1. 程式人生 > >Android WebView 快取機制和模式詳解

Android WebView 快取機制和模式詳解

package com.example.webviewtest;  
  
import java.io.File;  
  
import android.app.Activity;  
import android.graphics.Bitmap;  
import android.os.Bundle;  
import android.util.Log;  
import android.view.View;  
import android.webkit.JsPromptResult;  
import android.webkit.JsResult;  
import android.webkit.WebChromeClient;  
import android.webkit.WebSettings;  
import android.webkit.WebSettings.RenderPriority;  
import android.webkit.WebView;  
import android.webkit.WebViewClient;  
import android.widget.RelativeLayout;  
import android.widget.TextView;  
import android.widget.Toast;  
  
public class MainActivity extends Activity {  
  
    private static final String TAG = MainActivity.class.getSimpleName();  
    private static final String APP_CACAHE_DIRNAME = "/webcache";  
    private TextView tv_topbar_title;  
    private RelativeLayout rl_loading;  
    private WebView mWebView;  
    private String url;  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
          
        //url:http://m.dianhua.cn/detail/31ccb426119d3c9eaa794df686c58636121d38bc?apikey=jFaWGVHdFVhekZYWTBWV1ZHSkZOVlJWY&app=com.yulore.yellowsdk_ios&uid=355136051337627  
        url = "http://m.dianhua.cn/detail/31ccb426119d3c9eaa794df686c58636121d38bc?apikey=jFaWGVHdFVhekZYWTBWV1ZHSkZOVlJWY&app=com.yulore.yellowsdk_ios&uid=355136051337627";  
        findView();  
    }  
  
    private void findView() {  
          
        tv_topbar_title = (TextView) findViewById(R.id.tv_topbar_title);  
          
        rl_loading = (RelativeLayout) findViewById(R.id.rl_loading);  
          
        mWebView = (WebView) findViewById(R.id.mWebView);  
          
        initWebView();  
          
        mWebView.setWebViewClient(new WebViewClient() {  
  
            @Override  
            public void onLoadResource(WebView view, String url) {  
                  
                Log.i(TAG, "onLoadResource url="+url);  
                  
                super.onLoadResource(view, url);  
            }  
  
            @Override  
            public boolean shouldOverrideUrlLoading(WebView webview, String url) {  
  
                Log.i(TAG, "intercept url="+url);  
                  
                webview.loadUrl(url);  
  
                return true;  
            }  
  
            @Override  
            public void onPageStarted(WebView view, String url, Bitmap favicon) {  
                  
                Log.e(TAG, "onPageStarted");  
                  
                rl_loading.setVisibility(View.VISIBLE); // 顯示載入介面  
            }  
  
            @Override  
            public void onPageFinished(WebView view, String url) {  
  
                String title = view.getTitle();  
  
                Log.e(TAG, "onPageFinished WebView title=" + title);  
  
                tv_topbar_title.setText(title);  
                tv_topbar_title.setVisibility(View.VISIBLE);  
  
                rl_loading.setVisibility(View.GONE); // 隱藏載入介面  
            }  
  
            @Override  
            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {  
  
                rl_loading.setVisibility(View.GONE); // 隱藏載入介面  
  
                Toast.makeText(getApplicationContext(), "",  
                        Toast.LENGTH_LONG).show();  
            }  
        });  
  
        mWebView.setWebChromeClient(new WebChromeClient() {  
  
            @Override  
            public boolean onJsAlert(WebView view, String url, String message, JsResult result) {  
  
                Log.e(TAG, "onJsAlert " + message);  
  
                Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();  
  
                result.confirm();  
  
                return true;  
            }  
  
            @Override  
            public boolean onJsConfirm(WebView view, String url, String message, JsResult result) {  
  
                Log.e(TAG, "onJsConfirm " + message);  
  
                return super.onJsConfirm(view, url, message, result);  
            }  
  
            @Override  
            public boolean onJsPrompt(WebView view, String url, String message, String defaultValue, JsPromptResult result) {  
  
                Log.e(TAG, "onJsPrompt " + url);  
  
                return super.onJsPrompt(view, url, message, defaultValue, result);  
            }  
        });  
          
        mWebView.loadUrl(url);  
    }  
  
    private void initWebView() {  
          
        mWebView.getSettings().setJavaScriptEnabled(true);  
        mWebView.getSettings().setRenderPriority(RenderPriority.HIGH);  
        mWebView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);  //設定 快取模式  
        // 開啟 DOM storage API 功能  
        mWebView.getSettings().setDomStorageEnabled(true);  
        //開啟 database storage API 功能  
        mWebView.getSettings().setDatabaseEnabled(true);   
        String cacheDirPath = getFilesDir().getAbsolutePath()+APP_CACAHE_DIRNAME;  
//      String cacheDirPath = getCacheDir().getAbsolutePath()+Constant.APP_DB_DIRNAME;  
        Log.i(TAG, "cacheDirPath="+cacheDirPath);  
        //設定資料庫快取路徑  
        mWebView.getSettings().setDatabasePath(cacheDirPath);  
        //設定  Application Caches 快取目錄  
        mWebView.getSettings().setAppCachePath(cacheDirPath);  
        //開啟 Application Caches 功能  
        mWebView.getSettings().setAppCacheEnabled(true);  
    }  
      
    /** 
     * 清除WebView快取 
     */  
    public void clearWebViewCache(){  
          
        //清理Webview快取資料庫  
        try {  
            deleteDatabase("webview.db");   
            deleteDatabase("webviewCache.db");  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
          
        //WebView 快取檔案  
        File appCacheDir = new File(getFilesDir().getAbsolutePath()+APP_CACAHE_DIRNAME);  
        Log.e(TAG, "appCacheDir path="+appCacheDir.getAbsolutePath());  
          
        File webviewCacheDir = new File(getCacheDir().getAbsolutePath()+"/webviewCache");  
        Log.e(TAG, "webviewCacheDir path="+webviewCacheDir.getAbsolutePath());  
          
        //刪除webview 快取目錄  
        if(webviewCacheDir.exists()){  
            deleteFile(webviewCacheDir);  
        }  
        //刪除webview 快取 快取目錄  
        if(appCacheDir.exists()){  
            deleteFile(appCacheDir);  
        }  
    }  
      
    /** 
     * 遞迴刪除 檔案/資料夾 
     *  
     * @param file 
     */  
    public void deleteFile(File file) {  
  
        Log.i(TAG, "delete file path=" + file.getAbsolutePath());  
          
        if (file.exists()) {  
            if (file.isFile()) {  
                file.delete();  
            } else if (file.isDirectory()) {  
                File files[] = file.listFiles();  
                for (int i = 0; i < files.length; i++) {  
                    deleteFile(files[i]);  
                }  
            }  
            file.delete();  
        } else {  
            Log.e(TAG, "delete file no exists " + file.getAbsolutePath());  
        }  
    }  
  
}