Android WebView详解

MainActivity.java

package com.example.web;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {
    private WebView webView;
    private ProgressDialog dialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button intentButton = (Button) findViewById(R.id.intent);

        Button webviewButton = (Button) findViewById(R.id.webviewButton);
        init();

        intentButton.setOnClickListener(this);
        webviewButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        // 使用内置系统浏览器打开网页
        case R.id.intent:
            Intent intent = new Intent(Intent.ACTION_VIEW);
            Uri uri = Uri.parse("http://www.baidu.com");
            intent.setData(uri);
            // Intent intent =new Intent(Intent.ACTION_VIEW,uri)
            startActivity(intent);
            break;
        case R.id.webviewButton:
            // webview默认使用系统浏览器打开网页,setWebViewClient让网页在webview中打开
            webView.loadUrl("http://www.baidu.com");
            break;
        default:
            break;
        }

    }

    private void init() {
        webView = (WebView) findViewById(R.id.webView);
        // WebView加载本地资源
        // webView.loadUrl("file:///android_asset/example.html");
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setScrollBarStyle(0);
        webView.getSettings().setAllowFileAccess(true);
        webView.getSettings().setBuiltInZoomControls(true);
        // WebView加载页面优先使用缓存加载
        webView.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
        // 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) {
                // WebViewClient帮助WebView去处理一些页面控制和请求通知
                // 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;
            }

        });

        //打开网页时添加进度条
        webView.setWebChromeClient(new WebChromeClient() {
            @Override
            public void onProgressChanged(WebView view, int newProgress) {
                // 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() {
            
                if (dialog != null && dialog.isShowing()) {
                    dialog.dismiss();
                    dialog = null;
                }
            }

            private void openDialog(int newProgress) {

                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) {
        
        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);
    }

}

参考文章：

http://www.cnblogs.com/mengdd/archive/2013/03/01/2938295.html

视频：

http://www.imooc.com/video/2269