android BroadcastReceiver遇到 java.lang.IllegalAccessException解决方法

android BroadcastReceiver 遇到java.lang.IllegalAccessException解决方法

我在android 中监听wifi变化服务时，遇到错误

java.lang.IllegalAccessException，sth is not accessible from class android.app.ActivityThread，主要是app中其他地方调用了默认的构造函数，必须增加默认构造函数且访问权限为public

1.错误的部分代码

//通过一个BroadcastReceiver（android 四大组建之一），用于动态注册监听网络变化
public class NetworkConnectChangedReceiver extends BroadcastReceiver{
OnWifiChangedListener changed;

Activity act;

public NetworkConnectChangedReceiver(Activity act){
this.act = act;
}

public void setChangedListener(OnWifiChangedListener changed) {
this.changed = changed;
}
@Override
public void onReceive(Context context, Intent intent) {

if (null == intent.getAction()){
return ;
}
// TODO Auto-generated method stub
if(intent.getAction().equals(WifiManager.RSSI_CHANGED_ACTION)){
//signal strength changed
}
else if(intent.getAction().equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)){//wifi连接上与否
System.out.println("网络状态改变");
NetworkInfo info = intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
if (null == info.getState()){
return ;
}
if(info.getState().equals(NetworkInfo.State.DISCONNECTED)){
System.out.println("wifi网络连接断开");
if (act != null){
//CommonAction.showToastMessageL(act, "wifi网络连接断开");
}
}
else if(info.getState().equals(NetworkInfo.State.CONNECTED)){

WifiManager wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();

if ((null != wifiInfo) && (null != wifiInfo.getSSID()) && (!wifiInfo.getSSID().contains("unknown"))){
//获取当前wifi名称
System.out.println("连接到网络 " + wifiInfo.getSSID());
if (act != null){
//                      CommonAction.showToastMessageL(act, "连接到网络 " + wifiInfo.getSSID());
changed.onChange(wifiInfo.getSSID());
}
}

}

}
else if(intent.getAction().equals(WifiManager.WIFI_STATE_CHANGED_ACTION)){//wifi打开与否
int wifistate = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, WifiManager.WIFI_STATE_DISABLED);

if(wifistate == WifiManager.WIFI_STATE_DISABLED){
System.out.println("系统关闭wifi");
//CommonAction.showToastMessageL(act, "系统关闭wifi");
changed.onClose();
}
else if(wifistate == WifiManager.WIFI_STATE_ENABLED){
System.out.println("系统开启wifi");
//CommonAction.showToastMessageL(act, "系统开启wifi");
}
}
}

public interface OnWifiChangedListener {
void onChange(String wifiName);
void onClose();
}

//Activity 中使用上面BroadcastReceiver及注册的代码

public class ComListActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_com_list);

registerNetChangerReciver();
}

private void registerNetChangerReciver() {
IntentFilter filter = new IntentFilter();
filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
if (null == netChangeRec){
netChangeRec = new NetworkConnectChangedReceiver(this);
netChangeRec.setChangedListener(new OnWifiChangedListener(){

@Override
public void onChange(String wifiName) {
// TODO 自动生成的方法存根
if (!connectWifiName.equals(wifiName)){// connected wifi is chanded
CommonAction.showToastMessageL(ComListActivity.this, "连接到网络 " + wifiName);
updateAutoMemorytData();
updateListViewData();
connectWifiName = wifiName;
}
}

@Override
public void onClose() {
// TODO 自动生成的方法存根
connectWifiName = "";
}

});
}
registerReceiver(netChangeRec, filter);
}
}

2.错误提示如下：

FATAL EXCEPTION: main

Process: com.chaoyuan.signalmachineconfig, PID: 4087

java.lang.RuntimeException: Unable to instantiate receiver com.chaoyuan.signalmachineconfig.NetworkConnectChangedReceiver: java.lang.IllegalAccessException: com.chaoyuan.signalmachineconfig.NetworkConnectChangedReceiver() is not accessible from class android.app.ActivityThread

at android.app.ActivityThread.handleReceiver(ActivityThread.java:2565)

at android.app.ActivityThread.access1700(ActivityThread.java:147)atandroid.app.ActivityThreadH.handleMessage(ActivityThread.java:1362)

at android.os.Handler.dispatchMessage(Handler.java:102)

at android.os.Looper.loop(Looper.java:135)

at android.app.ActivityThread.main(ActivityThread.java:5238)

at java.lang.reflect.Method.invoke(Native Method)

at java.lang.reflect.Method.invoke(Method.java:372)

at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)

at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)

Caused by: java.lang.IllegalAccessException: com.chaoyuan.signalmachineconfig.NetworkConnectChangedReceiver() is not accessible from class android.app.ActivityThread

at java.lang.Class.newInstance(Class.java:1569)

at android.app.ActivityThread.handleReceiver(ActivityThread.java:2560)

… 9 more

3.错误修改说明

错误原因主要是app中其他地方调用了默认的构造函数，必须增加默认构造函数且访问权限为public:

public class NetworkConnectChangedReceiver extends BroadcastReceiver{

........

//添加默认构造函数，且为public
public NetworkConnectChangedReceiver(){

}

public NetworkConnectChangedReceiver(Activity act){
this.act = act;
}
.......

}