無法將數據從會議室數據庫獲取到Spinner
[英]Cannot fetch data from room database to Spinner
問題描述
這個應用程式是要從api.github.com/users擷取資料，並反映在Spinner上
我在日志中獲得的數據Splash.java但不能反映數據Home.java
MyAppDatabase.java
@Database(entities = {Users.class}, version = 1, exportSchema = false)
public abstract class MyAppDatabase extends RoomDatabase {
public abstract MyDao myDao();
}
MyDao.java
@Dao
public interface MyDao {
@Insert(onConflict = OnConflictStrategy.REPLACE)
void addUsers(Users users);
@Query("SELECT * FROM Users")
List<Users> getUsers();
@Query("SELECT node_id FROM Users")
List<String> getNodeId();
}
Splash.java上的getData()
public class Splash extends AppCompatActivity {
MyAppDatabase myAppDatabase;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
myAppDatabase = Room.databaseBuilder(getApplicationContext(), MyAppDatabase.class, "MyDao").allowMainThreadQueries().build();
//get data from webservice and store locally
getData();
}
}, 500);
}
private void getData() {
//Creating a string request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Config.DATA_URL, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.e("response", response.toString());
response.length();
for (int i = 0; i < response.length(); i++) {
try {
JSONObject jsonObject = response.getJSONObject(i);
Users users = new Users();
//Set fields in Users object.
users.setLogin(jsonObject.getString(Config.TAG_Login));
users.setId(jsonObject.getString(Config.TAG_Id));
users.setNode_id(jsonObject.getString(Config.TAG_Node));
users.setAvatar_url(jsonObject.getString(Config.TAG_Avatar));
users.setGravatar_id(jsonObject.getString(Config.TAG_Gravatar_id));
users.setUrl(jsonObject.getString(Config.TAG_url));
users.setHtml_url(jsonObject.getString(Config.TAG_htmi_url));
users.setFollowers_url(jsonObject.getString(Config.TAG_Followers_url));
users.setFollowing_url(jsonObject.getString(Config.TAG_Following_url));
users.setGists_url(jsonObject.getString(Config.TAG_Gists_url));
users.setStarred_url(jsonObject.getString(Config.TAG_Starred_url));
users.setSubscriptions_url(jsonObject.getString(Config.TAG_Subscriptions_url));
users.setOrganizations_url(jsonObject.getString(Config.TAG_Organizations_url));
users.setRepos_url(jsonObject.getString(Config.TAG_Repos_url));
users.setReceived_events_url(jsonObject.getString(Config.TAG_Received_events_url));
users.setType(jsonObject.getString(Config.TAG_Type));
users.setSite_admin(jsonObject.getString(Config.TAG_Site_admin));
users.setEvents_url(jsonObject.getString(Config.TAG_events_url));
myAppDatabase.myDao().addUsers(users);
} catch (JSONException e) {
e.printStackTrace();
}
}
Intent intent = new Intent(Splash.this, Home.class);
// intent.putExtra("remember", "true");
startActivity(intent);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("Volley", error.toString());
}
});
RequestQueue requestQueue = Volley.newRequestQueue(this);
jsonArrayRequest.setRetryPolicy(new DefaultRetryPolicy(
10000,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
requestQueue.add(jsonArrayRequest);
}
}
putData()上的Home.java putData()
public class Home extends AppCompatActivity {
MyAppDatabase myAppDatabase;
//To add into spinner
private ArrayList<String> userType;
//List of users from Db
List<Users> users;
private Spinner spinner;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
userType = new ArrayList<>();
spinner = findViewById(R.id.sp_user_type);
myAppDatabase = Room.databaseBuilder(getApplicationContext(), MyAppDatabase.class,"UsersDb").allowMainThreadQueries().build();
//get data from Db and put into arrayList for spinner
putData();
}
private void putData() {
users =myAppDatabase.myDao().getUsers();
userType.add("Select UserType"); //Dummy addition
for(int i = 0; i < users.size(); i++){
userType.add(users.get(i).getType());
Log.e("DistNames",users.get(i).getType());
}
users.size();
spinner.setAdapter(new ArrayAdapter<>(Home.this, android.R.layout.simple_spinner_dropdown_item, userType));
}
}
1 個解決方案
解決方案1
0 2019-08-19 07:34:58
因為您是在循環本身中開始活動，所以實際上應該在循環之外。
實際上，您所犯的錯誤是它將在第一次迭代中啟動Home活動，因此您不會從API響應中獲取所有數據。 為了解決這個問題，讓循環遍歷每個條目並添加到數據庫中，並在完成時啟動活動，如此循環之外。
錯誤：
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Config.DATA_URL, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.e("response", response.toString());
for (int i = 0; i < response.length(); i++) {
try {
JSONObject jsonObject = response.getJSONObject(i);
Users users = new Users();
//Set fields in Users object.
users.setLogin(jsonObject.getString(Config.TAG_Login));
users.setId(jsonObject.getString(Config.TAG_Id));
users.setNode_id(jsonObject.getString(Config.TAG_Node));
users.setAvatar_url(jsonObject.getString(Config.TAG_Avatar));
users.setGravatar_id(jsonObject.getString(Config.TAG_Gravatar_id));
users.setUrl(jsonObject.getString(Config.TAG_url));
users.setHtml_url(jsonObject.getString(Config.TAG_htmi_url));
users.setFollowers_url(jsonObject.getString(Config.TAG_Followers_url));
users.setFollowing_url(jsonObject.getString(Config.TAG_Following_url));
users.setGists_url(jsonObject.getString(Config.TAG_Gists_url));
users.setStarred_url(jsonObject.getString(Config.TAG_Starred_url));
users.setSubscriptions_url(jsonObject.getString(Config.TAG_Subscriptions_url));
users.setOrganizations_url(jsonObject.getString(Config.TAG_Organizations_url));
users.setRepos_url(jsonObject.getString(Config.TAG_Repos_url));
users.setReceived_events_url(jsonObject.getString(Config.TAG_Received_events_url));
users.setType(jsonObject.getString(Config.TAG_Type));
users.setSite_admin(jsonObject.getString(Config.TAG_Site_admin));
users.setEvents_url(jsonObject.getString(Config.TAG_events_url));
myAppDatabase.myDao().addUsers(users);
Intent intent = new Intent(Splash.this, Home.class);
// intent.putExtra("remember", "true");
startActivity(intent);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("Volley", error.toString());
}
});
正確：
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Config.DATA_URL, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.e("response", response.toString());
for (int i = 0; i < response.length(); i++) {
try {
JSONObject jsonObject = response.getJSONObject(i);
Users users = new Users();
//Set fields in Users object.
users.setLogin(jsonObject.getString(Config.TAG_Login));
users.setId(jsonObject.getString(Config.TAG_Id));
users.setNode_id(jsonObject.getString(Config.TAG_Node));
users.setAvatar_url(jsonObject.getString(Config.TAG_Avatar));
users.setGravatar_id(jsonObject.getString(Config.TAG_Gravatar_id));
users.setUrl(jsonObject.getString(Config.TAG_url));
users.setHtml_url(jsonObject.getString(Config.TAG_htmi_url));
users.setFollowers_url(jsonObject.getString(Config.TAG_Followers_url));
users.setFollowing_url(jsonObject.getString(Config.TAG_Following_url));
users.setGists_url(jsonObject.getString(Config.TAG_Gists_url));
users.setStarred_url(jsonObject.getString(Config.TAG_Starred_url));
users.setSubscriptions_url(jsonObject.getString(Config.TAG_Subscriptions_url));
users.setOrganizations_url(jsonObject.getString(Config.TAG_Organizations_url));
users.setRepos_url(jsonObject.getString(Config.TAG_Repos_url));
users.setReceived_events_url(jsonObject.getString(Config.TAG_Received_events_url));
users.setType(jsonObject.getString(Config.TAG_Type));
users.setSite_admin(jsonObject.getString(Config.TAG_Site_admin));
users.setEvents_url(jsonObject.getString(Config.TAG_events_url));
myAppDatabase.myDao().addUsers(users);
} catch (JSONException e) {
e.printStackTrace();
}
}
Intent intent = new Intent(Splash.this, Home.class);
// intent.putExtra("remember", "true");
startActivity(intent);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("Volley", error.toString());
}
});
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