【发布时间】：2018-06-08 12:08:09
【问题描述】：
我有一个活动来实现一个待办事项列表，其中包含一个 recyclerview，每个项目都是一个复选框和 textview，每个任务都是从一个 edittext 添加的。 它使用 Realm.io 存储数据。我不断得到的行为是 recyclerview 中的单个元素只是得到更新，而不是膨胀！请帮忙。
TasksActivity -
public class TasksActivity extends AppCompatActivity implements View.OnClickListener{
TextView courseTitle;
RecyclerView TaskList;
EditText addTask;
Button addButton;
String transName; //Transferred Course name from MainActivity
TaskAdapter TA;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tasks);
courseTitle = findViewById(R.id.CourseName);
TaskList = findViewById(R.id.TaskListRV);
TaskList.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
addTask = findViewById(R.id.InputTask);
addButton = findViewById(R.id.AddTaskButton);
//Course name is the obtained from the previous acivity.
transName =getIntent().getExtras().getString("CourseName");
courseTitle.setText(transName);
TA = new TaskAdapter(transName);
TaskList.setAdapter(TA);
addButton.setOnClickListener(this);
}
@Override
public void onClick(View view) {
String task = addTask.getText().toString();
// Checking if the text is empty.
boolean flag = false;
for(int i = 0;i<task.length();i++)
{
if(task.charAt(i)!=' ')
flag = true;
}
if(!flag || task.equals(""))
{
Toast emptyWarning = Toast.makeText(getApplicationContext(),"Task cannot be Empty!",Toast.LENGTH_SHORT);
emptyWarning.show();
}
else
{
addTask.setText("");
TA.addNewTask(task);
}
}
}
TasksAdapter -
public class TaskAdapter extends RecyclerView.Adapter<TaskViewHolder> implements RealmChangeListener<RealmResults<TaskModel>>
{
private ArrayList<TaskModel> TaskList;
private String course;
private final Realm realm;
public TaskAdapter(String course)
{
this.course = course;
this.TaskList = new ArrayList<>();
realm = Realm.getDefaultInstance();
loadTaskData();
}
void loadTaskData()
{
RealmResults<TaskModel> taskModelRealmResults = realm.where(TaskModel.class).equalTo("courseName",course).findAll();
taskModelRealmResults.addChangeListener(this);
for(TaskModel iTM : taskModelRealmResults)
{
TaskList.add(realm.copyFromRealm(iTM));
}
notifyDataSetChanged();
}
@Override
public TaskViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
View view= layoutInflater.inflate(R.layout.item_task,parent,false);
TaskViewHolder Tvh = new TaskViewHolder(view);
return Tvh;
}
@Override
public void onBindViewHolder(TaskViewHolder holder, int position) {
holder.populateTask(TaskList.get(position));
}
@Override
public int getItemCount() {
return TaskList.size();
}
public void addNewTask(String task)
{
TaskModel newTaskObj = new TaskModel(task,course,false);
TaskList.add(newTaskObj);
notifyDataSetChanged();
realm.beginTransaction();
realm.insertOrUpdate(newTaskObj);
realm.commitTransaction();
}
@Override
public void onChange(RealmResults<TaskModel> taskModels) {
taskModels = realm.where(TaskModel.class).equalTo("courseName",course).findAll();
this.TaskList = new ArrayList<>();
for(TaskModel iTM : taskModels)
{
this.TaskList.add(realm.copyFromRealm(iTM));
}
notifyDataSetChanged();
}
}
TaskViewHolder 和 TaskModel -（如果你可能需要它们）
public class TaskModel extends RealmObject {
String task;
@PrimaryKey
String courseName;
boolean isDone;
public TaskModel() {
task = "";
courseName = "";
isDone = false;
}
public TaskModel(String task, String courseName, boolean isDone) {
this.task = task;
this.courseName = courseName;
this.isDone = isDone;
}
public String getTask() {
return task;
}
public void setTask(String task) {
this.task = task;
}
public boolean isDone() {
return isDone;
}
public void setDone(boolean done) {
isDone = done;
}
}
public class TaskViewHolder extends RecyclerView.ViewHolder {
CheckBox isdone;
TextView Taskname;
public TaskViewHolder(View itemView) {
super(itemView);
isdone = itemView.findViewById(R.id.TaskCheckBox);
Taskname = itemView.findViewById(R.id.TaskName);
}
void populateTask(final TaskModel T)
{
Taskname.setText(T.getTask());
isdone.setChecked(T.isDone());
isdone.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
T.setDone(isdone.isChecked());
}
});
}
}
【问题讨论】：
-
merely get updated, and not inflated!不是RecyclerView的工作原理吗？重复使用视图而不是创建新视图？ -
我的意思是 update 因为在同一组视图中被下一组数据替换。一次只显示一个单个视图。
-
这可能是因为该视图的布局足够大，可以覆盖整个 RecyclerView。
-
onChange是否返回整个列表？还是只是最后一项已更改？ -
private ArrayList<TaskModel> TaskList;和TaskList.add(realm.copyFromRealm(iTM));为什么？？？什么例子说明了这一点？因为我知道officials don't
标签： java android realm android-recyclerview