我正在Android工作室中创建一个应用程序，要求用户从一个活动的可扩展列表视图中选择一个子项，并将其显示在另一个活动上。我是java和android工作室的新手，但仍然不明白如何做到这一点。如果有人有任何示例代码或可以帮助那将是伟大的，谢谢！
答案 0 :(得分：0)
您应该使用ExpandableListView类中的setOnChildClickListener方法为列表元素创建ClickListener，然后使用Intent打开新活动。在为ListView设置适配器后，应设置设置侦听器的调用。
Here有一个使用ExpandableListView的教程，它展示了如何为元素设置ClickListener。
而且here还有Android开发人员的文档，其中显示了如何通过按钮的点击创建和打开新活动。
答案 1 :(得分：0)
**You should use the setOnChildClickListener method from the ExpandableListView class to create a ClickListener for the list elements and then use a Intent to open the new activity. The call to set the listener should be set after you've set the adapter for the ListView and create the xml file for child and parent.child will be Expandable TextView **
**layout file**
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
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="com.example.elite_android.explistview1.MainActivity">
<RelativeLayout
android:id="@+id/main_number_picker_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginTop="17dp">
<NumberPicker
android:id="@+id/main_number_picker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:text="Next" />
<TextView
android:id="@+id/main_txt_patient_count"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toLeftOf="@id/main_number_picker"
android:text="Select number of patient"
android:textColor="@color/colorAccent"
android:layout_marginLeft="80dp"/>
</RelativeLayout>
<ExpandableListView
android:id="@+id/exp_Listview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@id/main_number_picker_layout">
</ExpandableListView>
</RelativeLayout>
**Main Activity.java file**
package com.example.elite_android.explistview1;
import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.ExpandableListView;
import android.view.View.OnFocusChangeListener;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ListView;
import android.widget.NumberPicker;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.NumberPicker;
public class MainActivity extends AppCompatActivity {
ExpandableListView expandableListView;
private MyAdapter mAdapter;
ExpandableListView expand;
NumberPicker numberPicker;
private List<String> headerItems;
private ArrayList childDetails;
private HashMap<String, List<String>> childList;
private Context ctx;
EditText editText1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// get reference to the EditText
editText1 = (EditText) findViewById(R.id.child_item);
// //set the onFocusChange listener
// // editText1.setOnFocusChangeListener(editText1.getOnFocusChangeListener());
//
//// //get reference to EditText
//// editText2 = (EditText) findViewById(R.id.sequence);
//// // set the on focusChange listner
//// editText2.setOnFocusChangeListener(editText2.getOnFocusChangeListener());
//
// //Generate list View from ArrayList;
//
//
// EditText editText = (EditText) findViewById(R.id.child_item);
// editText.requestFocus();
// InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
// imm.showSoftInput(editText, InputMethodManager.SHOW_IMPLICIT);
//
//
//// editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
// // @Override
// // public void onFocusChange(View v, boolean hasFocus) {
// // //editText.setOnFocusChangeListener();
// // return;
// // }
// //});
//
String[] numbers = new String[10];
for (int count = 0; count < 10; count++)
numbers[count] = String.valueOf(count);
numberPicker = (NumberPicker) findViewById(R.id.main_number_picker);
numberPicker.setMaxValue(numbers.length);
numberPicker.setMinValue(1);
numberPicker.setDisplayedValues(numbers);
numberPicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
generateListItems(newVal);
loadRecycleView();
}
});
}
private void generateListItems(int childCount) {
if (headerItems != null)
headerItems.clear();
else
headerItems = new ArrayList<>();
if (childList != null)
childList.clear();
else
childList = new HashMap();
if (childDetails == null) {
childDetails = new ArrayList();
childDetails.add("Name");
childDetails.add("Age");
childDetails.add("Gender");
}
// Put header items
for (int count = 0; count < childCount; count++) {
headerItems.add(" Parent " + count);
childList.put(headerItems.get(count), childDetails);
}
}
private void loadRecycleView() {
if (expandableListView == null) {
expandableListView = (ExpandableListView) findViewById(R.id.exp_Listview);
mAdapter = new MyAdapter(this, headerItems, childList);
expandableListView.setAdapter(mAdapter);
} else {
expandableListView.invalidate();
mAdapter.setHeaderData(headerItems);
mAdapter.setListData(childList);
mAdapter.notifyDataSetChanged();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return true;
}
}
**Adapter class.java**
package com.example.elite_android.explistview1;
import android.content.Context;
import android.graphics.Color;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.InputMethodManager;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.NumberPicker;
import android.widget.TextView;
import android.widget.EditText;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.view.View.OnFocusChangeListener;
/**
* Created by ELITE-ANDROID on 28-02-2017.
*/
// this is provides all needs methods implementing an Expandable List VIew
public class MyAdapter extends BaseExpandableListAdapter {
// We need some Variables here so therer are some Variables here
private List<String> header_titles; // This is for Representing the HeadLine(Array list)
private HashMap<String, List<String>> child_titles; // defin the HashMap for the child item how to Represent the Parent Handing so Hash Map, need some Variables
private Context ctx;
private NumberPicker numberPicker;
EditText editText;
View view;
private static LayoutInflater inflater = null;
//for initalized for all Variables we need some Constructor
public MyAdapter(Context context, List<String> header_titles, HashMap<String, List<String>> child_titles) {
super();
this.ctx = context;
this.child_titles = child_titles;
this.header_titles = header_titles;
}
public void refreshHeader_titles(List<String> events) {
this.header_titles.clear();
this.header_titles.addAll(header_titles);
notifyDataSetChanged();
}
;
@Override
// From this Override method How to Return how many elements are the Group count like parent
public int getGroupCount() {
return header_titles.size();
}
@Override
//here the number of child items are in each heading. There are three Heading - PAtien Name ,Age, Gender
public int getChildrenCount(int groupPosition) {
// Log.d("xxx", )
return child_titles.get(header_titles.get(groupPosition)).size(); //how to Return the size of HashMap
}
@Override
public Object getGroup(int groupPosition) {
return header_titles.get(groupPosition);
}
@Override
// here how to retuen child items on the particular headings and Positions.
public Object getChild(int groupPosition, int childPosition) {
return child_titles.get(header_titles.get(groupPosition)).get(childPosition);
}
@Override
//return the groupo position
public long getGroupId(int groupPosition) {
return groupPosition;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public boolean hasStableIds() {
return false;
}
@Override
// Here return the Group View
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
// ListViewHolder viewHolder;
// if (view == null) {
// viewHolder = new ListViewHolder();
// LayoutInflater inflater = context.getLayoutInflater();
// view = inflater.inflate(R.layout.listitems, null, true);
// viewHolder.itmName = (TextView) view.findViewById(R.id.Item_name);
// viewHolder.itmPrice = (EditText) view.findViewById(R.id.Item_price);
// view.setTag(viewHolder);
// } else {
// viewHolder = (ListViewHolder) view.getTag();
//// loadSavedValues();
// }
// Here how to get the Heading Title here Decalered String Variables, now how to get title of heading from getGroup methods so simple call Backed Methods.
String title = (String) this.getGroup(groupPosition);
if (convertView == null) {
LayoutInflater layoutInflater = (LayoutInflater) this.ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.prent, null);
}
TextView textView = (TextView) convertView.findViewById(R.id.heading_item);
textView.setText(title); // for Heading bold style ,title
return convertView;
}
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
String title = (String) this.getChild(groupPosition, childPosition);
if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = infalInflater.inflate(R.layout.child, null);
}
String cellData = child_titles.get(header_titles.get(groupPosition)).get(childPosition);
EditText childItem = (EditText) convertView.findViewById(R.id.child_item);
childItem.setHint(cellData);
childItem.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
// Log.d("xxxx", "Has focus " + hasFocus);
if (!hasFocus) {
// int itemIndex = View.getId();
// String enteredName = ((EditText)v).getText().toString();
// selttems.put(itemIndex, enteredName);
} else {
}
return;
}
});
return convertView;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
public void setListData(HashMap<String, List<String>> lData) {
child_titles = lData;
}
public void setHeaderData(List<String> hData) {
header_titles = hData;
}
}
**child.Xml file**
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#ffff">
<EditText
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/child_item"
android:textSize="25dp"
android:textStyle="bold"
android:gravity="center_vertical"
android:layout_marginLeft="10dp"/>
<!--<EditText-->
<!--android:id="@+id/sequence"-->
<!--android:layout_width="wrap_content"-->
<!--android:layout_height="wrap_content"-->
<!--android:layout_alignParentLeft="true"-->
<!--android:layout_alignParentTop="true"-->
<!--android:paddingLeft="35sp"-->
<!--android:layout_marginRight="10dp"-->
<!--android:textAppearance="?android:attr/textAppearanceMedium" />-->
</LinearLayout>
<!--This Layout File Represent the Child Items.
This Field Represent the Child Item IN the List VIew -->
**parent.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="50dp"
android:orientation="vertical">
<TextView
android:id="@+id/heading_item"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="10dp"
android:gravity="center_vertical"
android:textColor="@color/colorAccent"
android:textSize="25dp" />
</LinearLayout>
<!--This Layout file for Heading -Lines.-->