Service Intent must be explicit的解决方法

        今天在学习android的Service组件的时候，在AndroidMainfest.xml中定义了

<service
            android:name=".BindService"
            android:enabled="true"
            android:exported="true" >
            <intent-filter>
                <action android:name="com.example.user.firstapp.FIRST_SERVICE"/>
            </intent-filter>
        </service>

        然后在activity中用如下代码绑定service：

final Intent intent = new Intent();
intent.setAction("com.example.user.firstapp.FIRST_SERVICE");
bindService(intent,coon,Service.BIND_AUTO_CREATE);

        这时候会报错：

        IllegalArgumentException: Service Intent must be explicit

        经过查找相关资料，发现是因为Android5.0中service的intent一定要显性声明，当这样绑定的时候不会报错。

final Intent intent = new Intent(this,BindService.class);
bindService(intent,coon,Service.BIND_AUTO_CREATE)

在http://blog.android-develop.com/2014/10/android-l-api-21-javalangillegalargumen.html上看到一个解决方法，可以将隐性调用变成显性调用。先定义一个函数：

/***
     * Android L (lollipop, API 21) introduced a new problem when trying to invoke implicit intent,
     * "java.lang.IllegalArgumentException: Service Intent must be explicit"
     *
     * If you are using an implicit intent, and know only 1 target would answer this intent,
     * This method will help you turn the implicit intent into the explicit form.
     *
     * Inspired from SO answer: http://stackoverflow.com/a/26318757/1446466
     * @param context
     * @param implicitIntent - The original implicit intent
     * @return Explicit Intent created from the implicit original intent
     */
    public static Intent createExplicitFromImplicitIntent(Context context, Intent implicitIntent) {
        // Retrieve all services that can match the given intent
        PackageManager pm = context.getPackageManager();
        List<ResolveInfo> resolveInfo = pm.queryIntentServices(implicitIntent, 0);
 
        // Make sure only one match was found
        if (resolveInfo == null || resolveInfo.size() != 1) {
            return null;
        }
 
        // Get component info and create ComponentName
        ResolveInfo serviceInfo = resolveInfo.get(0);
        String packageName = serviceInfo.serviceInfo.packageName;
        String className = serviceInfo.serviceInfo.name;
        ComponentName component = new ComponentName(packageName, className);
 
        // Create a new intent. Use the old one for extras and such reuse
        Intent explicitIntent = new Intent(implicitIntent);
 
        // Set the component to be explicit
        explicitIntent.setComponent(component);
 
        return explicitIntent;
    }

然后调用

final Intent intent = new Intent();
intent.setAction("com.example.user.firstapp.FIRST_SERVICE");
final Intent eintent = new Intent(createExplicitFromImplicitIntent(this,intent));
bindService(eintent,conn, Service.BIND_AUTO_CREATE);

这样也可以解决问题。

PS：调用本地service是这样的，不知道其他程序隐性调用service时会不会也有类似的问题，待续。

另一种简单点的解决方法可参考另一篇日志。