WebApp基础01-设置读取assets目录下文件

要读取assets下的目录，只需要修改三个地方即可

1.res/layout/activity_main.xml

2.AndroidManifest.xml

3.src\com\example\lcy\MainActivity.java

第一步.res/layout/activity_main.xml加入代码,需要在xml布局文件中声明WebView组件

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

全部代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:paddingBottom="@dimen/activity_vertical_margin"android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"tools:context=".MainActivity" ><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/hello_world" /><WebView android:id="@+id/webview"android:layout_width="fill_parent"android:layout_height="fill_parent"/></RelativeLayout>

第二部，AndroidManifest.xml 代码

加入代码：由于不是用Intent去调用系统组件，所以我们需要对程序进行权限的允许，在AndroidManifest.xml里对程序开放Inter权限

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

如果出现 webpage not available 在AndroidManifest.xml可以加入以上代码

全部代码

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="com.example.lcy"android:versionCode="1"android:versionName="1.0" ><uses-sdkandroid:minSdkVersion="8"android:targetSdkVersion="18" /><uses-permission android:name="android.permission.INTERNET"/><applicationandroid:allowBackup="true"android:icon="@drawable/ic_launcher"android:label="@string/app_name"android:theme="@style/AppTheme" ><activityandroid:name="com.example.lcy.MainActivity"android:label="@string/app_name" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application></manifest>

3.src\com\example\lcy\MainActivity.java 在Activity中实例化WebView，并且可通过loadUrl(url)方法打开指定url资源，加入代码

public class MainActivity extends Activity {private WebView webView;//private String url = "http://www.baidu.com";private String url = "file:///android_asset/www/index.html";private ProgressDialog progressDialog;@Overrideprotected 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*/@Overridepublic boolean shouldOverrideUrlLoading(WebView view, String url) {view.loadUrl(url);return true;}});webView.setWebChromeClient(new WebChromeClient() {@Overridepublic 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();}}});}@Overridepublic 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);}}

全部代码（有部分代码不用用管它，增加了public 、private 会自动增加，保证把上面的代码加进去就可以了）

package com.example.lcy;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 String url = "file:///android_asset/www/index.html";private ProgressDialog progressDialog;@Overrideprotected 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*/@Overridepublic boolean shouldOverrideUrlLoading(WebView view, String url) {view.loadUrl(url);return true;}});webView.setWebChromeClient(new WebChromeClient() {@Overridepublic 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();}}});}@Overridepublic 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);}}