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.srccomexamplelcyMainActivity.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" >

    <TextView
        android: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-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android: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.srccomexamplelcyMainActivity.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;

    @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);
    }

}

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;

    @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);
    }

}

详情查看  http://www.cnblogs.com/lichenwei/p/3959345.html

原文地址:https://www.cnblogs.com/wesky/p/3962784.html