我想实现一个待办事项列表应用程序。我有三个活动：一个主要活动，一个添加活动和一个编辑活动。在我的主要活动中，有一个添加按钮和一个显示待办事项的列表视图。当我单击添加按钮时，将执行添加活动。在这个活动中，有一个任务的编辑文本、一个日期选择器和一个优先级微调器。单击确定按钮时，所有这些输入值都将作为一行发送到主活动的列表视图。并且，当单击此列表中的项目时，将执行编辑活动并且用户可以更改值。但是，在我的代码中，当用户输入值时，我可以在我的自定义适配器类中访问它们，但我无法在列表视图中显示它们。列表视图保持为空。我怎样才能修复我的代码？
主要活动：
public class MainActivity extends Activity {
protected static final String edits = "mainTask";
private ToDoItemAdapter listAdapter;
//private ToDoItemAdapter myCustomAdapter;
//private ArrayList<String> listString;
public ArrayList<ToDoItem> listItems;
public static final int ADD_TASKS = 1;
public static final int EDIT_TASKS = 2;
Button button;
ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initUI();
setListener();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private void initUI() {
getViewReferences();
initializeToDoList();
}
private void setListener() {
// TODO Auto-generated method stub
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent addTaskIntent = new Intent(MainActivity.this, AddActivity.class);
startActivityForResult(addTaskIntent, ADD_TASKS);
}
});
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
System.out.println(arg2);
ToDoItemAdapter myAdapter = new ToDoItemAdapter(MainActivity.this,R.layout.editing_task,listItems);
listView.setAdapter(myAdapter);
Intent editTaskIntent = new Intent(MainActivity.this, EditingTask.class);
//editTaskIntent.putExtra("mainTask", arg2);
startActivityForResult(editTaskIntent, EDIT_TASKS);
}
});
}
private void getViewReferences() {
// TODO Auto-generated method stub
button = (Button) findViewById(R.id.addButton);
listView = (ListView) findViewById(R.id.listView);
}
private void initializeToDoList() {
// TODO Auto-generated method stub
listItems = new ArrayList<ToDoItem>();
//listString = new ArrayList<String>();
listAdapter = new ToDoItemAdapter(MainActivity.this, R.layout.activity_main, listItems);
listView.setAdapter(listAdapter);
View noTaskView = findViewById(R.id.emptyToDoList);
listView.setEmptyView(noTaskView);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
if (resultCode == Activity.RESULT_OK) {
switch (requestCode) {
case ADD_TASKS:
updateToDoList(data);
break;
case EDIT_TASKS:
break;
default:
break;
}
}
super.onActivityResult(requestCode, resultCode, data);
}
private void updateToDoList(Intent data) {
// TODO Auto-generated method stub
String task = AddActivity.tasks;
ArrayList<String> list = data.getStringArrayListExtra(task);
String addedTask = list.get(0);
String addedDeadline = list.get(1);
String addedPriority = list.get(2);
ToDoItem item = new ToDoItem(addedTask, addedDeadline ,"0", addedPriority);
listItems.add(item);
//listString.add(addedTask + " " + addedDeadline + " " + addedPriority);
Log.w("Items:",listItems.get(0).getTask());
//Log.w("String:",listString.get(0));
listAdapter.notifyDataSetChanged();
}
}
ToDoItemAdapter 类：
public class ToDoItemAdapter extends ArrayAdapter<ToDoItem> {
Context context;
private int resource;
ArrayList<ToDoItem> todoItem;
public ToDoItemAdapter(Context context, int resource, ArrayList<ToDoItem> objects) {
super(context, resource, objects);
this.context = context;
this.resource = resource;
this.todoItem = objects;
}
@Override
public ToDoItem getItem(int position) {
return this.todoItem.get(position);
}
@Override
public int getCount() {
return this.todoItem.size();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
View row = convertView;
if (convertView == null)
{
/*todoView = new LinearLayout(getContext());
String inflater = Context.LAYOUT_INFLATER_SERVICE;
LayoutInflater li;
li = (LayoutInflater)getContext().getSystemService(inflater);
li.inflate(resource, todoView, true);
*/
LayoutInflater inflater = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(resource, parent, false);
}
//LinearLayout todoView;
ToDoItem todo = getItem(position);
String taskString = todo.getTask();
Log.w("task:", taskString);
String dateString = todo.getDeadline();
String priorityString = todo.getPriority();
String itemRow = taskString + " " + dateString + " " + priorityString;
return row;
}
}
添加类：
public class AddActivity extends Activity{
private String[] states;
private Spinner spinner;
int position1;
String priority;
EditText etDate;
Button change_date;
final int Date_Dialog_ID=0;
int cDay,cMonth,cYear; // this is the instances of the current date
Calendar cDate;
int sDay,sMonth,sYear; // this is the instances of the entered date
protected static final String tasks = "addingTask";
private static final String LOG_TAG = "addingTaskActivity";
MainActivity main;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
initUI();
showDatePicker();
showPriorityLevel();
}
private void showPriorityLevel() {
// TODO Auto-generated method stub
states = getResources().getStringArray(R.array.priority_level);
spinner = (Spinner) findViewById(R.id.priority_spinner);
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, states);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(dataAdapter);
spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
position1 = spinner.getSelectedItemPosition();
switch(position1)
{
case 0: priority = "0";
break;
case 1: priority = "1";
break;
case 2: priority = "2";
break;
case 3: priority = "3";
break;
case 4: priority = "4";
break;
case 5: priority = "5";
break;
case 6: priority = "6";
break;
case 7: priority = "7";
break;
case 8: priority = "8";
break;
case 9: priority = "9";
break;
default: break;
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
private void showDatePicker() {
// TODO Auto-generated method stub
etDate=(EditText)findViewById(R.id.EditText01);
change_date=(Button)findViewById(R.id.Button01);
change_date.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//triggers the DatePickerDialog
showDialog(Date_Dialog_ID);
}
});
//getting current date
cDate=Calendar.getInstance();
cDay=cDate.get(Calendar.DAY_OF_MONTH);
cMonth=cDate.get(Calendar.MONTH);
cYear=cDate.get(Calendar.YEAR);
//assigning the edittext with the current date in the beginning
sDay=cDay;
sMonth=cMonth;
sYear=cYear;
updateDateDisplay(sYear,sMonth,sDay);
}
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case Date_Dialog_ID:
return new DatePickerDialog(this, onDateSet, cYear, cMonth,
cDay);
}
return null;
}
private void updateDateDisplay(int year,int month,int date) {
// TODO Auto-generated method stub
etDate.setText(date+"-"+(month+1)+"-"+year);
}
private OnDateSetListener onDateSet=new OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
// TODO Auto-generated method stub
sYear=year;
sMonth=monthOfYear;
sDay=dayOfMonth;
updateDateDisplay(sYear,sMonth,sDay);
}
};
private void initUI() {
// TODO Auto-generated method stub
setContentView(R.layout.adding_task);
final EditText editTextTask = (EditText) findViewById(R.id.edit_text_task);
Button OKbutton = (Button) findViewById(R.id.ok_Button);
final EditText editTextDate = (EditText) findViewById(R.id.EditText01);
OKbutton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
ArrayList<String> addedDatas = new ArrayList<String>();
String addingTask = editTextTask.getText().toString();
String deadline = editTextDate.getText().toString();
//String concatenate = priority + " " + addingTask + " " + deadline;
Intent myIntent = new Intent();
addedDatas.add(addingTask);
addedDatas.add(deadline);
addedDatas.add(priority);
myIntent.putExtra("addingTask", addedDatas);
setResult(Activity.RESULT_OK, myIntent);
finish();
}
});
}
}
ToDoItem 类
public class ToDoItem {
String task;
String deadline;
String status;
String priority;
public ToDoItem(String task, String deadline, String status, String priority) {
super();
this.task = task;
this.deadline = deadline;
this.status = status;
this.priority = priority;
}
public String getTask() {
return task;
}
public String getDeadline() {
return deadline;
}
public String getStatus() {
return status;
}
public String getPriority() {
return priority;
}
@Override
public String toString() {
return priority + " " + task + " " + deadline + " " + status;
}