我正在构建一个具有RecyclerView的应用程序，其中包含从SharedPreferences中检索的对象。 不幸的是，RecyclerView绑定后滞后了。
这是我的适配器
public class ShiftAdapter extends RecyclerView.Adapter<ShiftAdapter.ViewHolder>{
private List<Shift> mDataSet;
private Context mContext;
private static final String TAG = "ShiftAdapter";
public int previousExpandedPosition = -1;
public int mExpandedPosition = -1;
private static SharedPreferences mPrefs;
private LinearLayout mShiftIn;
private LinearLayout mShiftOut;
private Boolean isStart;
private Date shiftIn;
private Date shiftOut;
private Date mDate;
public EditText mshiftInText;
public EditText mshiftOutText;
public Date date;
public ShiftAdapter(Context context, List<Shift> list) {
mDataSet = list;
mContext = context;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mDate;
public TextView mTime;
public TextView mPay;
public RelativeLayout mRelativeLayout;
public LinearLayout mExepandableLayout;
public Date mshiftIn;
public Date mshiftOut;
public EditText mshiftInText;
public EditText mshiftOutText;
public Button mUpdateButton;
public Button mDeleteButton;
public ViewHolder(View v) {
super(v);
mDate = (TextView) v.findViewById(R.id.date_TV);
mTime = (TextView) v.findViewById(R.id.time_TV);
mPay = (TextView) v.findViewById(R.id.pay_TV);
mRelativeLayout = (RelativeLayout) v.findViewById(R.id.rel_layout);
mExepandableLayout = (LinearLayout) v.findViewById(R.id.expandableLayout);
mshiftInText = (EditText) v.findViewById(R.id.setShiftIn);
mshiftOutText = (EditText) v.findViewById(R.id.setShiftOut);
mUpdateButton = (Button) v.findViewById(R.id.updateButton);
mDeleteButton = (Button) v.findViewById(R.id.deleteButton);
}
}
@Override
public ShiftAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(mContext)
.inflate(R.layout.shift, parent, false);
ViewHolder vh = new ViewHolder(itemView);
return vh;
}
//TODO:Bind all the view elements to Shift Properties
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int i) {
// Format double
String hours = new DecimalFormat("##.##").format(mDataSet.get(i).getHours());
String pay = new DecimalFormat("##.##").format(mDataSet.get(i).getPay());
//set the Text
holder.mTime.setText(hours);
holder.mDate.setText(mDataSet.get(i).dateToString());
holder.mPay.setText(pay);
Log.d(TAG, "onBindViewHolder: called");
// new AsyncTask<>().ex
//Expand mExapndableLayout
final int position = i;
final boolean isExpanded = position ==mExpandedPosition;
holder.mExepandableLayout.setVisibility(isExpanded?View.VISIBLE:View.GONE);
holder.itemView.setActivated(isExpanded);
// //set shift Times
// shiftIn = mDataSet.get(position).getInDate();
// shiftOut = mDataSet.get(position).getInDate();
if (isExpanded)
previousExpandedPosition = position;
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mExpandedPosition = isExpanded ? -1:position;
notifyItemChanged(previousExpandedPosition);
notifyItemChanged(position);
}
});
//fill expandable layout
holder.mshiftInText.setText(mDataSet.get(position).fullTimeToString(0));
final EditText in = holder.mshiftInText;
final EditText out = holder.mshiftOutText;
//edit mShiftIn Text
holder.mshiftInText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
isStart =true;
timePickerDialog(in,out);
}
});
holder.mshiftOutText.setText(mDataSet.get(position).fullTimeToString(1));
//edit MshiftOut Text
holder.mshiftOutText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
isStart =false;
timePickerDialog(in,out);
}
});
//updateButton onClick
holder.mUpdateButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
try {
shiftIn = mDataSet.get(position).getInDate();
shiftOut = mDataSet.get(position).getOutDate();
if(Validate.getValidate().isDateValid(shiftIn,shiftOut)) {
SharedPrefs.getInstance(mContext).editShift(newShift(shiftIn, shiftOut),Integer.toString(position));
int length = SharedPrefs.getInstance(mContext).getLength() - 1;
if (SharedPrefs.getInstance(mContext).getShift(length) != null) {
Log.d(TAG, "Edit Shift onClick: Success");
SharedPrefs.getInstance(mContext).saveShiftList(SharedPrefs.getInstance(mContext).sortList(SharedPrefs.getInstance(mContext).getShiftList()));
ShiftsFragment.updateUI();
Toast.makeText(mContext, "success", Toast.LENGTH_SHORT).show();
}
} else {
mShiftOut.setBackgroundResource(R.drawable.red_border);
Toast.makeText(mContext, "error", Toast.LENGTH_SHORT).show(); }
} catch(Exception e){
Log.d(TAG, "onDateSelected: "+e.toString());
Toast.makeText(mContext,"update FAIL", Toast.LENGTH_SHORT).show();
}
// update the Shift
}
});
holder.mDeleteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
areYouSure(mExpandedPosition);
}
});
}
@Override
public int getItemCount() {
return mDataSet.size();
}
public Date timePickerDialog(EditText in,EditText out) {
mshiftInText = in;
mshiftOutText = out;
new SingleDateAndTimePickerDialog.Builder(mContext)
.title(mContext.getResources().getString(R.string.choose_time))
.displayListener(new SingleDateAndTimePickerDialog.DisplayListener() {
@Override
public void onDisplayed(SingleDateAndTimePicker picker) {
if(!isStart) {
date = mDate;
}
}
}).defaultDate(returnDate(date))
.listener(new SingleDateAndTimePickerDialog.Listener() {
@Override
public void onDateSelected(Date date) {
mDate = date;
if (isStart) {
updateShiftIn(mDate);
mshiftInText.setText(dateToString(mDate));
} else {
updateShiftOut(mDate);
mshiftOutText.setText(dateToString(mDate));
}
}
}).display();
return mDate;
}
public String dateToString(Date date)
{
DateFormat df = new SimpleDateFormat("dd-MM-yyyy HH:mm");
String string = df.format(date);
return string;
}
private void updateShiftIn(Date date) {
shiftIn = date;
}
private void updateShiftOut(Date date) {
shiftOut = date;
}
private Date returnDate(Date date)
{
if(date!=null)
{
return date;
}
else return mDate;
}
private void areYouSure(int i)
{
final String position = Integer.toString(i);
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which){
case DialogInterface.BUTTON_POSITIVE:
Log.d(TAG, "onClick: isSure=true;");
SharedPrefs.getInstance(mContext).removeShift(position);
ShiftsFragment.updateUI();
case DialogInterface.BUTTON_NEGATIVE:
Log.d(TAG, "onClick: isSure= false");
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
builder.setMessage(mContext.getResources().getString(R.string.are_you_sure)).setPositiveButton(mContext.getResources().getString(R.string.confirm), dialogClickListener)
.setNegativeButton(mContext.getResources().getString(R.string.cancel), dialogClickListener).show();
}
private Shift newShift(Date start,Date stop)
{
int id = SharedPrefs.getInstance(mContext).getLength();
Shift shift = new Shift(dateToCalendar(start),dateToCalendar(stop),id);
return shift;
}
这是具有RecyclerView的片段
public class ShiftsFragment extends Fragment {
private Toolbar mToolbar;
private TimePicker timePicker1;
private List<Shift> shiftList = new ArrayList<>();
private RecyclerView recyclerView;
private RelativeLayout relativeLayout;
private RecyclerView.LayoutManager layoutManager;
private LinearLayout mShiftIn;
private LinearLayout mShiftOut;
private Context mContext;
private ShiftAdapter mAdapter;
private MenuItem mAdd;
private Menu optionsMenu;
private LinearLayout mShiftAddLL;
private SharedPreferences mPrefs;
private static FragmentManager mFragmentManager;
private static final String TAG = "ShiftsFragment";
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
Log.d(TAG,"Clicked");
final View view = inflater.inflate(R.layout.shifts_layout,container,false);
mToolbar = view.findViewById(R.id.topbar);
mToolbar.inflateMenu(R.menu.toolbarmenu);
mShiftAddLL = view.findViewById(R.id.add_shiftLayout);
mAdd = mToolbar.getMenu().getItem(0);
timePicker1 = (TimePicker) view.findViewById(R.id.timePicker);
mFragmentManager = getFragmentManager();
//TODO:Add a summary bar on the bottom.
//get the context
mContext = getContext();
recyclerView = (RecyclerView) view.findViewById(R.id.shift_list);
// Define a layout for RecyclerView
layoutManager = new GridLayoutManager(mContext,1);
recyclerView.setLayoutManager(layoutManager);
// Initialize a new Shift array
List<Shift> shiftList = initShifts();
Log.d(TAG,"shift array initiated");
// Initialize an array list from array
// Initialize a new instance of RecyclerView Adapter instance
mAdapter = new ShiftAdapter(mContext,shiftList);
// Set the adapter for RecyclerView
recyclerView.setAdapter(mAdapter);
recyclerView.setNestedScrollingEnabled(false);
recyclerView.setHasFixedSize(true);
//Menu add button onClick
//Opens Add_Shift_Fragment
mAdd.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem menuItem) {
Fragment selectedFragment = new Add_Shift_Fragment();
getFragmentManager().beginTransaction().replace(R.id.fragment_container,
selectedFragment).commit();
return false;
}
});
return view;
}
//Initializes the Shift list from SharedPreferences and returns it.
private List<Shift> initShifts() {
return SharedPrefs.getInstance(mContext).getShiftList();
}
public static void updateUI()
{
Fragment selectedFragment = new ShiftsFragment();
mFragmentManager.beginTransaction().replace(R.id.fragment_container,
selectedFragment).commit();
}
}
每次我启动ShiftsFragment时都会跳过一些帧，并且滚动时断时续。
也许我的SharedPreferences处理是什么使事情变慢了？
public class SharedPrefs {
private static SharedPrefs mSharedPrefs;
private SharedPreferences mPrefs;
private SharedPreferences.Editor mPrefsEditor;
protected Context mContext;
public static final String ID = "shiftList";
private SharedPrefs(Context context) {
mContext = context;
mPrefs = context.getSharedPreferences(ID, Context.MODE_PRIVATE);
mPrefsEditor = mPrefs.edit();
}
public static SharedPrefs getInstance(Context context) {
if (mSharedPrefs == null) {
mSharedPrefs = new SharedPrefs(context.getApplicationContext());
}
return mSharedPrefs;
}
public void saveShiftList(List<Shift> shiftList) {
Gson gson = new Gson();
String json = gson.toJson(shiftList);
mPrefsEditor.putString(ID, json);
mPrefsEditor.apply();
}
public void addShift (Shift shift)
{
List<Shift> shiftList= getShiftList();
shiftList.add(shift);
saveShiftList(shiftList);
}
//Replaced the shift@id with shift
public void editShift(Shift shift,String id)
{
removeShift(id);
addShift(shift);
}
public void removeShift(String id) {
List<Shift> shiftList = getShiftList();
int pos = Integer.parseInt(id);
shiftList.remove(pos);
saveShiftList(shiftList);
}
public void removeShift(int id) {
List<Shift> shiftList = getShiftList();
shiftList.remove(id);
saveShiftList(shiftList);
}
public Shift getShift(int id) {
Gson gson = new Gson();
List<Shift> shiftList;
String json = mPrefs.getString(ID, null);
Type type = new TypeToken<List<Shift>>() {
}.getType();
shiftList = gson.fromJson(json, type);
Shift shift = shiftList.get(id);
return shift;
}
public List<Shift> getShiftList() {
Gson gson = new Gson();
List<Shift> shiftList;
String json = mPrefs.getString(ID, null);
Type type = new TypeToken<List<Shift>>() {
}.getType();
shiftList = gson.fromJson(json, type);
if (shiftList!=null) {
return shiftList;
} else{
shiftList = new ArrayList<>();
return shiftList;
}
}
public List<Shift> sortList(List<Shift> shiftList)
{
Collections.sort(shiftList, new Comparator<Shift>() {
public int compare(Shift shift1, Shift shift2) {
if (shift1.getShiftStart() == null || shift2.getShiftStart() == null)
return 0;
return shift1.getShiftStart().compareTo(shift2.getShiftStart());
}
});
return shiftList;
}
public int getLength()
{
return getShiftList().size();
}
}
我只在图像加载中发现了这个问题，而不仅仅是SharedPrefs中Object的字符串。