Question

我有以下自定义侦听器

package home.dan.signalstrengthatlocation;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.telephony.PhoneStateListener;
import android.telephony.SignalStrength;
import android.util.Log;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;



public class CustomPhoneStateListener extends PhoneStateListener {
Context mContext;
public static String LOG_TAG = "CPhoneStateListener";

public CustomPhoneStateListener(Context context) {
    mContext = context;
}

@Override
public void onSignalStrengthsChanged(SignalStrength signalStrength) {
    super.onSignalStrengthsChanged(signalStrength);
    Log.i(LOG_TAG, "onSignalStrengthsChanged: " + signalStrength);

    Intent i = new Intent("Signal_update");
    i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    i.putExtra("signals","signals updated");
    CustomPhoneStateListener.this.mContext.startActivity(i);
    //mContext.startActivity(i); also does not work
}

}

在最后一个命令中，它尝试将数据发送到MainActivity类，以便通过它的onReceive方法获取。

但这不起作用。我收到以下错误。

android.content.ActivityNotFoundException: No Activity found to handle Intent

将数据从上面的Listner类发送到MainActivity类的最佳方法是什么？

编辑 -

下面的课程应该接收来自上述意图的信息

package home.dan.signalstrengthatlocation;

import android.app.Activity;
import android.telephony.TelephonyManager;
import android.telephony.PhoneStateListener;

import android.Manifest;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private static final int NETWORKTYPE_WIFI = 0;
private static final int NETWORKTYPE_4G = 1;
private static final int NETWORKTYPE_2G = 2;
private static final int NETWORKTYPE_NONE = 3;

public TelephonyManager mTelephonyManager;
public PhoneStateListener mListener;

private Button start_btn,stop_btn;
private TextView textview;
private BroadcastReceiver broadcastReceiver;

private String coordinates;

public String getCoordinates() {
    return coordinates;
}

public void setCoordinates(String coordinates) {
    this.coordinates = coordinates;
}

private String signalStrength;

public String getSignalStrength() {
    return signalStrength;
}

public void setSignalStrength(String signalStrength) {
    this.signalStrength = signalStrength;
}

@Override
protected void onResume() {
    super.onResume();

    if(broadcastReceiver == null){
        broadcastReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                setCoordinates(intent.getExtras().get("coordinates").toString());
                updateScrollText();
            }
        };
    }
    registerReceiver(broadcastReceiver,new IntentFilter("location_update"));
}





private void updateScrollText(){
    textview.append("\n"+getCoordinates()+" "+getSignalStrength());
}

@Override
protected void onDestroy() {
    super.onDestroy();
    if(broadcastReceiver != null){
        unregisterReceiver(broadcastReceiver);
    }
}

GPS_Service gps;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mTelephonyManager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
    mTelephonyManager.listen(new CustomPhoneStateListener(this), PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);

    start_btn   = (Button) findViewById(R.id.button1);
    stop_btn    = (Button) findViewById(R.id.button2);
    textview    = (TextView) findViewById(R.id.textview);

    if(!runtime_permissions()){
        enable_buttons();
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == Activity.RESULT_OK) {
        // TODO Extract the data returned from the child Activity.
        setSignalStrength(data.getStringExtra("signals"));
        updateScrollText();
    }

}

private void enable_buttons(){

    start_btn.setEnabled(true);
    stop_btn.setEnabled(false);

    start_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent i = new Intent(getApplicationContext(),GPS_Service.class);
            startService(i);

            if(!stop_btn.isEnabled()){
                start_btn.setEnabled(false);
                stop_btn.setEnabled(true);
            }
        }
    });



    stop_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent i = new Intent(getApplicationContext(),GPS_Service.class);
            stopService(i);

            if(!start_btn.isEnabled()){
                start_btn.setEnabled(true);
                stop_btn.setEnabled(false);
            }
        }
    });
}



private boolean runtime_permissions(){
    if(Build.VERSION.SDK_INT >= 23
            &&
            ContextCompat.checkSelfPermission(this,
                    Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
            &&
            ContextCompat.checkSelfPermission(this,
                    Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
            &&
            ContextCompat.checkSelfPermission(this,
                    Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION,
                                 Manifest.permission.ACCESS_COARSE_LOCATION,
                                 Manifest.permission.READ_PHONE_STATE},
                    100);
            return true;
    }
    return false;
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(requestCode == 100){
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
            enable_buttons();
        }else{
            runtime_permissions();
        }

    }
}

}

Answer 1

在MainActivity的onResume（）中，添加以下内容

IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("location_update");
intentFilter.addAction("signal_update);

registerReceiver(broadcastReceiver, intentFilter);

然后在CustomPhoneStateListener中使用sendBroadcast而不是startActivity。

Intent i = new Intent("signal_update");
i.putExtra("signals","signals updated");    
CustomPhoneStateListener.this.mContext.sendBroadcast(i);

您将在此处同时收到信号和位置更新：

public void onReceive(Context context, Intent intent) {
    if("signal_update".equals(intent.getAction())) {
        //update UI for signal update
    } else if ("location_update".equals(intent.getAction())) {
        // update UI for location update
    }
}

如何从Android中的CustomListener发送Intent

1 个答案: