Android开发：TelephonyManager.setRadioPower无法解析问题求助

Hey there! Let's break down why you're hitting that error and get your feature working properly.

Why the setRadioPower Error Happens #

The setRadioPower() method you're trying to use is a hidden system API—it's not available to regular third-party apps. Even if you could resolve the method call, Android restricts access to this functionality (especially from Android 10/API 29 onwards) to system-level apps only. On top of that, your code uses an undefined disabled value, which adds to the error.

Correct Approach to Toggle Cellular Radio #

Instead of relying on the hidden API, we'll use official, supported methods based on the Android version. Here's how to implement your desired logic:

Step 1: Update Permissions in AndroidManifest.xml #

Add the necessary permissions to modify network state and access phone info:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
          package="com.example.vk9621.radiocall">

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

    <application 
        android:allowBackup="true" 
        android:icon="@mipmap/ic_launcher" 
        android:label="@string/app_name" 
        android:roundIcon="@mipmap/ic_launcher_round" 
        android:supportsRtl="true" 
        android:theme="@style/AppTheme">
        
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

Step 2: Modified MainActivity.java Code #

This code handles dynamic permissions, call state listening, and uses version-appropriate methods to toggle cellular data:

import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

public class MainActivity extends AppCompatActivity {
    private TelephonyManager telephonyManager;

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

        // Check for READ_PHONE_STATE permission first
        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.READ_PHONE_STATE}, 100);
            return;
        }

        telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);

        PhoneStateListener callStateListener = new PhoneStateListener() {
            @Override
            public void onCallStateChanged(int state, String incomingNumber) {
                super.onCallStateChanged(state, incomingNumber);
                switch (state) {
                    case TelephonyManager.CALL_STATE_RINGING:
                        Toast.makeText(getApplicationContext(), "Phone Is Ringing", Toast.LENGTH_LONG).show();
                        break;
                    case TelephonyManager.CALL_STATE_OFFHOOK:
                        Toast.makeText(getApplicationContext(), "Phone is Currently in A call", Toast.LENGTH_LONG).show();
                        break;
                    case TelephonyManager.CALL_STATE_IDLE:
                        // Disable cellular radio when device is idle (not ringing/calling)
                        toggleCellularRadio(false);
                        break;
                }
            }
        };

        telephonyManager.listen(callStateListener, PhoneStateListener.LISTEN_CALL_STATE);
    }

    private void toggleCellularRadio(boolean enable) {
        try {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
                // For Android 12+ (API 31+), use official TelephonyManager method
                if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.CHANGE_NETWORK_STATE) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.CHANGE_NETWORK_STATE}, 101);
                    return;
                }
                // Use default subscription ID (adjust for multi-SIM devices if needed)
                int defaultSubId = telephonyManager.getSubscriptionId();
                telephonyManager.setCellularDataEnabled(defaultSubId, enable);
            } else {
                // For older Android versions, modify system settings
                if (!Settings.System.canWrite(this)) {
                    // Request WRITE_SETTINGS permission via system settings
                    Intent settingsIntent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS);
                    startActivity(settingsIntent);
                    return;
                }
                Settings.Secure.putInt(getContentResolver(), Settings.Secure.MOBILE_DATA, enable ? 1 : 0);
            }
            Toast.makeText(this, enable ? "Cellular radio turned ON" : "Cellular radio turned OFF", Toast.LENGTH_SHORT).show();
        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(this, "Failed to toggle cellular radio", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case 100:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    // Re-initialize after permission is granted
                    recreate();
                } else {
                    Toast.makeText(this, "READ_PHONE_STATE permission is required to detect calls", Toast.LENGTH_SHORT).show();
                }
                break;
            case 101:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    toggleCellularRadio(false);
                } else {
                    Toast.makeText(this, "CHANGE_NETWORK_STATE permission is required to toggle radio", Toast.LENGTH_SHORT).show();
                }
                break;
        }
    }
}

Key Notes to Keep in Mind #

• Dynamic Permissions: Android 6.0+ requires runtime permissions for READ_PHONE_STATE and CHANGE_NETWORK_STATE. The WRITE_SETTINGS permission can't be requested via standard dialogs—users have to enable it manually through system settings.
• Multi-SIM Devices: The code uses the default SIM subscription. If you need to handle multiple SIMs, you'll need to fetch all subscription IDs and toggle each one individually.
• Manufacturer Restrictions: Some Android OEMs may restrict third-party apps from modifying cellular data settings. Adding error handling ensures your app doesn't crash if this happens.

内容的提问来源于stack exchange，提问作者vinny kinger