我知道这个问题之前已被问了几次，我尝试了那里的所有建议，在我向列表中添加新项目后仍然无法刷新列表视图 任何人都可以试着解释我该怎么办？ thnaks
这是添加的代码：
公共类MainActivity扩展了ListActivity {
private DBHandler dataBase;
private ArrayList<Movies> list;
private ArrayAdapter<Movies> adapter;
private ListView lv;
private ImageButton addMovie;
private Intent intent;
final static int FLAG_FOR_ADDING=1;
final static int FLAG_FOR_EDITING=2;
final static int FLAG_FROM_MENU=3;
private int selected_movie;
private String the_movie;
private String movie_title;
private String movie_description;
private String movie_url;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
dataBase = new DBHandler(MainActivity.this);
// by pressing this button the user will get instructions about how to use this application
Button start = (Button)findViewById(R.id.how_to_start);
start.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Toast.makeText(MainActivity.this, "Press the plus button for adding a movie or the menu button for the menu", Toast.LENGTH_LONG).show();
}
});
// by pressing this button, the menu of this application will open
ImageButton menu = (ImageButton)findViewById(R.id.menu_context);
menu.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
openOptionsMenu();
}
});
addMovie = (ImageButton)findViewById(R.id.add_movie);
addMovie.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
registerForContextMenu(addMovie);
openContextMenu(addMovie);
}
});
// the array list is getting the movies from the database
list = dataBase.getAllMovies();
// here i am setting the adapter that will handle the list
adapter = new ArrayAdapter<Movies>(MainActivity.this, R.layout.row,list);
// i am getting a default xml
lv=getListView();
// i am connecting between the list and the adapter
lv.setAdapter(adapter);
// by short pressing an item on the list the user will move to the edit_a_movie page
// in order to edit the movie
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
intent = new Intent(MainActivity.this,Edit_A_Movie.class);
// i am sending the information of the item that been pressed to the edit_a_movie page
// the id, title,description and the url_photo
intent.putExtra("item_id", list.get(position).getId());
intent.putExtra("item_title", list.get(position).getTitle().toString());
intent.putExtra("item_description", list.get(position).getDescription().toString());
intent.putExtra("item_url", list.get(position).getPhoto_url().toString());
startActivityForResult(intent, FLAG_FOR_EDITING);
}
});
// a long press on a movie in the list will open a context menu for deleting or editing the item
lv.setOnItemLongClickListener(new OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
// i am getting the information of the movie that was pressed
selected_movie = list.get(position).getId();
the_movie = String.valueOf(selected_movie);
movie_title = list.get(position).getTitle().toString();
movie_description = list.get(position).getDescription().toString();
movie_url = list.get(position).getPhoto_url().toString();
// i register to a context menu
registerForContextMenu(lv);
openContextMenu(lv);
return true;
}
});
}
@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;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()){
// by pressing the exit option, the user will exit the application
case R.id.menu_exit:
finish();
android.os.Process.killProcess(android.os.Process.myPid());
super.onDestroy();
break;
// this option will delete all the movies from the list
case R.id.menu_delete:
dataBase.deleteAllMovies();
break;
default:
break;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
// if the user will press the menu button he will get the menu and if he will press
// the plus button he will get 2 options: 1. move to the edit a movie page
// 2. move to the search a movie from the Internet page
// if the user will press a long press on a movie he will get 2 options:
//1. update the movie
//2. delete the movie
if(v.getId() == R.id.menu_context){
getMenuInflater().inflate(R.menu.main, menu);
}
else if (v.getId() == R.id.add_movie){
getMenuInflater().inflate(R.menu.aad_menu, menu);
}
else {
getMenuInflater().inflate(R.menu.edit_or_delete, menu);
}
}
@Override
public boolean onContextItemSelected(MenuItem item) {
switch(item.getItemId()){
// selecting this option will exit the application
case R.id.menu_exit:
finish();
android.os.Process.killProcess(android.os.Process.myPid());
super.onDestroy();
break;
// this option will delete all the movies from the list
case R.id.menu_delete:
dataBase.deleteAllMovies();
break;
// this option will move the user to the edit a movie page
case R.id.move_to_edit:
intent = new Intent(MainActivity.this,Edit_A_Movie.class);
startActivityForResult(intent, FLAG_FOR_ADDING);
break;
// this option will get the user move to the add a movie from the Internet page
case R.id.move_to_search:
break;
// if the user will press on a movie he will be able to update the movie or delete it
//this option will delete the movie
case R.id.delete_menu_movie:
dataBase.deleteMovie(the_movie);
break;
// this option will move the user to the edit_a_movie page
case R.id.edit_menu_movie:
intent = new Intent(MainActivity.this,Edit_A_Movie.class);
// i am sending the information of the pressed movie
intent.putExtra("item_id",selected_movie);
intent.putExtra("item_title", movie_title);
intent.putExtra("item_description", movie_description);
intent.putExtra("item_url", movie_url);
startActivityForResult(intent, FLAG_FROM_MENU);
break;
default:
break;
}
return super.onContextItemSelected(item);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
// this is the info i am getting from the edit_a_movie page in order to put it in the database
// i am using it to add a new movie to the list
if(requestCode==FLAG_FOR_ADDING && resultCode==RESULT_OK){
// this is the info i received
String title_from_adding = data.getStringExtra("user_title");
String description_from_adding = data.getStringExtra("user_desciption");
String url_from_adding = data.getStringExtra("user_url");
// here i am putting the info in the database
dataBase.addMovie(title_from_adding, description_from_adding, url_from_adding);
// in case that the user pressed the cancel button he will get a massage
} else if
(requestCode==FLAG_FOR_ADDING && resultCode==RESULT_CANCELED){
Toast.makeText(MainActivity.this, "No movie has been added", Toast.LENGTH_LONG).show();
}
// i am using the info from the edit_a_movie page in order to update a movie
else if
(requestCode==FLAG_FOR_EDITING && resultCode==RESULT_OK ){
String position_from_editing = data.getStringExtra("position");
String title_from_editing = data.getStringExtra("user_title");
String description_from_editing = data.getStringExtra("user_desciption");
String url_from_editing = data.getStringExtra("user_url");
// the database is being updating
dataBase.updateMovie(position_from_editing, title_from_editing, description_from_editing, url_from_editing);
}
// this case is for editing the movie that was long pressed
else if
(requestCode==FLAG_FROM_MENU && resultCode==RESULT_OK){
// i am receiving the updated information from the edit_a_movie page
String position_from_menu = data.getStringExtra("position");
String title_from_menu = data.getStringExtra("user_title");
String description_from_menu = data.getStringExtra("user_desciption");
String url_from_menu = data.getStringExtra("user_url");
//the database is being updating with the new information
dataBase.updateMovie(position_from_menu, title_from_menu, description_from_menu, url_from_menu);
}
}
}
答案 0 :(得分：1)