如何将ArrayList中的Class类从一个Activity传递给另一个Activity

时间：2014-06-19 10:19:58

标签： java android arraylist

我想将ArrayList<Links>的一个对象传递给Next Activity。

我已检查过使用Parcelable来实现此目的但我在Stream类中有Links类的另一个类对象。

如何将此链接对象传递给下一个活动

Links class：

public class Links implements Parcelable {

    private String name;
    private Streams streams;

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param streams the streams to set
     */
    public void setStreams(Streams streams) {
        this.streams = streams;
    }

    /**
     * @return the streams
     */
    public Streams getStreams() {
        return streams;
    }

    @Override
    public int describeContents() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        // TODO Auto-generated method stub
        /**
         ** WHAT CAN I DO HERE...???
         **/
    }
}

Stream分类：

public class Streams {
    private String link;
    private String stream;

    /**
     * @param link the link to set
     */
    public void setLink(String link) {
        this.link = link;
    }
    /**
     * @return the link
     */
    public String getLink() {
        return link;
    }
    /**
     * @param stream the stream to set
     */
    public void setStream(String stream) {
        this.stream = stream;
    }
    /**
     * @return the stream
     */
    public String getStream() {
        return stream;
    }
}

我想将ArrayList对象发送到下一个活动。我怎么能够？

更新

我在Logcat:

中得到了这个 
06-19 16:23:00.820: E/AndroidRuntime(21080): FATAL EXCEPTION: main
06-19 16:23:00.820: E/AndroidRuntime(21080): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gtu.gtupapers/com.gtu.gtupapers.StreamSelection}: java.lang.NullPointerException: expected receiver of type com.gtu.gtupapers.Links, but got null
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2129)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2154)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.ActivityThread.access$700(ActivityThread.java:146)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1260)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Looper.loop(Looper.java:137)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.ActivityThread.main(ActivityThread.java:4949)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at java.lang.reflect.Method.invokeNative(Native Method)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at java.lang.reflect.Method.invoke(Method.java:511)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1043)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at dalvik.system.NativeStart.main(Native Method)
06-19 16:23:00.820: E/AndroidRuntime(21080): Caused by: java.lang.NullPointerException: expected receiver of type com.gtu.gtupapers.Links, but got null
06-19 16:23:00.820: E/AndroidRuntime(21080):    at java.lang.reflect.Field.getField(Native Method)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at java.lang.reflect.Field.get(Field.java:269)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Parcel.readParcelable(Parcel.java:2066)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Parcel.readValue(Parcel.java:1965)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Parcel.readListInternal(Parcel.java:2235)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Parcel.readArrayList(Parcel.java:1655)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Parcel.readValue(Parcel.java:1986)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Parcel.readMapInternal(Parcel.java:2226)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Bundle.unparcel(Bundle.java:223)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.os.Bundle.getParcelableArrayList(Bundle.java:1209)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.content.Intent.getParcelableArrayListExtra(Intent.java:4477)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at com.gtu.gtupapers.StreamSelection.onCreate(StreamSelection.java:16)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.Activity.performCreate(Activity.java:5185)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
06-19 16:23:00.820: E/AndroidRuntime(21080):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2093)
06-19 16:23:00.820: E/AndroidRuntime(21080):    ... 11 more

您的帮助将不胜感激......

4 个答案:

答案 0 :(得分：2)

Links上课：

public class Links implements Parcelable {

    private String name;
    private Streams streams;

    public Links(String name, Streams streams) {
        this.name = name;
        this.streams = streams;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param streams the streams to set
     */
    public void setStreams(Streams streams) {
        this.streams = streams;
    }

    /**
     * @return the streams
     */
    public Streams getStreams() {
        return streams;
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(name);
        dest.writeParcelable(streams, flags);
    }

    public static Parcelable.Creator<Links> CREATOR = new Parcelable.Creator<Links>() {

        @Override
        public Links createFromParcel(Parcel source) {
            String name = source.readString();
            Streams streams = source.readParcelable(Streams.class.getClassLoader());
            return new Links(name, streams);
        }

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

Streams上课：

public class Streams implements Parcelable {
    private String link;
    private String stream;

    public Streams(String link, String stream) {
        this.link = link;
        this.stream = stream;
    }
    /**
     * @param link the link to set
     */
    public void setLink(String link) {
        this.link = link;
    }
    /**
     * @return the link
     */
    public String getLink() {
        return link;
    }
    /**
     * @param stream the stream to set
     */
    public void setStream(String stream) {
        this.stream = stream;
    }
    /**
     * @return the stream
     */
    public String getStream() {
        return stream;
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(link);
        dest.writeString(stream);
    }

    public static final Parcelable.Creator<Streams> CREATOR = new Parcelable.Creator<Streams>() {

        @Override
        public Streams createFromParcel(Parcel source) {
            String link = source.readString();
            String stream = source.readString();
            return new Streams(link, stream);
        }

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

}

然后你可以传递清单：

Intent intent = new Intent(this, OtherActivity.class);
intent.putParcelableArrayListExtra("links", yourList);
startActivity(intent);

在OtherActivity：

Intent intent = getIntent();
ArrayList<Links> links = intent.getParcelableArrayListExtra("links");

答案 1 :(得分：2)

使用http://www.parcelabler.com/

处的Parcelabler使两个类成为Parcelable

答案 2 :(得分：1)

感谢WonderCsabo创建了类Parcelable，但我使用此link创建了所以感谢Zhuinden this post。

我发布了完整的答案，对其他人也有帮助。

链接类：

public class Links implements Parcelable {

    private String name;
    private Streams streams;

    public Links() {
    // TODO Auto-generated constructor stud
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
    this.name = name;
    }

    /**
     * @return the name
     */
    public String getName() {
    return name;
    }

    /**
     * @param streams the streams to set
     */
    public void setStreams(Streams streams) {
    this.streams = streams;
    }

    /**
     * @return the streams
     */
    public Streams getStreams() {
    return streams;
    }

    protected Links(Parcel in) {
    name = in.readString();
    streams = (Streams) in.readValue(Streams.class.getClassLoader());
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(name);
    dest.writeValue(streams);
    }

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

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

Streams 类：

public class Streams implements Parcelable {

    private String link;
    private String stream;

    Streams() {
    // TODO Auto-generated constructor stub
    }

    protected Streams(Parcel in) {
    link = in.readString();
    stream = in.readString();
    }

    /**
     * @param link the link to set
     */
    public void setLink(String link) {
    this.link = link;
    }
    /**
     * @return the link
     */
    public String getLink() {
    return link;
    }
    /**
     * @param stream the stream to set
     */
    public void setStream(String stream) {
    this.stream = stream;
    }
    /**
     * @return the stream
     */
    public String getStream() {
    return stream;
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(link);
    dest.writeString(stream);
    }

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

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

然后最后使用：

发送到下一个Activity 
Intent intent = new Intent(MainActivity.this, StreamSelection.class);
intent.putExtra("position", position);
intent.putParcelableArrayListExtra("list", arrayList);
startActivity(intent);

接收：

ArrayList<Links> links =  getIntent().getParcelableArrayListExtra("list");
int pos = getIntent().getExtras().getInt("position");
Log.d("TAG", "Links: " + links.get(pos).getName());

感谢您的帮助。

答案 3 :(得分：0)

在 Links 类中实施Serializable。

public class Links implements Serializable {

private String name;
private Streams streams;

/**
 * @param name the name to set
 */
public void setName(String name) {
    this.name = name;
}

/**
 * @return the name
 */
public String getName() {
    return name;
}

/**
 * @param streams the streams to set
 */
public void setStreams(Streams streams) {
    this.streams = streams;
}

/**
 * @return the streams
 */
public Streams getStreams() {
    return streams;
}

@Override
public int describeContents() {
    // TODO Auto-generated method stub
    return 0;
}

}

我们将对象A发送给B 

Intent i = new Intent(this, B.class);
i.putExtra("Object", **Link class object**);
startActivity(i);

和B活动

Intent i = getIntent();
Links link = (Links)i.getSerializableExtra("Object");
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