android - 隐式意图 - java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法

Question

java.lang.NullPointerException: Attempt to invoke virtual method 'android.app.ActivityThread$ApplicationThread android.app.ActivityThread.getApplicationThread()' on a null object reference

当我尝试以隐式意图打开链接时出现此错误。我正在通过ImageView 上的适配器类调用活动openUrl(url: String)。Settings.ktSettingsAdapter.ktsetOnClcikListener

SettingsAdapter.kt类

private val settings = Settings()
youtubeLink.setOnClickListener {
            val url = "https://www.youtube.com/watch?v=i-0FtaAadeM"
            settings.openUrl(url)
        }

Settings.kt活动

fun openUrl(url: String) {
        val intent = Intent(Intent.ACTION_VIEW,Uri.parse(url))
        startActivity(intent)
    }

Answer 1

您正在遵循错误的方法。您可以通过两种方式做到这一点。

1. 您可以直接在适配器中调用代码片段

     youtubeLink.setOnClickListener {
        val url = "https://www.youtube.com/watch?v=i-0FtaAadeM"
        val intent = Intent(Intent.ACTION_VIEW,Uri.parse(url))
        context.startActivity(intent)
    }
   

2. 您可以在适配器中创建回调并在您的活动中实现

    private OnSettingsListener listener;
   
   void setOnSttingListener(OnSettingsListener listener){
     this.listener = listener;
   }
   
   youtubeLink.setOnClickListener {
        val url = "https://www.youtube.com/watch?v=i-0FtaAadeM"
        listener.onSettingClick(url);
    }
   
   interface OnSettingsListener {  
     void onSettingClick(String url);     
   }
   

   在您的活动中，实现此侦听器

    Settings implements SettingsAdapter.OnSettingsListener {
   
    @Override
    public void onSettingClick(String url) {
     openUrl(url)
   }
   }