android - 如何从 View 中获取上下文？

Question

我已经实现了 WebViewClient覆盖 onReceivedError() 事件。这是我的代码:

@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
    InternetConnectivityChecker internetConnectivityChecker = new InternetConnectivityChecker(view.getContext().getApplicationContext());

    onReceivedErrorListener.onReceivedError();
    if (internetConnectivityChecker.isConnected() == false) {

    }
}

而且，这是我的 InternetConnectivityChecker 类:

package com.sama7.sama;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class InternetConnectivityChecker {
    private Context context;

    public InternetConnectivityChecker(Context context) {
        context = context;
    }

    public boolean isConnected() {
        NetworkInfo info = ((ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();

        if (info == null || !info.isConnected()) {
            return false;
        }

        return true;
    }

}

运行这段代码时，我得到一个异常，说:

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
                                                                at com.sama7.sama.InternetConnectivityChecker.isConnected(InternetConnectivityChecker.java:15)

为什么我的上下文是一个空对象？还有，我该如何解决这个问题？

Answer 1

替换:

context = context;

与:

this.context = context;

以便您设置字段的值。就目前而言，您正在为其自身设置一个方法参数。