WebView--(双击退出)

来源：互联网发布：余南平知乎编辑：程序博客网时间：2024/06/07 07:54
package com.rong.webView;import android.os.Bundle;import android.view.KeyEvent;import android.view.View;import android.webkit.JsResult;import android.webkit.WebChromeClient;import android.webkit.WebSettings;import android.webkit.WebView;import android.webkit.WebViewClient;import android.widget.Toast;import android.app.Activity;import android.app.AlertDialog;import android.app.AlertDialog.Builder;import android.content.DialogInterface;import android.graphics.Bitmap;public class MainActivity extends Activity {    private WebView webView;@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);      //得到WebView对象        webView = (WebView) findViewById(R.id.webView);        //得到WebSettings对象        WebSettings webSettings = webView.getSettings();        //设置是否支持js（javaScript）        webSettings.setJavaScriptEnabled(true);        //打开webView自带的缩放按钮        webSettings.setBuiltInZoomControls(true);        //设置webView加载页面的方法        setWebView();    }private long exetime;//设置返回键为回退@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {/*if(keyCode==KeyEvent.KEYCODE_BACK&&webView.canGoBack()){webView.goBack();return true;}*///再按一次就退出if(System.currentTimeMillis()-exetime>2000){Toast.makeText(MainActivity.this, "再按一次退出程序", Toast.LENGTH_SHORT).show();exetime=System.currentTimeMillis();}else{System.exit(0);}return true;}/** *  * @param v *  * 点击加载网页 */public void alert(View v){//访问assets文件夹中的html页面webView.loadUrl("file:///android_asset/jstest.html");//设置浏览器的处理类webView.setWebChromeClient(new WebChromeClient(){@Overridepublic boolean onJsAlert(WebView view, String url, String message,final JsResult result) {AlertDialog.Builder builder=new Builder(MainActivity.this);builder.setMessage(message);builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {result.confirm();}});builder.setNegativeButton("关闭", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {result.cancel();}});AlertDialog alertDialog = builder.create();alertDialog.show();return true;}});}    /**     * 设置webView加载页面的方法     *      */private void setWebView() {webView.setWebViewClient(new WebViewClient(){@Overridepublic boolean shouldOverrideUrlLoading(WebView view, String url) {//返回值为false时，当前url交给当前webView处理return super.shouldOverrideUrlLoading(view, url);}//开始加载页面@Overridepublic void onPageStarted(WebView view, String url, Bitmap favicon) {super.onPageStarted(view, url, favicon);}//完成页面加载@Overridepublic void onPageFinished(WebView view, String url) {super.onPageFinished(view, url);}});}}
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