package com.imooc.android_webview;

import android.app.Activity;

import android.app.ActionBar;

import android.app.Fragment;

import android.app.ProgressDialog;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.util.Log;

import android.view.KeyEvent;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.webkit.WebChromeClient;

import android.webkit.WebSettings;

import android.webkit.WebView;

import android.webkit.WebViewClient;

import android.widget.Toast;

import android.os.Build;

public class MainActivity extends Activity {

	private String url = "http://2014.qq.com/";

	private WebView webView;

    private ProgressDialog dialog;

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.web);

		// Uri uri = Uri.parse(url); //url为你要链接的地址

		// Intent intent =new Intent(Intent.ACTION_VIEW, uri);

		// startActivity(intent);

		init();

	}

	private void init() {

		// TODO Auto-generated method stub

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

		// 1 WebView加载本地资源

		// webView.loadUrl("file:///android_asset/example.html");

		// 2 WebView加载web资源

		webView.loadUrl(url);

		// 3 覆盖WebView默认通过第三方或者是系统浏览器打开网页的行为，使得网页可以在WebVIew中打开

		webView.setWebViewClient(new WebViewClient(){

			@Override

			public boolean shouldOverrideUrlLoading(WebView view, String url) {

				// TODO Auto-generated method stub

				//返回值是true的时候控制网页在WebView中去打开，如果为false调用系统浏览器或第三方浏览器去打开

				view.loadUrl(url);

				return true;

			}

			//WebViewClient帮助WebView去处理一些页面控制和请求通知

		});

		//启用支持JavaScript

		WebSettings settings = webView.getSettings();

		settings.setJavaScriptEnabled(true);

		//WebView加载页面优先使用缓存加载

		settings.setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);

		webView.setWebChromeClient(new WebChromeClient(){

			@Override

			public void onProgressChanged(WebView view, int newProgress) {

				// TODO Auto-generated method stub

                //newProgress 1-100之间的整数

				if(newProgress==100)

				{

					//网页加载完毕，关闭ProgressDialog

					closeDialog();

				}

				else

				{

					//网页正在加载,打开ProgressDialog

					openDialog(newProgress);

				}

			}

			private void closeDialog() {

				// TODO Auto-generated method stub

                  if(dialog!=null&&dialog.isShowing())

                  {

                	     dialog.dismiss();

                	     dialog=null;

                  }

			}

			private void openDialog(int newProgress) {

				// TODO Auto-generated method stub

				if(dialog==null)

				{

					dialog=new ProgressDialog(MainActivity.this);

					dialog.setTitle("正在加载");

					dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

					dialog.setProgress(newProgress);

					dialog.show();

				}

				else

				{

					dialog.setProgress(newProgress);

				}

			}

		});

	}

	//改写物理按键——返回的逻辑

	@Override

	public boolean onKeyDown(int keyCode, KeyEvent event) {

		// TODO Auto-generated method stub

		if(keyCode==KeyEvent.KEYCODE_BACK)

		{

			//Toast.makeText(this, webView.getUrl(), Toast.LENGTH_SHORT).show();

			if(webView.canGoBack())

			{

				webView.goBack();//返回上一页面

				return true;

			}

			else

			{

				System.exit(0);//退出程序

			}

		}

		return super.onKeyDown(keyCode, event);

	}

}