我有一个应用程序，其中我放置了一个开关切换按钮。我的应用程序的目的是，只要将开关按钮设置为ON，就应阻止所有来电。我可以阻止所有呼叫但是当开关设置为ON时我无法阻止。
我创建了一个名为MyClassReceiver的类，它扩展了Broadcast Receiver，所有的调用阻塞都在这个类中完成。我在Manifest文件中添加了接收器代码，该代码完美无缺。
这是我正在使用的代码： -
MainActivity.java
package com.chinmay.smsender;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.media.AudioManager;
import android.os.Bundle;
import android.view.Menu;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Switch;
public class MainActivity extends Activity {
public Switch mySwitch;
//private LinearLayout bgElement;
private AudioManager mAudio;
boolean switchChecked;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mySwitch = (Switch) findViewById(R.id.switch1);
//bgElement = (LinearLayout) findViewById(R.id.container);
mAudio = (AudioManager) getBaseContext().getSystemService(Context.AUDIO_SERVICE);
mySwitch.setOnCheckedChangeListener(new OnCheckedChangeListener(){
@Override
public void onCheckedChanged(CompoundButton arg0, boolean isChecked) {
if(isChecked) {
mAudio.setRingerMode(AudioManager.RINGER_MODE_SILENT);
broadcastIntent(true);
//bgElement.setBackgroundColor(Color.GREEN);
} else {
mAudio.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
broadcastIntent(false);
//bgElement.setBackgroundColor(Color.RED);
}
}
});
}
public void broadcastIntent(boolean isChecked) {
Intent intent = new Intent();
intent.setAction("com.chinmay.CUSTOM_INTENT");
intent.putExtra("switchChecked", isChecked);
sendBroadcast(intent);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
MyClassReceiver.java
package com.chinmay.smsender;
import java.lang.reflect.Method;
import com.android.internal.telephony.ITelephony;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.TelephonyManager;
import android.widget.Toast;
public class MyClassReceiver extends BroadcastReceiver {
private ITelephony telephonyService;
Context context = null;
boolean isChecked;
@Override
public void onReceive(Context context, Intent intent) {
TelephonyManager telephony = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
isChecked = intent.getExtras().getBoolean("switchChecked");
if(isChecked) {
Toast.makeText(context, "Blocking calls", Toast.LENGTH_LONG).show();
if(intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_RINGING)) {
//String incomingNumber = intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
//Toast.makeText(context, "Call from: "+incomingNumber, Toast.LENGTH_LONG).show();
try {
Class<?> c = Class.forName(telephony.getClass().getName());
Method m = c.getDeclaredMethod("getITelephony");
m.setAccessible(true);
telephonyService = (ITelephony) m.invoke(telephony);
//telephonyService.silenceRinger();
telephonyService.endCall();
} catch (Exception e) {
e.printStackTrace();
}
}
} else if(isChecked == false) {
Toast.makeText(context, "Blocking calls off", Toast.LENGTH_LONG).show();
}
/* else if(intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_IDLE) || intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_OFFHOOK)) {
Toast.makeText(context, "Detected Call Hangup Event.", Toast.LENGTH_LONG).show();
}*/
}
}
Android Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.chinmay.smsender"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.chinmay.smsender.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name="com.chinmay.smsender.MyClassReceiver">
<intent-filter>
<action android:name="android.intent.action.PHONE_STATE" />
<action android:name="com.chinmay.CUSTOM_INTENT" />
</intent-filter>
</receiver>
</application>
</manifest>
如果我运行此代码，这是我得到的错误
10-31 13:03:26.283: E/AndroidRuntime(759): FATAL EXCEPTION: main
10-31 13:03:26.283: E/AndroidRuntime(759): Process: com.chinmay.smsender, PID: 759
10-31 13:03:26.283: E/AndroidRuntime(759): java.lang.RuntimeException: Unable to start receiver com.chinmay.smsender.MyClassReceiver: java.lang.NullPointerException
10-31 13:03:26.283: E/AndroidRuntime(759): at android.app.ActivityThread.handleReceiver(ActivityThread.java:2441)
10-31 13:03:26.283: E/AndroidRuntime(759): at android.app.ActivityThread.access$1700(ActivityThread.java:139)
10-31 13:03:26.283: E/AndroidRuntime(759): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1286)
10-31 13:03:26.283: E/AndroidRuntime(759): at android.os.Handler.dispatchMessage(Handler.java:102)
10-31 13:03:26.283: E/AndroidRuntime(759): at android.os.Looper.loop(Looper.java:136)
10-31 13:03:26.283: E/AndroidRuntime(759): at android.app.ActivityThread.main(ActivityThread.java:5086)
10-31 13:03:26.283: E/AndroidRuntime(759): at java.lang.reflect.Method.invokeNative(Native Method)
10-31 13:03:26.283: E/AndroidRuntime(759): at java.lang.reflect.Method.invoke(Method.java:515)
10-31 13:03:26.283: E/AndroidRuntime(759): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
10-31 13:03:26.283: E/AndroidRuntime(759): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
10-31 13:03:26.283: E/AndroidRuntime(759): at dalvik.system.NativeStart.main(Native Method)
10-31 13:03:26.283: E/AndroidRuntime(759): Caused by: java.lang.NullPointerException
10-31 13:03:26.283: E/AndroidRuntime(759): at com.chinmay.smsender.MyClassReceiver.onReceive(MyClassReceiver.java:49)
10-31 13:03:26.283: E/AndroidRuntime(759): at android.app.ActivityThread.handleReceiver(ActivityThread.java:2434)
10-31 13:03:26.283: E/AndroidRuntime(759): ... 10 more
我认为因为我向MyClassReceiver发送了两个意图，我收到了这个错误。
请告诉我如何知道MyClassReceiver本身的开关按钮状态，并在开关打开时阻止每次通话。
答案 0 :(得分：0)