Question

我用kotlin写一个扩展方法

    -(void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void(^)(UIBackgroundFetchResult))completionHandler
{    
    if( SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO( @"10.0" ) )
    {
        NSLog( @"iOS version >= 10. Let NotificationCenter handle this one." );
        return;
    }
    NSLog( @"HANDLE PUSH, didReceiveRemoteNotification: %@", userInfo );

    if( [UIApplication sharedApplication].applicationState == UIApplicationStateInactive )
    {
        NSLog( @"INACTIVE" );
        completionHandler( UIBackgroundFetchResultNewData );
    }
    else if( [UIApplication sharedApplication].applicationState == UIApplicationStateBackground )
    {
        NSLog( @"BACKGROUND" );
        completionHandler( UIBackgroundFetchResultNewData );
    }  
    else  
    {  
        NSLog( @"FOREGROUND" );  
        completionHandler( UIBackgroundFetchResultNewData );  
    }  
}

- (void)userNotificationCenter:(UNUserNotificationCenter *)center
       willPresentNotification:(UNNotification *)notification
         withCompletionHandler:(void (^)(UNNotificationPresentationOptions options))completionHandler
{
    NSLog( @"Handle push from foreground" );
}

- (void)userNotificationCenter:(UNUserNotificationCenter *)center
didReceiveNotificationResponse:(UNNotificationResponse *)response
         withCompletionHandler:(void (^)())completionHandler
{
    NSLog( @"Handle push from background or closed" );
}

当我在package com.zhongan.zachat.extention import android.content.Context import android.widget.Toast /** * Created by Carl on 2016/12/1. * * */ fun Context.toastLong(msg:String) = Toast.makeText(this,msg,Toast.LENGTH_LONG).show() fun Context.toastshort(msg:String) = Toast.makeText(this,msg,Toast.LENGTH_SHORT).show()致电kotlin activity时没问题。
但在toastLong("test") IDE中说无法找到这种方法。

如何在java代码中调用kotlin扩展方法

Answer 1

基于this page

扩展实际上并不会修改它们扩展的类。

应该注意，不能从对象类调用扩展，因为原始类仍然是相同的。（因此Context不会神奇地拥有额外的函数，因此无法使用Java中的Context.functionName调用它）

您应该可以使用以下方式调用它：

com.zhongan.zachat.extention.<fileName>.toastLong(ctx,"string")

e.g。如果文件名为kotlinFile.kt：

com.zhongan.zachat.extention.KotlinFileKt.toastLong(ctx,"string")

Java如何调用kotlin扩展方法

1 个答案: