Question

6.01中的蓝牙似乎无法正常工作，具有以下代码和权限，根据更新+ appCompat for Kitkat 4.4.4。

没有返回任何结果，附近有几个可发现的设备。

任何人都有任何洞察力？我在Nexus 5上运行。

 <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

package bluetoothscanneractivity;

import android.app.Activity;
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.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;

public class BluetoothScannerActivity extends Activity {
    //private final BroadcastReceiver FoundReceiver = null;
    protected ArrayList<BluetoothDevice> foundDevices = new ArrayList<BluetoothDevice>();
    private ListView foundDevicesListView;
    private ArrayAdapter<BluetoothDevice> btArrayAdapter;

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bluetooth_scanner);
        final BluetoothAdapter myBlueToothAdapter = BluetoothAdapter.getDefaultAdapter();
        final Button scanb = (Button) findViewById(R.id.button);
        final ListView foundDevicesListView = (ListView) findViewById(R.id.listView1);

        btArrayAdapter = new ArrayAdapter<BluetoothDevice>(this,
                android.R.layout.simple_list_item_1, foundDevices);
        foundDevicesListView.setAdapter(btArrayAdapter);

        //Turn on Bluetooth
        if (myBlueToothAdapter == null)
            Toast.makeText(BluetoothScannerActivity.this, "Your device doesnot support Bluetooth", Toast.LENGTH_LONG).show();
        else if (!myBlueToothAdapter.isEnabled()) {
            Intent BtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(BtIntent, 0);
            Toast.makeText(BluetoothScannerActivity.this, "Turning on Bluetooth", Toast.LENGTH_LONG).show();
        }
        //scan
        scanb.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                btArrayAdapter.clear();
                myBlueToothAdapter.startDiscovery();
                Toast.makeText(BluetoothScannerActivity.this, "Scanning Devices", Toast.LENGTH_LONG).show();

            }
        });

        registerReceiver(FoundReceiver, new IntentFilter(BluetoothDevice.ACTION_FOUND));
        IntentFilter filter = new IntentFilter(
                BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        this.registerReceiver(FoundReceiver, filter);

    }

    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        unregisterReceiver(FoundReceiver);
    }

    private final BroadcastReceiver FoundReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {

            String action = intent.getAction();

            // When discovery finds a new device
            if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                // Get the BluetoothDevice object from the Intent
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                if (!foundDevices.contains(device)) {
                    foundDevices.add(device);
                    btArrayAdapter.notifyDataSetChanged();
                }
            }

            // When discovery cycle finished
            if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                if (foundDevices == null || foundDevices.isEmpty()) {
                    Toast.makeText(BluetoothScannerActivity.this, "No Devices", Toast.LENGTH_LONG).show();
                }
            }

        }
    };


}

Answer 1

您知道自Marshmallow以来，您需要为您的任务提供这些权限 -

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

自Marshmallow起，您必须以编程方式请求权限，即使您已在清单文件中声明了这些权限。

因此，您必须在startDiscovery()

之前申请位置许可

 ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 1001); //Any number

用户接受这些权限后，您可以startDiscovery()。如果他/她否认，你就无法发现这些设备。您可以在

中查看用户操作

onRequestPermissionsResult()回调。

Answer 2

使用添加的权限，将最小SDk版本更改为23 - 它可以使用以下内容：

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_create_blog);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    final EditText blogContentInput = (EditText) findViewById(R.id.blogContent);
    String blogContent = null;
    if (blogContentInput != null) {
        blogContent = String.valueOf(blogContentInput.getText());
    }else{
        Log.e("Blog Content","BLog content not instantiated");
    }

    BlogDbHelper dbHelper = new BlogDbHelper(getApplicationContext());
    final SQLiteDatabase db = dbHelper.getWritableDatabase();

    if (fab != null) {
        final String finalBlogContent = blogContent;
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.e("Content", "Blog content " + String.valueOf(blogContentInput.getText()));
                ContentValues values = new ContentValues();
                values.put(BlogContract.BlogEntry.BLOG_TITLE, "Practice_02");
                values.put(BlogContract.BlogEntry.BLOG_AUTHOR, "MarkoVlaic");
                values.put(BlogContract.BlogEntry.BLOG_CONTENT, String.valueOf(blogContentInput.getText()));
                long newRowId;
                newRowId = db.insertWithOnConflict(BlogContract.BlogEntry.TABLE_NAME, null, values,SQLiteDatabase.CONFLICT_REPLACE);
                blogContentInput.setText("");
                Snackbar.make(view, "You uploaded a blog", Snackbar.LENGTH_SHORT).show();
                /*Intent intent = new Intent(view.getContext(),MainActivity.class);
                startActivity(intent);*/
            }
        });
    }
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}

Answer 3

以下方法仅在SDK版本为＆gt;时执行。棒糖。当我尝试使用它没有这个限制我的应用程序崩溃。只需在使用.startDiscovery（）;

之前调用此方法

public void checkBTPermissions(){
    if(Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP){
            int permissionCheck = this.checkSelfPermission("Manifest.permission.ACCESS_FINE_LOCATION");
        permissionCheck += this.checkSelfPermission("Manifest.permission.ACCESS_COARSE_LOCATION");
        if (permissionCheck != 0) {

            this.requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 1001); //Any number
        }
    }else{
        Log.d(TAG, "checkBTPermissions: No need to check permissions. SDK version < LOLLIPOP.");
    }
}

Android Marshmallow 6.0.1蓝牙扫描无法返回结果

3 个答案: