java - 添加或删除数据时，房间数据库未正确更新 ID

Question

我正在构建一个允许用户存储用户名和密码的应用程序。用户单击 FAB，AddEditEntry.java Activity 启动。用户输入用户名，输入或生成密码，输入提示并单击保存。新数据显示在 Mainactivity.java 中的列表中。如果用户选择编辑条目，他/她需要做的就是长按该条目，相同的 AddEditEntry.java 类会从字段中的先前数据开始。然后用户可以更改该数据并点击保存以更新条目。操作栏上还有一个按钮可以删除所有条目，或者用户可以向左/向右滑动条目以将其从数据库中删除。

相反，这是发生的事情:

• 用户能够成功添加新条目。
• 长按后，AddEditEntry.java 成功地用以前的数据填充字段
• 当用户删除条目时(无论是通过向左/向右滑动还是点击删除所有按钮)，新条目不会从 ID 值 1 开始。条目从上一个条目停止的地方开始。因此，如果我删除 ID = 1 的条目，则新条目的 ID = 2。
• 更糟糕的是，当我点击保存按钮更新一个条目时，ID 变成了-1。当发生这种情况时，条目的值根本不存在，因为我在每个状态下使用 Toast 消息检查它们。因此没有更新，条目保持不变。

应用程序是用 MVVM 架构构建的，所以我有(实体、DAO、数据库、存储库、 View 模型)类，以及必要的适配器类。我将只发布相关代码以避免尽可能困惑。我可以根据请求添加更多代码。

主要 Activity .java:

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        //Sends the existing entry for editing
        adapter.setOnItemLongClickListener(new RecyclerViewAdapter.OnItemLongClickListener() {
            @Override
            public void onItemLongClick(Entries entries) {
                Intent intent = new Intent(MainActivity.this, AddEditEntry.class);

                intent.putExtra(AddEditEntry.EXTRA_USERNAME, entries.getUsername());
                intent.putExtra(AddEditEntry.EXTRA_HINT, entries.getHint());
                intent.putExtra(AddEditEntry.EXTRA_PASSWORD, entries.getPassword());
                intent.putExtra(AddEditEntry.EXTRA_ID, entries.getId());
                startActivityForResult(intent, EDIT_ENTRY_REQUEST);

                Toast.makeText(MainActivity.this, entries.getUsername(), Toast.LENGTH_SHORT).show();
                Toast.makeText(MainActivity.this, entries.getHint(), Toast.LENGTH_SHORT).show();
                Toast.makeText(MainActivity.this, entries.getPassword(), Toast.LENGTH_SHORT).show();
                Toast.makeText(MainActivity.this, String.valueOf(entries.getId()), Toast.LENGTH_SHORT).show();
            }
        });
    }
...
    //The onActivityResult retrieves the result when the user adds
    // or edits an entry by checking for the specific request code
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == ADD_ENTRY_REQUEST && resultCode == RESULT_OK){
            String username = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_USERNAME);
            String password = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_PASSWORD);
            String hint = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_HINT);

            Entries entry = new Entries(username, hint, password);
            viewModel.insert(entry);

            Toast.makeText(this, "Entry added!", Toast.LENGTH_SHORT).show();

        }else if(requestCode == EDIT_ENTRY_REQUEST && resultCode == RESULT_OK){
            int id = getIntent().getIntExtra(AddEditEntry.EXTRA_ID, -1);
            String username = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_USERNAME);
            String password = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_PASSWORD);
            String hint = Objects.requireNonNull(data).getStringExtra(AddEditEntry.EXTRA_HINT);

            if (id == -1){Toast.makeText(this, "Something went wrong", Toast.LENGTH_SHORT).show();}

            Entries entry = new Entries(username, hint, password);
            entry.setId(id);
            viewModel.update(entry);

            Toast.makeText(this, String.valueOf(id), Toast.LENGTH_SHORT).show();
            Toast.makeText(this, username, Toast.LENGTH_SHORT).show();
            Toast.makeText(this, password, Toast.LENGTH_SHORT).show();
            Toast.makeText(this, hint, Toast.LENGTH_SHORT).show();

            Toast.makeText(this, "Entry updated", Toast.LENGTH_SHORT).show();

        }else{Toast.makeText(this, "Entry not added!", Toast.LENGTH_SHORT).show();}
    }

添加编辑条目.java

public class AddEditEntry extends AppCompatActivity {

    public static final String EXTRA_USERNAME = "com.ozbek.cryptpass.EXTRA_USERNAME";
    public static final String EXTRA_HINT = "com.ozbek.cryptpass.EXTRA_HINT";
    public static final String EXTRA_PASSWORD = "com.ozbek.cryptpass.EXTRA_PASSWORD";
    public static final String EXTRA_ID = "com.ozbek.cryptpass.EXTRA_ID";
    public static final int EDIT_ENTRY_REQUEST = 3;

    ...

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...

        final Intent intent = getIntent();
        // If the ID was passed, gets the extras for editing
        if(intent.hasExtra(EXTRA_ID)){
            setTitle("Edit Entry");
            saveEntry.setText("Update Entry");
            usernameEditText.setText(getIntent().getStringExtra(EXTRA_USERNAME));
            passwordEditText.setText(getIntent().getStringExtra(EXTRA_PASSWORD));
            hintEditText.setText(getIntent().getStringExtra(EXTRA_HINT));
            int id = getIntent().getIntExtra(EXTRA_ID, -1);

            Toast.makeText(this, "Info Received!!!", Toast.LENGTH_SHORT).show();
            Toast.makeText(this, getIntent().getStringExtra(EXTRA_USERNAME), Toast.LENGTH_SHORT).show();
            Toast.makeText(this, getIntent().getStringExtra(EXTRA_PASSWORD), Toast.LENGTH_SHORT).show();
            Toast.makeText(this, getIntent().getStringExtra(EXTRA_HINT), Toast.LENGTH_SHORT).show();
            Toast.makeText(this, String.valueOf(id), Toast.LENGTH_SHORT).show();
        }

        else{setTitle("Add Entry");}

        generatePassword.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {passwordEditText.setText(generatedPassword());}});

        saveEntry.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent data = new Intent();
                data.putExtra(EXTRA_USERNAME, usernameEditText.getText().toString());
                data.putExtra(EXTRA_HINT, hintEditText.getText().toString());
                data.putExtra(EXTRA_PASSWORD, passwordEditText.getText().toString());

                setResult(RESULT_OK, data);
                finish();
            }
        });
    }

    ...
}

EntryViewModel.java

public class EntryViewModel extends AndroidViewModel {
    private EntryRepository repository;
    private LiveData<List<Entries>> allEntries;


    public EntryViewModel(@NonNull Application application) {
        super(application);
        repository = new EntryRepository(application);
        allEntries = repository.getAllEntries();
    }

    public void insert(Entries entries){repository.insert(entries);}

    public void update(Entries entries){repository.update(entries);}

    public void delete(Entries entries){repository.delete(entries);}

    public void deleteAll(){repository.deleteAllEntries();}

    public LiveData<List<Entries>> getAllEntries() {return allEntries;}
}

条目.java

@Entity(tableName = "entries_table")
public class Entries {
    @PrimaryKey(autoGenerate = true)
    private int id;

    private String username, hint, password;

    public Entries(String username, String hint, String password){
        this.username = username;
        this.hint = hint;
        this.password = password;
    }

    public Entries(){}

    public int getId() {return id;}

    public void setId(int id) {this.id = id;}

    public String getUsername() {return username;}

    public void setUsername(String username) {this.username = username;}

    public String getHint() {return hint;}

    public void setHint(String hint) {this.hint = hint;}

    public String getPassword() {return password;}

    public void setPassword(String password) {this.password = password;}
}

这是 full source code

Answer 1

只需添加这些修复。

在 AddEditEntry.java 中 saveEntry(我假设它是一个按钮)的 onClick() 中，将其更改为:

    saveEntry.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent data = new Intent();
            data.putExtra(EXTRA_USERNAME, usernameEditText.getText().toString());
            data.putExtra(EXTRA_HINT, hintEditText.getText().toString());
            data.putExtra(EXTRA_PASSWORD, passwordEditText.getText().toString());

            //You were missing these 2 lines
            int id  = getIntent().getIntExtra(EXTRA_ID, -1);
            if(id != -1){data.putExtra(EXTRA_ID, id);}

            setResult(RESULT_OK, data);
            finish();
        }
    });

然后在 MainActivity.java 中的 onActivityResult 方法中，执行此快速修复:

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if(requestCode == ADD_ENTRY_REQUEST && resultCode == RESULT_OK){
        ...

    }else if(requestCode == EDIT_ENTRY_REQUEST && resultCode == RESULT_OK){
        int id = Objects.requireNonNull(data).getIntExtra(AddEditEntry.EXTRA_ID, -1);

        if (id == -1){
            Toast.makeText(this, "Something went wrong", Toast.LENGTH_SHORT).show();
            return;
        }

        ...

    }else{Toast.makeText(this, "Entry not added!", Toast.LENGTH_SHORT).show();}
}

它应该在这些之后工作。如果您有任何问题，请告诉我。