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安卓Handler消息和ListView

androidlistviewmessage-queuemessagehandler
9

以下是我的错误信息：

*** Uncaught remote exception!  (Exceptions are not yet supported across processes.)
android.util.AndroidRuntimeException: { what=1008 when=368280372 } This message is already in use.
at android.os.MessageQueue.enqueueMessage(MessageQueue.java:171)
at android.os.Handler.sendMessageAtTime(Handler.java:457)
at android.os.Handler.sendMessageDelayed(Handler.java:430)
at android.os.Handler.sendMessage(Handler.java:367)
at android.view.ViewRoot.dispatchAppVisibility(ViewRoot.java:2748)

我尝试创建一个列表视图，由自定义列表项填充。每个列表项有多个视图，并且每个视图都附带了一个点击监听器。当这个onClickListener被按下时，它会向一个Handler发送一个what和arg1参数的消息。 点击其中一个元素会触发意图启动新的活动。 点击另一个则显示一个toast。 当以组合方式按下这些按钮时，我得到上面的错误。即先点击文本来启动意图（然后按返回键），然后点击图像来显示toast，再次点击文本来启动意图时，我会得到FC（强制关闭）。
以下是代码，我尽可能地删除了一些无用的内容以达到错误的核心：
如果您想跳过无关紧要的内容，请查看ConversationAdapter.class中的onClickListener以及它们与StartPage.class的交互。
Android清单：
<?xml version="1.0" encoding="utf-8"?>
  <manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.handler.test"
    android:versionCode="1"
    android:versionName="1.0">
      <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".StartPage"
              android:label="@string/app_name">
            <intent-filter>
              <action android:name="android.intent.action.MAIN" />
              <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    <activity
        android:name=".DetailsPage"
        android:label="DetailsPage"
        >
    </activity> 
    </application>
    <uses-sdk android:minSdkVersion="3" />
</manifest>

StartPage.class:

package com.handler.test;

import java.util.ArrayList;

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;

public class StartPage extends ListActivity {

private ArrayList<Conversation> mConversations = null;
private ConversationAdapter mAdapter;
private Context mContext;
private ProgressDialog mProgressDialog;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    mContext = this;

    mConversations = new ArrayList<Conversation>();
    this.mAdapter = new ConversationAdapter(mContext, R.layout.inbox_row, mConversations, mHandler);
    setListAdapter(this.mAdapter);

    new Thread(new Runnable() {
        @Override
        public void run() {
            getConversations();
        }
    }).start();

    mProgressDialog = ProgressDialog.show(StartPage.this, "Please wait...", "Retrieving data ...", true);
}

private void getConversations() {
    try {
        mConversations = new ArrayList<Conversation>();
        Conversation o1 = new Conversation();
        o1.setStatus("SF services");
        o1.setMessage("Pending");           
        mConversations.add(o1);
    } catch (Exception e) {
        Log.e("BACKGROUND_PROC", e.getMessage());
    }
    runOnUiThread(returnRes);
}

private Runnable returnRes = new Runnable() {
    @Override
    public void run() {
        if(mConversations != null && mConversations.size() > 0){
            mAdapter.notifyDataSetChanged();
            for(int i=0;i<mConversations.size();i++)
                mAdapter.add(mConversations.get(i));
        }
        mProgressDialog.dismiss();
        mAdapter.notifyDataSetChanged();
    }
  };

private Handler mHandler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        int convIndex = msg.arg1;
        int viewTouched = msg.what;
        switch(viewTouched){
            case ConversationAdapter.PROF_ICON:
                showNumber(convIndex);
            break;
            case ConversationAdapter.MESSAGE:
                showMessageDetails(convIndex);
            break;
        }
        super.handleMessage(msg);
    }
};

private void showNumber(int convIndex) {
    Toast.makeText(mContext, "Pressed: "+convIndex, Toast.LENGTH_LONG).show();
}

private void showMessageDetails(int convIndex) {
    final Conversation conv = mConversations.get(convIndex);
    Intent i = new Intent(mContext, DetailsPage.class);
    i.putExtra("someExtra", conv);
    startActivity(i);
}
}

DetailsPage.class

package com.handler.test;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class DetailsPage extends Activity {


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Log.i("Test", "Details Page");      
}


}

Conversation.class:

package com.handler.test;

import java.io.Serializable;

public class Conversation implements Serializable {

private static final long serialVersionUID = -437261671361122258L;

private String status;

public String getStatus() {
    return status;
}
public void setStatus(String status) {
    this.status = status;
}
}

ConversationAdapter.class:

package com.handler.test;

import java.util.ArrayList;

import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class ConversationAdapter extends ArrayAdapter<Conversation> {

public static final int PROF_ICON = 0;
public static final int MESSAGE = 1;

private Context mContext;
private Handler mHandler;
private ArrayList<Conversation> mItems;
private int mXmlId;

private LinearLayout detailsOfConv;
private ImageView iconImage;

public ConversationAdapter(Context context, int textViewResourceId, ArrayList<Conversation> items, Handler handler) {
    super(context, textViewResourceId, items);
    this.mContext = context;
    this.mItems = items;
    this.mXmlId = textViewResourceId;
    this.mHandler = handler;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    if (v == null) {
        LayoutInflater vi = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = vi.inflate(mXmlId, null);
    }
    final Message m = new Message();
    m.arg1 = position;
    Conversation c = mItems.get(position);
    if (c != null) {
        iconImage = (ImageView) v.findViewById(R.id.icon);
        if (iconImage != null) {
            iconImage.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    m.what = PROF_ICON;
                    mHandler.sendMessage(m);
                }
            });
        }

        detailsOfConv = (LinearLayout) v.findViewById(R.id.details);
        if(detailsOfConv != null){
            detailsOfConv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    m.what = MESSAGE;
                    mHandler.sendMessage(m);
                }
            });
        }
    }
    return v;
}
}

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dip"
>
<ListView
 android:id="@+id/android:list"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:cacheColorHint="#00000000"
 />
</LinearLayout>

inbox_row.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="?android:attr/listPreferredItemHeight"
  android:padding="6dip">
  <ImageView
    android:id="@+id/icon"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:layout_marginRight="6dip"
    android:src="@drawable/icon" />
  <LinearLayout
    android:id="@+id/details"
    android:orientation="vertical"
    android:layout_width="0dip"
    android:layout_weight="1"
    android:layout_height="fill_parent">
    <TextView
        android:id="@+id/toptext"
        android:textColor="#99FF66"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="1"
        android:singleLine="true"
        android:text="123456789"
        />       
  </LinearLayout>
</LinearLayout>
1个回答
33

我的猜测是你发送了两次相同的消息。因为在代码中有一个new Message()和两个可能都被执行的mHandler.sendMessage(m)。

尝试每次发送消息时创建一个新的消息对象。

编辑:

Message.obtain()比Message m = new Message()更可取（因为它在底层回收已使用的消息）

在你的情况下，如果你需要现有消息的副本，可以使用new.copyFrom(old)。

嗯，这确实有效，我试图通过每个视图只有一个而不是每次单击时都有一个来节省资源（是的，数量很少）。我可以看到如果两者都被执行，会抛出错误。但是对于布局视图，我无法想象这种情况可能发生，操作系统必须缺少清理？无论如何，现在它已经工作了。通过将新的Message（）移动到onClick中。 - Blundell
啊，太好了，我不知道这个，谢谢！新的Message()已经改成Message.obtain()了。 - Blundell
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