Java 从ListView中选择项目并在单击-Android待办事项列表应用程序时将其删除
我对Android Dev/Java非常陌生,我正在在线学习一个教程,并尝试为Android创建一个简单的待办事项列表应用程序。看起来本教程有点过时,依赖DPAD在任务列表中上下导航,以确定列表项的目标,并使用“应用程序”菜单中的“删除按钮”将其删除。我很难弄清楚如何在单击时“选择”列表项,然后使用“删除”按钮将其删除。现在,当一个用户单击一个列表项时,它什么也不做,所以当我单击“删除”按钮时,应用程序不知道选择了哪个。这是我的XML和Java代码。任何见解都会非常有用 XMLJava 从ListView中选择项目并在单击-Android待办事项列表应用程序时将其删除,java,android,android-listview,Java,Android,Android Listview,我对Android Dev/Java非常陌生,我正在在线学习一个教程,并尝试为Android创建一个简单的待办事项列表应用程序。看起来本教程有点过时,依赖DPAD在任务列表中上下导航,以确定列表项的目标,并使用“应用程序”菜单中的“删除按钮”将其删除。我很难弄清楚如何在单击时“选择”列表项,然后使用“删除”按钮将其删除。现在,当一个用户单击一个列表项时,它什么也不做,所以当我单击“删除”按钮时,应用程序不知道选择了哪个。这是我的XML和Java代码。任何见解都会非常有用 XML 爪哇 pac
爪哇
package com.example.todo;
导入java.util.ArrayList;
导入java.util.Calendar;
导入android.app.Activity;
导入android.app.AlertDialog;
导入android.content.DialogInterface;
导入android.os.Bundle;
导入android.view.KeyEvent;
导入android.view.Menu;
导入android.view.MenuItem;
导入android.view.view;
导入android.view.view.OnKeyListener;
导入android.widget.AdapterView;
导入android.widget.AdapterView.OnItemClickListener;
导入android.widget.ArrayAdapter;
导入android.widget.Button;
导入android.widget.EditText;
导入android.widget.ListView;
导入android.widget.TextView;
导入android.widget.Toast;
公共类MainActivity扩展活动实现View.OnClickListener、DialogInterface.OnClickListener、OnKeyListener{
编辑文本项;
按钮btnAdd;
按钮btnDelete;
列表视图列表项;
ArrayList toDoItems;
ArrayAdapter aa;
字符串[]日期={“电影”、“晚餐”、“饮料”};
String[]gym={“有氧运动”、“上半身”、“下半身”};
字符串[]会议={“30分钟会议”、“1小时会议”、“2小时会议”};
字符串[]作业={“论文”、“练习”、“作业”};
String[]project={“App”,“Web”,“Graphic Design”};
字符串菜单;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textItem=(EditText)findViewById(R.id.textItem);
btnAdd=(按钮)findviewbyd(R.id.btnAdd);
btnDelete=(按钮)findViewById(R.id.btnDelete);
listItems=(ListView)findViewById(R.id.listItems);
btnAdd.setOnClickListener(此);
textItem.setOnKeyListener(此);
toDoItems=新的ArrayList();
aa=新的ArrayAdapter(这是android.R.layout.simple\u list\u item\u 1,toDoItems);
setAdapter(aa);
/*--将标题设置为今天的日期--*/
TextView tvDisplayDate=(TextView)findViewById(R.id.heading);
最终日历c=Calendar.getInstance();
int yy=c.get(日历年);
int mm=c.get(日历月);
int dd=c.get(日历日/月);
//将当前日期设置为文本视图
tvDisplayDate.setText(新的StringBuilder()
//月份以0为基础,只需添加1
.append(mm+1)。append(“/”)。append(dd)。append(“/”)。append(yy));
}
公共布尔onCreateOptions菜单(菜单){
super.onCreateOptions菜单(菜单);
菜单项;
项目=菜单。添加(“删除”);
项目.设置图标(R.可绘制.移除);
项目=菜单。添加(“日期”);
项目设置图标(R.可绘制日期);
项目=菜单。添加(“健身房”);
项目。设置图标(R.可牵引。健身房);
项目=菜单。添加(“会议”);
项目.设置图标(R.可绘制会议);
项目=菜单。添加(“家庭作业”);
项目.设置图标(R.可绘制.作业);
项目=菜单。添加(“项目”);
项目设置图标(R.可绘制项目);
返回true;
}
公共布尔值onOptionsItemSelected(菜单项项){
super.onOptionsItemSelected(项目);
if(item.hasSubMenu()==false){
if(item.getTitle()=“日期”){
currentMenu=“日期”;
this.displayPopup(“日期选项”,this.Date);
}
if(item.getTitle()=“gym”){
currentMenu=“gym”;
this.displayPopup(“健身房选项”,this.Gym);
}
if(item.getTitle()=“会议”){
currentMenu=“会议”;
this.displayPopup(“会议选项”,this.Meeting);
}
if(item.getTitle()=“家庭作业”){
currentMenu=“家庭作业”;
this.displayPopup(“家庭作业选项”,this.homography);
}
if(item.getTitle()=“项目”){
currentMenu=“项目”;
this.displayPopup(“项目选项”,this.Project);
}
if(item.getTitle()=“删除”){
int index=listItems.getSelectedItemPosition();
本条删除项目(索引);
}
}
返回true;
}
私有void附加项(字符串项){
如果(item.length()>0){
Toast.makeText(getApplicationContext(),item+“added”,Toast.LENGTH_SHORT.show();
this.toDoItems.add(项);
this.aa.notifyDataSetChanged();
此.textItem.setText(“”);
}
}
私有void deleteItem(int itemId){
如果(itemId>=0){
String itemName=(String)listItems.getItemAtPosition(itemId);
Toast.makeText(getApplicationContext(),itemName+“delete”,Toast.LENGTH\u SHORT.show();
this.toDoItems.remove(itemId);
aa.notifyDataSetChanged();
}
}
私有void显示弹出窗口(字符串标题,字符串[]项){
AlertDialog.Builder=新建AlertDialog.Builder(此);
建造商名称(名称);
builder.setItems(items,this);
builder.show();
}
@凌驾
公共void onClick(视图v){
如果(v==this.btnAdd){
this.addItem(this.textItem.getText
<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" >
<EditText
android:id="@+id/textItem"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:ems="10" />
<Button
android:id="@+id/btnAdd"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textItem"
android:layout_below="@+id/textItem"
android:text="@string/add" />
<ListView
android:id="@+id/listItems"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/btnAdd"
android:layout_alignRight="@+id/btnAdd"
android:layout_below="@+id/btnAdd"
android:layout_marginTop="20dp" >
</ListView>
</RelativeLayout>
package com.example.todo;
import java.util.ArrayList;
import java.util.Calendar;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity implements View.OnClickListener, DialogInterface.OnClickListener, OnKeyListener {
EditText textItem;
Button btnAdd;
Button btnDelete;
ListView listItems;
ArrayList<String> toDoItems;
ArrayAdapter<String> aa;
String[] date = {"Movie", "Dinner", "Drinks"};
String[] gym = {"Cardio", "Upper Body", "Lower Body"};
String[] meeting = {"30min Meeting", "1 Hour Meeting", "2 Hour Meeting"};
String[] homework = {"Paper", "Exercise", "Assignment"};
String[] project = {"App", "Web", "Graphic Design"};
String currentMenu;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textItem = (EditText)findViewById(R.id.textItem);
btnAdd = (Button)findViewById(R.id.btnAdd);
btnDelete = (Button)findViewById(R.id.btnDelete);
listItems = (ListView)findViewById(R.id.listItems);
btnAdd.setOnClickListener(this);
textItem.setOnKeyListener(this);
toDoItems = new ArrayList<String>();
aa = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, toDoItems);
listItems.setAdapter(aa);
/*--Set heading to todays Date--*/
TextView tvDisplayDate = (TextView) findViewById(R.id.heading);
final Calendar c = Calendar.getInstance();
int yy = c.get(Calendar.YEAR);
int mm = c.get(Calendar.MONTH);
int dd = c.get(Calendar.DAY_OF_MONTH);
// set current date into textview
tvDisplayDate.setText(new StringBuilder()
// Month is 0 based, just add 1
.append(mm + 1).append("/").append(dd).append("/").append(yy));
}
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
MenuItem item;
item = menu.add("delete");
item.setIcon(R.drawable.remove);
item = menu.add("date");
item.setIcon(R.drawable.date);
item = menu.add("gym");
item.setIcon(R.drawable.gym);
item = menu.add("meeting");
item.setIcon(R.drawable.meeting);
item = menu.add("homework");
item.setIcon(R.drawable.homework);
item = menu.add("project");
item.setIcon(R.drawable.project);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
if (item.hasSubMenu() == false) {
if (item.getTitle() == "date") {
currentMenu = "date";
this.displayPopup("Date Options", this.date);
}
if (item.getTitle() == "gym") {
currentMenu = "gym";
this.displayPopup("Gym Options", this.gym);
}
if (item.getTitle() == "meeting") {
currentMenu = "meeting";
this.displayPopup("Meeting Options", this.meeting);
}
if (item.getTitle() == "homework") {
currentMenu = "homework";
this.displayPopup("Homework Options", this.homework);
}
if (item.getTitle() == "project") {
currentMenu = "project";
this.displayPopup("Project Options", this.project);
}
if(item.getTitle() == "delete") {
int index = listItems.getSelectedItemPosition();
this.deleteItem(index);
}
}
return true;
}
private void addItem(String item) {
if (item.length() > 0 ) {
Toast.makeText(getApplicationContext(), item+" added", Toast.LENGTH_SHORT).show();
this.toDoItems.add(item);
this.aa.notifyDataSetChanged();
this.textItem.setText("");
}
}
private void deleteItem(int itemId) {
if (itemId >=0) {
String itemName = (String)listItems.getItemAtPosition(itemId);
Toast.makeText(getApplicationContext(), itemName+" delete", Toast.LENGTH_SHORT).show();
this.toDoItems.remove(itemId);
aa.notifyDataSetChanged();
}
}
private void displayPopup(String title, String[] items) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle(title);
builder.setItems(items, this);
builder.show();
}
@Override
public void onClick(View v) {
if (v == this.btnAdd) {
this.addItem(this.textItem.getText().toString());
}
}
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN && keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
this.addItem(this.textItem.getText().toString());
}
return false;
}
@Override
public void onClick(DialogInterface dialog, int item) {
if (currentMenu == "date") this.addItem(date[item]);
if (currentMenu == "gym") this.addItem(gym[item]);
if (currentMenu == "meeting") this.addItem(meeting[item]);
if (currentMenu == "homework") this.addItem(homework[item]);
if (currentMenu == "project") this.addItem(project[item]);
listItems.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,int position, long id) {
listItems.setSelection(position);
view.setSelected(true);
}
});}
}
listItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// remove the item from the array
toDoItems.remove(position);
// call a UI update for the list
aa.notifyDataSetChanged();
}
});
int selectedItem = -1;
listItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//save the clicked item position
// and the when the delete button is pressed, use it.
// keep in mind that this is not that good if you are using recycled list
selectedItem = position; }
});
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,int position, long id) {
listview.setSelection(position);
view.setSelected(true);
}
});