Question

我在SD卡上打开了一个文件。当有人安装SD卡时，它会导致我的应用程序崩溃。我正在尝试注册ACTION_MEDIA_EJECT广播事件，我收到了，但似乎为时已晚。当我得到它的时候，它已经破坏了我的应用程序。在崩溃我的应用程序之前，有什么方法可以得到通知吗？

添加了一些非常简单的示例代码。当我这样做的时候，当我打开USB（MSC模式）时，它会导致服务崩溃。

测试.java

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    try {
        startService(new Intent(this, TestService.class));
        bindService(new Intent(this, TestService.class), serviceConnection, Context.BIND_AUTO_CREATE);
    } catch (Exception e) {

    }
}

protected TestService testService;
private ServiceConnection serviceConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        TestService.LocalBinder binder = (TestService.LocalBinder) service;
        testService = binder.getService();
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        testService = null;
    }

};

测试服务.java

@Override
public void onCreate() {
    super.onCreate();
    try {
        mFileOutputStream = new FileOutputStream("/sdcard/test2", true);
    } catch (Exception e) {
    }
}

@Override
public IBinder onBind(Intent intent) { return binder; }

public static class LocalBinder extends Binder {
    public static TestService getService() {
        return _this;
    }
}

Answer 1

它正在扼杀你的应用程序，因为在android中，当需要从设备上卸载SD卡（例如，将USB安装到连接的PC上）时，扼杀任何持有SD卡打开句柄的进程是一个有文件记录的设计决定。

仍然具有打开的文件句柄的文件系统无法完全卸载。在操作系统级别，除了终止授予文件句柄的进程之外，没有办法撤销文件句柄，所以这就是android最终要做的。

Answer 2

if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
    //access external file
}

在不了解更多抛出的异常的情况下，我只能推荐这些。

此外，环境类文档中的以下代码可能会有所帮助：

BroadcastReceiver mExternalStorageReceiver;
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;

void updateExternalStorageState() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        mExternalStorageAvailable = mExternalStorageWriteable = true;
    } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
        mExternalStorageAvailable = true;
        mExternalStorageWriteable = false;
    } else {
        mExternalStorageAvailable = mExternalStorageWriteable = false;
    }
    handleExternalStorageState(mExternalStorageAvailable,
            mExternalStorageWriteable);
}

void startWatchingExternalStorage() {
    mExternalStorageReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.i("test", "Storage: " + intent.getData());
            updateExternalStorageState();
        }
    };
    IntentFilter filter = new IntentFilter();
    filter.addAction(Intent.ACTION_MEDIA_MOUNTED);
    filter.addAction(Intent.ACTION_MEDIA_REMOVED);
    registerReceiver(mExternalStorageReceiver, filter);
    updateExternalStorageState();
}

void stopWatchingExternalStorage() {
    unregisterReceiver(mExternalStorageReceiver);
}

友情链接