如何使另一个 Android 类文件中的方法在电话铃声响起时运行？

发布于 2024-12-23 07:45:28 字数 1248 浏览 2 评论 0原文

我的情况是，我想调用一个特定的方法，从扩展 BroadcastReceiver 类的 ClassB 内部从 ClassA 调用。我了解如何从另一个类文件等内部执行此操作以及如何设置 BroadcastReceiver，或者我是这么想的。

下面是扩展 BroadcastReceiver 的类文件。 public class WatchPhone extends BroadcastReceiver {

private ClassA classA;

@Override
public void onReceive(Context context, Intent BackToMain) {
    // TODO Auto-generated method stub
    TelephonyManager telephony = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE); 
    int state = telephony.getCallState(); 
    switch(state) { 
        case TelephonyManager.CALL_STATE_RINGING:
            Log.d("TestServiceReceiver", "IDLE"); 
            classA.IwantToDoThis();
            break; 
    }
}

如果我手动请求它，我尝试调用的方法在应用程序中效果很好。在我的 AndroidManifest.xml 中，我

    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>

在底部的关闭应用程序标记上方添加了这个和这个。

            <receiver android:name=".WatchPhone">
                    <intent-filter> 
                    <action android:name="android.intent.action.PHONE_STATE" /> 
                    </intent-filter> 
            </receiver>

当电话响起时，应用程序崩溃然后关闭。关于我应该做什么的任何想法。

原文

My situation is that I want to call a particular method to get called from ClassA from inside my ClassB which extends the BroadcastReceiver class. I understand how to do this from inside another class file etc and how to setup the BroadcastReceiver, or so I thought.

Below is the class file that extends the BroadcastReceiver.
public class WatchPhone extends BroadcastReceiver {

private ClassA classA;

@Override
public void onReceive(Context context, Intent BackToMain) {
    // TODO Auto-generated method stub
    TelephonyManager telephony = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE); 
    int state = telephony.getCallState(); 
    switch(state) { 
        case TelephonyManager.CALL_STATE_RINGING:
            Log.d("TestServiceReceiver", "IDLE"); 
            classA.IwantToDoThis();
            break; 
    }
}

The method that I am trying to call does work great in the application if I manually request it.
In my AndroidManifest.xml I added this

    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>

and this at the bottom just above the closing application tag.

            <receiver android:name=".WatchPhone">
                    <intent-filter> 
                    <action android:name="android.intent.action.PHONE_STATE" /> 
                    </intent-filter> 
            </receiver>

When the phone rings, the application crashes then closes. Any ideas on what I should do.

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要走就滚别墨迹 2024-12-30 07:45:28

我立即看到一个问题：您声明了 ClassA 的一个实例，但没有实例化它。这意味着 classA = null 并且您在使用它时可能会收到 NullPointerException 。

试试这个：

private ClassA classA = new ClassA();

或者，您可以在 onReceive() 顶部附近实例化它：

classA = new ClassA();

I can see one problem immediately: you declared an instance of ClassA but did not instantiate it. That means classA = null and you are probably getting a NullPointerException when you use it.

Try this instead: