java - 找不到符号方法startActivity(android.content.Intent)

Question

我是制作 Android 应用程序的初学者。我制作了一个显示我的网页的 WebView 。我的网页包含我希望在邮件和拨号等外部应用程序中打开的联系人按钮。因此我得到了一些帮助并得到了这样的代码

import android.app.Activity;
import android.content.Intent;
import android.net.MailTo;
import android.net.Uri;
import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class ourViewClient extends WebViewClient {

@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
    try{
        System.out.println("url called:::" + url);
        if (url.startsWith("tel:")) {
            Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse(url));
            startActivity(intent);
        }  else if (url.startsWith("http:")
                || url.startsWith("https:")) {

            Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
            startActivity(intent);

        }  else if (url.startsWith("mailto:")) {

            MailTo mt=MailTo.parse(url);

            send_email(mt.getTo());

        }
        else {
            return false;
        }
    }catch(Exception e){
        e.printStackTrace();
    }

    return true;
}



public void send_email(String email_add) {
    System.out.println("Email address::::" + email_add);

    final Intent emailIntent = new Intent(
            android.content.Intent.ACTION_SEND);
    emailIntent.setType("plain/text");
    emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL,
            new String[] { email_add });
    emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "");
    emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, "");
    startActivity(
            Intent.createChooser(emailIntent, "Send mail..."));

}

}

但是后来我收到了这个错误“找不到符号方法startActivity(android.content.Intent)”startactivity 有什么问题吗？

Answer 1

WebViewClient 没有上下文，因此您无法直接启动 Activity

Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
view.getContext().startActivity(intent);

---

或者，使用其构造函数将上下文传递给 webViewClient

public class ourViewClient extends WebViewClient {

Context context;


public ourViewClient (Context c){
    this.context = c;
}


@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
    try{
        System.out.println("url called:::" + url);
        if (url.startsWith("tel:")) {
            Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse(url));
            context.startActivity(intent);
        }  else if (url.startsWith("http:")
                || url.startsWith("https:")) {

            Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
            context.startActivity(intent);

        }  else if (url.startsWith("mailto:")) {

            MailTo mt=MailTo.parse(url);

            send_email(mt.getTo());

        }
        else {
            return false;
        }
    }catch(Exception e){
        e.printStackTrace();
    }


    return true;
}