本文引用的源码为android 4.4.4版本

使用WebView的load(data,"text/html", "utf-8")加载含有中文的网页时，页面上的中文字符显示为乱码。网页没有问题，使用PC浏览器查看显示正常。 load方法源码

public void loadData(String data, String mimeType, String encoding) {

checkThread();

if (DebugFlags.TRACE_API) Log.d(LOGTAG, "loadData");

mProvider.loadData(data, mimeType, encoding);

}

真正执行加载网页操作的是mProvider，而它是什么类型的对象呢?

private WebViewProvider mProvider;

...

private void ensureProviderCreated() {

checkThread();

if (mProvider == null) {

// As this can get called during the base class constructor chain, pass the minimum

// number of dependencies here; the rest are deferred to init().

//调用方法getFactory获取WebViewFactoryProvider对象，然后使用该对象的createWebView方法创建。

mProvider = getFactory().createWebView(this, new PrivateAccess());

}

}

//生成WebViewFactoryProvider方法

private static synchronized WebViewFactoryProvider getFactory() {

return WebViewFactory.getProvider();

}

WebViewFactoryProvider是一个接口，那么就查看WebViewFactory类。WebViewFactory的getProvider方法调用getFactoryClass()获取到字节码，然后通过反射创建了WebViewChromiumFactoryProvider对象。

public final class WebViewFactory {

//类路径

private static final String CHROMIUM_WEBVIEW_FACTORY =

"com.android.webview.chromium.WebViewChromiumFactoryProvider";

...

private static class Preloader {

static WebViewFactoryProvider sPreloadedProvider;

//静态代码块，字节码加载进来便创建了WebViewFactoryProvider对象

static {

try {

//通过反射创建对象

sPreloadedProvider = getFactoryClass().newInstance();

} catch (Exception e) {

Log.w(LOGTAG, "error preloading provider", e);

}

}

}

…

static WebViewFactoryProvider getProvider() {

synchronized (sProviderLock) {

//存在对象，则返回

if (sProviderInstance != null) return sProviderInstance;

Class providerClass;

try {

//获取字节码对象

providerClass = getFactoryClass();

} catch (ClassNotFoundException e) {

Log.e(LOGTAG, "error loading provider", e);

throw new AndroidRuntimeException(e);

}

//对象存在且字节码相同

if (Preloader.sPreloadedProvider != null &&

Preloader.sPreloadedProvider.getClass() == providerClass) {

//赋值

sProviderInstance = Preloader.sPreloadedProvider;

return sProviderInstance;

}

StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();

try {

//通过字节码创建对象

sProviderInstance = providerClass.newInstance();

if (DEBUG) Log.v(LOGTAG, "Loaded provider: " + sProviderInstance);

return sProviderInstance;

} catch (Exception e) {

Log.e(LOGTAG, "error instantiating provider", e);

throw new AndroidRuntimeException(e);

} finally {

StrictMode.setThreadPolicy(oldPolicy);

}

}

}

//获取字节码的方法

private static Class getFactoryClass() throws ClassNotFoundException {

return (Class) Class.forName(CHROMIUM_WEBVIEW_FACTORY);

}

}

WebViewFactory被加载进来，便创建WebViewChromiumFactoryProvider对象。源码在frameworks/webview/chromium/java/com/android/webview/chromium/WebViewChromiumFactoryProvider.java。 那就看看WebViewChromiumFactoryProvider.loadData方法代码：

public WebViewProvider createWebView(WebView webView, WebView.PrivateAccess privateAccess) {

WebViewChromium wvc = new WebViewChromium(this, webView, privateAccess);

synchronized (mLock) {

if (mWebViewsToStart != null) {

mWebViewsToStart.add(new WeakReference(wvc));

}

}

ResourceProvider.registerResources(webView.getContext());

return wvc;

}

该方法创建了WebViewChromium对象，并返回了该对象。在ensureProviderCreated方法中创建了该对象，并将其赋值给WebView中的mProvider属性。也就是说，在WebView中网页相关的操作都是WebViewChromium真正在执行。

WebViewChromium的源码在：frameworks/webview/chromium/java/com/android/webview/chromium/WebViewChromium.java。 看看WebViewChromium的loadData方法：

public void loadData(String data, String mimeType, String encoding) {

loadUrlOnUiThread(LoadUrlParams.createLoadDataParams(

fixupData(data), fixupMimeType(mimeType), isBase64Encoded(encoding)));

}

使用LoadUrlParams类的静态方法createLoadDataParams对传入的参数做了封装。 继续查看LoadUrlParams，源码在：external/chromium_org/content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java。

public static LoadUrlParams createLoadDataParams(

String data, String mimeType, boolean isBase64Encoded) {

return createLoadDataParams(data, mimeType, isBase64Encoded, null);

}

public static LoadUrlParams createLoadDataParams(

String data, String mimeType, boolean isBase64Encoded, String charset) {

StringBuilder dataUrl = new StringBuilder("data:");

//类型

dataUrl.append(mimeType);

//编码类型

if (charset != null && !charset.isEmpty()) {

dataUrl.append(";charset=" + charset);

}

//是否为base64编码

if (isBase64Encoded) {

dataUrl.append(";base64");

}

//分割符

dataUrl.append(",");

//网页

dataUrl.append(data);

LoadUrlParams params = new LoadUrlParams(dataUrl.toString());

params.setLoadType(LoadUrlParams.LOAD_TYPE_DATA);

params.setTransitionType(PageTransitionTypes.PAGE_TRANSITION_TYPED);

return params;

}

由以上源码可知：WebView的loadData方法传入的参数encoding并没有被封装到LoadUrlParams中，所以导致中文显示乱码。 调用createLoadDataParams( String data, String mimeType, boolean isBase64Encoded, String charset)方法肯定是能够将编码类型封装到LoadUrlParams。往回看看，哪里调用了该方法。WebViewChromium中的方法loadDataWithBaseURL(String baseUrl, String data, String mimeType, String encoding, String historyUrl)有调用到。

public void loadDataWithBaseURL(String baseUrl, String data, String mimeType, String encoding,

String historyUrl) {

data = fixupData(data);

mimeType = fixupMimeType(mimeType);

LoadUrlParams loadUrlParams;

baseUrl = fixupBase(baseUrl);

historyUrl = fixupHistory(historyUrl);

if (baseUrl.startsWith("data:")) {

// For backwards compatibility with WebViewClassic, we use the value of |encoding|

// as the charset, as long as it's not "base64".

boolean isBase64 = isBase64Encoded(encoding);

//如果是base64编码：传入的编码类型为null；不是则传入设置的编码类型

loadUrlParams = LoadUrlParams.createLoadDataParamsWithBaseUrl(

data, mimeType, isBase64, baseUrl, historyUrl, isBase64 ? null : encoding);

} else {

// When loading data with a non-data: base URL, the classic WebView would effectively

// "dump" that string of data into the WebView without going through regular URL

// loading steps such as decoding URL-encoded entities. We achieve this same behavior by

// base64 encoding the data that is passed here and then loading that as a data: URL.

try {

//设置为utf-8编码

loadUrlParams = LoadUrlParams.createLoadDataParamsWithBaseUrl(

Base64.encodeToString(data.getBytes("utf-8"), Base64.DEFAULT), mimeType,

true, baseUrl, historyUrl, "utf-8");

} catch (java.io.UnsupportedEncodingException e) {

Log.wtf(TAG, "Unable to load data string " + data, e);

return;

}

}

loadUrlOnUiThread(loadUrlParams);

}

WebView中的loadDataWithBaseURL(String baseUrl, String data, String mimeType, String encoding, String historyUrl) 方法调用了该方法，所以使用该方法能够解决乱码问题。 使用这种方式便可以解决中文乱码。

loadDataWithBaseURL(null, "html", "text/html", "UTF-8", null);