我有一些蓝牙示例代码在mainactivity中运行良好。然后，我将其移至新的活动，并创建了一个按钮以运行页面。我可以进入活动并单击按钮来激活我的蓝牙功能，但是到线路时它会崩溃：if (!myBluetoothAdapter.isEnabled())里面Set_Up_Connection.java但是行myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();和if(myBluetoothAdapter == null)工作正常。
主要活动
package com.evenfurtherbeyond.bluetoothsendrecieve;
//imports are created automatically when requested by functions
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.util.Set;
public class MainActivity extends Activity {
//define the settings button variable
private Button settingsBtn;
public BluetoothAdapter myBluetoothAdapter;
protected Set<BluetoothDevice> pairedDevices;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// take an instance of BluetoothAdapter - Bluetooth radio
myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
//on the apps creation set the content view to the activity_my.xml layout.
setContentView(R.layout.activity_main);
//define settings button
settingsBtn = (Button) findViewById(R.id.settingsbt);
//set up an on click listener
settingsBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//define an intent to start a new activity
//for starting Activity because you will need to pass Application or component
// context as first parameter to Intent Constructor when you are creating
// intent for a specific component of application.
Intent settingsIntent = new Intent(v.getContext(), Set_Up_Connection.class);
//start the intent.
startActivity(settingsIntent);
}
});
}
}建立连接
package com.evenfurtherbeyond.bluetoothsendrecieve;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Set;
public class Set_Up_Connection extends Activity {
private Button onBtn;
private TextView text;
private BluetoothAdapter myBluetoothAdapter;
protected Set<BluetoothDevice> pairedDevices;
//sets the paired device object as a bluetooth device object container.
protected ListView myListView;
private ArrayAdapter<String> BTArrayAdapter;
//containers for variables, many of the variables relate to the buttons defined in the activity_my.xml.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.set_up_bt);
//on the apps creation set the content view to the activity_my.xml layout.
// take an instance of BluetoothAdapter - Bluetooth radio
myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
//get the default adater string/id and place it in myBluetoothAdapter
if(myBluetoothAdapter == null) {
//if an adapter doesn't exist
onBtn.setEnabled(false);
text.setText("Status: not supported");
Toast.makeText(getApplicationContext(), "Your device does not support Bluetooth",
Toast.LENGTH_LONG).show();
//display a long notification that the device doesn't have bluetooth.
} else {
text = (TextView) findViewById(R.id.text);
//make the text variable equal the type 'TextView' of the 'R.id.text' id value.
//text =/= 'R.id.text but rather text = the address of 'R.id.text'
//whatever 'R.id.text' equals, 'text' now equals.
onBtn = (Button)findViewById(R.id.turnOn);
//onBtn = type 'Button' address 'R.id.turnOn'
onBtn.setOnClickListener(new View.OnClickListener() {
//set an onclick listener to do something.
@Override
public void onClick(View v) {
on(v);
}
//when the 'turnon' button is pressed run the method 'on' and pass it the current view 'v'
});
myListView = (ListView)findViewById(R.id.listView1);
// create the arrayAdapter that contains the BTDevices, and set it to the ListView
BTArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1);
//create an array adapter object of type String using 'this' context and the 'simple list item 1' layout.
myListView.setAdapter(BTArrayAdapter);
//set the ListView to the Array Adapter creating a list of the 'BTArrayAdapter' array
}
}
public void on(View view) {
if (!myBluetoothAdapter.isEnabled()) {
//isEnabled checks if the bluetooth adapter is enabled.
Intent turnOnIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
//start an intent to show a system activity that allows the user to turn on Bluetooth.
}
else{
Toast.makeText(getApplicationContext(),"Bluetooth is already on",
Toast.LENGTH_LONG).show();
//else display a notification that BT is already on.
}
}
}AndroidManifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.evenfurtherbeyond.bluetoothsendrecieve" >
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Set_Up_Connection"
android:label="Set Up Bluetooth"
android:parentActivityName=".MainActivity">
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.evenfurtherbeyond.MainActivity"/>
</activity>
</application>
</manifest>
日志猫
11-17 19:38:09.585 8472-8472/com.evenfurtherbeyond.bluetoothsendrecieve E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.SecurityException: Need BLUETOOTH_ADMIN permission: Neither user 10084 nor current process has android.permission.BLUETOOTH_ADMIN.
at android.os.Parcel.readException(Parcel.java:1425)
at android.os.Parcel.readException(Parcel.java:1379)
at android.bluetooth.IBluetooth$Stub$Proxy.disable(IBluetooth.java:1048)
at android.bluetooth.BluetoothAdapter.disable(BluetoothAdapter.java:527)
at com.evenfurtherbeyond.bluetoothsendrecieve.Set_Up_Connection.off(Set_Up_Connection.java:211)
at com.evenfurtherbeyond.bluetoothsendrecieve.Set_Up_Connection$2.onClick(Set_Up_Connection.java:88)
at android.view.View.performClick(View.java:4209)
at android.view.View$PerformClick.run(View.java:17431)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:5297)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
最佳答案
有人请求日志猫后，我看到问题已记录。
使用以下命令更新清单以包括Bluetooth和Bluetooth_Admin权限后：
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
来自教程http://developer.android.com/guide/topics/security/permissions.html
该应用程序运行顺利。