WebView似乎没有在Android 4.4中创建或使用缓存,因此它不必要地消耗大量带宽。
在4.2.2中运行这个简单的测试应用程序会显示正确的结果:
========================================================
Dumping Webview cache at /data/data/com.example.user.myapplication/cache/webviewCacheChromium
0th file: f_000006 33026
1th file: f_000005 40828
2th file: f_000004 37666
3th file: f_000003 76566
4th file: f_000002 66429
5th file: f_000001 20327
6th file: data_3 4202496
7th file: data_2 1056768
8th file: data_1 270336
9th file: data_0 45056
10th file: index 262512
Webview cache contains 11 files and takes up 5 Mb.
========================================================
但是在4.4.4上,根本没有WebView缓存:
========================================================
Neither webviewCache nor webviewCacheChromium exists! Dumping App Cache instead.
Dumping App cache at /data/data/com.example.user.myapplication/cache
0th file: com.android.opengl.shaders_cache 10947
App cache contains 1 files and takes up 0 Mb.
========================================================
这是我的源代码:
MainActivity.java:
package com.example.user.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import java.io.File;
public class MainActivity extends AppCompatActivity {
private WebView webview;
private static final String TAG = "myapp";
private static final String BAR = "========================================================";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
webview = (WebView) findViewById(R.id.webview);
webview.getSettings().setJavaScriptEnabled(true);
webview.getSettings().setDomStorageEnabled(true);
webview.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);
webview.getSettings().setAppCacheEnabled(true);
webview.getSettings().setAppCacheMaxSize(100 * 1000 * 1000);
webview.setWebViewClient(new WebViewClient() {
});
webview.loadUrl("https://www.reddit.com/");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
String msg = dumpWebviewCache();
Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_LONG).show();
return true;
}
return super.onOptionsItemSelected(item);
}
private String dumpWebviewCache() {
Log.d(TAG, BAR);
File appCache = getCacheDir();
File webviewCache = new File(appCache, "webviewCache");
File webviewCacheChromium = new File(appCache, "webviewCacheChromium");
if (!webviewCache.exists() && !webviewCacheChromium.exists()) {
Log.e(TAG, "Neither webviewCache nor webviewCacheChromium exists! Dumping App Cache instead.");
return dumpDir("App cache", appCache);
}
if (!webviewCache.exists())
webviewCache = webviewCacheChromium;
return dumpDir("Webview cache", webviewCache);
}
private String dumpDir(String dirName, File dirFile) {
Log.d(TAG, "Dumping " + dirName + " at " + dirFile.getAbsolutePath());
int i = 0, totalSize = 0;
for (File file : dirFile.listFiles()) {
Log.d(TAG, String.format("%1$3s", i++) + "th file: " + file.getName() + " " + file.length());
totalSize += file.length();
}
String msg = dirName + " contains " + dirFile.listFiles().length + " files and takes up " + totalSize / (1024 * 1024) + " Mb.";
Log.d(TAG, msg);
Log.d(TAG, BAR);
return msg;
}
}
activity_main.xml中:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.user.myapplication.MainActivity">
<WebView
android:id="@+id/webview"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</RelativeLayout>
的strings.xml:
<resources>
<string name="app_name">My Application</string>
</resources>
的AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.user.myapplication" >
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label=""
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
menu_main.xml:
<menu 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" tools:context=".MainActivity">
<item android:id="@+id/action_settings" android:title="Dump WebView cache"
android:orderInCategory="100" app:showAsAction="never" />
</menu>
答案 0 :(得分:0)
是什么让您认为必须调用缓存目录webviewCache
或webviewCacheChromium
?这是一个实现细节,您不应该依赖于此。在更新的版本中,缓存目录在Java包名称之后调用 - org.chromium.android_webview
。