Android Service Intent must be explicit的解決方法

今天在學習Android的Service組件的時候，在AndroidMainfest.xml中定義了

       <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中用如下代碼綁定service：

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

   這時候會報錯：

        IllegalArgumentException: Service Intent must be explicit

        經過查找相關資料，發現是因為Android5.0中service的intent一定要顯性聲明，當這樣綁定的時候不會報錯。

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上看到一個解決方法，可以將隱性調用變成顯性調用。先定義一個函數：

/***
     * 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;
    }

然后調用

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);

這樣也可以解決問題。