android - 如何获取蓝牙的RSSI
问题描述
我正在尝试获取蓝牙连接的 RSSI。首先我想显示附近所有设备的 RSSI,所以我检查了互联网 - 获取了蓝牙类的一些信息并检查了一些示例。我尝试了很多东西,但没有成功。我处于无法理解问题到底出在哪里的阶段。
目标 SDK 为 29,最小 SDK 为 19。我正在 Android 10 (SDK 29) 上测试它
MainActivity.java
package com.example.myapplication;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.BlendMode;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.CompoundButton;
import android.widget.TextView;
import android.widget.ToggleButton;
import androidx.appcompat.app.AppCompatActivity;
import java.util.Set;
public class MainActivity extends AppCompatActivity implements CompoundButton.OnCheckedChangeListener {
BluetoothAdapter BA;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
registerReceiver(receiver, new IntentFilter(BluetoothDevice.ACTION_FOUND));
BA = BluetoothAdapter.getDefaultAdapter();
BA.startDiscovery();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.options, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.settings:
Intent intent = new Intent(this, SettingsActivity.class);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private final BroadcastReceiver receiver = new BroadcastReceiver(){
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if(BluetoothDevice.ACTION_FOUND.equals(action)) {
int rssi = intent.getShortExtra(BluetoothDevice.EXTRA_RSSI,Short.MIN_VALUE);
TextView rssi_msg = (TextView) findViewById(R.id.textView1);
rssi_msg.setText(rssi_msg.getText() + "" + rssi + "dBm\n");
}
}
};
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myapplication">
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<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=".Main2Activity"></activity>
<activity
android:name=".SettingsActivity"
android:label="@string/title_activity_settings"
android:parentActivityName=".MainActivity" />
<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>
解决方案
I found a "work around answer" but still can't do it properly. So the things that helped me and now it is working are: I made the targetSdkVersion to 26 (it was 29 before), minSdkVersion is still 19 (like before) and compileSdkVersion is still 29 (like before). This was in the gradle. And after I changed the target SDK I added this in my onCreate() method on the MainActivity
if (ActivityCompat.checkSelfPermission((Activity)this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions((Activity)this, new String[]{
android.Manifest.permission.ACCESS_COARSE_LOCATION
}, 10);
}
and now it is working on android 10, but I still can't do it for target SDK 29
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