【发布时间】：2018-08-13 19:18:47
【问题描述】：
我是 Android 新手，我正在尝试使用 bundle 和 parcelable 从数据库发送一些数据到片段以显示 recyclerview 和 layouttab。使用虚拟数据，我可以在 2 个选项卡中显示 recyclerview。但是当我尝试使用从活动中获取的数据库中的数据时，我遇到了一些麻烦，无法将我得到的数据发送到片段。
我在帖子中尝试了许多相似的解决方案。但直到这次我还不能完全找到正确的解决方案。
这是我的 MainActivity.java
public class MainActivity extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
private ViewPagerAdapter adapter;
private static final String URL = "http://myweb.com/api/getID.php?id=1";
private String[] ar_id, ar_stat;
private int arr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tabLayout = (TabLayout) findViewById(R.id.tablayout_id);
viewPager = (ViewPager) findViewById(R.id.viewpager_id);
adapter = new ViewPagerAdapter(getSupportFragmentManager());
//Add Fragment
adapter.AddFragment(new FragmentActive(), "Active");
adapter.AddFragment(new FragmentHistory(), "History");
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
getDataOrder();
}
private void getDataOrder(){
final JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(
Request.Method.GET, URL, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray list = response.getJSONArray("result");
ArrayList<Active> arrayList = new ArrayList<Active>();
arr = list.length();
ar_id = new String[arr];
ar_stat = new String[arr];
for (int i = 0; i < arr; i++) {
JSONObject data = list.getJSONObject(i);
ar_id[i] = data.getString("id");
ar_stat[i] = data.getString("status");
arrayList.add(new Active(ar_id[i], ar_stat[i]));
}
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("ac_array", arrayList);
bundle.putString("test", "123");
FragmentActive fragmentActive = new FragmentActive();
fragmentActive.setArguments(bundle);
} catch (JSONException e) {
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d("Fetching ERROR", "ERROR");
}
}
);
Volley.newRequestQueue(this).add(jsonObjectRequest);
}
}
另外，这是对象类，Active.java
public class Active implements Parcelable {
private String status;
public Active(){
}
public Active(Parcel in){
super();
readFromParcel(in);
}
public Active(String id, String status) {
this.id = id;
this.status = status;
}
public static final Parcelable.Creator<Active> CREATOR = new Parcelable.Creator<Active>() {
public Active createFromParcel(Parcel in) {
return new Active(in);
}
public Active[] newArray(int size) {
return new Active[size];
}
};
public void readFromParcel(Parcel in){
id = in.readString();
status = in.readString();
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(id);
dest.writeString(status);
}
public String getId() {
return id;
}
public String getStatus() {
return status;
}
public void setId(String id) {
this.id = id;
}
public void setStatus(String status) {
this.status = status;
}
}
这是片段类，FragmentActive.java
public class FragmentActive extends Fragment {
View v;
private RecyclerView myrecyclerview;
private ArrayList<Active> lstActive;
//private ArrayList<Active> getArray;
public FragmentActive() {
}
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
ArrayList<Active> activeArrayList = new ArrayList<Active>();
if (getArguments()!=null) {
activeArrayList = getArguments().getParcelableArrayList("ac_array");
String test = getArguments().getString("test");
Log.d("List", test);
}else{
Log.d("List", "Null?");
}
v = inflater.inflate(R.layout.active_fragment, container, false);
myrecyclerview = (RecyclerView) v.findViewById(R.id.active_recyclerview);
RecyclerViewAdapter recyclerAdapter = new RecyclerViewAdapter(getContext(), ***activeArrayList***);
myrecyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));
myrecyclerview.setAdapter(recyclerAdapter);
return v;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Dummy Data
lstActive = new ArrayList<>();
lstActive.add(new Active("1", "1"));
lstActive.add(new Active("2", "0"));
lstActive.add(new Active("3", "1"));
}
}
当我运行应用程序时，完全没有错误，只是没有显示 recyclerview，但是当我更改 FragmentActive.onCreateView 上的 activeArrayList到 dummy ArrayList，虚拟数据出现。
然后，我尝试打印从数据库中获取的数据，它显示。但是当我尝试从 MainActivity 打印 arrayList 时，这是我从运行调试文本中得到的
D/调试列表：[com.xxx.xxx.app.Active@79e903c, com.xxx.xxx.app.Active@8dde1c5, com.xxx.xxx.app.Active@4a1571a]
I/System.out: [com.xxx.xxx.app.Active@79e903c, com.xxx.xxx.app.Active@8dde1c5, com.xxx.xxx.app.Active@4a1571a]
它们是数据库中的 3 行吗？因为我选择的数据库显示 3 行。我应该怎么做才能获取、发送和显示数据？
【问题讨论】：
-
你得到答案了吗？
标签： java android android-fragments arraylist