Reducing imageview buttons code

Question

This code is very long, and you need a separate method. How can I implement it?

I have 6 (x2) imageview buttons and 6 edittext.

public void onClick(View v) {
 // TODO Auto-generated method stub
 switch (v.getId())
 {
 case R.id.imageViewPlusSubEdit1:
 if(editTextInputNameSubEdit1.getText().toString().trim().length() == 0)
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items1.size() > 23)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items1.add(editTextInputNameSubEdit1.getText().toString());
 adapterList1.notifyDataSetChanged(); 
 editTextInputNameSubEdit1.setText("");
 }
 break;
 case R.id.imageViewMinusSubEdit1:
 SparseBooleanArray checkedItemPositions = listViewSubEdit1.getCheckedItemPositions();
 int itemCount = listViewSubEdit1.getCount();
 for(int i = itemCount - 1; i >= 0; i--)
 {
 if(checkedItemPositions.get(i))
 {
 adapterList1.remove(items1.get(i));
 }
 }
 checkedItemPositions.clear();
 adapterList1.notifyDataSetChanged(); 
 break;
 case R.id.imageViewPlusSubEdit2:
 if(editTextInputNameSubEdit2.getText().toString().trim().length() == 0)
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items2.size() > 23)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items2.add(editTextInputNameSubEdit2.getText().toString());
 adapterList2.notifyDataSetChanged(); 
 editTextInputNameSubEdit2.setText("");
 }
 break;
 case R.id.imageViewMinusSubEdit2:
 SparseBooleanArray checkedItemPositions2 = listViewSubEdit2.getCheckedItemPositions();
 int itemCount2 = listViewSubEdit2.getCount();
 for(int i = itemCount2 - 1; i >= 0; i--)
 {
 if(checkedItemPositions2.get(i))
 {
 adapterList2.remove(items2.get(i));
 }
 }
 checkedItemPositions2.clear();
 adapterList2.notifyDataSetChanged(); 
 break;
 case R.id.imageViewPlusSubEdit3:
 if(editTextInputNameSubEdit3.getText().toString().trim().length() == 0)
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items3.size() > 23)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items3.add(editTextInputNameSubEdit3.getText().toString());
 adapterList3.notifyDataSetChanged(); 
 editTextInputNameSubEdit3.setText("");
 }
 break;
 case R.id.imageViewMinusSubEdit3:
 SparseBooleanArray checkedItemPositions3 = listViewSubEdit3.getCheckedItemPositions();
 int itemCount3 = listViewSubEdit3.getCount();
 for(int i = itemCount3 - 1; i >= 0; i--)
 {
 if(checkedItemPositions3.get(i))
 {
 adapterList3.remove(items3.get(i));
 }
 }
 checkedItemPositions3.clear();
 adapterList3.notifyDataSetChanged(); 
 break;
 case R.id.imageViewPlusSubEdit4:
 if(editTextInputNameSubEdit4.getText().toString().trim().length() == 0)
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items4.size() > 23)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items4.add(editTextInputNameSubEdit4.getText().toString());
 adapterList4.notifyDataSetChanged(); 
 editTextInputNameSubEdit4.setText("");
 }
 break;
 case R.id.imageViewMinusSubEdit4:
 SparseBooleanArray checkedItemPositions4 = listViewSubEdit4.getCheckedItemPositions();
 int itemCount4 = listViewSubEdit4.getCount();
 for(int i = itemCount4 - 1; i >= 0; i--)
 {
 if(checkedItemPositions4.get(i))
 {
 adapterList4.remove(items4.get(i));
 }
 }
 checkedItemPositions4.clear();
 adapterList4.notifyDataSetChanged(); 
 break;
 case R.id.imageViewPlusSubEdit5:
 if(editTextInputNameSubEdit5.getText().toString().trim().length() == 0)
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items5.size() > 23)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items5.add(editTextInputNameSubEdit5.getText().toString());
 adapterList5.notifyDataSetChanged(); 
 editTextInputNameSubEdit5.setText("");
 }
 break;
 case R.id.imageViewMinusSubEdit5:
 SparseBooleanArray checkedItemPositions5 = listViewSubEdit5.getCheckedItemPositions();
 int itemCount5 = listViewSubEdit5.getCount();
 for(int i = itemCount5 - 1; i >= 0; i--)
 {
 if(checkedItemPositions5.get(i))
 {
 adapterList5.remove(items5.get(i));
 }
 }
 checkedItemPositions5.clear();
 adapterList5.notifyDataSetChanged(); 
 break;
 case R.id.imageViewPlusSubEdit6:
 if(editTextInputNameSubEdit6.getText().toString().trim().length() == 0)
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items6.size() > 23)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items6.add(editTextInputNameSubEdit6.getText().toString());
 adapterList6.notifyDataSetChanged(); 
 editTextInputNameSubEdit6.setText("");
 }
 break;
 case R.id.imageViewMinusSubEdit6:
 SparseBooleanArray checkedItemPositions6 = listViewSubEdit6.getCheckedItemPositions();
 int itemCount6 = listViewSubEdit6.getCount();
 for(int i = itemCount6 - 1; i >= 0; i--)
 {
 if(checkedItemPositions6.get(i))
 {
 adapterList6.remove(items6.get(i));
 }
 }
 checkedItemPositions6.clear();
 adapterList6.notifyDataSetChanged(); 
 break;
 }

Answer 1

Step #1: create a function for the body of each case in your switch statement

public void onClick(View v) {
 // TODO Auto-generated method stub
 switch (v.getId())
 {
 case R.id.imageViewPlusSubEdit1:
 handleImageViewPlusSubEdit1();
 break;
 case R.id.imageViewMinusSubEdit1:
 handleImageViewMinusSubEdit1();
 break;
 ...
 }
}

Step #2: create your own click handler interface - or re-use the existing one

interface ClickHandler {
 void onClick();
}

Step #3: create specific classes for each of the different ways that you handle the clicks. For example:

class PlusClickHander implements ClickHandler {
 public void onClick() {
 handleImageViewPlusSubEdit1();
 }
}

Step #4: replace the switch statements that directly call the functions, with calls to the ClickHandlers

public void onClick(View v) {
 // TODO Auto-generated method stub
 switch (v.getId())
 {
 case R.id.imageViewPlusSubEdit1:
 ClickHandler plusClickHandler = new PlusClickHandler();
 plusClickHandler.onClick();
 break;
 case R.id.imageViewMinusSubEdit1:
 ClickHandler minusClickHandler = new MinusClickHandler();
 minusClickHandler.onClick();
 break;
 ...
 }
}

Step #5: move the click handlers into a Map, so that you can look them up.

public void onClick(View v) {
 Map<Id,ClickHandler> handlers = new HashMap<Id,ClickHandler>();
 handlers.put(R.id.imageViewPlusSubEdit1, new PlusClickHandler();
 handlers.put(R.id.imageViewMinusSubEdit1, new MinusClickHandler();
 ...
 ClickHandler clickHandler = handlers.get(v.getId());
 clickHandler.onClick();
}

Step #6: create a new function to get the map you need

public Map<Id,ClickHandler> createHandlers() {
 Map<Id,ClickHandler> handlers = new HashMap<Id,ClickHandler>();
 handlers.put(R.id.imageViewPlusSubEdit1, new PlusClickHandler();
 handlers.put(R.id.imageViewMinusSubEdit1, new MinusClickHandler();
 ...
 return handlers;
}
public void onClick(View v) {
 Map<Id,ClickHandler> handlers = createHandlers();
 ClickHandler clickHandler = handlers.get(v.getId());
 clickHandler.onClick();
}

Here's an example of what PlusClickHandler might look like...

public class PlusClickHandler implements ClickHandler {
 private final ? editTextInput;
 private final ? items;
 private final ? adapterList;
 private final int itemLimit = 23;
 public PlusClickHandler(...) {
 editTextInput = ?
 items = ?
 adapterList = ?
 }
 public void onClick() {
 String input = editTextInput.getText().toString();
 if(input.isEmpty())
 {
 Toast.makeText(this, "Empty text!", Toast.LENGTH_SHORT).show();
 }
 else if(items.size() > itemLimit)
 {
 Toast.makeText(this, "Too many elements!", Toast.LENGTH_SHORT).show();
 }
 else
 { 
 items.add(input);
 adapterList.notifyDataSetChanged(); 
 editTextInput.setText("");
 }
 }
}