount){
                    spinnerInitializedCount++;
                } else {
                    //get selected unit
                    unit = parent.getItemAtPosition(position).toString();
                }
                break;

            case R.id.reminder_list:
                //set spinner text appearance
                ((TextView)parent.getChildAt(0)).setTextSize(13);
                ((TextView)parent.getChildAt(0)).setTextColor(Color.DKGRAY);

                //get selected reminder
                reminder = parent.getItemAtPosition(position).toString();
                break;
                }
        }}


    public void onNothingSelected(AdapterView<?> parent) {
    }
};

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater){
    super.onCreateOptionsMenu(menu, inflater);
    menu.clear();
    inflater.inflate(R.menu.menu_add_item, menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item){
    switch (item.getItemId()){
        case R.id.delete:
            if(currentItem != null){
                promptForDelete();
            }
            else{
                makeToast("Cannot delete item that has not been saved");
            }
            break;
        case R.id.save:
            if(saveItem()){
                makeToast(currentItem != null ? "Item updated" : "Item saved");
            }
            break;
    }
    return super.onOptionsItemSelected(item);
}

private void makeToast(String message){
    Toast.makeText(getActivity(), message, Toast.LENGTH_SHORT).show();
}


private boolean saveItem(){

    Note = noteEditText.getText().toString();
    date = dateText.getText().toString();

    title = itemEditText.getText().toString();
    if(TextUtils.isEmpty(title)){
        itemEditText.setError("Item is required");
        return false;
    }

    quantity = quantityEditText.getText().toString();
    if(TextUtils.isEmpty(quantity)){
        quantityEditText.setError("Quantity is required");
        return false;
    }

    if(unit.equals("None")){
        unitError = (TextView)spinner.getSelectedView();
        unitError.setError("");
        unitError.setTextColor(Color.RED);
        unitError.setTextSize(R.dimen.text_size_normal);
        unitError.setText("Select a unit!");
        return false;
    }

    if(currentItem != null){
        currentItem.setTitle(title);
        currentItem.setQuantity(quantity);
        currentItem.setUnit(unit);
        currentItem.setDate(date);
        currentItem.setNote(Note);
        ItemManager.newInstance(getActivity()).update(currentItem);
    }

    else {
        Item item = new Item();
        item.setTitle(title);
        item.setQuantity(quantity);
        item.setUnit(unit);
        item.setDate(date);
        item.setNote(Note);
        ItemManager.newInstance(getActivity()).create(item);
    }
    return true;
}

private void populateFields(){
    itemEditText.setText(currentItem.getTitle());
    quantityEditText.setText(currentItem.getQuantity());
    noteEditText.setText(currentItem.getNote());
    dateText.setText(currentItem.getDate());
}

@Override
public void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putString("title", title);
    outState.putString("quantity", quantity);
    outState.putString("selunit", unit);
    outState.putString("seldate", date);
    outState.putString("note", Note);
}


public void promptForDelete(){
    final String itemToBeDeleted = currentItem.getTitle();
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(getActivity());
    alertDialog.setTitle("Delete" + itemToBeDeleted + "?");
    alertDialog.setMessage("Are you sure you want to delete " + itemToBeDeleted + "?");
    alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            ItemManager.newInstance(getActivity()).delete(currentItem);
            makeToast(itemToBeDeleted + "deleted");
            startActivity(new Intent(getActivity(), MainActivity.class));
        }
    });
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });
    alertDialog.show();
}

}

public class ItemListAdapter extends RecyclerView.Adapter<ItemListAdapter.ViewHolder> {

private List<Item> mItems;
private Context mContext;

public ItemListAdapter(List<Item> items, Context context){
    mItems = items;
    mContext = context;

}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View rowView = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_item_list, parent, false);
    ViewHolder viewHolder = new ViewHolder(rowView);
    return viewHolder;
}

@Override
public void onBindViewHolder(final ViewHolder holder, int position) {

    holder.itemx.setText(mItems.get(position).getTitle());
    holder.quantity.setText(String.valueOf(mItems.get(position).getQuantity()));
    holder.unit.setText(mItems.get(position).getUnit());
    holder.note.setText(mItems.get(position).getNote());
    holder.expDate.setText(mItems.get(position).getDate());
holder.item.getParent().setOnClick(new OnClickListener(){

onclick(View view){
//todo here
openFragment(new ItemFragment(item.getId()), "Add Item")
}
})
}

@Override
public int getItemCount() {

    return mItems.size();
}


public static class ViewHolder extends RecyclerView.ViewHolder {
    public final TextView itemx;
    public final TextView quantity;
    public final TextView unit;
    public final TextView note;
    public final TextView expDate;


    public ViewHolder(View itemView) {
        super(itemView);

        itemx = (TextView)itemView.findViewById(R.id.tv_item);
        quantity = (TextView)itemView.findViewById(R.id.tv_quantity);
        unit = (TextView)itemView.findViewById(R.id.tv_unit);
        note = (TextView)itemView.findViewById(R.id.tv_note);
        expDate = (TextView)itemView.findViewById(R.id.tv_exp_date);
    }


}


public void promptForDelete(final int position){
    String fieldToBeDeleted = mItems.get(position).getTitle();
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
    alertDialog.setTitle("Delete " + fieldToBeDeleted + " ?");
    alertDialog.setMessage("Are you sure you want to delete the item " + fieldToBeDeleted + "?");
    alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            mItems.remove(position);
            notifyItemRemoved(position);
        }
    });
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });
    alertDialog.show();
}
}