如何在列表视图中添加时间戳? [英] how to add a time stamp to a List View?
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问题描述
我想在listView上添加timeStamp，以便它向您显示在此代码中创建项目的时间.有什么办法，我可以去做.如果有人知道该怎么做，请告诉我.
to_do_item_layout
I want to add a timeStamp to the listView so it shows you when the item was created in this code. Is there any way, I can go about doing this. if some knows how to do this please let me know.
to_do_item_layout
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<CheckBox
android:id="@+id/checkBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/item"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="20sp"/>
<ImageButton
android:id="@+id/delete_Button"
android:src="@drawable/delete_item_button"
android:background="@android:color/transparent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/delete_item"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/timeStamp"
/>
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "todo.db";
public static final int DATABASE_VERSION = 1;
public static final String ITEMS_TABLE = "items";
private static DatabaseHelper instance = null;
public static DatabaseHelper getInstance(Context context) {
if(instance == null) {
instance = new DatabaseHelper(context);
}
return instance;
}
private DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String createQuery = "CREATE TABLE " + ITEMS_TABLE + " (" +
"_id INTEGER PRIMARY KEY AUTOINCREMENT," +
"description TEXT NOT NULL, " +
"completed INTEGER NOT NULL DEFAULT 0)"+
"timeStamp INTEGER NOT NULL)";
db.execSQL(createQuery);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
该按钮可以正常工作，但不会永久删除，我不知道它是否是代码，或者是否是我将其放置在我的MainActivity中的位置，如果有人请告诉我，将不胜感激.
The button works fine but it does not delete permently I don't know if it is the code or if it is where I am placing it in my MainActivity if someone would please tell that would much appreciated.
MainActivity.java
public class MainActivity extends AppCompatActivity {
private static final String LOG_TAG = "ToDoApp";
private ToDoListManager listManager;
private ToDoItemAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView todoList = (ListView) findViewById(R.id.todo_list);
listManager = new ToDoListManager(getApplicationContext());
adapter = new ToDoItemAdapter(
this,
listManager.getList()
);
todoList.setAdapter(adapter);
ImageButton addButton = (ImageButton) findViewById(R.id.add_item);
addButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onAddButtonClick();
}
});
}
@Override
protected void onPause() {
super.onPause();
}
private void onAddButtonClick() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle(R.string.add_item);
final EditText input = new EditText(this);
input.setInputType(InputType.TYPE_CLASS_TEXT);
builder.setView(input);
builder.setPositiveButton(
R.string.ok,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
ToDoItem item = new ToDoItem(
input.getText().toString(),
false
);
listManager.addItem(item);
adapter.swapItems(listManager.getList());
}
});
builder.setNegativeButton(
R.string.cancel,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
}
private class ToDoItemAdapter extends ArrayAdapter<ToDoItem> {
private Context context;
private List<ToDoItem> items;
private LayoutInflater inflater;
public ToDoItemAdapter(
Context context,
List<ToDoItem> items
) {
super(context, -1, items);
this.context = context;
this.items = items;
this.inflater = LayoutInflater.from(context);
}
public void swapItems(List<ToDoItem> items) {
this.items = items;
notifyDataSetChanged();
}
@Override
public int getCount() {
return items.size();
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ItemViewHolder holder;
if(convertView == null) {
convertView = inflater.inflate(R.layout.to_do_item_layout, parent, false);
holder = new ItemViewHolder();
holder.itemDescription = (TextView) convertView.findViewById(R.id.item);
holder.itemState = (CheckBox) convertView.findViewById(R.id.checkBox);
holder.itemTimeStamp = (TextView) convertView.findViewById(R.id.timeStamp);
holder.itemTimeStamp.setText(getPassedTimeForCreation(item.getTimeStamp()));
convertView.setTag(holder);
}else {
holder = (ItemViewHolder) convertView.getTag();
}
holder.itemDescription.setText(items.get(position).getDescription());
holder.itemState.setChecked(items.get(position).isComplete());
holder.itemState.setTag(items.get(position));
convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ToDoItem item = (ToDoItem) holder.itemState.getTag();
item.toggleComplete();
listManager.updateItem(item);
notifyDataSetChanged();
}
});
ImageButton deleteButton = (ImageButton) convertView.findViewById(R.id.delete_Button);
deleteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
long itemId = items.get(position).getId();
items.remove(items.get(position));
listManager.deleteItem(itemId);
notifyDataSetChanged();
}
});
holder.itemState.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ToDoItem item = (ToDoItem) holder.itemState.getTag();
item.toggleComplete();
listManager.updateItem(item);
notifyDataSetChanged();
}
});
return convertView;
}
}
public static class ItemViewHolder{
public TextView itemDescription;
public CheckBox itemState;
}
String getPassedTimeFromCreation(Long timeStamp){
Calendar now = Calendar.getInstance();
Long differece = now.getTimeInMillis() - timeStamp;
if (differece < (5 * 60 * 1000)) { // (5 minute in milliseconds)
return "5 min ago";
}
else if(differece < (2 * 24 * 60 * 60 * 1000)){ // (2 days in millisecond)
return "2 days ago";
}else{
return "long time ago";
}
}
}
ToDoListManager.java
public class ToDoListManager {
private DatabaseHelper dbHelper;
public ToDoListManager(Context context) {
dbHelper = DatabaseHelper.getInstance(context);
}
public List<ToDoItem> getList() {
SQLiteDatabase db = dbHelper.getReadableDatabase();
Cursor cursor = db.rawQuery(
"SELECT * FROM " + DatabaseHelper.ITEMS_TABLE,
null
);
List<ToDoItem> items = new ArrayList<>();
if(cursor.moveToFirst()) {
while(!cursor.isAfterLast()) {
ToDoItem item = new ToDoItem(
cursor.getString(cursor.getColumnIndex("description")),
cursor.getInt(cursor.getColumnIndex("completed")) != 0,
cursor.getLong(cursor.getColumnIndex("_id")),
cursor.getLong(cursor.getColumnIndex("timeStamp"))
);
items.add(item);
cursor.moveToNext();
}
}
cursor.close();
return items;
}
public void addItem(ToDoItem item) {
ContentValues newItem = new ContentValues();
newItem.put("description", item.getDescription());
newItem.put("completed", item.isComplete());
newItem.put("timeStamp", item.getTimeStamp());
SQLiteDatabase db = dbHelper.getWritableDatabase();
db.insert(DatabaseHelper.ITEMS_TABLE, null, newItem);
}
public void updateItem(ToDoItem item) {
ContentValues editItem = new ContentValues();
editItem.put("description", item.getDescription());
editItem.put("completed", item.isComplete());
newItem.put("timeStamp", item.getTimeStamp());
SQLiteDatabase db = dbHelper.getWritableDatabase();
String[] args = new String[] { String.valueOf(item.getId()) };
db.update(DatabaseHelper.ITEMS_TABLE, editItem, "_id=?", args);
}
public void deleteItem(long itemId) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
db.delete(DatabaseHelper.ITEMS_TABLE, "_id = ?",
new String[] { String.valueOf(itemId) });
}
}
ToDoItem.java
import java.util.Calendar;
public class ToDoItem {
private long timeStamp;
private String description;
private boolean isComplete;
private long id;
public ToDoItem(String description, boolean isComplete, long id, long timeStamp) {
this.description = description;
this.isComplete = isComplete;
this.id = id;
this.timeStamp = timeStamp;
}
public ToDoItem(String description, boolean isComplete, long id) {
this.description = description;
this.isComplete = isComplete;
this.id = id;
Calendar now = Calendar.getInstance();
this.timeStamp = now.getTimeInMillis();
}
public String getDescription() {
return description;
}
public boolean isComplete() {
return isComplete;
}
public void toggleComplete() {
isComplete = !isComplete;
}
public long getId() {return id;}
@Override
public String toString() {
return getDescription();
}
}
推荐答案
我认为此修改对您有所帮助，我只写了主要部分，您需要自己应用更改.祝你好运！
I think this modification helps you, I just write the main parts, you need to apply changes yourself. good luck!
DatabaseHelper.java
@Override
public void onCreate(SQLiteDatabase db) {
String createQuery = "CREATE TABLE " + ITEMS_TABLE + " (" +
"_id INTEGER PRIMARY KEY AUTOINCREMENT," +
"description TEXT NOT NULL, " +
"completed INTEGER NOT NULL DEFAULT 0," +
"timeStamp INTEGER NOT NULL)";
db.execSQL(createQuery);
}
ToDoItem.java
public class ToDoItem {
private Long timeStamp;
private String description;
private boolean isComplete;
private long id;
// I just added two getter and setter methods
public void setTimeStamp(Long timeStamp){
this.timeStamp = timeStamp;
}
public Long getTimeStamp(){
return timeStamp;
}
public ToDoItem(String description,boolean isComplete,long id, Long timeStamp) {
this.description = description;
this.isComplete = isComplete;
this.id = id;
this.timeStamp = timeStamp;
}
public ToDoItem(String description,boolean isComplete,long id) {
this.description = description;
this.isComplete = isComplete;
this.id = id;
Calendar now = Calendar.getInstance();
this.timeStamp = now.getTimeInMillis();
}
}
ToDoListManager.java
public List<ToDoItem> getList() {
...
ToDoItem item = new ToDoItem(
cursor.getString(cursor.getColumnIndex("description")),
cursor.getInt(cursor.getColumnIndex("completed")) != 0,
cursor.getLong(cursor.getColumnIndex("_id")),
cursor.getLong(cursor.getColumnIndex("timeStamp"))
);
...
}
public void addItem(ToDoItem item) {
...
// add this line
newItem.put("timeStamp", item.getTimeStamp());
...
}
public void updateItem(ToDoItem item) {
...
// add this line
editItem.put("timeStamp", item.getTimeStamp());
...
}
ToDoItemAdapter 类
我假设您将TextView timeStamp添加到to_do_item_layout和ItemViewHolder类
I assume that you add a TextView timeStamp to your to_do_item_layout and your ItemViewHolder class
ItemViewHolder 类
public static class ItemViewHolder{
public TextView itemDescription;
public CheckBox itemState;
public TextView itemTimeStamp;
}
}
getView 添加这行
holder.itemTimeStamp = (TextView) convertView.findViewById(R.id.timeStamp);
holder.itemTimeStamp.setText(getPassedTimeForCreation(item.getTimeStamp()));
getPassedTimeForCreation(长时间戳)
String getPassedTimeFromCreation(Long timeStamp){
Calendar now = Calendar.getInstance();
Long differece = now.getTimeInMillis() - timeStamp;
if (differece < (5 * 60 * 1000)) { // (5 minute in milliseconds)
return "5 min ago";
}
else if(differece < (2 * 24 * 60 * 60 * 1000)){ // (2 days in millisecond)
return "2 days ago";
}else{
return "long time ago";
}
}
在MainActivity类中添加getPassedTimeForCreation函数，而不是在MainActivity的函数体内！
add getPassedTimeForCreation function in MainActivity class, not inside of MainActivity's function body!!!
@Override
protected void onCreate(Bundle savedInstanceState) {
`...`
}
@Override
protected void onPause() {
`...`
}
private void onAddButtonClick() {
`...`
}
private class ToDoItemAdapter extends ArrayAdapter<ToDoItem> {
`...`
}
public static class ItemViewHolder{
`...`
}
/**
* this is the place that you must put the function!
*/
String getPassedTimeFromCreation(Long timeStamp){
`...`
}
这篇关于如何在列表视图中添加时间戳?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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