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

当我尝试以隐含意图打开 link 时出现此错误。我通过 ImageView 上的 setOnClcikListener 从它的适配器 class SettingsAdapter.kt 在 Settings.kt activity 中调用 openUrl(url: String)。

SettingsAdapter.kt Class

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

Settings.kt Activity

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

Answer 1

您采用了错误的方法。您可以通过两种方式执行此操作。

您可以直接在您的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)
 }

您可以在适配器中创建回调并在 activity

中实施

 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 activity 中，实施此侦听器

 Settings implements SettingsAdapter.OnSettingsListener {

 @Override
 public void onSettingClick(String url) {
  openUrl(url)
}
}

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

Implicit Intent - java.lang.NullPointerException: Attempt to invoke virtual method on a null object reference

android

kotlin

android-implicit-intent