返回null布尔数组的包裹

Question

我创建了一个包含布尔数组的parcelable对象

public class Alarm implements Parcelable {
private int hours;
private int minutes;
private int alarmTime;
private int ID;
private boolean alarmSet;
private boolean[] days;
private String[] symbols;
private String sound;
private boolean snooze;
private String picture;
public Alarm() {
    days = new boolean[7];
    symbols = new String[]{"月","火","水","木","金","土","日","毎日"};
}
protected Alarm(Parcel in) {
    hours = in.readInt();
    minutes = in.readInt();
    alarmTime = in.readInt();
    in.readBooleanArray(days);
    ID = in.readInt();
    alarmSet = in.readByte() != 0x00;
    sound = in.readString();
    snooze = in.readByte() != 0x00;
    symbols = new String[]{"月","火","水","木","金","土","日","毎日"};
    picture = in.readString();
}
@Override
public int describeContents() {
    return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeInt(hours);
    dest.writeInt(minutes);
    dest.writeInt(alarmTime);
    dest.writeInt(ID);
    dest.writeBooleanArray(days);
    dest.writeByte((byte) (alarmSet ? 0x01 : 0x00));
    dest.writeString(sound);
    dest.writeByte((byte) (snooze ? 0x01 : 0x00));
    dest.writeString(picture);
}
public static final Parcelable.Creator<Alarm> CREATOR = new Parcelable.Creator<Alarm>() {
    @Override
    public Alarm createFromParcel(Parcel in) {
        return new Alarm(in);
    }
    @Override
    public Alarm[] newArray(int size) {
        return new Alarm[size];
    }
};

数组在写入之前不是null，但在另一端，当我尝试执行时，会出现null数组错误

in.readBooleanArray(days);
days = createBooleanArray();

我认为我遵循了创建可分割对象的正确方法，大多数值似乎都很好（还没有检查所有值）

这是logcat

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.test.alarm/com.android.test.alarm.AlarmSettings}: java.lang.NullPointerException: Attempt to get length of null array
                                                                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
                                                                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413)
                                                                        at android.app.ActivityThread.access$800(ActivityThread.java:155)
                                                                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317)
                                                                        at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                        at android.os.Looper.loop(Looper.java:135)
                                                                        at android.app.ActivityThread.main(ActivityThread.java:5343)
                                                                        at java.lang.reflect.Method.invoke(Native Method)
                                                                        at java.lang.reflect.Method.invoke(Method.java:372)
                                                                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
                                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700)
                                                                     Caused by: java.lang.NullPointerException: Attempt to get length of null array
                                                                        at android.os.Parcel.readBooleanArray(Parcel.java:807)
                                                                        at com.android.test.alarm.Alarm.<init>(Alarm.java:149)
                                                                        at com.android.test.alarm.Alarm$1.createFromParcel(Alarm.java:181)
                                                                        at com.android.test.alarm.Alarm$1.createFromParcel(Alarm.java:178)
                                                                        at android.os.Parcel.readParcelable(Parcel.java:2252)
                                                                        at android.os.Parcel.readValue(Parcel.java:2152)
                                                                        at android.os.Parcel.readArrayMapInternal(Parcel.java:2485)
                                                                        at android.os.BaseBundle.unparcel(BaseBundle.java:221)
                                                                        at android.os.Bundle.getParcelable(Bundle.java:755)
                                                                        at com.android.test.alarm.AlarmSettings.onCreate(AlarmSettings.java:19)
                                                                        at android.app.Activity.performCreate(Activity.java:6010)
                                                                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1129)
                                                                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
                                                                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413) 
                                                                        at android.app.ActivityThread.access$800(ActivityThread.java:155) 
                                                                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317) 
                                                                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                        at android.os.Looper.loop(Looper.java:135) 
                                                                        at android.app.ActivityThread.main(ActivityThread.java:5343) 
                                                                        at java.lang.reflect.Method.invoke(Native Method) 
                                                                        at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
                                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700) 

Answer 1

是的，它是null。查看您的read、write:

// your Alarm(Parcel in)
hours = in.readInt();
minutes = in.readInt();
alarmTime = in.readInt();
in.readBooleanArray(days);
// Your write function:
 dest.writeInt(hours);
dest.writeInt(minutes);
dest.writeInt(alarmTime);
dest.writeInt(ID);
dest.writeBooleanArray(days);

在上面的函数中，您将BooleanArrays写入第5个值，但您将其读取为第4个值-->当然它是空的。因此，您应该更改写入位置或读取位置。

Answer 2

我认为您尚未启动数组。将this()添加到第二个构造函数

protected Alarm(Parcel in) {
    this();//add this to make sure arrays are initialised
    dest.writeInt(hours);
    dest.writeInt(minutes);