【发布时间】:2021-06-05 18:15:01
【问题描述】:
我使用 RecyclerView、LiveData 和 Room 创建了一个简单的应用程序(我认为是这样)。你可以在 GitHub MyProject看到我的整个项目
我有主活动,那里有一个带有 TextView 的单词计数器,两个用于检查单词的按钮,并在每次单击后将其发送到另一个活动。当我打开第二个活动(YesList)时,我什么也看不到。那里是空的。我该如何解决?
public class MainActivity extends AppCompatActivity {
public static final String EXTRA_YES = "com.saturnpro.wcounter.YES";
public static final String EXTRA_NO = "com.saturnpro.wcounter.NO";
public static final int NEW_WORD_ACTIVITY_REQUEST_CODE = 1;
private TextView text;
private TextView counterTxt;
List<String> words;
int count = 0;
int i = 0;
Intent intentYes;
Intent intentNo;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text = findViewById(R.id.txt);
counterTxt = findViewById(R.id.countertext);
words = new ArrayList<>();
words.add("hello");
words.add("hi");
words.add("cat");
words.add("dog");
words.add("drink");
words.add("planet");
words.add("space");
words.add("kind");
text.setText(words.get(0));
counterTxt.setText(count+"");
intentYes = new Intent(MainActivity.this, YesList.class);
intentNo = new Intent(MainActivity.this, NoList.class);
}
public void addToYesList(View view) {
i++;
if(i < words.size()) {
String word = words.get(i);
text.setText(word);
count++;
counterTxt.setText(count+"");
Intent replyIntent = new Intent();
if (TextUtils.isEmpty(word)) {
setResult(RESULT_CANCELED, replyIntent);
} else {
replyIntent.putExtra(EXTRA_YES, word);
setResult(RESULT_OK, replyIntent);
}
}
else {
text.setText("Слов больше нет");
}
}
public void addToNoList(View view) {
i++;
if (i < words.size()) {
String word = words.get(i);
text.setText(word);
}
else {
text.setText("Слов больше нет");
}
}
public void iknow(View view) {
startActivityForResult(intentYes, NEW_WORD_ACTIVITY_REQUEST_CODE);
}
public void idontknow(View view) {
startActivity(intentNo);
}
}
第二个活动YesList。
public class YesList extends AppCompatActivity {
private WordViewModel mWordViewModel;
public static final int NEW_WORD_ACTIVITY_REQUEST_CODE = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_yes_list);
RecyclerView recyclerViewYes = findViewById(R.id.listYes);
final WordListAdapter adapter = new WordListAdapter(new WordListAdapter.WordDiff());
recyclerViewYes.setAdapter(adapter);
recyclerViewYes.setLayoutManager(new LinearLayoutManager(this));
// mWordViewModel = new ViewModelProvider(this).get(WordViewModel.class);
mWordViewModel = new ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory.getInstance(getApplication())).get(WordViewModel.class);
mWordViewModel.getAllWords().observe(this, words -> {
// Update the cached copy of the words in the adapter.
adapter.submitList(words);
});
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == NEW_WORD_ACTIVITY_REQUEST_CODE && resultCode == RESULT_OK) {
Words word = new Words(data.getStringExtra(MainActivity.EXTRA_YES));
mWordViewModel.insert(word);
Log.d("proverka", mWordViewModel.toString());
} else {
Toast.makeText(
getApplicationContext(),
R.string.empty_not_saved,
Toast.LENGTH_LONG).show();
}
}
}
【问题讨论】:
标签: java android android-recyclerview android-room android-livedata