java - SwipeRefreshLayout不会更新列表视图

java - SwipeRefreshLayout不会更新列表视图,第1张

我想在片段中为我的列表视图添加刷卡刷新,但它似乎无法正常工作,因为它根本不更新我的列表视图。以下是我的活动的工作方式:

  1. 用户打开PictureFragment图片列表(listview) 显示。
  2. 用户按"添加按钮"这将打开UploadImageActivity以添加图片。
  3. 完成后,UploadImageActivity将关闭,用户现在返回PictureFragment(尚未更新其最新图片上传)。
  4. 用户向下滑动以更新,<<不会将最新图像更新为listview!
  5. 希望善良的灵魂能帮助我解决这个问题。

    public class PictureFragment extends Fragment {
    
    private ListView listView;
    private int smiley_id;
    private String title, date, caption, image;
    private ImageButton addPicButton;
    private SwipeRefreshLayout swipeRefreshLayout;
    private PictureAdapter adapter;
    private TableDatabase tableDatabase;
    private Cursor cursor;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
    
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    
        View rootView = inflater.inflate(R.layout.fragment_picture, container, false);
    
        // Set listview
        listView = (ListView) rootView.findViewById(R.id.piclistView);
        adapter = new PictureAdapter(getActivity().getApplicationContext(), R.layout.row_feed);
        listView.setAdapter(adapter);
        // Retrieve data from database
        tableDatabase = new TableDatabase(getActivity());
        // Get rows of database
        cursor = tableDatabase.getInformation(tableDatabase);
    
        // Start from the last so that listview displays latest image first
        // Check for existing rows
        if(cursor.moveToLast()) {
            do {
                // Get items from each column
                smiley_id = cursor.getInt(0);
                title = cursor.getString(1);
                date = cursor.getString(2);
                caption = cursor.getString(3);
                image = cursor.getString(4);
    
                // Saves images added by user into listview
                PictureItem pictureItem = new PictureItem(smiley_id, title, date, caption, image);
                adapter.add(pictureItem);
            } while (cursor.moveToPrevious());
        }
    
        // Swipe on refresh
        swipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swipe_refresh);
        swipeRefreshLayout.setEnabled(false);
    
        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                swipeRefreshLayout.setRefreshing(true);
                (new Handler()).postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        adapter.notifyDataSetChanged();
                        swipeRefreshLayout.setRefreshing(false);
                    }
                }, 1000);
            }
        });
    
        listView.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
    
            }
    
            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                if(firstVisibleItem == 0) swipeRefreshLayout.setEnabled(true);
                else swipeRefreshLayout.setEnabled(false);
            }
        });
    
        // Lead user to UploadImageActivity to insert image to listview
        addPicButton = (ImageButton) rootView.findViewById(R.id.addPictureButton);
        addPicButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(getActivity().getApplicationContext(), UploadImageActivity.class));
            }
        });
    
        return rootView;
    }
    

    UploadImageActivity.java

    public class UploadImageActivity extends ActionBarActivity implements View.OnClickListener{
    
    private Calendar cal = Calendar.getInstance();
    private SimpleDateFormat dateFormatter = new SimpleDateFormat("dd MMM yyyy, EEE @ hh:mm a");
    
    EditText pic_title, pic_caption;
    ImageView picture;
    Button smiley1, smiley2, smiley3, smiley4, smiley5, selected_smiley;
    
    // To store in database
    int smiley_id = R.drawable.smile1; // Set default smiley as first smiley if not chosen
    String title, date, caption;
    String uriPicture;    // Save uri in string format to store image as text format in database
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_picture);
    
        // Removes shadow under action bar
        getSupportActionBar().setElevation(0);
    
        pic_title = (EditText) findViewById(R.id.picture_title);
        pic_caption = (EditText) findViewById(R.id.picture_caption);
    
        picture = (ImageView) findViewById(R.id.imagebutton);
        smiley1 = (Button) findViewById(R.id.button1);
        smiley2 = (Button) findViewById(R.id.button2);
        smiley3 = (Button) findViewById(R.id.button3);
        smiley4 = (Button) findViewById(R.id.button4);
        smiley5 = (Button) findViewById(R.id.button5);
        selected_smiley = (Button) findViewById(R.id.select_smiley);
    
        picture.setOnClickListener(this);
        smiley1.setOnClickListener(this);
        smiley2.setOnClickListener(this);
        smiley3.setOnClickListener(this);
        smiley4.setOnClickListener(this);
        smiley5.setOnClickListener(this);
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_event, menu);
        return true;
    }
    
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
    
        if (id == R.id.action_ok) {
            title = pic_title.getText().toString();
            date = dateFormatter.format(cal.getTime());
            caption = pic_caption.getText().toString();
    
            // Do not save data
            if(title.isEmpty()) {
                alertUser("Upload failed!", "Please enter title.");
            }
    
            else if(caption.isEmpty()) {
                alertUser("Upload failed!", "Please enter caption.");
            }
    
            else if(uriPicture.isEmpty()) {
                alertUser("Upload failed!", "Please upload an image.");
            }
    
            // Save data when title, caption and image are not empty
            else {
                // Add information into database
                TableDatabase tableDatabase = new TableDatabase(this);
                tableDatabase.putInformation(tableDatabase, smiley_id, title, date, caption, uriPicture);
                Toast.makeText(getBaseContext(), "Details successfully saved", Toast.LENGTH_LONG).show();
                finish();
            }
    
            return true;
        }
    
        return super.onOptionsItemSelected(item);
    }
    
    @Override
    public void onClick(View v) {
        switch(v.getId()) {
            // Show the image picked by user
            case R.id.imagebutton:
                picture.setImageDrawable(null);
                Crop.pickImage(this);
                break;
    
            // Saves the user's smiley choice
            case R.id.button1:
                selected_smiley.setBackgroundResource(R.drawable.smile1);
                selected_smiley.setText("");
                setSmileyID(R.drawable.smile1);
                break;
            case R.id.button2:
                selected_smiley.setBackgroundResource(R.drawable.smile2);
                selected_smiley.setText("");
                setSmileyID(R.drawable.smile2);
                break;
            case R.id.button3:
                selected_smiley.setBackgroundResource(R.drawable.smile3);
                selected_smiley.setText("");
                setSmileyID(R.drawable.smile3);
                break;
            case R.id.button4:
                selected_smiley.setBackgroundResource(R.drawable.smile4);
                selected_smiley.setText("");
                setSmileyID(R.drawable.smile4);
                break;
            case R.id.button5:
                selected_smiley.setBackgroundResource(R.drawable.smile5);
                selected_smiley.setText("");
                setSmileyID(R.drawable.smile5);
                break;
    
            default:
                break;
        }
    }
    
    // This method sets the smiley ID according to what the user picks.
    private void setSmileyID(int smileyID) {
        this.smiley_id = smileyID;
    }
    
    // This method calls alert dialog to inform users a message.
    private void alertUser(String title, String message) {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(UploadImageActivity.this);
        dialogBuilder.setTitle(title);
        dialogBuilder.setMessage(message);
        dialogBuilder.setPositiveButton("Ok", null);
        dialogBuilder.show();
    }
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(requestCode == Crop.REQUEST_PICK && resultCode == RESULT_OK) {
            beginCrop(data.getData());
        } else if(requestCode == Crop.REQUEST_CROP) {
            handleCrop(resultCode, data);
        }
    }
    
    // This method allows users to crop image in square.
    private void beginCrop(Uri source) {
        Uri destination = Uri.fromFile(new File(getCacheDir(), "cropped"));
        Crop.of(source, destination).asSquare().start(this);
    }
    
    // This method ensures there are no errors in cropping.
    private void handleCrop(int resultCode, Intent result) {
        if(resultCode == RESULT_OK) {
            picture.setImageURI(Crop.getOutput(result));
            uriPicture = Crop.getOutput(result).toString();
        } else if(resultCode == Crop.RESULT_ERROR) {
            Toast.makeText(this, Crop.getError(result).getMessage(), Toast.LENGTH_SHORT).show();
        }
    }
    

    TableDatabase.java

    public class TableDatabase extends SQLiteOpenHelper {
    
    public String query = "CREATE TABLE "   TableData.TableInfo.TABLE_NAME   " ("  
                                            TableData.TableInfo.SMILEY   " INTEGER NOT NULL, "  
                                            TableData.TableInfo.TITLE   " TEXT, "  
                                            TableData.TableInfo.DATE   " TEXT, "  
                                            TableData.TableInfo.CAPTION   " TEXT, "  
                                            TableData.TableInfo.IMAGE   " TEXT);";
    
    public TableDatabase(Context context) {
        super(context, TableData.TableInfo.DATABASE_NAME, null, TableData.TableInfo.DATABASE_VERSION);
        // Check if database is created
        Log.d("Database operations", "Database created");
    }
    
    @Override
    public void onCreate(SQLiteDatabase db) {
        // Create table
        db.execSQL(query);
        Log.d("Database operations", "Table created");
    }
    
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    
    }
    
    // Insert user information into the database
    public void putInformation(TableDatabase data, int smiley, String title, String date, String caption, String image) {
        // Write data into database
        SQLiteDatabase sqLiteDatabase = data.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
    
        // Add value from each column into contentvalue
        contentValues.put(TableData.TableInfo.SMILEY, smiley);
        contentValues.put(TableData.TableInfo.TITLE, title);
        contentValues.put(TableData.TableInfo.DATE, date);
        contentValues.put(TableData.TableInfo.CAPTION, caption);
        contentValues.put(TableData.TableInfo.IMAGE, image);
    
        // Insert into sqlite database
        sqLiteDatabase.insert(TableData.TableInfo.TABLE_NAME, null, contentValues);
        Log.d("Database operations", "One row inserted");
    }
    
    // Retrieve data from database
    public Cursor getInformation(TableDatabase data) {
        // Read data from sqlite database
        SQLiteDatabase sqLiteDatabase = data.getReadableDatabase();
        String[] columns = { TableData.TableInfo.SMILEY, TableData.TableInfo.TITLE, TableData.TableInfo.DATE, TableData.TableInfo.CAPTION, TableData.TableInfo.IMAGE };
    
        // Points to first row of table
        return sqLiteDatabase.query(TableData.TableInfo.TABLE_NAME, columns, null, null, null, null, null);
    }
    

    最佳答案:

    0 个答案:

    没有答案
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