[英]Android - Passing an ArrayList of Custom Objects to Another Activity
[英]Passing arraylist of custom object to another activity
單擊單元格時,對象將添加到數組中。 該數組需要傳遞到另一個活動中。 為了進行測試,我通過了只有一個對象DoctorObject的數組。 然后在下一個活動中,我使用.getName()作為字符串獲取名稱,並將其顯示在吐司中。 但是,吐司是空的。
這是一些代碼片段
賓語:
public class DoctorObject implements Parcelable {
private List<Object> mChildrenList;
public DoctorObject(String name) {
Docname = name;
}
public DoctorObject (Parcel in){
this.DocPic = in.readInt();
this.Docname= in.readString();
this.Docspecialty = in.readString();
this.DocLocation = in.readString();
}
String Docname = "";
public String getDocname() {
return Docname;
}
public void setDocname(String docname) {
Docname = docname;
}
public int getDocPic() {
return DocPic;
}
public void setDocPic(int docPic) {
DocPic = docPic;
}
public String getDocspecialty() {
return Docspecialty;
}
public void setDocspecialty(String docspecialty) {
Docspecialty = docspecialty;
}
public String getDocLocation() {
return DocLocation;
}
public void setDocLocation(String docLocation) {
DocLocation = docLocation;
}
int DocPic;
String Docspecialty = "";
String DocLocation = "";
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
}
public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
public DoctorObject createFromParcel(Parcel in) {
return new DoctorObject(in);
}
public DoctorObject[] newArray(int size) {
return new DoctorObject[size];
}
};
活動:
ArrayList<DoctorObject> selectedItems = new ArrayList<>();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_my_team);
context = this;
/* Regular Expand listview
*/
// get the listview
expListView = (ExpandableListView) findViewById(R.id.newTeamListView);
// preparing list data
prepareListData();
listAdapter = new ExpandableListAdapter(this, listDataDoc, listDataChildStaff);
// setting list adapter
expListView.setAdapter(listAdapter);
// expListView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
// Listview on child click listener
expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
@Override
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
// TODO Auto-generated method stub
DoctorObject currentDoc = listDataDoc.get(groupPosition);
StaffObject currentStaff = listDataChildStaff.get(listDataDoc.get(groupPosition)).get(childPosition);
selectedItems.add(currentDoc);
String toastname = currentDoc.getDocname();
String toastStaff = currentStaff.getStaffname();
Toast.makeText(getApplicationContext(),
toastStaff,
Toast.LENGTH_SHORT).show();
return true;
}
});
/* End of regular expand listview
*/
nextButton = (Button) findViewById(R.id.nextbuttonTeam);
nextButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent myIntent = new Intent(CreateMyTeamActivity.this, CreateReferralTeamActivity.class);
myIntent.putParcelableArrayListExtra("NAME", selectedItems);
//myIntent.putExtra("Selections",selectedItems);
CreateMyTeamActivity.this.startActivity(myIntent);
}
});
}
下一個活動:
public class CreateReferralTeamActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_referral_team);
Intent b = getIntent();
ArrayList<DoctorObject> list = (ArrayList<DoctorObject>) b.getSerializableExtra("NAME");
String lists ="";
for (int i=0; i < list.size(); i++){
lists = list.get(i).getDocname();
}
//TextView text = (TextView) findViewById(R.id.sampleText);
//text.setText(lists);
Toast.makeText(getApplicationContext(),
lists,
Toast.LENGTH_SHORT).show();
}
}
當我運行它似乎數組是空的。
這是一個動畫的gif:
如果T對象不是Parcelable對象,則可以使用Gson庫將ArrayList傳遞給另一個Activity。 通用類型在哪里。 您的情況是ArrayList
步驟1:首先使用Gradle腳本導入Gson庫
在您的Gradle依賴項中添加此行
dependencies {
compile 'com.google.code.gson:gson:2.7'
}
步驟2:將ArrayList轉換為JSON字符串,並將JSON字符串從活動1傳遞到活動2
ArrayList<DoctorObject> doctors = new ArrayList<Location>();
doctors.add(new DoctorObject(params));
doctors.add(new DoctorObject(params));
Gson gson = new Gson();
String jsonString = gson.toJson(doctors);
Intent intent = new Intent(MainActivity.this,MapsActivity.class);
intent.putExtra("KEY",jsonString);
startActivity(intent);
步驟3:從Bundle中獲取JSON字符串,並將其轉換回ArrayList
import java.lang.reflect.Type;
Bundle bundle = getIntent().getExtras();
String jsonString = bundle.getString("KEY");
Gson gson = new Gson();
Type listOfdoctorType = new TypeToken<List<DoctorObject>>() {}.getType();
ArrayList<DoctorObject> doctors = gson.fromJson(jsonString,listOfdoctorType );
使用getParcelableArrayListExtra
而不是getSerializableExtra
因為使用putParcelableArrayListExtra
從上一個Activity發送ArrayList對象:
ArrayList<DoctorObject> list = b.getParcelableArrayListExtra("NAME");
您不能將DoctorObject#writeToParcel()
空,這實際上是復制對象數據的方式。
@Override
public void writeToParcel(Parcel dest, int flags) {
// the order you write to the Parcel has to be the same order you read from the Parcel
dest.writeInt(DocPic);
dest.writeString(Docname);
dest.writeString(Docspecialty);
dest.writeString(DocLocation);
}
並在其他活動中回讀數據,請使用getParcelableArrayListExtra
ArrayList<DoctorObject> list = b.getParcelableArrayListExtra("NAME");
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