利用Parcelable在两个活动中发送数组

Question

我正在尝试在两个活动之间发送一个名为“Exercise”的创建类的填充数组，并且我已经阅读了最好的方法，我使用了Parcelable类。

活动2一旦开始就崩溃。我已经在线跟踪了这个教程，这就是他们对待数据发送的方式。

练习课：

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

public class Exercise implements Parcelable {

    public String Name = "";
    public int Time = 0;
    public boolean SwitchDirection = false;

    Exercise(String n, int l, boolean s){
        Name = n;
        Time = l;
        SwitchDirection = s;
    }

    protected Exercise(Parcel in) {
        Name = in.readString();
        Time = in.readInt();
        SwitchDirection = in.readByte() != 0;
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(Name);
        dest.writeInt(Time);
        dest.writeByte((byte) (SwitchDirection ? 1 : 0));
    }

    public static final Creator<Exercise> CREATOR = new Creator<Exercise>() {
        @Override
        public Exercise createFromParcel(Parcel in) {
            return new Exercise(in);
        }

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

活动1：

     Exercise[] Exercises = new Exercise[]{
             new Exercise("Scisssors", 60, false),
             new Exercise("Cross Knee Planks", 60, false),
             new Exercise("Twisting Pistons", 30, false),
             new Exercise("Accordion Crunches", 60, true),
             new Exercise("Canoe Crunch", 30, false),
             new Exercise("Upper Circle Crunches", 30, true)
    };


    Intent i = new Intent(this, Activity2.class);
    i.putExtra("Exercises", Exercises);
    startActivity(i);

活动2：

    Exercise[] Exercises;
    Exercises = (Exercise[]) getIntent().getParcelableArrayExtra("Exercises");

Answer 1

我想你不应该发送并获得一个Parcelable数组。您应该为Parcelable提供一个数组，并在Activity 2中获取它。我有一个示例，它在2个活动之间发送HashMap。

public class BaseData implements Parcelable {

protected HashMap<String, Object> mData;

public BaseData(HashMap<String, Object> data) {
    mData = data;
}

protected BaseData(Parcel in) {
    try {
        mData = in.readHashMap(HashMap.class.getClassLoader());
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static final Creator<BaseData> CREATOR = new Creator<BaseData>() {
    @Override
    public BaseData createFromParcel(Parcel in) {
        return new BaseData(in);
    }

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

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

@Override
public void writeToParcel(Parcel dest, int flags) {
    try {

        if (null == mData) {
            return;
        }

        dest.writeValue(mData);
    } catch (Exception e) {

    }
}

public HashMap<String, Object> getData() {
    return mData;
}

}

在活动1中，您将发送以下数据：

  HashMap<String, Object> hm = new HashMap<>();
    hm.put("data_1", array_data_1);
    hm.put("data_2",array_data_2);
    BaseData baseData = new BaseData(hm);
    BaseData baseData = new BaseData(data);
    Bundle bundle = new Bundle();
    bundle.putParcelable("base_data", baseData);
    Intent intent = new Intent(context,Activity2.class)
    intent.putExtra("data",bundle);

在Activity 2中，您将收到一个bundle，然后从bundle获取basedata并从basedata获取HashMap。

   Bundle bundle = getIntent().getBundleExtra("data");
    BaseData baseData = bundle.getParcelable("base_data");
    HashMap<String,Object> hm = baseData.getData();

您可以用Array替换HashMap。如果你不能实现它，请告诉我，我会给你一个完整的例子。