【问题标题】:Sending data to a Fragment instead of an Activity with a Parcelable object使用 Parcelable 对象将数据发送到 Fragment 而不是 Activity
【发布时间】:2014-06-06 09:19:46
【问题描述】:

我想用我创建的 Parcelable 类将数据发送到 Fragment。

我知道这就是您在使用 Activity 时的处理方式(ObjectA 是扩展 Parcelable 的类):

ObjectA obj = new ObjectA();   
// Set values etc.   
Intent i = new Intent(this, MyActivity.class); 
i.putExtra("com.package.ObjectA", obj);   
startActivity(i); 

但由于您不能对 Fragments 使用 Intent,所以我不知道该怎么做。

我什至可以使用 Parcelable 类吗?如果没有,我应该使用什么?我有可能,怎么做?

编辑/更新:

我已根据您的建议进行了更新,但仍然没有得到所有信息。

这是我们用来创建列表视图的片段:

package com.tsjd.HotMeals;

import java.util.ArrayList;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;

import com.example.tabtest.R;

public class RecipeListViewFragment extends Fragment {

    ArrayList<String> titles;
    ArrayList<String> descriptions;
    ArrayList<String> images;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        RecipeListViewParcer object = getArguments().getParcelable("extraObject");
        titles = object.getTitles();
        descriptions = object.getDescriptions();
        images = object.getImages();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_recipelistview, container,
                false);

        final ListView listview = (ListView) v.findViewById(R.id.listview);


        RecipeListViewAdapter adapter = new RecipeListViewAdapter(
                getActivity(), titles);
        listview.setAdapter(adapter);

        return v;
    }

    public void onListItemClick(ListView l, View v, int position, long id) {
        // do something with the data
    }
}

我想将这个 ListView 用于不同的事情,所以我希望能够将三个 ArrayList 发送给它。为此,我创建了一个实现 Parcelable 的类,就是这样:

package com.tsjd.HotMeals;

import java.util.ArrayList;

import android.os.Parcel;
import android.os.Parcelable;

public class RecipeListViewParcer implements Parcelable{

    private ArrayList<String> titles;
    private ArrayList<String> descriptions;
    private ArrayList<String> images;

     @SuppressWarnings("unchecked")
    private RecipeListViewParcer(Parcel in) {
            titles = (ArrayList<String>) in.readSerializable();
            descriptions = (ArrayList<String>) in.readSerializable();
            images = (ArrayList<String>) in.readSerializable();
        }

    public int describeContents() {
        return 0;
    }

    public ArrayList<String> getTitles()
    {
        return titles;
    }

    public void setTitles(ArrayList<String> titles){
        this.titles = titles;
    }

    public ArrayList<String> getDescriptions()
    {
        return descriptions;
    }

    public void setDescriptions(ArrayList<String> descriptions){
        this.descriptions = descriptions;
    }

    public ArrayList<String> getImages()
    {
        return images;
    }

    public void setImages(ArrayList<String> images){
        this.images = images;
    }

    public void writeToParcel(Parcel out, int flags) {
        out.writeSerializable(titles);
        out.writeSerializable(descriptions);
        out.writeSerializable(images);
    }

    public static final Parcelable.Creator<RecipeListViewParcer> CREATOR
            = new Parcelable.Creator<RecipeListViewParcer>() {
        public RecipeListViewParcer createFromParcel(Parcel in) {
            return new RecipeListViewParcer(in);
        }

        public RecipeListViewParcer[] newArray(int size) {
            return new RecipeListViewParcer[size];
        }
    };



}

最后,这是一个Fragment,它使用listview来显示最喜欢的菜谱,这里我要发送三个ArrayList,这是目前唯一有错误的代码。我不知道如何为我的 Parcelable 类的构造函数声明我需要的 Parcel,我应该怎么做? (我还没有在我的 ArrayLists 中放任何东西,但我希望这个想法很清楚)。

package com.tsjd.HotMeals;

import java.util.ArrayList;

import android.os.Bundle;
import android.os.Parcel;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;

public class MyRecipesFragment extends Fragment {


    ArrayList<String> titles = new ArrayList<String>();
    ArrayList<String> descriptions = new ArrayList<String>();
    ArrayList<String> images = new ArrayList<String>();



    Parcel in = new Parcel();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        Fragment fragment = new RecipeListViewFragment();

        RecipeListViewParcer obj = new RecipeListViewParcer(in);

        obj.setDescriptions(descriptions);
        obj.setTitles(titles);
        obj.setImages(images);

        Bundle bundle = new Bundle();
        bundle.putParcelable("extraObject", obj);
        fragment.setArguments(bundle);

        fragmentTransaction.commit();
    }

}

【问题讨论】:

  • 使用 bundle 并设置到片段
  • 尝试调试,RecipeListViewParcer(Parcel in)构造函数方法中收到了什么?

标签: java android android-intent android-fragments parcelable


【解决方案1】:

你必须使用 FragmentManager:

在Activity中发送3个ArrayList:

       FragmentManager fragmentManager = getFragmentManager();
       FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
       Fragment fragment = new ViewControllerFragment();

       ObjectA obj = new ObjectA();
       Bundle bundle = new Bundle();
       bundle.putStringArrayList("Titles", obj.getTitles());
       bundle.putStringArrayList("Descriptions", obj.getDescriptions());
       bundle.putStringArrayList("Images", obj.getImages());
       fragment.setArguments(bundle);

       fragmentTransaction.commit();

获取片段中的对象:

Bundle bundle = getArguments();                    
 titles = bundle.getStringArrayList("Titles");            
descriptions= bundle.getStringArrayList("Descriptions");            
images= bundle.getStringArrayList("Images");

或者试试其他帖子:Send data from activity to fragment in android

【讨论】:

  • 你能看看我的更新/编辑吗?它提供了有关情况的更多信息,我还有一些小问题需要解决
  • 忘掉 Parcelables 的想法,尝试在 Activity 中获得 3 个 ArrayList 并将它们放入包中: bundle.putStringArrayList("extraTitles", object.getTitles()); bundle.putStringArrayList("XXX", object.getXXX);
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