使用parcelable在活动之间传递ArrayList对象 [英] Passing ArrayList Object between activities using parcelable
本文介绍了使用parcelable在活动之间传递ArrayList对象的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我首先要说的是，我已经看过所有其他处理此问题的帖子并尝试了所有帖子.
Ill first start this off saying i have seen all the other posts that deal with this and have tried all of them.
我正在尝试执行其他帖子中要求的相同操作，即使用 Intent 将 ArrayList 的值从一个活动传递到另一个活动.
Im trying to do the same thing asked in the other posts, which is to pass the values of a ArrayList from one activity to another using Intent.
我觉得我已经正确地实现了我的类.我正在使用的主类 (Route_Class) 如下.
I feel I have implemented my class(es) correctly. The main class (Route_Class) i am using is below.
```
public class Route_Class implements Parcelable {
private double latitude = 0;
private double longitude = 0;
private double startingLat = 0;
private double startingLong = 0;
private String name = null;
private String routeName = null;
private String GeoPoints = null;
private String layout_width= null;
private String layout_height = null;
private String orientation = null;
private String xmlns = null;
private String id = null;
private boolean clickable = false;
private boolean enabled = false;
private String layout_width2 = null;
private String layout_height2 = null;
private String apiKey = null;
private ArrayList<GeoPoints_Class> geoPoints_arraylist = new ArrayList<GeoPoints_Class>();
public Route_Class() {
System.out.println("crash 110");
}
public Route_Class(String name, double latitude, double longitude, double startingLat, double startingLong, String routeName, String GeoPoints, String layout_width, String layout_height, String orientation, String xmlns, String id, boolean clickable, boolean enabled, String layout_width2, String layout_height2, String apiKey, ArrayList<GeoPoints_Class> geoPoints_arraylist) {
this.name = name;
this.latitude = latitude;
this.longitude = longitude;
this.layout_width2 = layout_width2;
this.latitude = latitude;
this.longitude = longitude;
this.startingLat = startingLat;
this.startingLong = startingLong;
this.routeName = routeName;
this.GeoPoints = GeoPoints;
this.layout_width = layout_width;
this.layout_height = layout_height;
this.orientation = orientation;
this.xmlns = xmlns;
this.id = id;
this.clickable = clickable;
this.enabled = enabled;
this.layout_height2 = layout_height2;
this.apiKey = apiKey;
this.geoPoints_arraylist = geoPoints_arraylist;
System.out.println("crash 16");
}
/* everything below here is for implementing Parcelable */
// 99.9% of the time you can just ignore this
public int describeContents() {
System.out.println("crash 17");
return this.hashCode();
}
// write your object's data to the passed-in Parcel
public void writeToParcel(Parcel dest, int flags) {
System.out.println("crash 18");
dest.writeDouble(latitude);
dest.writeDouble(longitude);
dest.writeDouble(startingLat);
dest.writeDouble(startingLong);
dest.writeString(name);
dest.writeString(routeName);
dest.writeString(GeoPoints);
dest.writeString(layout_width);
dest.writeString(layout_height);
dest.writeString(orientation);
dest.writeString(xmlns);
dest.writeString(id);
dest.writeInt(clickable ? 0 : 1 );
dest.writeInt(enabled ? 0 : 1 );
dest.writeString(layout_width2);
dest.writeString(layout_height2);
dest.writeString(apiKey);
dest.writeTypedList(geoPoints_arraylist);
// dest.writeList((List<GeoPoints_Class>)geoPoints_arraylist);
// dest.writeParcelable((Parcelable) geoPoints_arraylist, 0);
}
// this is used to regenerate your object. All Parcelables must have a CREATOR that implements these two methods
public static final Parcelable.Creator<Route_Class> CREATOR = new Parcelable.Creator<Route_Class>() {
public Route_Class createFromParcel(Parcel in) {
System.out.println("crash 20");
return new Route_Class(in);
}
public Route_Class[] newArray(int size) {
System.out.println("crash 21");
return new Route_Class[size];
}
};
// example constructor that takes a Parcel and gives you an object populated with it's values
private Route_Class(Parcel in) {
layout_width2 = in.readString();
latitude = in.readDouble();
longitude = in.readDouble();
startingLat = in.readDouble();
startingLong = in.readDouble();
name = in.readString();
routeName = in.readString();
GeoPoints = in.readString();
layout_width = in.readString();
layout_height = in.readString();
orientation = in.readString();
xmlns = in.readString();
id = in.readString();
clickable = in.readInt() == 0;
enabled = in.readInt() == 0;
layout_height2 = in.readString();
apiKey = in.readString();
System.out.println("crash 5");
//geoPoints_arraylist = new ArrayList<GeoPoints_Class>();
if (geoPoints_arraylist == null) {
geoPoints_arraylist = new ArrayList<GeoPoints_Class>();
}
try {
in.readTypedList(geoPoints_arraylist, GeoPoints_Class.CREATOR);
} catch (Exception e) {
System.out.println("Error " + e);
}
// in.readList(geoPoints_arraylist, com.breckbus.app.GeoPoints_Class.class.getClassLoader());
System.out.println("crash 6");
// geoPoints_arraylist = (ArrayList<GeoPoints_Class>)in.readParcelable(com.breckbus.app.Route_Class.GeoPoints_Class. class.getClassLoader());
}
public double getlatitude() {
return latitude;
}
public void setlatitude(double latitude) {
this.latitude = latitude;
}
public double getlongitude() {
return longitude;
}
public void setlongitude(double longitude) {
this.longitude = longitude;
}
public double getstartingLat() {
return startingLat;
}
public void setstartingLat(double startingLat) {
this.startingLat = startingLat;
}
public double getstartingLong() {
return startingLong;
}
public void setstartingLong(double startingLong) {
this.startingLong = startingLong;
}
public String getname() {
return name;
}
public void setname(String name) {
this.name = name;
}
public String getrouteName() {
return routeName;
}
public void setrouteName(String routeName) {
this.routeName = routeName;
}
public String getGeoPoints() {
return GeoPoints;
}
public void setGeoPoints(String GeoPoints) {
this.GeoPoints = GeoPoints;
}
public String getLayout_width() {
return layout_width;
}
public void setLayout_width(String layout_width) {
this.layout_width = layout_width;
}
public String getLayout_height() {
return layout_height;
}
public void setLayout_height(String layout_height) {
this.layout_height = layout_height;
}
public boolean isEnabled() {
return enabled;
}
public void setEnabled(boolean enabled) {
this.enabled = enabled;
}
public String getOrientation() {
return orientation;
}
public void setOrientation(String orientation) {
this.orientation = orientation;
}
public String getXmlns() {
return xmlns;
}
public void setXmlns(String xmlns) {
this.xmlns = xmlns;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public boolean isClickable() {
return clickable;
}
public void setClickable(boolean clickable) {
this.clickable = clickable;
}
public String getLayout_width2() {
return layout_width2;
}
public void setLayout_width2(String layout_width2) {
this.layout_width2 = layout_width2;
}
public String getLayout_height2() {
return layout_height2;
}
public void setLayout_height2(String layout_height2) {
this.layout_height2 = layout_height2;
}
public String getApiKey() {
return apiKey;
}
public void setApiKey(String apiKey) {
this.apiKey = apiKey;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Route Class Details:").append("\n\n");
sb.append("latitude: ").append(getlatitude());
sb.append("\n");
sb.append("longitude: ").append(getlongitude());
sb.append("\n");
sb.append("startingLat: ").append(getstartingLat());
sb.append("\n");
sb.append("startingLong: ").append(getstartingLong());
sb.append("\n");
sb.append("name: ").append(getname());
sb.append("\n");
sb.append("routeName: ").append(getrouteName());
sb.append("\n");
sb.append("GeoPoints: ").append(getGeoPoints());
sb.append("\n");
sb.append("layout_width: ").append(getLayout_width());
sb.append("\n");
sb.append("layout_height: ").append(getLayout_height());
sb.append("\n");
sb.append("orientation: ").append(getOrientation());
sb.append("\n");
sb.append("xmlns: ").append(getXmlns());
sb.append("\n");
sb.append("id: ").append(getId());
sb.append("\n");
sb.append("clickable: ").append(isClickable());
sb.append("\n");
sb.append("enabled: ").append(isEnabled());
sb.append("\n");
sb.append("layout_width2: ").append(layout_width2);
sb.append("\n");
sb.append("layout_height2: ").append(getLayout_height2());
sb.append("\n");
sb.append("apiKey: ").append(getApiKey());
return sb.toString();
}
// public ArrayList<GeoPoints_Class> getGeoPoints_arraylist() {
// return geoPoints_arraylist;
// }
public ArrayList<GeoPoints_Class> getGeoPoints_arraylist() {
return geoPoints_arraylist;
}
public void setGeoPoints_arraylist(ArrayList<GeoPoints_Class> geoPoints_arraylist) {
this.geoPoints_arraylist = geoPoints_arraylist;
}
public GeoPoints_Class getGeoPoints(int i) {
return geoPoints_arraylist.get(i);
}
public void addGeoPoint(double lat, double lon, String location) {
this.geoPoints_arraylist.add(new GeoPoints_Class(lat, lon, location));
}
}
```
这是我在 Route_Class 中使用的第二个类 (GeoPoints_Class).
Here is my second class (GeoPoints_Class) that is used in Route_Class.
```
package com.breckbus.app;
import android.os.Parcel;
import android.os.Parcelable;
class GeoPoints_Class implements Parcelable {
private double lat;
private double lon;
private String location;
public GeoPoints_Class(){
System.out.println("crash 99");
}
public GeoPoints_Class(double lat, double lon, String location){
System.out.println("crash 7");
this.lat = lat;
this.lon = lon;
this.location = location;
}
public int describeContents() {
return this.hashCode();
}
// write your object's data to the passed-in Parcel
public void writeToParcel(Parcel dest, int flags) {
System.out.println("crash 11");
dest.writeDouble(lat);
dest.writeDouble(lon);
dest.writeString(location);
System.out.println("crash 12");
}
// this is used to regenerate your object. All Parcelables must have a CREATOR that implements these two methods
public static final Parcelable.Creator<GeoPoints_Class> CREATOR = new Parcelable.Creator<GeoPoints_Class>() {
public GeoPoints_Class createFromParcel(Parcel in) {
System.out.println("crash 28");
return new GeoPoints_Class(in);
}
public GeoPoints_Class[] newArray(int size) {
System.out.println("crash 29");
return new GeoPoints_Class[size];
}
};
// example constructor that takes a Parcel and gives you an object populated with it's values
private GeoPoints_Class(Parcel in) {
System.out.println("crash 13");
lat = in.readDouble();
lon = in.readDouble();
location = in.readString();
System.out.println("crash 14");
}
public double getLat() {
return lat;
}
public void setLat(double lat) {
this.lat = lat;
}
public double getLon() {
return lon;
}
public void setLon(double lon) {
this.lon = lon;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("GeoPoint Class Details:").append("\n\n");
sb.append("latitude: ").append(getLat());
sb.append("\n");
sb.append("longitude: ").append(getLon());
sb.append("\n");
sb.append("location: ").append(getLocation());
sb.append("\n");
return sb.toString();
}
}
```
接下来是我使用 putExtra 放置对象的地方.
Next is where I put the objects using putExtra.
```
Intent i = new Intent("com.breckbus.app.ROUTE");
// i.putParcelableArrayListExtra("route_Classes_temp", route_Classes);
i.putExtra("route_Classes_temp",route_Classes);
System.out.println("crash 1");
```
然后我在哪里得到对象.
Then where i get the objects.
```
Bundle extras = getIntent().getExtras();
Intent d = getIntent();
System.out.println("crash 25");
route_Classes = d.getParcelableArrayListExtra("route_Classes_temp");
System.out.println("crash 2");
// route_Classes = getIntent().getParcelableArrayListExtra("route_Classes_temp");
```
您会注意到我所有的手动调试语句，因为 Eclipse 在调试模式(断点和其他东西)下不适用于 android 应用程序.(如果您知道解决方案，那将大有帮助).
You will notice all of my manual debug statements since Eclipse doesnt work with android applications in debug mode (breakpoints and stuff). (Which if you know the solution to that, it would greatly help).
接下来是我遇到的唯一错误以及我在代码中输入的手动调试语句停止的地方.我不知道它在哪里崩溃了.
Next is the only error i get and where the manual debug statements i entered in the code stop. I dont know where it is crashing anymore.
这是前几个错误:
```
10-26 00:03:50.165: I/System.out(323): crash 13
10-26 00:03:50.165: I/System.out(323): crash 14
10-26 00:03:50.165: I/System.out(323): crash 28
10-26 00:03:50.165: I/System.out(323): crash 13
10-26 00:03:50.165: I/System.out(323): crash 14
10-26 00:03:50.185: I/System.out(323): crash 6
10-26 00:03:50.195: D/AndroidRuntime(323): Shutting down VM
10-26 00:03:50.195: W/dalvikvm(323): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
10-26 00:03:50.225: E/AndroidRuntime(323): FATAL EXCEPTION: main
10-26 00:03:50.225: E/AndroidRuntime(323): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.breckbus.app/com.breckbus.app.route}: java.lang.RuntimeException: Parcel android.os.Parcel@44edd958: Unmarshalling unknown type code 6553714 at offset 968
10-26 00:03:50.225: E/AndroidRuntime(323): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
10-26 00:03:50.225: E/AndroidRuntime(323): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
10-26 00:03:50.225: E/AndroidRuntime(323): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
10-26 00:03:50.225: E/AndroidRuntime(323): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
10-26 00:03:50.225: E/AndroidRuntime(323): at android.os.Handler.dispatchMessage(Handler.java:99)
10-26 00:03:50.225: E/AndroidRuntime(323): at android.os.Looper.loop(Looper.java:123)
10-26 00:03:50.225: E/AndroidRuntime(323): at android.app.ActivityThread.main(ActivityThread.java:4627)
10-26 00:03:50.225: E/AndroidRuntime(323): at java.lang.reflect.Method.invokeNative(Native Method)
10-26 00:03:50.225: E/AndroidRuntime(323): at java.lang.reflect.Method.invoke(Method.java:521)
```
我希望我提供了足够的信息.请告诉我在尝试使用 Intent 将对象类型 Route_Class 的 route_class ArrayList 从一个活动传递到另一个活动时我做错了什么.这两行:
I hope i provided enough information. Please tell me what i am doing wrong when trying to pass the route_class ArrayList of Object type Route_Class from one activity to another using Intent. These two lines:
i.putExtra("route_Classes_temp",route_Classes);
route_Classes = d.getParcelableArrayListExtra("route_Classes_temp");
感谢您的帮助，非常感谢.
Thank you for your help, it is much appreciated.
推荐答案
确实，您提供的信息太多了.
It is true that you have provided too much information.
但是，这是在同一个进程中吗(即仅您自己的应用程序?)如果是，则完全避免这样做.打包/解包这些对象会太慢.
However, is this on the same process (i.e. your own app only?) If yes, then avoid doing that entirely. It will be too slow to parcel/unparcel these objects.
使用存储数据的单例，并从每个活动访问单例.
Use a singleton where you store your data and just access the singleton from each activity.
这篇关于使用parcelable在活动之间传递ArrayList对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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