android-無法在意圖傳遞parcelable到另一個活動

嘿，我有一個問題傳遞一個parcelable POJO到一個新的活動。我有一個listview列出了一堆新聞來源，它工作正常。當我點擊一個項目時，我傳遞了一個parcelable對象的意圖，並期望在「DetailsActivity」中，parcelable會在那裏，但它的null，任何想法？在我開始活動之前，我看到數據已成功投入了意圖。下面是一些代碼：android-無法在意圖傳遞parcelable到另一個活動

結果類實際上是我的parcelable POJO，看起來像這樣：

public class Result implements Parcelable 
{ 

    @SerializedName("section") 
    @Expose 
    private String section; 
    @SerializedName("subsection") 
    @Expose 
    private String subsection; 
    @SerializedName("title") 
    @Expose 
    private String title; 
    @SerializedName("abstract") 
    @Expose 
    private String _abstract; 
    @SerializedName("url") 
    @Expose 
    private String url; 
    @SerializedName("byline") 
    @Expose 
    private String byline; 
    @SerializedName("item_type") 
    @Expose 
    private String itemType; 
    @SerializedName("updated_date") 
    @Expose 
    private String updatedDate; 
    @SerializedName("created_date") 
    @Expose 
    private String createdDate; 
    @SerializedName("published_date") 
    @Expose 
    private String publishedDate; 
    @SerializedName("material_type_facet") 
    @Expose 
    private String materialTypeFacet; 
    @SerializedName("kicker") 
    @Expose 
    private String kicker; 
    @SerializedName("des_facet") 
    @Expose(serialize = false, deserialize = false) 
    private List<String> desFacet = null; 
    @SerializedName("org_facet") 
    @Expose(serialize = false, deserialize = false) 
    private String orgFacet; 
    @SerializedName("per_facet") 
    @Expose(serialize = false, deserialize = false) 
    private String perFacet; 
    @SerializedName("geo_facet") 
    @Expose(serialize = false, deserialize = false) 
    private List<String> geoFacet = null; 
    @SerializedName("multimedia") 
    @Expose 
    private List<Multimedium> multimedia = null; 
    public final static Parcelable.Creator<Result> CREATOR = new Creator<Result>() { 


     @SuppressWarnings({ 
       "unchecked" 
     }) 
     public Result createFromParcel(Parcel in) { 
      Result instance = new Result(); 
      instance.section = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.subsection = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.title = ((String) in.readValue((String.class.getClassLoader()))); 
      instance._abstract = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.url = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.byline = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.itemType = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.updatedDate = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.createdDate = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.publishedDate = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.materialTypeFacet = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.kicker = ((String) in.readValue((String.class.getClassLoader()))); 
      in.readList(instance.desFacet, (java.lang.String.class.getClassLoader())); 
      instance.orgFacet = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.perFacet = ((String) in.readValue((String.class.getClassLoader()))); 
      in.readList(instance.geoFacet, (java.lang.String.class.getClassLoader())); 
      in.readList(instance.multimedia, (Multimedium.class.getClassLoader())); 
      return instance; 
     } 

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

    } 
      ; 

    public String getSection() { 
     return section; 
    } 

    public void setSection(String section) { 
     this.section = section; 
    } 

    public String getSubsection() { 
     return subsection; 
    } 

    public void setSubsection(String subsection) { 
     this.subsection = subsection; 
    } 

    public String getTitle() { 
     return title; 
    } 

    public void setTitle(String title) { 
     this.title = title; 
    } 

    public String getAbstract() { 
     return _abstract; 
    } 

    public void setAbstract(String _abstract) { 
     this._abstract = _abstract; 
    } 

    public String getUrl() { 
     return url; 
    } 

    public void setUrl(String url) { 
     this.url = url; 
    } 

    public String getByline() { 
     return byline; 
    } 

    public void setByline(String byline) { 
     this.byline = byline; 
    } 

    public String getItemType() { 
     return itemType; 
    } 

    public void setItemType(String itemType) { 
     this.itemType = itemType; 
    } 

    public String getUpdatedDate() { 
     return updatedDate; 
    } 

    public void setUpdatedDate(String updatedDate) { 
     this.updatedDate = updatedDate; 
    } 

    public String getCreatedDate() { 
     return createdDate; 
    } 

    public void setCreatedDate(String createdDate) { 
     this.createdDate = createdDate; 
    } 

    public String getPublishedDate() { 
     return publishedDate; 
    } 

    public void setPublishedDate(String publishedDate) { 
     this.publishedDate = publishedDate; 
    } 

    public String getMaterialTypeFacet() { 
     return materialTypeFacet; 
    } 

    public void setMaterialTypeFacet(String materialTypeFacet) { 
     this.materialTypeFacet = materialTypeFacet; 
    } 

    public String getKicker() { 
     return kicker; 
    } 

    public void setKicker(String kicker) { 
     this.kicker = kicker; 
    } 

    public List<String> getDesFacet() { 
     return desFacet; 
    } 

    public void setDesFacet(List<String> desFacet) { 
     this.desFacet = desFacet; 
    } 

    public String getOrgFacet() { 
     return orgFacet; 
    } 

    public void setOrgFacet(String orgFacet) { 
     this.orgFacet = orgFacet; 
    } 

    public String getPerFacet() { 
     return perFacet; 
    } 

    public void setPerFacet(String perFacet) { 
     this.perFacet = perFacet; 
    } 

    public List<String> getGeoFacet() { 
     return geoFacet; 
    } 

    public void setGeoFacet(List<String> geoFacet) { 
     this.geoFacet = geoFacet; 
    } 

    public List<Multimedium> getMultimedia() { 
     return multimedia; 
    } 

    public void setMultimedia(List<Multimedium> multimedia) { 
     this.multimedia = multimedia; 
    } 

    public void writeToParcel(Parcel dest, int flags) { 
     dest.writeValue(section); 
     dest.writeValue(subsection); 
     dest.writeValue(title); 
     dest.writeValue(_abstract); 
     dest.writeValue(url); 
     dest.writeValue(byline); 
     dest.writeValue(itemType); 
     dest.writeValue(updatedDate); 
     dest.writeValue(createdDate); 
     dest.writeValue(publishedDate); 
     dest.writeValue(materialTypeFacet); 
     dest.writeValue(kicker); 
     dest.writeList(desFacet); 
     dest.writeValue(orgFacet); 
     dest.writeValue(perFacet); 
     dest.writeList(geoFacet); 
     dest.writeList(multimedia); 
    } 

    public int describeContents() { 
     return 0; 
    }

，並使用另一個被稱爲多介質parcelable類：在

public class Multimedium implements Parcelable 
{ 

    @SerializedName("url") 
    @Expose 
    private String url; 
    @SerializedName("format") 
    @Expose 
    private String format; 
    @SerializedName("height") 
    @Expose 
    private Integer height; 
    @SerializedName("width") 
    @Expose 
    private Integer width; 
    @SerializedName("type") 
    @Expose 
    private String type; 
    @SerializedName("subtype") 
    @Expose 
    private String subtype; 
    @SerializedName("caption") 
    @Expose 
    private String caption; 
    @SerializedName("copyright") 
    @Expose 
    private String copyright; 
    public final static Parcelable.Creator<Multimedium> CREATOR = new Creator<Multimedium>() { 


     @SuppressWarnings({ 
      "unchecked" 
     }) 
     public Multimedium createFromParcel(Parcel in) { 
      Multimedium instance = new Multimedium(); 
      instance.url = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.format = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.height = ((Integer) in.readValue((Integer.class.getClassLoader()))); 
      instance.width = ((Integer) in.readValue((Integer.class.getClassLoader()))); 
      instance.type = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.subtype = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.caption = ((String) in.readValue((String.class.getClassLoader()))); 
      instance.copyright = ((String) in.readValue((String.class.getClassLoader()))); 
      return instance; 
     } 

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

    } 
    ; 

    public String getUrl() { 
     return url; 
    } 

    public void setUrl(String url) { 
     this.url = url; 
    } 

    public String getFormat() { 
     return format; 
    } 

    public void setFormat(String format) { 
     this.format = format; 
    } 

    public Integer getHeight() { 
     return height; 
    } 

    public void setHeight(Integer height) { 
     this.height = height; 
    } 

    public Integer getWidth() { 
     return width; 
    } 

    public void setWidth(Integer width) { 
     this.width = width; 
    } 

    public String getType() { 
     return type; 
    } 

    public void setType(String type) { 
     this.type = type; 
    } 

    public String getSubtype() { 
     return subtype; 
    } 

    public void setSubtype(String subtype) { 
     this.subtype = subtype; 
    } 

    public String getCaption() { 
     return caption; 
    } 

    public void setCaption(String caption) { 
     this.caption = caption; 
    } 

    public String getCopyright() { 
     return copyright; 
    } 

    public void setCopyright(String copyright) { 
     this.copyright = copyright; 
    } 

    public void writeToParcel(Parcel dest, int flags) { 
     dest.writeValue(url); 
     dest.writeValue(format); 
     dest.writeValue(height); 
     dest.writeValue(width); 
     dest.writeValue(type); 
     dest.writeValue(subtype); 
     dest.writeValue(caption); 
     dest.writeValue(copyright); 
    } 

    public int describeContents() { 
     return 0; 
    } 
}

所以我Mainactivity我有以下方法在調試器中看起來很好：

@Override 
public void goToDetailsActivity(Result data) { 
    Intent intent = new Intent(MainActivity.this, DetailViewActivity.class); 
    intent.putExtra("newsInfo", data); 
    startActivity(intent); 
}

然後當我去DetailViewActivity該程序說以下是多餘的爲空，但爲什麼？

public class DetailViewActivity extends Activity { 
    private String storyURL = ""; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_detail); 

     Bundle extras = getIntent().getExtras(); 

     extras.getParcelable("newsInfo") //this is null , why ? 

     getIntent().hasExtra("newsInfo") //this is also false ? why ? 
//.... 
     }

來源

2017-02-25 j2emanue

尋找在logcat中與堆棧跟蹤警告。另外，你確定沒有'DetailViewActivity'的現有實例，可能沒有這個額外的，已經在內存中並且可能被重用（例如，通過清單中的android：launchMode？）。你也可以臨時切換到一個簡單的額外（例如，一些布爾值），看看是否能夠結束，如果問題出現在你的'Parcelable'實現中，或者問題覆蓋了所有額外特性，那麼可以幫助確定它是否結束。 – CommonsWare

傳遞一個字符串很好，只是試了一下。並且日誌中沒有任何內容。這個活動在清單中是這樣定義的： – j2emanue

好吧，如果一個字符串有效，這表明自定義的Parcleable存在問題，但我期望碰到一個崩潰如果是這樣的話。 [使用自定義'Parcelables'很冒險]（https://commonsware.com/blog/2016/07/22/be-careful-where-you-use-custom-parcelables.html），但是在你自己的兩個之間傳遞活動應該是安全的。嘗試使用[此代碼]（http://stackoverflow.com/questions/18000093/how-to-marshall-and-unmarshall-a-parcelable-to-a-byte-array-with-help-of-parcel/18000094 ＃18000094）將'Parcelable'轉換爲'byte []'，看看你是否崩潰等。 – CommonsWare

我建議你使用這個庫：https://github.com/johncarl81/parceler

來源

2017-02-25 19:58:34 ibado

一些如何使用這個庫解決了這個問題。我從http://www.jsonschema2pojo.org/生成parcelable，但不知道它有什麼不同，但謝謝！ – j2emanue

android-無法在意圖傳遞parcelable到另一個活動

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