所以我的代码基本上是当您按下底角的FAB时，出现一个视图框，textview，spinner，edittext和复选框。您可以多次添加这些set元素。
我在代码中添加了共享首选项，以便当用户返回到主活动然后又回到创建活动时，这些项仍然保留。很好
但是当用户按下视图框时，我具有一项功能，即删除了该组元素（该视图框，微调框，edittext，textview和带有它的复选框）。
所以当我现在按下它时，它会删除，然后我进入mainactivity屏幕，然后返回到create屏幕，但是 那些set元素仍然存在？ 该如何解决？
create.java
public class create extends AppCompatActivity {
private LinearLayout mLinearLayout;
private ArrayList<SearchableSpinner> mSpinners;
private List<AppCompatButton> mButtons = new ArrayList<>();
private List<CheckBox> mCheckboxes = new ArrayList<>();
private List<TextView> mTextviews = new ArrayList<>();
private List<EditText> mEdittexts = new ArrayList<>();
private List<View> mViews = new ArrayList<>();
private Map<String, String> numberItemValues = new HashMap<>();
private Spinner spinner;
private TextView textview;
private CheckBox checkbox;
List<String> itemList = new ArrayList<>();
LinearLayout verticallayout,horizontalLayout;
public static final String MY_PREFS_NAME = "MyPrefsFile";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
findViewById(R.id.my_linearLayout).requestFocus();
verticallayout = findViewById(R.id.verticalLayout); //got
//Arrays
ArrayList<String> items = new ArrayList<>();
items.add(String.valueOf(mSpinners)); // add you selected item
mSpinners = new ArrayList<>();
//Initializing Variables Here
mLinearLayout = findViewById(R.id.my_linearLayout);
//verticallayout = findViewById(R.id.verticalLayout);
textview = findViewById(R.id.textview);
checkbox = findViewById(R.id.checkbox);
SharedPreferences prefs = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE);
try {
JSONArray jsonArray2 = new JSONArray(prefs.getString("key", null));
for (int i = 0; i < jsonArray2.length(); i++) {
final Spinner spinner = makeSpinner();
mLinearLayout.addView(spinner);
mSpinners.add((SearchableSpinner) spinner);
final View newView = makeView();
//Add a new view
mLinearLayout.addView(newView);
mViews.add(newView);
final EditText newEdittext = makeEdittext();
mLinearLayout.addView(newEdittext);
mEdittexts.add(newEdittext);
final CheckBox newCheckbox = makeCheckbox();
mLinearLayout.addView(newCheckbox);
//TODO add checkbox to your list
mCheckboxes.add(newCheckbox);
final TextView newTextview = makeTextview();
mLinearLayout.addView(newTextview);
mTextviews.add(newTextview);
//TODO Add the spinner on item selected listener to get selected items
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String currentItem = itemList.get(position);
String aisleNumber = numberItemValues.get(currentItem);
//TODO you can use the above aisle number to add to your text view
//mTextviews.get(mTextviews.size() -1).setText(aisleNumber);
newTextview.setText(aisleNumber);
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// do nothing
}
});
final int listSize = mViews.size();
//TODO DELETIN ITEM
newView.setOnClickListener(new View.OnClickListener() {
//start
@Override
public void onClick(View view) {
//when the 'new button' is pressed, alert shows if you are sure you want to delete the item or not.
final View.OnClickListener context = this;
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(create.this);
// set title
alertDialogBuilder.setTitle("Delete Item");
// set dialog message
alertDialogBuilder
.setMessage("Are you sure you want to delete this item?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// if this button is clicked, close
// current activity
if (listSize > 0) {
mCheckboxes.get(listSize - 1).setVisibility(View.GONE);
mSpinners.get(listSize - 1).setVisibility(View.GONE);
mViews.get(listSize - 1).setVisibility(View.GONE);
mTextviews.get(listSize - 1).setVisibility(View.GONE);
mEdittexts.get(listSize - 1).setVisibility(View.GONE);
Toast.makeText(getBaseContext(), "Item removed.", Toast.LENGTH_SHORT).show();
}
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
});
int positionOfSpinner = (int) jsonArray2.get(i);
spinner.setSelection(positionOfSpinner);
}
} catch (Exception e) {
e.printStackTrace();
}
//end of shared pref code
//TODO FAB BUTTON
FloatingActionButton floatingActionButton =
(FloatingActionButton) findViewById(R.id.fab);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getBaseContext(), "Item added!", Toast.LENGTH_SHORT).show();
spinner = findViewById(R.id.spinner);
// Handle ze click.
final Spinner spinner = makeSpinner();
mLinearLayout.addView(spinner);
mSpinners.add((SearchableSpinner) spinner);
LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) spinner.getLayoutParams();
layoutParams.setMargins(5, 100, 10, 0); //top 70
Resources resources = getResources();
DisplayMetrics metrics = resources.getDisplayMetrics();
layoutParams.height = (int) (70 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)); //80
layoutParams.width = (int) (240 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)); //240
spinner.setLayoutParams(layoutParams);
final View newView = makeView();
mLinearLayout.addView(newView);
mViews.add(newView);
final EditText newEdittext = makeEdittext();
mLinearLayout.addView(newEdittext);
mEdittexts.add(newEdittext);
final int listSize = mViews.size();
//code for deleting the said item.
newView.setOnClickListener(new View.OnClickListener() {
//start
@Override
public void onClick(View view) {
//when the 'new button' is pressed, alert shows if you are sure you want to delete the item or not.
final View.OnClickListener context = this;
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(create.this);
// set title
alertDialogBuilder.setTitle("Delete Item");
// set dialog message
alertDialogBuilder
.setMessage("Are you sure you want to delete this item?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// if this button is clicked, close
// current activity
if (listSize > 0) {
mCheckboxes.get(listSize - 1).setVisibility(View.GONE);
mSpinners.get(listSize - 1).setVisibility(View.GONE);
// mSpinners.remove(listSize - 1);
mViews.get(listSize - 1).setVisibility(View.GONE);
mTextviews.get(listSize - 1).setVisibility(View.GONE);
mEdittexts.get(listSize - 1).setVisibility(View.GONE);
Toast.makeText(getBaseContext(), "Item removed.", Toast.LENGTH_SHORT).show();
}
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
});
//Add a new checkbox
final CheckBox newCheckbox = makeCheckbox();
mLinearLayout.addView(newCheckbox);
//TODO add checkbox to your list
mCheckboxes.add(newCheckbox);
final TextView newTextview = makeTextview();
mLinearLayout.addView(newTextview);
mTextviews.add(newTextview);
//TODO Add the spinner on item selected listener to get selected items
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String currentItem = itemList.get(position);
String aisleNumber = numberItemValues.get(currentItem);
//TODO you can use the above aisle number to add to your text view
//mTextviews.get(mTextviews.size() -1).setText(aisleNumber);
newTextview.setText(aisleNumber);
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// code here, do nothing
}
});
}
});
}
//TODO OVERFLOW MENU
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.create_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
/*Intent startSettingsActivity = new Intent(this, AppCompatPreferenceActivity.class);
startActivity(startSettingsActivity);
//start the settings activity here.*/
startActivity(new Intent(create.this, settings.class));
return true;
}
else if (id == R.id.action_delete) {
//code to delete list here.
SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
editor.clear();
editor.commit();
Toast.makeText(getBaseContext(), "List removed.", Toast.LENGTH_SHORT).show();
return true;
}
else if (id ==R.id.action_help) {
// setup the alert builder
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Help");
builder.setMessage("To use this app, first go to Create your Shopping List.\n" +
"Here, you can add items to your list. Once you have added all items, you can click the menu at the top right corner (or if it doesnt appear press your menu button beside your home button on your device, then click View your List.\n" +
"This will take you to the screen where you can view you shopping list with the items in aisle order to make your shop much easier.\n" +
"You can still add items at this point. Press the white background of each item to delete the item if you wish.");
// add a button
builder.setPositiveButton("OK", null);
// create and show the alert dialog
AlertDialog dialog = builder.create();
dialog.show();
return true;
}
else if (id == R.id.action_gotoview) {
//takes the size of the list of spinners, for reference
ArrayList<Integer> spinnerList = new ArrayList<>();
for(int i = 0; i < mSpinners.size(); i++) {
spinnerList.add(mSpinners.get(i).getSelectedItemPosition());
}
Bundle newBundle = new Bundle();
newBundle.putIntegerArrayList("arraylist", spinnerList);
Intent newIntent = new Intent(create.this, viewscreen.class);
newIntent.putExtra("extraBundle", newBundle);
startActivity(newIntent);
//code to go to view screen, aka intent
return true;
}
return super.onOptionsItemSelected(item);
}
public void createRow(View view){
createRow(); //got
}
private void createRow() { //got
horizontalLayout = new LinearLayout(this);
LinearLayout.LayoutParams horizontalParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
horizontalLayout.setOrientation(LinearLayout.HORIZONTAL);
horizontalLayout.setLayoutParams(horizontalParams);
makeEdittext();
makeCheckbox();
makeView();
verticallayout.addView(horizontalLayout);
}
//DUPLICATING ITEMS WHEN FAB IS PRESSED//
private CheckBox makeCheckbox() {
//Create new Checkbox
CheckBox checkbox = new CheckBox(this);
// Setup layout
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
//setup relative layout for the positioning of the objects
Resources resources = getResources();
DisplayMetrics metrics = resources.getDisplayMetrics();
RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams((int) (70 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)), (int) (240 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)));
relativeParams.addRule(RelativeLayout.RIGHT_OF, R.id.textview);
checkbox.setLayoutParams(relativeParams);
checkbox.setLayoutParams(layoutParams);
/* LinearLayout.LayoutParams checkParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
checkParams.setMargins(10, 10, 10, 10);
checkParams.gravity = Gravity.LEFT;
checkbox.setLayoutParams(checkParams);
horizontalLayout.addView(checkbox);*/
return checkbox;
}
private TextView makeTextview() {
//create new textview
TextView textview = new TextView(this);
//setup layout
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
textview.setLayoutParams(layoutParams);
textview.setTextSize(30);
return textview;
}
private EditText makeEdittext() {
//create new edittext
EditText edittext = new EditText(this);
//setup layout
final LinearLayout.LayoutParams lparams = new LinearLayout.LayoutParams(70, 50); // Width , height
edittext.setLayoutParams(lparams);
/* LinearLayout.LayoutParams editParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
editParams.setMargins(10, 10, 10, 10);*/
lparams.width = 70;
lparams.height = 50;
edittext.setLayoutParams(lparams);
/*
edittext.setLayoutParams(editParams);
horizontalLayout.addView(edittext);*/
edittext.setInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL | InputType.TYPE_NUMBER_FLAG_SIGNED);
edittext.setHint("qty");
return edittext;
}
private View makeView() {
//create new View
View view = new View(this);
view.setBackgroundColor(Color.parseColor("#ffffff"));
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams( LinearLayout.LayoutParams.MATCH_PARENT, 100);
new LinearLayout.LayoutParams( LinearLayout.LayoutParams.WRAP_CONTENT, 50);
view.setLayoutParams(layoutParams);
view.setClickable(true);
//view.setLayoutParams(layoutParams);
//setup layout
return view;
}
private Spinner makeSpinner() {
//opens csv
InputStream inputStream = getResources().openRawResource(R.raw.shopitems);
CSVFile csvFile = new CSVFile(inputStream);
//TODO I made this variable global, declared it at the very top of this file
itemList = csvFile.read();
//Create new spinner
// SearchableSpinner spinner = (SearchableSpinner) new Spinner(this, Spinner.MODE_DROPDOWN);
SearchableSpinner spinner = new SearchableSpinner(this);
// Setup layout
/* LinearLayout.LayoutParams spinnerParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
spinnerParams.setMargins(10, 10, 10, 10);
spinnerParams.gravity = Gravity.LEFT;
Resources resources = getResources();
DisplayMetrics metrics = resources.getDisplayMetrics();
spinnerParams.height = (int) (70 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)); //80
spinnerParams.width = (int) (240 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)); //240
spinner.setLayoutParams(spinnerParams);
horizontalLayout.addView(spinner);*/
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
spinner.setLayoutParams(layoutParams);
MyListAdapter adapter = new MyListAdapter(this, R.layout.listrow, R.id.txtid, itemList);
spinner.setAdapter(adapter);
//Add it to your list of spinners so you can retrieve their data when you click the getSpinner button
//mSpinners.add(spinner);
return spinner;
}
private class CSVFile {
InputStream inputStream;
public CSVFile(InputStream inputStream) {
this.inputStream = inputStream;
}
public List<String> read() {
List<String> resultList = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
try {
String line;
while ((line = reader.readLine()) != null) {
String[] row = line.split(",");
//TODO I edited this part so that you'd add the values in our new hash map variable
numberItemValues.put(row[1], row[0]);
resultList.add(row[1]);
}
} catch (IOException e) {
Log.e("Main", e.getMessage());
} finally {
try {
inputStream.close();
} catch (IOException e) {
Log.e("Main", e.getMessage());
}
}
return resultList;
}
}
//on stop, the things are saved into shared prefs
@Override
protected void onStop () {
//public static final String MY_PREFS_NAME = "MyPrefsFile";
SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
JSONArray jsonArray = new JSONArray();
for(int i = 0; i < mSpinners.size(); i++) {
jsonArray.put(mSpinners.get(i).getSelectedItemPosition());
}
editor.putString("key", jsonArray.toString());
editor.apply();
super.onStop();
}
}
答案 0 :(得分：0)
我不明白您的实际意图，但是从您的问题中得知， 您需要在完成某些任务后删除这些元素。因此，当您使用ArrayList <>存储视图时，可以从ArrayList删除所有视图 就像：
arraylist.clear()
根据您的情况：
private void clearViews(){
mButtons.clear();
mCheckboxes.clear();
mViews.clear();
mEdittexts.clear();
mTextviews.clear();
mSpinners.clear();
// more arrays you want to clear
}
是的，确实需要清除共享的首选项。 要使用共享首选项。，我为您提供一个示例。
public class SharedMemory {
SharedPreferences prefs;
public SharedMemory(Context ctx) {prefs = ctx.getSharedPreferences("SCREEN_SETTINGS", Context.MODE_PRIVATE);}
void setValue(String value) {prefs.edit().putString("uUrl", value).apply();}
public String getValue() {return prefs.getString("uUrl", "");}
}
，您可以在共享首选项中添加布尔值，字符串和其他数据类型。
您可以这样称呼
// initialisation
SharedMemory shared = new SharedMemory(this);
写入数据：
shared.setValue("your data");
读取数据：
shared.getValue("your data");
修改数据：
shared.setValue("modfied data");
删除数据：
shared.setValue("");
答案 1 :(得分：0)
您没有从SharedPreferences删除项目，这就是为什么它总是返回的原因。从视图中删除项目后，您还应该从SharedPreferences中删除项目。我看到您的SharedPreferences包含一个映射到json数组的键；从视图中删除时，从SharedPreferences获取json数组，循环遍历并删除已删除的项目。希望这很清楚。代码如下所示：
JSONArray jArray = new JSONArray(prefs.getString("key"));
for(int i = 0; i < jArray.length; i++) {
if(jArray.get(i).contains(mSpinners.get(listSize - 1).getSelectedItemPosition())){
jArray.remove(i);
}
}
//update the prefs
editor.putString("key",jArray);
editor.apply();
将其放置在“项目已删除”吐司之前。