Use of expandablelist in Android 2

Use of expandablelist in Android 2

This article introduces the use of expandablelist in Android, and makes many improvements based on the previous article, adding, deleting, and callback functions.

In the figure, "first line team no.: 1 class 2 of software engineering" is the information to be displayed.

First look:

 

First, define a layout containing expandablelistview. There is also text information displayed.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <ExpandableListView        android:id="@+id/expandableListView1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/textView1"        android:layout_below="@+id/textView1"        android:layout_marginTop="52dp" >    </ExpandableListView></RelativeLayout>

 

2. Prepare a data source for expandablelistview.

The classgroups List defines all classes.

Classdetails defines detailed information about the class. Including the class number, class name, class number, and teacher.

Private list <string> classgroups = new arraylist <string> (); Private list <string> classdetails = new arraylist <list <string> (); private string [] [] classdetailssource = {"20100801", "Software Engineering Class 1", "50", "instructor Wang" },{ "20100802 ", "Software Engineering Class 2", "47", "teacher" },{ "20100803", "network engineering class 1", "52" },{ "20100804 ", "Computer Science and Technology "}};

Use the additem method to initialize four classes.

Private void pareparedatasource () {for (INT I = 0; I <4; I ++) {additem ("Team ID:" + I, classdetailssource [I]);}

Add classdetails to all classes.

private void addItem(String string, String[] data) {// TODO Auto-generated method stubClassGroups.add(string);List<String> item = new ArrayList<String>();for (int i = 0; i < data.length; i++) {item.add(data[i]);}ClassDetails.add(item);}

 

 3. Use baseexpandablelistadapter to bind the data source.This article has been introduced in my previous article and is not described here.

@ Overridepublic void oncreate (bundle savedinstancestate) {super. oncreate (savedinstancestate); setcontentview (R. layout. activity_main); pareparedatasource (); tview = (textview) findviewbyid (R. id. textview1); expandablelistview = (expandablelistview) findviewbyid (R. id. expandablelistview1); expandablelistview. setadapter (New expandablelistadapter (); // The callback function of expandablelistview is used to listen to the ID that is expandexpandablelistview. setongroupclicklistener (New ongroupclicklistener () {@ overridepublic Boolean ongroupclick (expandablelistview parent, view V, int groupposition, long ID) {// todo auto-generated method stubtoast. maketext (expandablelist3.this, "you click" + groupposition + "group", toast. length_long ). show (); Return false ;}}); expandablelistview. setonchildclicklistener (New onchildclicklistener () {@ overridepublic Boolean onchildclick (expandablelistview parent, view V, int groupposition, int childposition, long ID) {// todo auto-generated method stubtoast. maketext (expandablelist3.this, "you click" + childposition + "child in group" + groupposition, toast. length_long ). show (); Return false ;}});}

 

Note: expandablelistview. setongroupclicklistener (New ongroupclicklistener () and expandablelistview. setonchildclicklistener (New onchildclicklistener () are callback methods.

The data source form of expandablelistadapter is as follows:

public class ExpandableListAdapter extends BaseExpandableListAdapter {@Overridepublic boolean isChildSelectable(int groupPosition, int childPosition) {// TODO Auto-generated method stubString string = ClassGroups.get(groupPosition)+ ClassDetails.get(groupPosition).get(childPosition); 
tView.setText(string);return true;}@Overridepublic boolean hasStableIds() {// TODO Auto-generated method stubreturn true;}@Overridepublic View getGroupView(int groupPosition, boolean isExpanded,View convertView, ViewGroup parent) {// TODO Auto-generated method stubLinearLayout layout = new LinearLayout(ExpandableList3.this);layout.setOrientation(0);layout.setPadding(50, 0, 0, 0);ImageView imageView = new ImageView(ExpandableList3.this);imageView.setImageResource(R.drawable.ic_launcher);layout.addView(imageView);TextView textView = getTextView();textView.setText(getGroup(groupPosition).toString());layout.addView(textView);return layout;}private TextView getTextView() {// TODO Auto-generated method stubAbsListView.LayoutParams lParams = new AbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 64);TextView textView = new TextView(ExpandableList3.this);textView.setLayoutParams(lParams);textView.setPadding(20, 0, 0, 0);textView.setGravity(Gravity.LEFT | Gravity.CENTER_VERTICAL);return textView;}@Overridepublic long getGroupId(int groupPosition) {// TODO Auto-generated method stubreturn groupPosition;}@Overridepublic int getGroupCount() {// TODO Auto-generated method stubreturn ClassGroups.size();}@Overridepublic Object getGroup(int groupPosition) {// TODO Auto-generated method stubreturn ClassGroups.get(groupPosition);}@Overridepublic int getChildrenCount(int groupPosition) {// TODO Auto-generated method stubreturn ClassDetails.get(groupPosition).size(); 
}@Overridepublic View getChildView(int groupPosition, int childPosition,boolean isLastChild, View convertView, ViewGroup parent) {// TODO Auto-generated method stubTextView textView = getTextView();textView.setText(getChild(groupPosition, childPosition).toString());return textView;}@Overridepublic long getChildId(int groupPosition, int childPosition) {// TODO Auto-generated method stubreturn childPosition;}@Overridepublic Object getChild(int groupPosition, int childPosition) {// TODO Auto-generated method stubreturn ClassDetails.get(groupPosition).get(childPosition); }};

 

2. Create two menus and call their respective methods. One is to create the class dialog, and the other is to create and delete the dialog.

@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);menu.add(Menu.NONE, Menu.FIRST + 1, 1, "Add").setIcon(R.drawable.ic_launcher);menu.add(Menu.NONE, Menu.FIRST + 2, 2, "Delete").setIcon(R.drawable.ic_launcher);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {switch (item.getItemId()) {case Menu.FIRST + 1:createAddDialog();break;case Menu.FIRST + 2:createDeleteDialog();break;}return false;}

 

1. The added layout add_item.xml is as follows: four texts, one confirmation button, and one cancel button are put in the text box respectively.

<? XML version = "1.0" encoding = "UTF-8"?> <Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android" Android: layout_width = "match_parent" Android: layout_height = "match_parent" Android: Orientation = "vertical"> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: Orientation = "horizontal"> <textview Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margin = "5dp" Android: text = "class number"/> <edittext Android: Id = "@ + ID/add_item1" Android: layout_width = "200dip" Android: layout_height = "wrap_content" Android: layout_margin = "5dp"/> </linearlayout> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: orientation = "horizontal"> <textview Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margin = "5dp" Android: TEXT = "Class Name"/> <edittext Android: Id = "@ + ID/add_item2" Android: layout_width = "200dip" Android: layout_height = "wrap_content" Android: layout_margin = "5dp"/> </linearlayout> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: Orientation = "horizontal"> <textview Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margin = "5dp" Android: text = "class size"/> <edittext Android: id = "@ + ID/add_item3" Android: layout_width = "200dip" Android: layout_height = "wrap_content" Android: layout_margin = "5dp"/> </linearlayout> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: Orientation = "horizontal"> <textview Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margin = "5dp" Android: text = ""/> <edittext Android: Id = "@ + ID/add_item4" Android: layout_width = "200dip" Android: layout_height = "wrap_content" Android: layout_margin = "5dp"/> </linearlayout> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: orientation = "horizontal"> <button Android: Id = "@ + ID/OK" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margin = "5dp" Android: text = "OK"/> <button Android: Id = "@ + ID/cancle" Android: layout_width = "200dip" Android: layout_height = "wrap_content" Android: layout_margin = "5dp" Android: text = "cancle"/> </linearlayout>

 

2. The added code is as follows: add the class information by additem (class_no.gettext (). tostring (), data. Close the current dialog when you cancel the button.

private EditText class_no;private EditText class_name;private EditText stu_num;private EditText teacher;private Dialog addDialog;public void createAddDialog() {View addView = getLayoutInflater().inflate(R.layout.add_item, null);addDialog = new Dialog(this);addDialog.setContentView(addView);addDialog.setTitle("Add class dialog");class_no = (EditText) addView.findViewById(R.id.add_item1);class_name = (EditText) addView.findViewById(R.id.add_item2);stu_num = (EditText) addView.findViewById(R.id.add_item3);teacher = (EditText) addView.findViewById(R.id.add_item4);Button ok = (Button) addView.findViewById(R.id.ok);Button cancle = (Button) addView.findViewById(R.id.cancle);ok.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString[] data = { class_no.getText().toString(),class_name.getText().toString(), stu_num.getText().toString(),teacher.getText().toString() };addItem(class_no.getText().toString(), data);addDialog.dismiss();}});cancle.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubaddDialog.dismiss();}});addDialog.show();}

 

3. added the following:

 

4. Similarly, layout is delete_item.xml.

<? XML version = "1.0" encoding = "UTF-8"?> <Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android" Android: layout_width = "match_parent" Android: layout_height = "match_parent" Android: Orientation = "vertical"> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: Orientation = "horizontal"> <textview Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: TEXT = "deleted team ID:"/> <edittext Android: Id = "@ + ID/delete_id" Android: layout_width = "200dip" Android: layout_height = "wrap_content"/> </linearlayout> <linearlayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: Orientation = "horizontal"> <button Android: id = "@ + ID/Delete" Android: layout_width = "90dip" Android: layout_height = "wrap_content" Android: text = "delete"/> <button Android: id = "@ + ID/cancle_delete" Android: layout_width = "90dip" Android: layout_height = "wrap_content" Android: text = "canlce"/> </linearlayout>

 

5. The deletion code is: Enter the number, for example, 2. delete all the information of the class whose team number is 2. The classgroups. Remove (I); classdetails. Remove (I); method is called.

Dialog deleteDialog;EditText delete_group_id;public void createDeleteDialog() {View deleteView = getLayoutInflater().inflate(R.layout.delete_item,null);deleteDialog = new Dialog(this);deleteDialog.setContentView(deleteView);deleteDialog.setTitle("Delete class dialog");delete_group_id = (EditText) deleteView.findViewById(R.id.delete_id);Button ok = (Button) deleteView.findViewById(R.id.delete);Button cancle = (Button) deleteView.findViewById(R.id.cancle_delete);ok.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString deleteId = delete_group_id.getText().toString();if (!deleteId.equals("")) {int i = Integer.parseInt(deleteId);ClassGroups.remove(i);ClassDetails.remove(i);}deleteDialog.dismiss();}});cancle.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubdeleteDialog.dismiss();}});deleteDialog.show();}

 

6. Delete the following:

 

 

 

Iii. Use of callback Functions.

When you click a group, the group information is displayed. Click item information to display the information of the combined item. For example, the information shown in the bottom right corner of the first image.

// The callback function of expandablelistview is used to listen to the ID that is expandexpandablelistview. setongroupclicklistener (New ongroupclicklistener () {@ overridepublic Boolean ongroupclick (expandablelistview parent, view V, int groupposition, long ID) {// todo auto-generated method stubtoast. maketext (expandablelist3.this, "you click" + groupposition + "group", toast. length_long ). show (); Return false ;}}); expandablelistview. setonchildclicklistener (New onchildclicklistener () {@ overridepublic Boolean onchildclick (expandablelistview parent, view V, int groupposition, int childposition, long ID) {// todo auto-generated method stubtoast. maketext (expandablelist3.this, "you click" + childposition + "child in group" + groupposition, toast. length_long ). show (); Return false ;}});

The use of expandablelist is described here. This article also records your learning situation, so that you can learn it again later.