WebApp基础01-设置读取assets目录下文件

<WebView 
         android:id="@+id/webview"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
        />

package com.example.webview;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.view.KeyEvent;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class MainActivity extends Activity {

    private WebView webView;
    private String url = "http://www.baidu.com";
    private ProgressDialog progressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initWebView();
    }

    private void initWebView() {
        webView = (WebView) findViewById(R.id.webview);// 获取控件
        webView.loadUrl(url);// 载入指定url（系统自带浏览器，若想用自身webview需要重写方法,提供client）
        WebSettings webSettings = webView.getSettings();// 获取配置信息
        webSettings.setJavaScriptEnabled(true);// 是否允许加载js文件
        webSettings.setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);// 打开缓存
        webView.setWebViewClient(new WebViewClient() {
            /**
             * 重写shouldOverrideUrlLoading，返回值若为true则用webview，false则是系统自身浏览器
             */
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }
        });

        webView.setWebChromeClient(new WebChromeClient() {
            @Override
            public void onProgressChanged(WebView view, int newProgress) {// newProgress当前进度
                if (newProgress == 100) {
                    // 加载完毕，关闭进度条
                    closeProgressDialog();
                } else {
                    //加载未完成，显示进度
                    showProgressDialog(newProgress);
                }
                super.onProgressChanged(view, newProgress);
            }

            private void closeProgressDialog() {
                progressDialog.dismiss();
                progressDialog=null;
                
            }

            private void showProgressDialog(int newProgress) {
                if (progressDialog == null) {
                    progressDialog = new ProgressDialog(MainActivity.this);

                    progressDialog.setTitle("页面正在加载中..请稍后");
                    progressDialog
                            .setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);//设置进度条样式
                    progressDialog.setProgress(newProgress);//设置进度
                    progressDialog.show();
                } else {
                    progressDialog.setProgress(newProgress);
                    progressDialog.show();
                }

            }
        });

    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {// keyCode代表按键的数字标示符
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (webView.canGoBack()) {
                webView.goBack();
                return true;
            } else {
                System.exit(0);
            }
        }

        return super.onKeyDown(keyCode, event);
    }

}

<uses-permission android:name="android.permission.INTERNET"/>