android - webview 的用法
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增加webview的办法，非常简单，向特定的activity xml 中添加：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".NewWebviewActivity">
<WebView
android:id="@+id/webView"
android:layout_width="match_parent"
android:layout_height="match_parent">
</WebView>
</android.support.constraint.ConstraintLayout>
activity中：
@Override
protected void onCreate(Bundle savedInstanceState) {
//mShouldDeepStatus = false;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_new_webview);
WebView webView = (WebView) findViewById(R.id.webView);
//声明WebSettings子类
WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true);
settings.setDomStorageEnabled(true);
settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NORMAL); //排版适应屏幕
settings.setLoadWithOverviewMode(true); // setUseWideViewPort方法设置webview推荐使用的窗口。setL
settings.setUseWideViewPort(true);
settings.setPluginState(WebSettings.PluginState.ON);
settings.setJavaScriptCanOpenWindowsAutomatically(true);
settings.setAllowFileAccess(true);
settings.setDefaultTextEncodingName("UTF-8");
settings.setCacheMode(WebSettings.LOAD_NO_CACHE);
// webView.setBackgroundColor(getResources().getColor(R.color.backGround));
webView.setVisibility( View.VISIBLE);
if(Build.VERSION.SDK_INT >= 21){
settings.setMixedContentMode(0);
webView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
}else if(Build.VERSION.SDK_INT >= 19){
webView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
}else if(Build.VERSION.SDK_INT < 19){
webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
webView.setWebViewClient(new GenericWebViewClient(getApplicationContext().getCacheDir()));
webView.setWebChromeClient(new WebChromeClient());
webView.loadUrl("https://siwei.me");
}
新建class:
package com.wondercv;
import android.graphics.Bitmap;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.util.Log;
import android.webkit.WebResourceResponse;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okio.BufferedSink;
import okio.Okio;
public class GenericWebViewClient extends WebViewClient {
public String TAG = this.getClass().getSimpleName();
public GenericWebViewClient(File folder){
this.cacheFolder = folder;
}
private File cacheFolder;
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
Log.d(TAG, "onPageStarted, 触发的url是====" + url);
super.onPageStarted(view, url, favicon);
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
Log.d(TAG, "取消小菊花开始...");
// 取消小菊花 放在这里才可以. 针对myorder 打开的时候小菊花不会消失。
}
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
@Override
public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
Log.d(TAG, "shouldInterceptRequest, 触发的url是====" + url);
if(url.contains("__webpack_hmr")) {
Log.d(TAG, "return empty response on __webpack_hmr");
return new WebResourceResponse(null,null, null);
}
if( shouldQueryFromCache(url)) {
return queryFromCacheIfPossible(url);
}
return super.shouldInterceptRequest(view, url);
}
public boolean shouldQueryFromCache(String url) {
// endsWith 方法貌似不支持 a | b 这样的表达式...只好这么写了 ... Orz
boolean result = url.endsWith("png") ||
url.endsWith("PNG") ||
url.endsWith("jpg") ||
url.endsWith("JPG") ||
url.endsWith("jpeg") ||
url.endsWith("JPEG") ||
url.endsWith("css") ||
url.endsWith("css.map") ||
url.endsWith("js") ||
url.endsWith("js.map")
;
return result;
}
/**
* 核心方法. 根据url, 向远程发起请求, 并保存文件到本地.
*/
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
public WebResourceResponse queryFromCacheIfPossible(final String url) {
Log.d(TAG, "== in queryFromCacheIfPossible, url: "+ url);
Log.d(TAG, "== cacheFolder : "+ cacheFolder);
String webResourceLocalFileName = getWebResourceLocalFileName(url);
File webResourceCacheFile = new File( cacheFolder, webResourceLocalFileName);
if(webResourceCacheFile.exists()){
Log.d(TAG, "== hit the cache: " + webResourceLocalFileName);
try{
FileInputStream fileInputStream = new FileInputStream(new File(cacheFolder, webResourceLocalFileName));
return new WebResourceResponse(getMimeTypeBySuffix(url), "utf-8", fileInputStream);
}catch (IOException e){
e.printStackTrace();
return new WebResourceResponse(getMimeTypeBySuffix(url), "utf-8", null);
}
}else{
Log.d(TAG, "== NOT hit the cache: " + webResourceLocalFileName);
OkHttpClient okHttpClient = new OkHttpClient();
Request request = new Request.Builder()
.url(url)
.build();
try {
Response response = okHttpClient.newCall(request).execute();
writeHttpResponseToFile(url, response);
Log.d(TAG, "== mime : " + getMimeTypeBySuffix(url));
// 这段代码可以让图片正常显示!
// js: doing...
FileInputStream fileInputStream = new FileInputStream(new File(cacheFolder, webResourceLocalFileName));
return new WebResourceResponse(getMimeTypeBySuffix(url), "utf-8", fileInputStream);
}catch (IOException e){
Log.e(TAG, "== got IOException");
e.printStackTrace();
return new WebResourceResponse(getMimeTypeBySuffix(url), "utf-8", null);
}
}
}
public String getWebResourceLocalFileName(String url){
String[] temp = url.split("/");
String fileName = temp[temp.length - 1];
return fileName;
}
public String writeHttpResponseToFile(String url, Response response){
String fileName = getWebResourceLocalFileName(url);
Log.d(TAG, "== in writeHttpResponseToFile");
// TODO Write file ...
File file = new File(cacheFolder, fileName);
try{
BufferedSink bufferedSink = Okio.buffer(Okio.sink(file));
bufferedSink.writeAll(response.body().source());
bufferedSink.close();
}catch(Exception e){
Log.e(TAG, "== got error in writeHttpResponseToFile");
e.printStackTrace();
}
return fileName;
}
public String getMimeTypeBySuffix(String url){
String result = "";
if(url.endsWith("png") || url.endsWith("PNG")){
result = "image/png";
}else if (url.endsWith("jpg") || url.endsWith("JPG")
|| url.endsWith("jpeg") || url.endsWith("JPEG")){
result = "image/jpg";
}else if (url.endsWith("css") || url.endsWith("css.map")){
result = "text/css";
}else if (url.endsWith("js") ||url.endsWith(".js.map") ){
result = "application/javascript";
}else{
result = "text/plain";
}
return result;
}
}