Question

我正在尝试将意图信息从活动传递到服务但它不起作用。

在startService（）之前，我向intent添加额外内容。执行startService（）时，服务尝试获取额外内容但指针为空

这是我的代码：

public class MainActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
    final ToggleButton btnPlayStop = (ToggleButton) findViewById(R.id.btnPlayStop);
    btnPlayStop.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            Intent intent = new Intent(getBaseContext(), MyService.class);
            intent.putExtra("song", "umake");
            /*
                Debugger displays:
                    intent.mExtras.mMap.table[1]
                        key = "song"
                        value = "umake"
             */

            startService(intent);
        }
    }
}

public class MyService extends Service
{
public int onStartCommand(Intent intent, int flags, int startId)
{
    try
    {
        Toast.makeText(this, "MyService Started", Toast.LENGTH_LONG).show();

       // intent = getIntent();                 
       // --> compiler error: The method getIntent() is undefined for the type MyService

        Bundle extras = intent.getExtras();
        String song = extras.getString("song");  // nope

        song = intent.getStringExtra("song");  // nope
        Bundle bundle = intent.getBundleExtra("song");  // nope
        song = bundle.getString("song");  // nope

        /*
            Neither of the above works since the map in extras is null
            Debugger displays:
                intent.mExtras.mMap == null

            whereas before startService is was filled all right
         */
    }...

好像数据在startService期间“丢失”了。怎么解决这个？

谢谢

克里斯

Answer 1

在服务中试用这些代码

 String song=intent.getStringExtra("song");

Answer 2

这是因为你没有在捆绑中获得字符串值。尝试添加extras.getString（＆＃34;＆＃34;）

Answer 3

如何使用

String song = intent.getBundleExtra("song");

Answer 4

在您声明意图的 MainActivity.java 中，尝试

 Intent intent = new Intent(v.getContext(), MyService.class);

然后在 MyService.java 中接收您的意图，尝试

public int onStartCommand(Intent intent, int flags, int startId)
{
  try
  {
      Toast.makeText(this, "MyService Started", Toast.LENGTH_LONG).show();
      intent = getIntent(); //Here You Want to make sure you are actually getting values from the previous activity
      Bundle extras = intent.getExtras();
    /*
        Debugger displays:
            intent.mExtras.mMap == null
     */
}

我认为你没有正确地表达你的意图，这就是为什么它一直给你这个错误

将intent从Activity转移到Service失败

4 个答案: