1

我正在开发一个应用程序。

此应用程序包含 2 个类

  • 实现可序列化的发现类

  • 扩展 Activity 的主类

在 Main 类中，我通过单击应用程序界面中的按钮调用 android Web 浏览器。这种行为会导致崩溃。

下面是代码：

MainTest.java

package com.heeere.androiddnssd.discovery;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainTest extends Activity {

    android.net.wifi.WifiManager.MulticastLock lock;
    private Discovery discovery; 
    private TextView textView;

    /** Called when the activity is first created. */

    @SuppressLint("NewApi") @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if ( savedInstanceState == null)
            discovery = new Discovery(this);
        else
            discovery = (Discovery) savedInstanceState.getSerializable("discovery");
        setContentView(R.layout.main);
        textView = (TextView)this.findViewById(R.id.text);
        Button b = (Button)this.findViewById(R.id.button);
        b.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                //discovery.setUp();
                Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com"));
                startActivity(browserIntent);
            }
        });

        android.net.wifi.WifiManager wifi = (android.net.wifi.WifiManager) getSystemService(android.content.Context.WIFI_SERVICE);
        lock = wifi.createMulticastLock("mylockthereturn");
        lock.setReferenceCounted(true);
        lock.acquire();

    }

    @Override
    protected void onSaveInstanceState(final Bundle outState) {
        outState.putSerializable("discovery", discovery);
        super.onSaveInstanceState(outState);
    }

    public void updateView () {
        String msg = discovery.getMsg();
        textView.setText(msg);
    }


    @SuppressLint("NewApi") @Override
    protected void onStop() {
        discovery.stop();
        lock.release();
        super.onStop();
    }


}

发现.java

package com.heeere.androiddnssd.discovery;

import java.io.IOException;
import java.io.Serializable;

import javax.jmdns.JmDNS;
import javax.jmdns.ServiceEvent;
import javax.jmdns.ServiceListener;

public class Discovery implements Serializable {


    private static final long serialVersionUID = 637576886455091135L;
    private String type = "_ikunet._tcp.local.";
    private String msg="";
    private JmDNS jmdns = null;
    private ServiceListener listener = null;
    private MainTest maintest;
    android.os.Handler handler = new android.os.Handler();

    public Discovery (MainTest maintest) {
        this.maintest = maintest;
        setUp();
    }

    public void setUp() {

        try {
            jmdns = JmDNS.create();
            jmdns.addServiceListener(type, listener = new ServiceListener() {

                public void serviceResolved(ServiceEvent ev) {
                    msg = msg + ev.getInfo().getName()+ "\n";
                    update();
                }

                public void serviceRemoved(ServiceEvent ev) {
                }

                public void serviceAdded(ServiceEvent event) {
                    jmdns.requestServiceInfo(event.getType(), event.getName(), 1);
                }
            });
        } catch (IOException e) {
            //e.printStackTrace();
            return;
        }
    }

    public String getMsg() {
        return msg;
    }

    private void update() {
        handler.postDelayed(new Runnable() {
            public void run() {
                maintest.updateView();
            }
        }, 1);
    }


    public void stop() {
        if (jmdns != null) {
            if (listener != null) {
                jmdns.removeServiceListener(type, listener);
                listener = null;
            }
            jmdns.unregisterAllServices();
            try {
                jmdns.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            jmdns = null;
        }
    }

}

日志猫

09-13 15:08:30.507: E/AndroidRuntime(15775): Uncaught handler: thread main exiting due to uncaught exception
09-13 15:08:30.517: E/AndroidRuntime(15775): java.lang.RuntimeException: Parcelable encountered IOException writing serializable object (name = com.heeere.androiddnssd.discovery.Discovery)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Parcel.writeSerializable(Parcel.java:1131)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Parcel.writeValue(Parcel.java:1085)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Parcel.writeMapInternal(Parcel.java:469)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Bundle.writeToParcel(Bundle.java:1445)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Parcel.writeBundle(Parcel.java:483)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.app.ActivityManagerProxy.activityPaused(ActivityManagerNative.java:1427)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:3106)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.app.ActivityThread.access$2400(ActivityThread.java:119)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1870)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Handler.dispatchMessage(Handler.java:99)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Looper.loop(Looper.java:123)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.app.ActivityThread.main(ActivityThread.java:4363)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.lang.reflect.Method.invokeNative(Native Method)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.lang.reflect.Method.invoke(Method.java:521)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at dalvik.system.NativeStart.main(Native Method)
09-13 15:08:30.517: E/AndroidRuntime(15775): Caused by: java.io.NotSerializableException: android.os.Handler
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1547)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1854)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1696)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1660)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1153)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:420)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1251)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1587)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1854)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1696)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1660)
09-13 15:08:30.517: E/AndroidRuntime(15775):    at android.os.Parcel.writeSerializable(Parcel.java:1126)
09-13 15:08:30.517: E/AndroidRuntime(15775):    ... 16 more
4

3 回答 3

1

问题是由于在创建相关对象时将主要活动传递给可序列化类。在我们的例子中，在创建对象时MainTest将对象传递给对象。Discovery解决方案：创建另一个包含所有发现数据（可序列化数据）的可序列化类。

于 2012-09-17T10:50:30.763 回答
-1

错误很明显：Caused by: java.io.NotSerializableException: android.os.Handler

弄清楚如何取出处理程序：android.os.Handler handler = new android.os.Handler();

于 2012-09-13T14:22:34.800 回答
-1

据我所知，Serializable 在 Android 上很慢，您应该改用 Parcelable，有关更多信息，请参阅此链接：Benefit of using Parcelable instead of serializing object

问候

于 2012-09-13T14:49:42.790 回答