来自manifest的Android元数据返回null

Question

我有一个类,有一个方法试图从清单中检索元数据.一切正常,除了我从应用程序信息创建的包返回空值

这是代码:

    private int getCurrentVersion(){
    int currVersion = 0;

    try {
        ApplicationInfo app = context.getPackageManager().getApplicationInfo(context.getPackageName(),PackageManager.GET_META_DATA);
        Bundle bundle = app.metaData;

        for (String key: bundle.keySet())
        {
          Log.d ("TEST", key + " is a key in the bundle");
        }

        Log.d("TEST","google: "+bundle.getString("com.google.android.gms.version"));
        Log.d("TEST","version: "+bundle.getString("dbVersion"));

        //currVersion = Integer.valueOf(bundle.getString("dbVersion"));
        currVersion = 1;
    } catch (NameNotFoundException e) {
        e.printStackTrace();
    } catch (NullPointerException e) {
        e.printStackTrace();         
    }

    return currVersion;
}


03-05 18:53:23.818: D/TEST(31400): com.google.android.gms.version is a key in the bundle
03-05 18:53:23.818: D/TEST(31400): dbVersion is a key in the bundle
03-05 18:53:23.828: D/TEST(31400): google: null
03-05 18:53:23.828: D/TEST(31400): version: null

正如您所看到的,我正在使用一些日志来查看捆绑包是否为空,但不是.

Answer 1

在某些情况下,你需要使用getInt()方法:

bundle.getInt("com.google.android.gms.version"));

因为这个元数据的值被定义为整数.

Log.d("TEST","google: "+bundle.getInt("com.google.android.gms.version"));

例如,如果元数据中定义的值是String:

     <meta-data 
         android:name="com.elenasys.a"
         android:value="abcXJ434" />  

使用:

   bundle.getString("com.elenasys.a"));   

如果值是整数:

   <meta-data 
         android:name="com.elenasys.b"
         android:value="1234" />  

使用 getInt()

 bundle.getInt("com.elenasys.b"));