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android-recyclerview - 添加数据后 RecyclerView 不更新

转载 作者:行者123 更新时间:2023-12-05 00:56:59 30 4
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我正在从 ListView 迁移到 RecyclerView,但是在 SQLite 中输入一些数据后,我的列表没有使用 notifyDataSetChanged() 更新;所以我总是要调用setAdapter()方法;

我已经简化了我的代码在这里发布。谁能帮我修复notifyDataSetChanged();请在我的代码中工作?

RecyclerViewAdapter

public class RecyclerViewAdapter extends RecyclerView.Adapter<ViewHolder> {

private List<Model> model;
private Context context;

public RecyclerViewAdapter(Context context, List<Model> model) {
this.context = context;
this.model = new ArrayList<>(model);
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.custom_layout, parent, false);
return new ViewHolder(context, view, model);
}

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
final Model model = model.get(position);
holder.bind(model);
}

@Override
public int getItemCount() {
return model.size();
} }

取景器
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

private List<Model> model = new ArrayList<>();
private Context context;

private TextView textViewGroup;
private TextView textViewName;

public ViewHolder(Context context, View itemView, List<Model> model) {
super(itemView);

this.model = model;
this.context = context;

itemView.setOnClickListener(this);

textViewGroup = (TextView) itemView.findViewById(R.id.textViewGroup);
textViewName = (TextView) itemView.findViewById(R.id.textViewName);

}

public void bind(Model model) {
textViewGroup.setText(model.getGroup());
textViewName.setText(model.getName());
}
}

@Override
public void onClick(View view) {
Model model = this.model.get(getAdapterPosition());
Intent intent = new Intent(this.context, ShowGroup.class);
intent.putExtra("DATA", model);
intent.putExtra("POSITION", getAdapterPosition());
((Activity) this.context).startActivityForResult(intent, 7);

Log.i(">>", "_IDHOLDER: " + model.getId());
Log.i(">>", "_POSITION: " + getAdapterPosition());
Log.i(">>", ".");
} }

型号
public class Model implements Serializable {

public static final String TABLE = "GROUP_NAME";
public static final String ID = "_ID";
public static final String GROUP = "GROUP";
public static final String NAME = "NAME";

private long id;
private String group;
private String name;

public Model() {
setId(0);
}

public long getId() {
return id;
}

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

public String getGroup() {
return group;
}

public void setGroup(String group) {
this.group = group;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
} }

存储库
public class Repository {

private SQLiteDatabase db;

public Repository(SQLiteDatabase db) {
this.db = db;
}

private ContentValues fillModelValues(Model model) {
ContentValues values = new ContentValues();
values.put(Model.GROUP, model.getGroup());
values.put(Model.NAME, model.getName());

return values;
}

public void insert(Model model) {
ContentValues values = fillModelValues(model);
db.insertOrThrow(Model.TABLE, null, values);
}

public List<Model> consDataBase(Context context) {

List<Model> listModel = new ArrayList<>();

Cursor cursor = db.query(Model.TABLE, null, null, null, null, null, null);

if (cursor.getCount() > 0) {
cursor.moveToFirst();

do {
Model model = new Model();
model.setId(cursor.getLong(cursor.getColumnIndex(Model.ID)));
model.setGroup(cursor.getString(cursor.getColumnIndex(Model.GROUP)));
model.setName(cursor.getString(cursor.getColumnIndex(Model.NAME)));

listModel.add(model);

} while (cursor.moveToNext());
}

cursor.close();

return listModel;
} }

主事件
public class MainActivity extends AppCompatActivity {

private List<Model> listModel;
private LinearLayoutManager layoutManager;
private RecyclerView recyclerView;
private RecyclerViewAdapter recyclerViewAdapter;

private FloatingActionButton fab;

private DataBase dataBase;
private SQLiteDatabase db;
private Repository repository;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

layoutManager = new LinearLayoutManager(this);
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(layoutManager);

fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivityForResult(new Intent(MainActivity.this, AddGroup.class), 4);
}
});

try {
dataBase = new DataBase(this);
db = dataBase.getWritableDatabase();
repository = new Repository(db);

listModel = repository.consDataBase(context);
recyclerViewAdapter = new RecyclerViewAdapter(context, listModel);
recyclerView.setAdapter(recyclerViewAdapter);
recyclerView.setHasFixedSize(true);

} catch (SQLException e) {

}
}

@Override
protected void onDestroy() {
super.onDestroy();
if (db != null) {
db.close();
}
}

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

if (requestCode == 4) {

listModel = repository.consDataBase(context);
recyclerViewAdapter = new RecyclerViewAdapter(context, listModel);
recyclerView.setAdapter(recyclerViewAdapter);
}
} }

添加群组
public class AddGroup extends AppCompatActivity {

private EditText editTextGroup;
private EditText editTextName;

private DataBase dataBase;
private SQLiteDatabase db;
private Repository repository;
private Model model;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_group);

editTextGroup = (EditText) findViewById(R.id.editTextGroup);
editTextName = (EditText) findViewById(R.id.editTextName);

try {
dataBase = new DataBase(this);
db = dataBase.getWritableDatabase();
repository = new Repository(db);
model = new Model();

} catch (SQLException e) {

}
}

private void saveModel() {
try {
model.setGroup(editTextGroup.getText().toString().trim());
model.setName(editTextName.getText().toString().trim());
if (model.getId() == 0) {
repository.insert(model);
}

} catch (Exception e) {

}
}

@Override
protected void onDestroy() {
super.onDestroy();
if (db != null) {
db.close();
}
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_add_group, menu);

return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == R.id.action_save) {
saveModel();

}
return super.onOptionsItemSelected(item);
} }

最佳答案

它现在工作

回收器 View 适配器

public class RecyclerViewAdapter extends RecyclerView.Adapter<ViewHolder> {

private List<Model> model;
private Context context;

public RecyclerViewAdapter(Context context, List<Model> model) {
this.context = context;
this.model = new ArrayList<>(model);
}

...

public void notify(List<Model> list) {
if (model != null) {
model.clear();
model.addAll(list);

} else {
model = list;
}
notifyDataSetChanged();
}
}

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

if (requestCode == 4) {
listModel = repository.consDataBase(this);
recyclerViewAdapter.notify(listModel);
}
}

谢谢你 :)

关于android-recyclerview - 添加数据后 RecyclerView 不更新,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35285375/

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