Question

点击broadcastReceivers时，我onResume注册了toggle button个onPause。在logcat我取消注册它们，但当我按下主页按钮时，应用程序崩溃@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); SetUpAllViews(R.layout.activity_main); } private void setViewState(int view, boolean state) { // TODO Auto-generated method stub switch(view) { case R.id.togbtn_connect: tog_connect.setEnabled(state); case R.id.et_ip: et_ip.setEnabled(state); case R.id.btn_send: btn_send.setEnabled(state); case R.id.et_msg: et_msg.setEnabled(state); } } private BroadcastReceiver mNetworkReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { // TODO Auto-generated method stub mConnMgr = (ConnectivityManager)getSystemService(network_service); networkInfo = mConnMgr.getActiveNetworkInfo(); if (networkInfo != null) { if (networkInfo.isConnected()) { setText(R.id.tv_conn_status, ""+networkInfo); registerReceiver(mWiFiReceiver, new IntentFilter(WifiManager.WIFI_STATE_CHANGED_ACTION)); setViewState(R.id.et_ip, true); setViewState(R.id.btn_send, false); setViewState(R.id.et_msg, false); }else if (networkInfo.isConnectedOrConnecting()) { setText(R.id.tv_conn_status, "Status: CONNECTED Or CONNECTING"); }else if (networkInfo.isFailover()){ setText(R.id.tv_conn_status, "Status: FailOver"); }else if (networkInfo.isRoaming()) { setText(R.id.tv_conn_status, "Status: Roaming"); }else if (networkInfo.isAvailable()) { setText(R.id.tv_conn_status, "Status: Available"); } }else { setText(R.id.tv_conn_status, "Status: No Default NetWork Connected"); } } }; private BroadcastReceiver mWiFiReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { // TODO Auto-generated method stub mWiFi_Mgr = (WifiManager) getSystemService(wifi_service); if (mWiFi_Mgr != null) mWiFi_Info = mWiFi_Mgr.getConnectionInfo(); int wifiExtras = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, WifiManager.WIFI_STATE_UNKNOWN); switch(wifiExtras) { case WifiManager.WIFI_STATE_ENABLING: setText(R.id.tv_wifi_state, "Enabling..."); break; case WifiManager.WIFI_STATE_ENABLED: setText(R.id.tv_wifi_state, "Enabled"); if (mWiFi_Info != null) { if (mWiFi_Info.getBSSID() != null) { setText(R.id.tv_conn_bssid, "BSSID: "+mWiFi_Info.getBSSID()); }else { setText(R.id.tv_conn_bssid, "BSSID: "+mWiFi_Info.getBSSID()); } setText(R.id.tv_conn_speed, "Speed: "+mWiFi_Info.getLinkSpeed()+WifiInfo.LINK_SPEED_UNITS); setText(R.id.tv_conn_strength, "RSSI: "+WifiManager.calculateSignalLevel(mWiFi_Info.getRssi(), 5)); setText(R.id.tv_conn_ip, getIPv4(mWiFi_Info.getIpAddress())); } break; case WifiManager.WIFI_STATE_DISABLING: setText(R.id.tv_wifi_state, "Disabling..."); break; case WifiManager.WIFI_STATE_DISABLED: setText(R.id.tv_wifi_state, "Disabled"); break; case WifiManager.WIFI_STATE_UNKNOWN: setText(R.id.tv_wifi_state, "Unkown_WiFi_State"); break; } } }; private void SetUpAllViews(int layout) { // TODO Auto-generated method stub setContentView(layout); tv_conn_status = (TextView) findViewById(R.id.tv_conn_status); tv_wifi_state = (TextView) findViewById(R.id.tv_wifi_state); tv_conn_bssid = (TextView) findViewById(R.id.tv_conn_bssid); tv_conn_speed = (TextView) findViewById(R.id.tv_conn_speed); tv_conn_strengt = (TextView) findViewById(R.id.tv_conn_strength); tv_conn_ip = (TextView) findViewById(R.id.tv_conn_ip); et_ip = (EditText) findViewById(R.id.et_ip); tog_connect = (ToggleButton) findViewById(R.id.togbtn_connect); et_msg = (EditText) findViewById(R.id.et_msg); btn_send = (Button) findViewById(R.id.btn_send); } private void setText(int view, String text) { // TODO Auto-generated method stub switch(view) { case R.id.tv_conn_status: tv_conn_status.setText(text); break; case R.id.tv_wifi_state: tv_wifi_state.setText(text); break; case R.id.tv_conn_bssid: tv_conn_bssid.setText(text); break; case R.id.tv_conn_speed: tv_conn_speed.setText(text); break; case R.id.tv_conn_strength: tv_conn_strengt.setText(text); break; case R.id.tv_conn_ip: tv_conn_ip.setText(text); break; } } private String getIPv4(int ip) { // TODO Auto-generated method stub String result = String.format("%d.%d.%d.%d", (ip & 0xff), (ip >> 8 & 0xff), (ip >> 16 & 0xff), (ip >> 24 & 0xff)); return result; } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); tog_connect.setOnCheckedChangeListener(new OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { // TODO Auto-generated method stub if (isChecked) { registerReceiver(mNetworkReceiver, new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)); }else { if (mWiFi_Mgr.getWifiState() == WifiManager.WIFI_STATE_ENABLED) mWiFi_Mgr.setWifiEnabled(false); if (mWiFiReceiver != null) unregisterReceiver(mWiFiReceiver); if (mNetworkReceiver != null) unregisterReceiver(mNetworkReceiver); } } }); } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); //if (mWiFiReceiver != null) //unregisterReceiver(mWiFiReceiver); if (mNetworkReceiver != null) unregisterReceiver(mNetworkReceiver); }会产生以下错误。

Code_Updated_2 ：

11-08 17:18:00.025: E/AndroidRuntime(5541): FATAL EXCEPTION: main
11-08 17:18:00.025: E/AndroidRuntime(5541): Process: com.example.wifi_socket_01, PID:  
5541
11-08 17:18:00.025: E/AndroidRuntime(5541): java.lang.RuntimeException: Unable to pause 
activity {com.example.wifi_socket_01/com.example.wifi_socket_01.wifi_socket_01}: 
java.lang.IllegalArgumentException: Receiver not registered:  
com.example.wifi_socket_01.wifi_socket_01$1@43033000
11-08 17:18:00.025: E/AndroidRuntime(5541): Caused by:  
java.lang.IllegalArgumentException: Receiver not registered: com.
example.wifi_socket_01.wifi_socket_01$1@43033000
11-08 17:18:00.025: E/AndroidRuntime(5541):     at  
android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:671)
11-08 17:18:00.025: E/AndroidRuntime(5541):     at 
android.app.ContextImpl.unregisterReceiver(ContextImpl.java:1785)
11-08 17:18:00.025: E/AndroidRuntime(5541):     at   
com.example.wifi_socket_01.wifi_socket_01.onPause(wifi_socket_01.java:184)

}

logcat的：

{{1}}

Answer 1

onResume（）您只注册一个接收器。但mWiFiReceiver从另一个接收器注册。当onPause执行时，它将自然地取消注册mNetworkReceiver。但unregisterReceiver（mWiFiReceiver）;给你错误，因为它没有在那里注册。

Answer 2

或者你可以在onPause（）方法中包含一个try {...} catch（IllegalArgumentException e）{...}结构。

会是这样的：

if (mWiFi_Mgr.getWifiState() == WifiManager.WIFI_STATE_ENABLED)
      mWiFi_Mgr.setWifiEnabled(false);
      if (mWiFiReceiver != null)
           try {
               unregisterReceiver(mWiFiReceiver);
           }  catch(IllegalArgumentException e) {
               //your catching code.
           } catch (Exception e) {
               //just in case other exception appears
           }
           ....

您将能够捕捉到未解决的问题。

Answer 3

例外情况You are attempting to unregister the receiver which is not registered

在您onResume()中只有一个接收者正在注册，但在onPause()中有两个接收者未注册。尝试取消注册not-registered接收器（wifi接收器）导致引发异常。

应用程序在进入onPause时崩溃了吗？

3 个答案: