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我想从连接到sharedPreferences的taskList中删除一个项目。 我设法删除所有项目，但问题是我无法找到一种方法来连接计数器从具有开关的列表中删除单个项目，并且当此开关为真时我需要通过索引编号从列表中删除项目。不能找到一种方法来删除sharedPreferences项目
public class TaskAdapter extends BaseAdapter {
//transfer context
Context context;
//transfer user to use for shared preferences
String userName;
//create a list of tasks.....
List<taskItem> myTasks;
Calendar calendar = Calendar.getInstance();
PendingIntent pendingIntent;
int pos;
//constructor, for creating the adapter we need from the user context and userName
public TaskAdapter(Context context, String userName) {
this.context = context;
this.userName = userName;
//go to user shared preferences and fill the list
getData();
notifyDataSetChanged();
}
//how many item to display
@Override
public int getCount() {
//return the myTasks size....
return myTasks.size();
}
//return a specific item by index
@Override
public Object getItem(int i) {
return myTasks.get(i);
}
//return index number
@Override
public long getItemId(int i) {
return i;
}
//create our view
@Override
public View getView(final int index, final View view, ViewGroup viewGroup) {
//inflate the view inside view object -> viewInflated
final View viewInflated = LayoutInflater.from(context).inflate(R.layout.task_item, null, false);
//set our inflated view behavior
//set pointer for our inflated view
//set pointer for task name....
final TextView txtTaskName = (TextView) viewInflated.findViewById(R.id.taskName);
//set pointer for taskInfo
final TextView txtTaskInfo = (TextView) viewInflated.findViewById(R.id.taskInfo);
//set pointer for task status....
final Switch swTask = (Switch) viewInflated.findViewById(taskDone);
//set task name, by the index of my myTasks collection
txtTaskName.setText(myTasks.get(index).taskName);
//set task info, by index of myTasks collection
txtTaskInfo.setText(myTasks.get(index).taskInfo);
//set task status , switch is getting true/false
swTask.setChecked(myTasks.get(index).taskStatus);
//show date and time dialog
final ImageView dtPicker = (ImageView) viewInflated.findViewById(R.id.imgTime);
dtPicker.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final AlertDialog.Builder ad = new AlertDialog.Builder(context);
final AlertDialog aDialog = ad.create();
final LinearLayout adLayout = new LinearLayout(context);
adLayout.setOrientation(LinearLayout.VERTICAL);
TextView txtTime = new TextView(context);
txtTime.setText("Choose time");
adLayout.addView(txtTime);
final TimePicker tp = new TimePicker(context);
adLayout.addView(tp);
final DatePicker dp = new DatePicker(context);
tp.setVisibility(View.GONE);
adLayout.addView(dp);
final Button btnNext = new Button(context);
btnNext.setText("Next>");
adLayout.addView(btnNext);
btnNext.setGravity(1);
Button btnCancel = new Button(context);
btnCancel.setText("Cancel");
adLayout.addView(btnCancel);
btnCancel.setGravity(1);
btnCancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
aDialog.cancel();
}
});
btnNext.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final int hour = tp.getHour();
final int min = tp.getMinute();
final String myHour = String.valueOf(hour);
final String myMin = String.valueOf(min);
calendar.set(Calendar.MONTH, dp.getMonth());
calendar.set(Calendar.YEAR, dp.getYear());
calendar.set(Calendar.DAY_OF_MONTH, dp.getDayOfMonth());
dp.setVisibility(View.GONE);
tp.setVisibility(View.VISIBLE);
btnNext.setText("Finish");
btnNext.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
calendar.set(Calendar.HOUR_OF_DAY, tp.getHour());
calendar.set(Calendar.MINUTE, tp.getMinute());
Intent my_intent = new Intent(context, RingtonePlayingService.class);
pendingIntent = PendingIntent.getService(context, 0, my_intent, PendingIntent.FLAG_UPDATE_CURRENT);
alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
if(hour > 12){
String myHour = String.valueOf(hour - 12);
}
if(min < 10)
{
String myMin = "0"+String.valueOf(min);
}
Toast.makeText(context, "Set for- "+tp.getHour()+":"+tp.getMinute() , Toast.LENGTH_LONG).show();
aDialog.cancel();
}
});
}
});
aDialog.setView(adLayout);
aDialog.show();
}
});
//create listener event, when switch is pressed
swTask.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//we using utlShared to update task status
//create instance of utlShared
utlShared myShared = new utlShared(context);
//calling method of task, and giving userName(shared preferences, taskName, taskStatus)
myShared.task(userName, txtTaskName.getText().toString(), txtTaskInfo.getText().toString(), swTask.isChecked());
//we sending a message to the user, and inform him/her about the change
Toast.makeText(context, swTask.isChecked() ? "Task done" : "Task undone", Toast.LENGTH_SHORT).show();
}
});
//return the view with the behavior.....
return viewInflated;
}
private void getData() {
//go to specific shared preferences by user name.....
SharedPreferences taskPref = context.getSharedPreferences(userName, context.MODE_PRIVATE);
//create instance of our myTasks list
myTasks = new ArrayList<>();
Map<String, ?> tasks = taskPref.getAll();
for (Map.Entry<String, ?> oneTask : tasks.entrySet()) {
//insert task to list by Key and Value, we check if value is equal to 1, becuase 1=true 0=false
for(int pos=0 ; pos<myTasks.size() ; pos++){
myTasks.get(pos);
}
String[] str = oneTask.getValue().toString().split(",");
myTasks.add(new taskItem(str[0], str[1], str[2].equals("1")));
}
}
}
而且我utlShared类是
public class utlShared {
//context to use later
Context context;
//declatrtion of shared preferences object
private SharedPreferences userPref;
//declaration of shared preferences editor
private SharedPreferences.Editor editor;
public utlShared() {}
public utlShared(Context context)
{
//get context to use it
this.context=context;
//declaretion of shared preferences with file name and file mode (private,public)
userPref=context.getSharedPreferences("users",Context.MODE_PRIVATE);
//declaration of editor
editor=userPref.edit();
}
//get user and password
public void addUser(String userName, String password)
{
//stores in the phone device under data\data\package name
//put in shared preferences user name and password
editor.putString(userName,password);
//commit (save/apply) the changes.
editor.commit();
}
public boolean checkUser(String userName)
{
//get name by key->userName
String checkString = userPref.getString(userName,"na");
//print to logcat a custom message.....
Log.e("checkUser", "checkUser: "+checkString);
//check if userName equals to responded data, if it's na, we don't have the user...
return !checkString.equals("na");
}
public boolean checkUserPassword(String userName, String userPassword)
{
String checkString = userPref.getString(userName,"na");
return checkString.equals(userPassword);
}
public void task(String userName,String taskName,String taskInfo, boolean taskDone)
{
//pointer to user task shared preferences
SharedPreferences taskPref=context.getSharedPreferences(userName, Context.MODE_PRIVATE);
//create editor to change the specific shared preferences
SharedPreferences.Editor taskEditor=taskPref.edit();
//add new task -> if true write 1 else write 0
if(!taskDone){
String myData = taskName+","+taskInfo+","+(taskDone?"1":"0");
taskEditor.putString(taskName,myData);
//apply the changes
taskEditor.commit();
}
}
public void clearTasks(String userName, String taskName, String taskInfo, boolean taskDone)
{
SharedPreferences taskPref=context.getSharedPreferences(userName, Context.MODE_PRIVATE);
SharedPreferences.Editor tskEditor=taskPref.edit();
tskEditor.clear();
tskEditor.commit();
}
}
这种方法是从我的欢迎类，这是
public class Welcome extends AppCompatActivity {
String userName;
Context context;
utlShared myUtl;
ListView taskList;
String taskName;
String taskInfo;
boolean taskDone;
AlarmManager alarmManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welcome);
setPointer();
}
private void setPointer()
{
this.context=this;
userName=getIntent().getStringExtra("userName");
myUtl = new utlShared(context);
taskList=(ListView)findViewById(R.id.taskList);
setListData();
alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
Toast.makeText(Welcome.this, "welcome user:"+userName, Toast.LENGTH_SHORT).show();
Button btnBack = (Button)findViewById(R.id.btnBack);
FloatingActionButton btnDelete=(FloatingActionButton)findViewById(R.id.btnDelete);
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
myUtl.clearTasks(userName, taskName, taskInfo, taskDone);
setListData();
}
});
btnBack.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(context, MainActivity.class);
startActivity(intent);
finish();
}
});
}
private void setListData() {
final TaskAdapter adapter = new TaskAdapter(context, userName);
taskList.setAdapter(adapter);
}
public void addCustomTask(View view)
{
//create builder
AlertDialog.Builder builder = new AlertDialog.Builder(context);
//set title
builder.setTitle("Add new task!");
//inflate view from layout ->custom layout,null,false as defualt values
View viewInflated= LayoutInflater.from(context).inflate(R.layout.dlg_new_task,null,false);
final EditText txtCustomLine = (EditText)viewInflated.findViewById(R.id.txtHLine);
final EditText txtCustomTask = (EditText)viewInflated.findViewById(R.id.txtTask);
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.dismiss();
}
});
builder.setPositiveButton("Add task", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.dismiss();
String myTaskCustom = txtCustomTask.getText().toString();
String myTaskLine = txtCustomLine.getText().toString();
myUtl.task(userName, myTaskCustom, myTaskLine, false);
setListData();
}
});
//display our inflated view in screen
builder.setView(viewInflated);
//show the dialog
builder.show();
}
}
称为很抱歉的长码，但我已经花了这个问题如此多的时间，并没有找到一个正常的方式来解决它......
在此先感谢你们，非常感谢！
为什么不使用类似SugarORM的东西呢？有了它，你可以在一行中删除/添加和选择用户。 – DEADMC
看到这个链接http://stackoverflow.com/questions/18806147/deleting-listview-item-from-list-and-sharedpreferences。我认为它可以帮助你解决你的问题。 – Sushrita
我正在看这个家伙的代码，它有点乱，但我会尽快尝试，谢谢，我会回复一个答案，希望它会有所帮助。 – z3r0