Question

我面对的是意想不到的令牌＆＃39; if-else条件中的错误使用＆amp;＆amp ;.没有任何其他错误可以看到。

import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar; 



public class Support extends AppCompatActivity {
    WebView webViewsupport;
    ProgressBar progressBar;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_support);

        webViewsupport = (WebView) findViewById(R.id.webView);
        progressBar = (ProgressBar)findViewById(R.id.progressBar2);

        webViewsupport.setWebViewClient(new myWebClient());
        webViewsupport.getSettings().setJavaScriptEnabled(true);
        webViewsupport.loadUrl("https://example.com");

    }
    public class myWebClient extends WebViewClient{
        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
            progressBar.setVisibility(View.GONE);
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
        }

        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return super.shouldOverrideUrlLoading(view, url);

        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if(keyCode==KeyEvent.KEYCODE_BACK) && webViewsupport.canGoBack(){
            webViewsupport.goBack();
        }
        return super.onKeyDown(keyCode, event);
    }
}

我无法理解为什么它在这里使用＆amp;＆amp;显示意外令牌。

input$Product

This is screenshot

Answer 1

你的代码中有一个拼写错误（你的结尾括号放在错误的位置）：

应该是：

if (keyCode == KeyEvent.KEYCODE_BACK) && webViewsupport.canGoBack(){
    webViewsupport.goBack();
}

因此而投票结束。

Answer 2

您需要在（）中添加整个条件：

public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode==KeyEvent.KEYCODE_BACK && webViewsupport.canGoBack()){
        webViewsupport.goBack();
    }
    return super.onKeyDown(keyCode, event);
}

＆安培;＆安培;显示为意外的令牌

2 个答案: