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POHow to delete elements from a list in Android?
 

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  1. POHow to delete elements from a list in Android?
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    <p>Can anyone explain how to remove a child item from my expandable list under <code>childMap</code> when the same child is clicked (called with <code>onChildClick</code>)? I've tried a few things can't seem to make it work.</p> <pre><code>public class Expense1 extends ExpandableListActivity { public static final String GROUP_ID = "Group"; public static final String CHILD_ID = "Child"; public static final int GROUPS = 1; int arrayLength; Button eButton; EditText eEdit; EditText nEdit; public int expenseVar; public String expenseComment; public String expenseInfo; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.expense1); SimpleExpandableListAdapter expandableListAdapter = new SimpleExpandableListAdapter( this, createGroupList(), // Creating group List. R.layout.group_row, // Group item layout XML. new String[] { GROUP_ID }, // the key of group item. new int[] { R.id.group_text }, // ID of each group item.-Data under the key goes into this TextView. createChildList(), // childData describes second-level entries. R.layout.child_row, // Layout for sub-level entries(second level). new String[] { CHILD_ID }, // Keys in childData maps to display. new int[] { R.id.child_text } // Data under the keys above go into these TextViews. ); setListAdapter(expandableListAdapter); // setting the adapter in the list. eButton = (Button)findViewById(R.id.expense_update); eEdit = (EditText)findViewById(R.id.expense_textField); nEdit = (EditText)findViewById(R.id.expenseComment_textField); eButton.setOnClickListener( new View.OnClickListener() { public void onClick(View view) { Common variableContext = ((Common)getApplicationContext()); expenseInfo = eEdit.getText().toString(); expenseComment = nEdit.getText().toString(); /* check REGULAR expense length and execute code */ if( expenseInfo.length() &lt; 1 &amp;&amp; expenseComment.length() &gt; 0 ) { new AlertDialog.Builder(Expense1.this).setTitle("Error") .setMessage("enter a value") .setPositiveButton("OK", null).show();} else if( expenseInfo.length() &gt;= 1 &amp;&amp; expenseComment.length() &lt; 1 ) { new AlertDialog.Builder(Expense1.this).setTitle("Error") .setMessage("enter a comment") .setPositiveButton("OK", null).show(); } else if( expenseInfo.length() &lt; 1 &amp;&amp; expenseComment.length() &lt; 1 ) { new AlertDialog.Builder(Expense1.this).setTitle("Error") .setMessage("Please fill out fields") .setPositiveButton("OK", null).show(); } else { /* if both fields are correct then set the 'expenseVar' variable to the received integer: * this stops the program crashing as it is executed after the fields are checked */ expenseVar = Integer.valueOf(eEdit.getText().toString()); /* set the values of the expense value and expense comment array by taking these from the fields * when the button is clicked and assigning them to whatever the 'ReturnExpenseCounter' is on: * the value returned depends on how many times the button has been clicked */ variableContext.setExpenseCounter(); String xxd = String.valueOf(expenseVar); int dds = variableContext.returnExpenseCounter(); variableContext.infoArray[dds] = xxd; variableContext.commentArray[dds] = expenseComment; /* reload the screen to make the array list update */ Intent reloadScreen = new Intent(Expense1.this, Expense1.class); startActivity(reloadScreen); finish(); } } }); } /* Creating the Hash-map for the row */ private List&lt;HashMap&lt;String, String&gt;&gt; createGroupList() { ArrayList&lt;HashMap&lt;String, String&gt;&gt; list = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;(); for( int i = 0 ; i &lt; GROUPS ; ++i ) { HashMap&lt;String, String&gt; groupMap = new HashMap&lt;String, String&gt;(); groupMap.put( GROUP_ID, "Group Item " + i ); list.add(groupMap); } return (List&lt;HashMap&lt;String, String&gt;&gt;)list; } /* create the HashMap for the children */ private List&lt;ArrayList&lt;HashMap&lt;String, String&gt;&gt;&gt; createChildList() { ArrayList&lt;ArrayList&lt;HashMap&lt;String, String&gt;&gt;&gt; result = new ArrayList&lt;ArrayList&lt;HashMap&lt;String, String&gt;&gt;&gt;(); ArrayList&lt;HashMap&lt;String, String&gt;&gt; subList = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;(); Common variableContext = ((Common)getApplicationContext()); arrayLength = variableContext.returnExpenseCounter() + 1; for( int n = 0 ; n &lt; arrayLength ; n++ ) { HashMap&lt;String, String&gt; childMap = new HashMap&lt;String, String&gt;(); childMap.put( CHILD_ID, "Amount: "+"£"+variableContext.infoArray[n] ); subList.add(childMap); } for (int i = 0; i &lt; GROUPS; ++i) { result.add(subList); } return result; } /* This function is called on each child click */ public boolean onChildClick( ExpandableListView parent, View v, int groupPosition,int childPosition,long id) { switch(childPosition){ case 0: //here for example i want to add something that removes an item from the child map //in this case the item at the start (because its case 0) Toast.makeText(this, "child 1", Toast.LENGTH_LONG).show(); Common variableContext = ((Common)getApplicationContext()); variableContext.minusExpenseCounter(); Intent bb = new Intent(Expense1.this, Expense1.class); startActivity(bb); finish(); break; } return true; }} </code></pre>
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