从 DialogFragement 获取数据，将其放入 SQLiteDB 并在回收器视图中显示所有结果

Posted 2023-04-19

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【中文标题】从 DialogFragement 获取数据，将其放入 SQLiteDB 并在回收器视图中显示所有结果【英文标题】：Getting data from a DialogFragement, putting it in a SQLiteDB and displaying all results in a recycler view 【发布时间】：2017-12-15 19:02:02 【问题描述】：

我需要将数据从 DialogFragment 发送到我的 FragmentActivity（基本上是 MainActivity）并将其添加到 SQLiteDB。然后查询所有要显示在recycler视图中的数据。这是 FragmentActivity：

@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fragment);
.....
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(this);
    RecyclerView FCRecycler = (RecyclerView) this.findViewById(R.id.FixedCostsRV);

    Cursor cursor = getAllFixedCosts();
    FCRecycler.setLayoutManager(mLayoutManager);
    mAdapter = new FixedCostsAdapter(this, cursor);

    FCRecycler.setAdapter(mAdapter);


    FixedCostsDbHelper dbHelper = new FixedCostsDbHelper(this);

    mDB = dbHelper.getWritableDatabase();
    readDB = dbHelper.getReadableDatabase();


    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);

    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);



private Cursor getAllCosts() 
    return mDB.query(
            FixedCostsContract.FixedCostsEntry.TABLE_NAME,
            null,
            null,
            null,
            null,
            null,
            null);


public void addCost(String Item, String CostAmount)
    if(Item.length() == 0 ||
            CostAmount.length() == 0)
        return;
    
        Cost = Integer.parseInt(FixedCostAmount);
    addFixedCostDB(Item, Cost);

    mAdapter.swapCursor(getAllCosts());


private long addCostDB(String Item,int Cost) 
    ContentValues cv = new ContentValues();
    cv.put(FixedCostsContract.FixedCostsEntry.COLUMN_COST_NAME, FixedCostItem);
    cv.put(FixedCostsContract.FixedCostsEntry.COLUMN_COST_AMOUNT, FixedCostItemAmount);
    return mDB.insert(FixedCostsContract.FixedCostsEntry.TABLE_NAME, null, cv);

我还将提供 fragmentClass 和 theDialogFragment 以防万一。片段：

    public class FixedCosts extends Fragment 

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) 
        View view = inflater.inflate(R.layout.fixed_costs_fragment, container, false);
        SharedPreferences sharedPrefs = this.getActivity().getSharedPreferences("MyPrefs", 0);
        Button launchDialog = (Button) view.findViewById(R.id.AddNewFixedCostsButton);
        launchDialog.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                DialogFragment dialog = new InfoDialogFragment();
                dialog.show(getFragmentManager(), "dialog");
            
        );

        String amount = (sharedPrefs.getString("AMOUNTMONEY", "WhatsUP"));
        String TextAmount = "$"+amount;

        TextView TitletextView = (TextView) view.findViewById(R.id.amountTitle);
        TitletextView.setText(TextAmount);

        return view;

Fragment 有一个按钮，可让您在 DialogFragment 中输入信息。这是 DialogFragmentClass：

public class InfoDialogFragment extends DialogFragment 

public InfoDialogFragment() 


@NonNull
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) 

    final AlertDialog.Builder adb = new AlertDialog.Builder(getActivity());
    final LayoutInflater inflater = getActivity().getLayoutInflater();
    View view = inflater.inflate(R.layout.info_dialogfrag, null);
    adb.setView(view);
    final EditText itemET = (EditText)view.findViewById(R.id.getItem);
    final EditText itemAmountET = (EditText)view.findViewById(R.id.getItemAmount);



            adb
            /*.setIcon()*/
            .setTitle("Fixed Cost")
            .setPositiveButton("Add", new DialogInterface.OnClickListener() 
                @Override
                public void onClick(DialogInterface dialog, int which) 
                    String FixedCostItem = itemET.getText().toString();
                    String FixedCostItemAmount = itemAmountET.getText().toString();
                    if(FixedCostItem.length() == 0 || FixedCostItemAmount.length() == 0)
                        Toast.makeText(getActivity(),"Enter Item and Amount", Toast.LENGTH_SHORT).show();
                    else
                        FragmentActivity fragmentActivity = new FragmentActivity();
                        fragmentActivity.addFixedCost(FixedCostItem, FixedCostItemAmount);
                        dialog.dismiss();
                    
                
            )
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() 
                @Override
                public void onClick(DialogInterface dialog, int which) 
                    InfoDialogFragment.this.getDialog().cancel();
                
            );
    return adb.create();

SQLiteDB：

public class FixedCostsDbHelper extends SQLiteOpenHelper 
private static final String DATABASE_NAME = "waitlist.db";

public static final int DATABASE_VERSION = 1;

public static final String TABLE_NAME = FixedCostsContract.FixedCostsEntry.TABLE_NAME;
public static final String ID_COLUMN = FixedCostsContract.FixedCostsEntry._ID;
public static final String COLUMN_COST_NAME = FixedCostsContract.FixedCostsEntry.COLUMN_COST_NAME;
public static final String COLUMN_COST_AMOUNT = FixedCostsContract.FixedCostsEntry.COLUMN_COST_AMOUNT;

public FixedCostsDbHelper(Context context) 
    super(context, DATABASE_NAME, null, DATABASE_VERSION);




@Override
public void onCreate(SQLiteDatabase db) 
    final String SQL_CREATE_FIXEDCOSTS_DB = "CREATE TABLE " + TABLE_NAME + " (" +
            ID_COLUMN + " INTEGER PRIMARY KEY AUTOINCREMENT," +
            COLUMN_COST_NAME + " TEXT NOT NULL, " +
            COLUMN_COST_AMOUNT + " INTEGER NOT NULL" +
            ")";
    db.execSQL(SQL_CREATE_FIXEDCOSTS_DB);



@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
    db.execSQL("DROP TABLE IF EXITS " + FixedCostsContract.FixedCostsEntry.TABLE_NAME);
    onCreate(db);

非常感谢所有帮助。

【问题讨论】：

【参考方案1】：

根据您的活动代码，您似乎在调用后正在初始化 mDB 光标光标 = getAllFixedCosts();。

getAllFiexedCosts() 正在使用仍未初始化的 mDB 变量。在这种情况下，您可能会得到 NullPointerException。

【讨论】：

谢谢你，我应该抓住这个。【参考方案2】：

我认为这里可以避免很多双极代码！！！

使用Material Dialogs 制作优雅而简单的对话框然后使用Activeandroid保存数据。

您只需 20 到 30 行代码即可完成所有这些工作

MaterialDialogshttps://github.com/afollestad/material-dialogs

ActiveAndroidhttps://github.com/pardom/ActiveAndroid