监测Android 2G CMCC Signal Strengt

activity_main.xml

<TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/tv"/>

AndroidManifest.xml

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

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private TextView tv;
    private TelephonyManager telephonyManager;
    private MyPhoneStateListener mListener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       tv=(TextView) findViewById(R.id.tv);
        telephonyManager= (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
        mListener=new MyPhoneStateListener();
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CHANGE_NETWORK_STATE)
                != PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.CHANGE_NETWORK_STATE},1);
        }else {
            telephonyManager.listen(mListener,PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);
        }


    }

    @Override
    public void onRequestPermissionsResult(int requestCode,String[] permissions,int[] grantResults){
        switch (requestCode){
            case 1:
                if (grantResults.length>0 && grantResults[0]== PackageManager.PERMISSION_GRANTED){
                   telephonyManager.listen(mListener,LISTEN_SIGNAL_STRENGTHS);
                }else {
                    Toast.makeText(this,"You denied permissions",Toast.LENGTH_SHORT).show();
                }
                break;
            default:
        }
    }
    //PhoneStateListener 
    private class MyPhoneStateListener extends PhoneStateListener{
        private int asu=0,lastSignal=0;

        @Override
        public void onSignalStrengthsChanged(SignalStrength signalStrength) {

            super.onSignalStrengthsChanged(signalStrength);
            asu=signalStrength.getGsmSignalStrength();
            lastSignal=-113+2*asu;
            Log.d("asu", String.valueOf(asu));
            Log.d("signal", String.valueOf(lastSignal));
            tv.setText("the current signal strength:"+lastSignal+"dBm");
        }
    }
}