java.lang.ClassCastException：实现可打包时无法强制转换为java.lang.String

Question

我对为什么我的parcelable实现确实引发ClassCastException的想法不多了。 我想知道为什么它会引发异常并找到解决方法。如果我仍然缺乏信息以帮助您，请告诉我。

IdModelDTO类

public class IdModelDTO implements Parcelable {
private String type;
private String surname;
private String givenName;
private String middleName;
private String birthDate;

protected IdModelDTO(Parcel in) {
    givenName = in.readString();
    middleName = in.readString();
    surname = in.readString();
    birthDate = in.readString();
    type = in.readString();
} 
public static final Creator<IdModelDTO> CREATOR = new Creator<IdModelDTO(){
    @Override
    public IdModelDTO createFromParcel(Parcel in) {
        return new IdModelDTO(in);
    }

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

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(givenName);
    dest.writeString(middleName);
    dest.writeString(surname);
    dest.writeString(birthDate);
    dest.writeString(type);
}

@Override
public String toString() {
    return "IdModelDTO{" + "givenName='" + givenName + '\''
            + ", middleName='" + middleName + '\'' +
            "surname='" + surname + '\'' +
            "birthdate=''" + birthDate + '\'' +
            "type='" + type +  '\'' + '}';
}

这是我将其用作捆绑包的地方。 在发送到下一个活动之前，我什至可以将它记录为一个包：

public void checkMplusRespCodes() {
        // Check if response codes are OK/Created:
        if(governmentIdRespCode == null){
            Log.d(TAG, "Government Id Response code: " + governmentIdRespCode );
        }
        if(saveSelfieResponse == null){
            Log.d(TAG, "saveSelfieResponse: " + saveSelfieResponse);
        }
        else if(governmentIdRespCode != null && saveSelfieResponse != null){
            if(governmentIdRespCode.equals("200") && saveSelfieResponse.equals("200")){
                //Create bundle here, then pass it to view:
                //Bundle idModelBundle = new Bundle();
                //idModelBundle.putParcelable(THISIDMODEL, thisIdModel);
                //viewContract.showNextActivity(idModelBundle);
                Log.d(TAG, " checkMplusRespCodes: " + idModelDTO.toString());
                Bundle idModelBundle = new Bundle();
                idModelBundle.putParcelable(THISIDMODEL, idModelDTO);
                viewContract.showDoneLoading();
                viewContract.showNextActivity(idModelBundle);
            }
        }

然后在nextactivity，它抛出ClassCastException：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_test1);
    /* */
    Intent previousIntent = getIntent();
    if(previousIntent.getExtras() != null){
        Bundle previousExtras = previousIntent.getExtras();
        if(previousExtras != null){
            IdModelDTO test = previousIntent.getParcelableExtra(THISIDMODEL);
            if(test != null){
                Log.d(TAG, " asd: " + test.toString());
            }
            /* Retrieve: */
        }
    }else{
        //proceed.
    }

任何帮助将不胜感激。

编辑：这是方法的日志，而我将Parcelable对象设置为包：

checkMplusRespCodes: IdModelDTO{givenName='test', middleName='asd'surname='Test'birthdate=''axx'type='asxd'}

异常发生在将其强制转换的nextActivity上：

IdModelDTO test = previousIntent.getParcelableExtra(THISIDMODEL);

Answer 1

以此替换您的代码

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_test1);
    /* */
    Intent previousIntent = getIntent();
    if(previousIntent.getExtras() != null){
        Bundle previousExtras = previousIntent.getExtras();
        if(previousExtras != null){
            IdModelDTO test = previousExtras.getParcelable(THISIDMODEL);
            if(test != null){
                Log.d(TAG, " asd: " + test.toString());
            }
            /* Retrieve: */
        }
    }else{
        //proceed.
    }

Answer 2

我认为您正在尝试解析不是String date对象。

这就是为什么您遇到此异常的原因。

Answer 3

好的，我解决了这个问题。 我正在将强制将Bundle对象投射到我的自定义IdModelDTO中，如您在此行中所见：

if(previousExtras != null){
        IdModelDTO test = previousIntent.getParcelableExtra(THISIDMODEL);
        ...

我删除了将我的对象放入捆绑包中的捆绑包部分，并使用putExtra以便能够检索其类型的对象：

Intent nextActivityIntent = new Intent(this, TestActivityX.class);
nextActivityIntent.putExtra(THISIDMODEL,idModelDTO);
Log.d(TAG, " Show next activity: " + idModelDTO.toString());
startActivity(nextActivityIntent);

然后，检索将在下一个活动中进行：

Intent previousIntent = getIntent();
    if (previousIntent.getExtras() != null) {
        Bundle previousExtras = previousIntent.getExtras();
        if (previousExtras != null) {
            // Retrieve:
            if (previousExtras.containsKey(THISIDMODEL)) {
                // Re-instanciate new user.
                IdModelDTO test = previousExtras.getParcelable(THISIDMODEL);
                Log.d(TAG, " Previous Details:" + test.toString());
            }
        }
    }

谢谢大家，我非常感谢您的评论。