Android WebView 缓存
android很多情况是使用webView用来显示界面，但是webview的加载速度略慢，想让这个webview更快一些所以需要使用缓存，在没有更新的时候使用缓存技术来提高速度。总体来讲有两个方案可以实现这个内容。1.用本地文件js，css，png替换网络请求下来的文件，2.直接使用webview的缓存。
第一种方法用本地文件js，css，png替换网络请求下来的文件是在webview的setWebViewClient里面的shouldInterceptRequest方法用本地文件进行替换。
mWebView.setWebViewClient(new WebViewClient(){
@Override
public void onPageFinished(WebView webView, String s) {
super.onPageFinished(webView, s);
mWebView.getSettings().setBlockNetworkImage(false);
//加载完成时调用
}
//新加载WebView的方法
@Override
public boolean shouldOverrideUrlLoading(final WebView webView, final String url) {
Log.e("sys","url="+url);
//判断url
if (!(url.startsWith("http") || url.startsWith("https"))) {
return true;
}
/**
* 推荐采用的新的二合一接口(payInterceptorWithUrl),只需调用一次
*/
final PayTask task = new PayTask(BaseWebActivity.this);
boolean isIntercepted = task.payInterceptorWithUrl(url, true, new H5PayCallback() {
@Override
public void onPayResult(final H5PayResultModel result) {
final String url=result.getReturnUrl();
Log.e("sys","url="+ url);
switch (result.getResultCode()) {
/*
9000——订单支付成功
8000——正在处理中
4000——订单支付失败
5000——重复请求
6001——用户中途取消
6002——网络连接出错
*/
case "4000":
webView.loadUrl("javascript:appCallJsShowOrder()");
Log.e("sys","4000");
break;
case "6001":
webView.loadUrl("javascript:appCallJsShowOrder()");
Log.e("sys","6001");
break;
case "6002":
webView.loadUrl("javascript:appCallJsShowOrder()");
Log.e("sys","6002");
break;
case "9000":
break;
}
}
}
});
/**
* 判断是否成功拦截
* 若成功拦截，则无需继续加载该URL；否则继续加载
*/
if(!isIntercepted) {
Log.e("is","update");
webView.loadUrl(url);
}
return true;
}
//获得下载列表
@Override
public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
WebResourceResponse response = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB){
response = super.shouldInterceptRequest(view,url);
if (url.contains(".js")||url.contains(".png")||url.contains(".css")){
Log.e("fileUrl",url);
String[] arr = StrUtil.getStrArr(url,"/");
String jsFileName = arr[arr.length-1];
String[] arrEnd = StrUtil.getStrArr(jsFileName,"\\.");
if (arr.length!=0){
if(arrEnd.length != 0) {
Log.e("arr",jsFileName);
if(jsFileName.equals("fastclick.min.js")){
Log.e("fastclick","fastclick");
try {
return new WebResourceResponse("application/x-javascript","utf-8",getBaseContext().getAssets().open("fastclick.min.js"));
} catch (IOException e) {
e.printStackTrace();
}
}
if(jsFileName.equals("geolocation.min.js")){
Log.e("geolocation","geolocation");
try {
return new WebResourceResponse("application/x-javascript","utf-8",getBaseContext().getAssets().open("geolocation.min.js"));
} catch (IOException e) {
e.printStackTrace();
}
}
if(jsFileName.equals("g2.min.js")){
try {
return new WebResourceResponse("application/x-javascript","utf-8",getBaseContext().getAssets().open("g2.min.js"));
} catch (IOException e) {
e.printStackTrace();
}
}
if(jsFileName.equals("login_bg.5563a40.png")){
try {
return new WebResourceResponse("application/x-javascript","utf-8",getBaseContext().getAssets().open("login_bg.5563a40.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
if(jsFileName.equals("favicon-16x16.png")){
try {
return new WebResourceResponse("application/x-javascript","utf-8",getBaseContext().getAssets().open("favicon-16x16.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
if(jsFileName.equals("favicon-32x32.png")){
try {
return new WebResourceResponse("application/x-javascript","utf-8",getBaseContext().getAssets().open("favicon-32x32.png"));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
return response;
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
WebResourceResponse response = null;
response = super.shouldInterceptRequest(view, request);
return response;
}
@Override
public void onReceivedError(final WebView webView, int i, String s, String s1) {
super.onReceivedError(webView, i, s, s1);
}
@Override
public void onReceivedError(WebView webView, WebResourceRequest webResourceRequest, WebResourceError webResourceError) {
super.onReceivedError(webView, webResourceRequest, webResourceError);
Log.e("sys","onReceivedError webResourceError");
}
});
2.首先设置webSetting设置成使用LOAD_DEFAULT这种缓存方式，数据从缓存中获取还是从网络中获取根据H5页面的参数判断，这样做的好处是可以动态的处理更新内容。再判断版本是否清理缓存。
//设置webview属性
private void initWebViewSettings() {
WebSettings webSetting = webView.getSettings();
webSetting.setJavaScriptEnabled(true);
webSetting.setJavaScriptCanOpenWindowsAutomatically(true);
webSetting.setAllowFileAccess(true);
webSetting.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
webSetting.setSupportZoom(true);
webSetting.setBuiltInZoomControls(true);
webSetting.setUseWideViewPort(true);
webSetting.setSupportMultipleWindows(true);
// webSetting.setLoadWithOverviewMode(true);
webSetting.setAppCacheEnabled(true);
// webSetting.setDatabaseEnabled(true);
webSetting.setDomStorageEnabled(true);
webSetting.setGeolocationEnabled(true);
webSetting.setDatabaseEnabled(true);
webSetting.setAppCacheMaxSize(Long.MAX_VALUE);
webSetting.setTextZoom(100);
webSetting.setBlockNetworkImage(true);
// webSetting.setPageCacheCapacity(IX5WebSettings.DEFAULT_CACHE_CAPACITY);
webSetting.setPluginState(WebSettings.PluginState.ON_DEMAND);
webSetting.setRenderPriority(WebSettings.RenderPriority.HIGH);
webSetting.setCacheMode(WebSettings.LOAD_DEFAULT);
String userAgent = webSetting.getUserAgentString().replace("Mobile","Snail");
webSetting.setUserAgentString(userAgent);
// this.getSettingsExtension().setPageCacheCapacity(IX5WebSettings.DEFAULT_CACHE_CAPACITY);//extension
// settings 的设计
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
if (this.mWebView != null) {
try
{
//在这里获得版本号 清除缓存
if(version!=lastVersion){
mWebView.clearCache(true);
context.deleteDatabase("webview.db");//删除数据库缓存
context.deleteDatabase("webviewCache.db");
}
}
catch (Exception e) {
}
mWebView.destroy();
}
}
