如何在android中使用Intent将对象的ArrayList从一个传递给另一个活动？

Question

我在我的onClick()方法中的代码中有以下内容

 List<Question> mQuestionsList = QuestionBank.getQuestions();

现在我有了这一行后的意图,如下:

  Intent resultIntent = new Intent(this, ResultActivity.class);
  resultIntent.putParcelableArrayListExtra("QuestionsExtra", (ArrayList<? extends Parcelable>) mQuestionsList);
  startActivity(resultIntent);

我不知道如何将这个问题列表从一个活动传递到另一个活动My Question类

public class Question {
    private int[] operands;
    private int[] choices;
    private int userAnswerIndex;

    public Question(int[] operands, int[] choices) {
        this.operands = operands;
        this.choices = choices;
        this.userAnswerIndex = -1;
    }

    public int[] getChoices() {
        return choices;
    }

    public void setChoices(int[] choices) {
        this.choices = choices;
    }

    public int[] getOperands() {
        return operands;
    }

    public void setOperands(int[] operands) {
        this.operands = operands;
    }

    public int getUserAnswerIndex() {
        return userAnswerIndex;
    }

    public void setUserAnswerIndex(int userAnswerIndex) {
        this.userAnswerIndex = userAnswerIndex;
    }

    public int getAnswer() {
        int answer = 0;
        for (int operand : operands) {
            answer += operand;
        }
        return answer;
    }

    public boolean isCorrect() {
        return getAnswer() == choices[this.userAnswerIndex];
    }

    public boolean hasAnswered() {
        return userAnswerIndex != -1;
    }

    @Override
    public String toString() {
        StringBuilder builder = new StringBuilder();

        // Question
        builder.append("Question: ");
        for(int operand : operands) {
            builder.append(String.format("%d ", operand));
        }
        builder.append(System.getProperty("line.separator"));

        // Choices
        int answer = getAnswer();
        for (int choice : choices) {
            if (choice == answer) {
                builder.append(String.format("%d (A) ", choice));
            } else {
                builder.append(String.format("%d ", choice));
            }
        }
        return builder.toString();
       }

      }

Answer 1

活动之间:为我工作

ArrayList<Object> object = new ArrayList<Object>();
Intent intent = new Intent(Current.class, Transfer.class);
Bundle args = new Bundle();
args.putSerializable("ARRAYLIST",(Serializable)object);
intent.putExtra("BUNDLE",args);
startActivity(intent);

在Transfer.class中

Intent intent = getIntent();
Bundle args = intent.getBundleExtra("BUNDLE");
ArrayList<Object> object = (ArrayList<Object>) args.getSerializable("ARRAYLIST");

希望这有帮助的人.

使用Parcelable在Activity之间传递数据

这通常在您创建DataModel时有效

例如假设我们有一个类型的json

{
    "bird": [{
        "id": 1,
        "name": "Chicken"
    }, {
        "id": 2,
        "name": "Eagle"
    }]
}

这里的鸟是一个List,它包含两个元素

我们将使用jsonschema2pojo创建模型

现在我们有模型类Name BirdModel和Bird BirdModel包含Bird和Bird的List包含name和id

转到bird类并添加接口" implements Parcelable "

通过Alt + Enter在android studio中添加implementsmets方法

注意:将出现一个对话框,指出Add implements方法按Enter键

按Alt + Enter添加Parcelable实现

注意:将出现一个对话框,说明添加Parcelable实施并再次输入

现在把它传递给意图.

List<Bird> birds = birdModel.getBird();
Intent intent = new Intent(Current.this, Transfer.class);
Bundle bundle = new Bundle();
bundle.putParcelableArrayList("Birds", birds);
intent.putExtras(bundle);
startActivity(intent);

并且关于转移活动onCreate

List<Bird> challenge = this.getIntent().getExtras().getParcelableArrayList("Birds");

谢谢

如果有任何问题,请告诉我.

Answer 2

脚步:

1. 将您的对象类实现为可序列化

   public class Question implements Serializable`
   

2. 把它放在你的Source Activity中

   ArrayList<Question> mQuestionList = new ArrayList<Question>;
   mQuestionsList = QuestionBank.getQuestions();  
   mQuestionList.add(new Question(ops1, choices1));
   
   Intent intent = new Intent(SourceActivity.this, TargetActivity.class);
   intent.putExtra("QuestionListExtra", mQuestionList);
   

3. 把它放在你的目标活动中

    ArrayList<Question> questions = new ArrayList<Question>();
    questions = (ArrayList<Questions>) getIntent().getSerializableExtra("QuestionListExtra");
   

Answer 3

效果很好,

public class Question implements Serializable {
    private int[] operands;
    private int[] choices;
    private int userAnswerIndex;

   public Question(int[] operands, int[] choices) {
       this.operands = operands;
       this.choices = choices;
       this.userAnswerIndex = -1;
   }

   public int[] getChoices() {
       return choices;
   }

   public void setChoices(int[] choices) {
       this.choices = choices;
   }

   public int[] getOperands() {
       return operands;
   }

   public void setOperands(int[] operands) {
       this.operands = operands;
   }

   public int getUserAnswerIndex() {
       return userAnswerIndex;
   }

   public void setUserAnswerIndex(int userAnswerIndex) {
       this.userAnswerIndex = userAnswerIndex;
   }

   public int getAnswer() {
       int answer = 0;
       for (int operand : operands) {
           answer += operand;
       }
       return answer;
   }

   public boolean isCorrect() {
       return getAnswer() == choices[this.userAnswerIndex];
   }

   public boolean hasAnswered() {
       return userAnswerIndex != -1;
   }

   @Override
   public String toString() {
       StringBuilder builder = new StringBuilder();

       // Question
       builder.append("Question: ");
       for(int operand : operands) {
           builder.append(String.format("%d ", operand));
       }
       builder.append(System.getProperty("line.separator"));

       // Choices
       int answer = getAnswer();
       for (int choice : choices) {
           if (choice == answer) {
               builder.append(String.format("%d (A) ", choice));
           } else {
               builder.append(String.format("%d ", choice));
           }
       }
       return builder.toString();
     }
  }

在您的源活动中,使用此:

  List<Question> mQuestionList = new ArrayList<Question>;
  mQuestionsList = QuestionBank.getQuestions();
  mQuestionList.add(new Question(ops1, choices1));

  Intent intent = new Intent(SourceActivity.this, TargetActivity.class);
  intent.putExtra("QuestionListExtra", ArrayList<Question>mQuestionList);

在您的目标活动中,使用此:

  List<Question> questions = new ArrayList<Question>();
  questions = (ArrayList<Question>)getIntent().getSerializableExtra("QuestionListExtra");

Answer 4

通过Parcelable传递对象。这是一个很好的入门指南。
第一个问题应该这样实现Parcelable并添加以下行：

public class Question implements Parcelable{
    public Question(Parcel in) {
        // put your data using = in.readString();
  this.operands = in.readString();;
    this.choices = in.readString();;
    this.userAnswerIndex = in.readString();;

    }

    public Question() {
    }

    @Override
    public int describeContents() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(operands);
        dest.writeString(choices);
        dest.writeString(userAnswerIndex);
    }

    public static final Parcelable.Creator<Question> CREATOR = new Parcelable.Creator<Question>() {

        @Override
        public Question[] newArray(int size) {
            return new Question[size];
        }

        @Override
        public Question createFromParcel(Parcel source) {
            return new Question(source);
        }
    };

}

然后像这样传递您的数据：

Question question = new Question();
// put your data
  Intent resultIntent = new Intent(this, ResultActivity.class);
  resultIntent.putExtra("QuestionsExtra", question);
  startActivity(resultIntent);

并像这样获取您的数据：

Question question = new Question();
Bundle extras = getIntent().getExtras();
if(extras != null){
    question = extras.getParcelable("QuestionsExtra");
}

这样就可以了！

Answer 5

您的bean或pojo类应该implements parcelable interface。

例如：

public class BeanClass implements Parcelable{
    String name;
    int age;
    String sex;

    public BeanClass(String name, int age, String sex) {
        this.name = name;
        this.age = age;
        this.sex = sex;
    } 
     public static final Creator<BeanClass> CREATOR = new Creator<BeanClass>() {
        @Override
        public BeanClass createFromParcel(Parcel in) {
            return new BeanClass(in);
        }

        @Override
        public BeanClass[] newArray(int size) {
            return new BeanClass[size];
        }
    };
    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(name);
        dest.writeInt(age);
        dest.writeString(sex);
    }
}

考虑这样一个场景，你要发送arraylist的beanclass从类型Activity1到Activity2。
使用以下代码

活动1：

ArrayList<BeanClass> list=new ArrayList<BeanClass>();

private ArrayList<BeanClass> getList() {
    for(int i=0;i<5;i++) {

        list.add(new BeanClass("xyz", 25, "M"));
    }
    return list;
}
private void gotoNextActivity() {
    Intent intent=new Intent(this,Activity2.class);
    /* Bundle args = new Bundle();
    args.putSerializable("ARRAYLIST",(Serializable)list);
    intent.putExtra("BUNDLE",args);*/

    Bundle bundle = new Bundle();
    bundle.putParcelableArrayList("StudentDetails", list);
    intent.putExtras(bundle);
    startActivity(intent);
}

活动2：

ArrayList<BeanClass> listFromActivity1=new ArrayList<>();

listFromActivity1=this.getIntent().getExtras().getParcelableArrayList("StudentDetails");

if (listFromActivity1 != null) {

    Log.d("listis",""+listFromActivity1.toString());
}

我认为这是基本了解的概念。

Answer 6

就那么简单 ！！为我工作

从活动

        Intent intent = new Intent(Viewhirings.this, Informaall.class);
        intent.putStringArrayListExtra("list",nselectedfromadapter);

        startActivity(intent);

TO 活动

Bundle bundle = getIntent().getExtras();
    nselectedfromadapter= bundle.getStringArrayList("list");

Answer 7

使用 Intent 传递 ArrayList 的最简单方法

1. 在依赖块 build.gradle 中添加这一行。

   implementation 'com.google.code.gson:gson:2.2.4'
   

2. 通过数组列表

   ArrayList<String> listPrivate = new ArrayList<>();
   
   
   Intent intent = new Intent(MainActivity.this, ListActivity.class);
   intent.putExtra("private_list", new Gson().toJson(listPrivate));
   startActivity(intent);
   

3. 在另一个活动中检索列表

   ArrayList<String> listPrivate = new ArrayList<>();
   
   Type type = new TypeToken<List<String>>() {
   }.getType();
   listPrivate = new Gson().fromJson(getIntent().getStringExtra("private_list"), type);
   

您也可以在类型中使用 object 而不是 String

为我工作..