我有一个应用程序,在其中我有一个WebView,我显示一些网站。它是有效的,点击网页中的链接会转到我的应用程序中的网站下一页。但当我点击手机的返回按钮时,它会直接带我进入我的应用程序。我想回到网站的上一页。我该怎么做呢?

下面是我正在使用的代码示例:

public class Webdisplay extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
        setContentView(R.layout.webdisplay);

        getWindow().setFeatureInt(Window.FEATURE_PROGRESS,
                Window.PROGRESS_VISIBILITY_ON); 

        Toast loadingmess = Toast.makeText(this,
                "Cargando El Diario de Hoy", Toast.LENGTH_SHORT);
        loadingmess.show();

        WebView myWebView;

        myWebView = (WebView) findViewById(R.id.webview);
        myWebView.getSettings().setJavaScriptEnabled(true);
        myWebView.loadUrl("http://www.elsalvador.com");
        myWebView.setWebViewClient(new WebViewClient());
        myWebView.setInitialScale(1);
        myWebView.getSettings().setBuiltInZoomControls(true);
        myWebView.getSettings().setUseWideViewPort(true);

        final Activity MyActivity = this;
        myWebView.setWebChromeClient(new WebChromeClient() 
        {
            public void onProgressChanged(WebView view, int progress)   
            {
                MyActivity.setTitle("Loading...");
                MyActivity.setProgress(progress * 100); 

                if(progress == 100)
                    MyActivity.setTitle(R.string.app_name);
            }
        });
    }
}

当前回答

这就是我的解。它也适用于Fragment。

webView.setOnKeyListener(new OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            WebView webView = (WebView) v;
            
            switch(keyCode) {
                case KeyEvent.KEYCODE_BACK:
                    if (webView.canGoBack()) {
                        webView.goBack();
                        return true;
                    }
                    break;
            }
        }
        
        return false;
    }
});

其他回答

我使用类似这样的东西在我的活动与WebViews:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_BACK:
                if (mWebView.canGoBack()) {
                    mWebView.goBack();
                } else {
                    finish();
                }
                return true;
        }

    }
    return super.onKeyDown(keyCode, event);
}

编辑:

为了让这段代码工作,你需要添加一个包含WebView的Activity字段:

private WebView mWebView;

在onCreate()方法中初始化它,您应该可以开始了。

mWebView = (WebView) findViewById(R.id.webView);

在onBackPressed中也应该检查聚焦

    @Override
    public void onBackPressed() {
        if (mWebview.isFocused() && mWebview.canGoBack()) {
            mWebview.goBack();       
        } else {
            super.onBackPressed();
            finish();
        }
    }

你可以尝试在一个片段webview:

private lateinit var webView: WebView

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    val root = inflater.inflate(R.layout.fragment_name, container, false)
    webView = root!!.findViewById(R.id.home_web_view)
    var url: String = "http://yoururl.com"
    webView.settings.javaScriptEnabled = true
    webView.webViewClient = WebViewClient()
    webView.loadUrl(url)
    webView.canGoBack()
    webView.setOnKeyListener{ v, keyCode, event ->
        if(keyCode == KeyEvent.KEYCODE_BACK && event.action == MotionEvent.ACTION_UP
            && webView.canGoBack()){
            webView.goBack()
            return@setOnKeyListener true
        }
        false
    }
    return root
}

这就是我的解。它也适用于Fragment。

webView.setOnKeyListener(new OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            WebView webView = (WebView) v;
            
            switch(keyCode) {
                case KeyEvent.KEYCODE_BACK:
                    if (webView.canGoBack()) {
                        webView.goBack();
                        return true;
                    }
                    break;
            }
        }
        
        return false;
    }
});

这是一个确认退出的代码:

@Override
    public void onBackPressed()
    {
        if(webView.canGoBack()){
            webView.goBack();
        }else{
            new AlertDialog.Builder(this)
            .setIcon(android.R.drawable.ic_dialog_alert)
            .setTitle("Exit!")
            .setMessage("Are you sure you want to close?")
            .setPositiveButton("Yes", new DialogInterface.OnClickListener()
            {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    finish();    
                }

            })
            .setNegativeButton("No", null)
            .show();    
        }   
    }