安卓：试图启动BluetoothSettings活动强制关闭并抛出NullPointerException异常

问题描述

我想打开的标准窗口的蓝牙设置（使用设备名，可发现性等等）。

I'm trying to bring up the standard window for Bluetooth Settings(with Device name, Discoverability etc).

然而，随着 startActivity一般方法（意向）结尾NullPointerException异常指向 BluetoothSettings.java的onCreate：135

However, general approach with startActivity(intent) ends with NullPointerException pointing toBluetoothSettings.java onCreate:135.

检查了Android code，我发现，在第135行，他们得到的意图的一些附加功能。所以我prepare相同的演员（名字我已经在Android的核心BluetoothDevicePicker界面中找到），并发出了它 - 与NullPointerException异常同样的效果

Checking with the Android code, I've found that at line 135 they get some extras from the intent. So I prepare the same extras (names I've found in android core BluetoothDevicePicker interface) and issue it -- the same effect with NullPointerException.

可能是额外的过错名字我prepare？

Might be the wrongs names of the extras I prepare?

那么，有没有一种方法，我可以看到那些群众演员（地名尤其是）从意图系统本身提交，当我打开蓝牙设置手动像个用户？

So is there a way I can see those extras (with names especially) from the intent the system itself submits when I open Bluetooth Settings manually acting like a user?

非常感谢。

我的code是：

Intent settingsIntent = new Intent();
settingsIntent.setClassName("com.android.settings",      com.android.settings.bluetooth.BluetoothSettings");
settingsIntent.putExtra("android.bluetooth.devicepicker.extra.LAUNCH_PACKAGE", "mypackage.bttoggle");
settingsIntent.putExtra("android.bluetooth.devicepicker.extra.DEVICE_PICKER_LAUNCH_CLASS", "mypackage.bttoggle.BluetoothWidget");
PendingIntent settingsPendingIntent = PendingIntent.getActivity(context, 0, settingsIntent, 0);
views.setOnClickPendingIntent(R.id.btnSettings, settingsPendingIntent);

这是一个小部件，所以我需要使用PendingIntent。

It's a widget so I need to use PendingIntent.

这code得到下面的异常运行时：

This code get the following Exception at runtime:

ERROR / AndroidRuntime（4905）：未捕获的处理程序：螺纹主力退出因  未捕获的异常错误/ AndroidRuntime（4905）：  java.lang.RuntimeException的：无法启动的活动  ComponentInfo {com.android.settings / com.android.settings.bluetooth.BluetoothSettings}：  显示java.lang.NullPointerException错误/ AndroidRuntime（4905）：在  android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2596）  ERROR / AndroidRuntime（4905）：在  android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2621）  ERROR / AndroidRuntime（4905）：在  android.app.ActivityThread.access $ 2200（ActivityThread.java:126）  ERROR / AndroidRuntime（4905）：在  android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1932）  ERROR / AndroidRuntime（4905）：在  android.os.Handler.dispatchMessage（Handler.java:99）  ERROR / AndroidRuntime（4905）：在android.os.Looper.loop（Looper.java:123）  ERROR / AndroidRuntime（4905）：在  android.app.ActivityThread.main（ActivityThread.java:4595）  ERROR / AndroidRuntime（4905）：在  java.lang.reflect.Method.invokeNative（本机方法）  ERROR / AndroidRuntime（4905）：在  java.lang.reflect.Method.invoke（Method.java:521）  ERROR / AndroidRuntime（4905）：在  com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:860）  ERROR / AndroidRuntime（4905）：在  com.android.internal.os.ZygoteInit.main（ZygoteInit.java:618）  ERROR / AndroidRuntime（4905）：在dalvik.system.NativeStart.main（母语  法）ERROR / AndroidRuntime（4905）：产生的原因：  显示java.lang.NullPointerException错误/ AndroidRuntime（4905）：在  com.android.settings.bluetooth.BluetoothSettings.onCreate（BluetoothSettings.java:135）  ERROR / AndroidRuntime（4905）：在  android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1047）  ERROR / AndroidRuntime（4905）：在  android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2544）  ERROR / AndroidRuntime（4905）：11 ...更多

经过调查，我发现，在BluetoothSettings.java线135有：

After investigating, I found that at line 135 in BluetoothSettings.java there is:

public class BluetoothSettings extends PreferenceActivity
{

 ... 132 mNeedAuth = intent.getBooleanExtra(BluetoothDevicePicker.EXTRA_NEED_AUTH, false);
 133 mFilterType = intent.getIntExtra(BluetoothDevicePicker.EXTRA_FILTER_TYPE, 134 BluetoothDevicePicker.FILTER_TYPE_ALL);
 135 mLaunchPackage = intent.getStringExtra(BluetoothDevicePicker.EXTRA_LAUNCH_PACKAGE);
 136 mLaunchClass = intent.getStringExtra(BluetoothDevicePicker.EXTRA_LAUNCH_CLASS); ...

我看着BluetoothDevicePicker找群众演员的名字：

I looked into BluetoothDevicePicker to find the names of the extras:

public interface BluetoothDevicePicker { public static final String EXTRA_NEED_AUTH = "android.bluetooth.devicepicker.extra.NEED_AUTH";
public static final String EXTRA_FILTER_TYPE = "android.bluetooth.devicepicker.extra.FILTER_TYPE";
public static final String EXTRA_LAUNCH_PACKAGE = "android.bluetooth.devicepicker.extra.LAUNCH_PACKAGE";
public static final String EXTRA_LAUNCH_CLASS = "android.bluetooth.devicepicker.extra.DEVICE_PICKER_LAUNCH_CLASS";

所以，我用他们在我的code至prepare这些特殊的演员。

So, I use them in my code to prepare those particular extras.

推荐答案

这code对我的作品

    Intent intentBluetooth = new Intent();
    intentBluetooth.setAction(android.provider.Settings.ACTION_BLUETOOTH_SETTINGS);
    startActivity(intentBluetooth);

您需要测试它在手机上，otherways您将获得在模拟器上奇怪的错误（不支持蓝牙）。

You need to test it on the phone, otherways you will get strange errors on the emulator (Bluetooth not supported).

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