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);
}
});
}
}
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);
完整的参考下一个按钮和进度条:放回和下一个按钮在webview
如果你想在点击手机的后退按钮时回到后退页，使用这个:
@Override
public void onBackPressed() {
if (webView.canGoBack()) {
webView.goBack();
} else {
super.onBackPressed();
}
}
你也可以像这样创建自定义后退按钮:
btnback.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (wv.canGoBack()) {
wv.goBack();
}
}
});
FoamyGuy的第一个答案是正确的，但我有一些补充;低声誉不允许我发表评论。如果由于某些原因您的页面加载失败，请确保您设置了一个标记来记录失败，然后在onBackPressed覆盖上检查它。否则，你的canGoBack()将永远执行而不前往实际的back活动，如果它在那里:
//flag with class wide access
public boolean ploadFailFlag = false;
//your error handling override
@Override
public void onReceivedError(WebView view, WebResourceRequest req, WebResourceError rerr) {
onReceivedError(view, rerr.getErrorCode(), rerr.getDescription().toString(), req.getUrl().toString());
ploadFailFlag = true; //note this change
.....
.....
}
//finally to the answer to this question:
@Override
public void onBackPressed() {
if(checkinWebView.canGoBack()){
//if page load fails, go back for web view will not go back - no page to go to - yet overriding the super
if(ploadFailFlag){
super.onBackPressed();
}else {
checkinWebView.goBack();
}
}else {
Toast.makeText(getBaseContext(), "super:", Toast.LENGTH_LONG).show();
super.onBackPressed();
}
}
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
}
