【问题标题】:Passing ArrayList through broadcast intent通过广播意图传递 ArrayList
【发布时间】:2012-11-06 17:25:54
【问题描述】:

我按照Help with passing ArrayList and parcelable Activity 的示例进行操作,但就我而言,我正尝试将意图从我的服务类(内部 Asynctask)广播到像这样的 Activity 类。

ArrayList<Malware> addyExtras = new ArrayList <Malware>();

for (int i = 0; i < fetch.size(); i++) {
    addyExtras.add (fetch.get(i));
}
Intent d = new Intent();
d.setAction(COMPLETED_INTENT);
d.putExtra("CurrentProgress", "completed");
d.putParcelableArrayListExtra("MalwareArray", addyExtras);
sendBroadcast(d);

我如何接收广播意图

ArrayList<Malware> myList;
myList = getIntent().getParcelableArrayListExtra("MalwareArray");
Log.d("onReceive", "got myList");

for (int i = 0; i < myList.size(); i++) {
    Malware a = myList.get(i);
    Log.d("onReceive", "App Name:" + a.getApp());
    //tv1.setText(a.getName() + " is from " + a.getState());
}

尝试接收意图时遇到空指针异常

11-07 01:21:51.315: E/AndroidRuntime(18769): FATAL EXCEPTION: main
11-07 01:21:51.315: E/AndroidRuntime(18769): java.lang.RuntimeException: Error receiving broadcast Intent { act=com.analyze.project.CompletedReceiver flg=0x10 (has extras) } in com.analyze.project.AnalyzeActivity$1@41889670
11-07 01:21:51.315: E/AndroidRuntime(18769):    at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:737)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at android.os.Handler.handleCallback(Handler.java:605)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at android.os.Handler.dispatchMessage(Handler.java:92)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at android.os.Looper.loop(Looper.java:137)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at android.app.ActivityThread.main(ActivityThread.java:4513)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at java.lang.reflect.Method.invokeNative(Native Method)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at java.lang.reflect.Method.invoke(Method.java:511)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:974)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:741)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at dalvik.system.NativeStart.main(Native Method)
11-07 01:21:51.315: E/AndroidRuntime(18769): Caused by: java.lang.NullPointerException
11-07 01:21:51.315: E/AndroidRuntime(18769):    at com.analyze.project.AnalyzeActivity$1.onReceive(AnalyzeActivity.java:197)
11-07 01:21:51.315: E/AndroidRuntime(18769):    at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:728)
11-07 01:21:51.315: E/AndroidRuntime(18769):    ... 9 more

【问题讨论】:

  • AnalyzeActivity 文件的第 197 行是什么?
  • 我是for (int i = 0; i &lt; myList.size(); i++) {

标签: android android-intent nullpointerexception broadcast parcelable


【解决方案1】:

从日志 AnalyzeActivity.java:197 中,您有一个变量,意外地,第 197 行为 null。

private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {

    Log.d("TAG", "onReceive1()");
    //setIntent(intent);

    ArrayList<Malware> myList;
    // use local var intent 
    myList = intent.getParcelableArrayListExtra("MalwareArray");
    Log.d("onReceive", "got myList");

    for (int i = 0; i < myList.size(); i++) {
        Malware a = myList.get(i);
        Log.d("onReceive", "App Name:" + a.getApp());
        //tv1.setText(a.getName() + " is from " + a.getState());
    }
}

【讨论】:

  • 这是一个内部广播接收器类,我在AnalyzeActivity 中使用它来接收来自我的服务的广播不认为我可以这样做吗?
  • 我编辑了答案以使用支持包中的本地广播接收器。试试看。
  • 它现在正在工作,但我的代码的问题是我也试图传递一个可绘制对象。我是否必须将我的可绘制对象转换为字节才能传递它?
  • 是的,如果它不是你可以通过 'getResources().getDrawable()' 获取的东西,那么将其转换为字节。如果它很大,它可能会很慢
  • 任何时候,调用 setintent 都会设置活动的意图。如果您在代码的其他地方大量使用 getIntent(),则在某些情况下您可能不希望这样做。为了解决这个问题,我稍微改变了答案。
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