我在意圖中有一個自定義 FlightData 對象的 ArrayList。我加載意圖并將數組列表設置為 null，并且 foreach 循環還強制我使用Objectas 類型。將 arraylist 保存到意圖中：intent.putParcelableArrayListExtra("FlightDataList", (ArrayList<? extends Parcelable>) flightDataList);加載意圖：Intent intent = getIntent();LinearLayout layout_datasheet = findViewById(R.id.layout_datasheet);List flightDataList = intent.getParcelableArrayListExtra("FlightDataList");if (flightDataList == null){ Log.d("flightDataList_size", "FlightDataList is null"); // this fires}assert flightDataList != null;for (Object data : flightDataList){ data = (FlightData) data; // items in list are of type FlightData TextView tv = new TextView(this); tv.setText(data.toString()); layout_datasheet.addView(tv);}我的自定義類的可分割函數（x，y，時間，有 getters-setters）：@Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeDouble(x); dest.writeDouble(y); dest.writeDouble(time); } public static final Creator<FlightData> CREATOR = new Creator<FlightData>() { @Override public FlightData createFromParcel(Parcel in) { return new FlightData(in); } @Override public FlightData[] newArray(int size) { return new FlightData[size]; } };
3 回答
皈依舞
TA貢獻1851條經驗 獲得超3個贊
我懷疑您是否在 FlightData 中實現了 Parcable https://medium.com/techmacademy/how-to-implement-and-use-a-parcelable-class-in-android-part-1-28cca73fc2d1
慕沐林林
TA貢獻2016條經驗 獲得超9個贊
它應該有效。我在你的例子中唯一缺少的是構造函數。它可以解釋null你所得到的。
嘗試添加這個構造函數FlightData
public FlightData(Parcel in) {
x = in.readDouble();
y = in.readDouble();
time = in.readDouble();
}
九州編程
TA貢獻1785條經驗 獲得超4個贊
您是否嘗試創建一個實現 Parcelable 的數據結構？
public class flightDataList implements Parcelable{
String dataThingyString;
int dataThingyInt;
public flightDataList(String dataThingyString, int dataThingyInt){
this.dataThingyString = dataThingyString;
this.dataThingyInt = dataThingyInt;
}
public flightDataList(Parcle in){
this.dataThingyString = in.readString();
this.dataThingyInt = in.readInt();
}
@Override
public void writeToParcel(Parcel dest, int flags){
dest.writeString(dataThingyString);
dest.writeInt(dataThingyInt);
}
public static final Creator<flightDataList> CREATOR = new Creator<flightDataList>(){
@Override
public flightDataList createFromParcel(Parcel source){
return new flightDataList(source);
}
@Override
public flightDataList[] newArray(int size){
return new flightDataList[size];
}
}
public void setdataThingyString(String stringData){
this.dataThingyString = stringData;
}
public void setdataThingyInt(int intData){
this.dataThingyInt = intData;
}
public String getdataThingyString(){
return dataThingyString;
}
public int getdataThingyInt(){
return dataThingyInt;
}
@Override
public int describeContents(){
return 0;
}
}
守著星空守著你
TA貢獻1799條經驗 獲得超8個贊
1.首先在FlightData對象模型/pojo/class中實現Parceable
2.val flightDataList= ArrayList<FlightData>()
3.val args = Bundle()
4.args.putParcelableArrayList("FlightDataList", flightDataList)
5.intent.putExtra(args)
然后獲取列表
val flightDataList = context.getIntent().getExtras().getParcelableArrayList("FlightDataList")
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