通过意图传递数组列表

我正在尝试使用意图将一个 arrayList 传递给另一个活动。

case R.id.editButton:
Toast.makeText(this, "edit was clicked", Toast.LENGTH_LONG).show();
Intent intent = new Intent(this, editList.class);
intent.putStringArrayListExtra("stock_list", stock_list);
startActivity(intent);
break;

这是我试图在第二个活动中检索列表的地方。这里有什么问题吗?

Intent i = new Intent(); //This should be getIntent();
stock_list = new ArrayList<String>();


stock_list = i.getStringArrayListExtra("stock_list");
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In your receiving intent you need to do:

Intent i = getIntent();
stock_list = i.getStringArrayListExtra("stock_list");

The way you have it you've just created a new empty intent without any extras.

If you only have a single extra you can condense this down to:

stock_list = getIntent().getStringArrayListExtra("stock_list");

if you using Generic Array List with Class instead of specific type like

EX:

private ArrayList<Model> aListModel = new ArrayList<Model>();

Here, Model = Class

Receiving Intent Like :

aListModel = (ArrayList<Model>) getIntent().getSerializableExtra(KEY);

MUST REMEMBER:

Here Model-class must be implemented like: ModelClass implements Serializable

I have done this one by Passing ArrayList in form of String.

  1. Add compile 'com.google.code.gson:gson:2.2.4' in dependencies block build.gradle.

  2. Click on Sync Project with Gradle Files

Cars.java:

public class Cars {
public String id, name;
}

FirstActivity.java

When you want to pass ArrayList:

List<Cars> cars= new ArrayList<Cars>();
cars.add(getCarModel("1", "A"));
cars.add(getCarModel("2", "B"));
cars.add(getCarModel("3", "C"));
cars.add(getCarModel("4", "D"));


Gson gson = new Gson();


String jsonCars = gson.toJson(cars);


Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
intent.putExtra("list_as_string", jsonCars);
startActivity(intent);

Get CarsModel by Function:

private Cars getCarModel(String id, String name){
Cars cars = new Cars();
cars.id = id;
cars.name = name;
return cars;
}

SecondActivity.java

You have to import java.lang.reflect.Type ;

on onCreate() to retrieve ArrayList:

String carListAsString = getIntent().getStringExtra("list_as_string");


Gson gson = new Gson();
Type type = new TypeToken<List<Cars>>(){}.getType();
List<Cars> carsList = gson.fromJson(carListAsString, type);
for (Cars cars : carsList){
Log.i("Car Data", cars.id+"-"+cars.name);
}

Hope this will save time, I saved it.

Done

    public class StructMain implements Serializable {
public  int id;
public String name;
public String lastName;
}

this my item . implement Serializable and create ArrayList

ArrayList<StructMain> items =new ArrayList<>();

and put in Bundle

Bundle bundle=new Bundle();
bundle.putSerializable("test",items);

and create a new Intent that put Bundle to Intent

Intent intent=new Intent(ActivityOne.this,ActivityTwo.class);
intent.putExtras(bundle);
startActivity(intent);

for receive bundle insert this code

Bundle bundle = getIntent().getExtras();
ArrayList<StructMain> item = (ArrayList<StructMain>) bundle.getSerializable("test");

Suppose you need to pass an arraylist of following class from current activity to next activity // class of the objects those in the arraylist // remember to implement the class from Serializable interface // Serializable means it converts the object into stream of bytes and helps to transfer that object

public class Question implements Serializable {
...
...
...
}

in your current activity you probably have an ArrayList as follows

ArrayList<Question> qsList = new ArrayList<>();
qsList.add(new Question(1));
qsList.add(new Question(2));
qsList.add(new Question(3));


// intialize Bundle instance
Bundle b = new Bundle();
// putting questions list into the bundle .. as key value pair.
// so you can retrieve the arrayList with this key
b.putSerializable("questions", (Serializable) qsList);
Intent i = new Intent(CurrentActivity.this, NextActivity.class);
i.putExtras(b);
startActivity(i);

in order to get the arraylist within the next activity

//get the bundle
Bundle b = getIntent().getExtras();
//getting the arraylist from the key
ArrayList<Question> q = (ArrayList<Question>) b.getSerializable("questions");
//arraylist/Pojo you can Pass using bundle  like this
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
Bundle args = new Bundle();
args.putSerializable("imageSliders",(Serializable)allStoriesPojo.getImageSliderPojos());
intent.putExtra("BUNDLE",args);
startActivity(intent);




Get SecondActivity like this
Intent intent = getIntent();
Bundle args = intent.getBundleExtra("BUNDLE");
String filter = bundle.getString("imageSliders");


//Happy coding