WebView 寫一個自己的簡單瀏覽器

 <pre name="code" class="java"><pre name="code" class="java">/*
 * 第一種
 * //URL爲你所鏈接的地址
 * Uri uri = Uri.parse(url);
 * Intent intent = new Intent(Intent.ACTION_VIEW,uri);
 * startActivity(intent);
 */

/*
 * 第二種
 * （1）WebView加入你的應用
 * （2）使用WebView加載頁面
 * （3）獲取網絡訪問權限
 * （4）在WebView中使用Javacsript
 * （5）處理頁面導航
 * （6）後臺與前進
 * （7）判斷頁面加載過程
 * （8）WebView緩存的運用
 */

package com.example.webview;

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.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class MainActivity extends Activity {
	
	private String url="http://baidu.com";
	private WebView webView;
	private ProgressDialog dialog;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		init();
	}

	private void init() {
		// TODO Auto-generated method stub
		webView = (WebView) findViewById(R.id.webView);
		//獲取網絡訪問權限AndroidManifest.xml
                /*<uses-sdk
          * android:minSdkVersion="14"
          * android:targetSdkVersion="19" />
              * <uses-permission android:name="android.permission.INTERNET"/>
                 */
               //打開本地資源
		//webView.loadUrl("file:///android_asset/login.html");
		//打開web資源
		webView.loadUrl(url);
		//覆蓋WebView默認通過第三方或者系統瀏覽器打開網頁的行爲
		webView.setWebViewClient(new WebViewClient(){
			@Override
			public boolean shouldOverrideUrlLoading(WebView view, String url) {
				// TODO Auto-generated method stub
				//返回值是true的時候控制頁面在WebView中去打開，如果是false在調用系統瀏覽器或第三方瀏覽器打開
				view.loadUrl(url);
				return true;
			}
			// WebViewClient幫助WebView處理頁面控制
		});
		//啓用支持javascript
		WebSettings settings = webView.getSettings();
		settings.setJavaScriptEnabled(true);
		//WebView加載頁面優先使用緩存加載
		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之間的整數
				if(newProgress == 100)
				{
					//頁面加載完畢,關閉progressDialog
					closeDialog(newProgress);
					if(dialog != null && dialog.isShowing())
					{
						dialog.dismiss();
						dialog = null;
					}
				}
				else
				{
					//頁面正在加載，打開progressDialog
					openDialog(newProgress);
					if(dialog == null)
					{
						//顯示進度調
						dialog = new ProgressDialog(MainActivity.this);
						dialog.setTitle("正在加載");
						dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
						dialog.setProgress(newProgress);
						dialog.show();
					}
					else
					{
						//設置進度調的進度
						dialog.setProgress(newProgress);
					}
				}
				super.onProgressChanged(view, newProgress);
			}

			private void closeDialog(int newProgress) {
				// TODO Auto-generated method stub
				
			}

			private void openDialog(int newProgress) {
				// TODO Auto-generated method stub
				
			}
		});
	}
    //改寫物理按鍵--返回邏輯
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		// TODO Auto-generated method stub
		if(keyCode == KeyEvent.KEYCODE_BACK)
		{
			if(webView.canGoBack())
			{
				//返回上一個頁面
				webView.goBack();
				return true;
			}
			else
			{
				//退出程序
				System.exit(0);
			}
		}
		return super.onKeyDown(keyCode, event);
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		int id = item.getItemId();
		if (id == R.id.action_settings) {
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
}