< html > < head > < title > WebViewCacheDemo < / title > < meta http - equiv = " keywords " content = " keyword 1 , keyword 2 , keyword 3 " > < meta http - equiv = " description " content = " this is my page " > < meta http - equiv = " content - type " content = " text / html ; charset = UTF - 8 " > < / head > < body > < img src = " http : / / img 04 . taobaocdn . com / imgextra / i 4 / 608825099 / T 2 nGXBXXpaXXXXXXXX _ ! ! 608825099 . jpg _ 310 x 310 . jpg " / > < / body > < / html > < ? xml version = " 1 . 0 " encoding = " utf - 8 " ? > < LinearLayout xmlns : android = " http : / / schemas . android . com / apk / res / android " android : orientation = " vertical " android : layout _ width = " fill _ parent " android : layout _ height = " fill _ parent " > < WebView android : layout _ width = " fill _ parent " android : layout _ height = " wrap _ content " android : id = " @ + id / webView " / > < Button android : layout _ width = " wrap _ content " android : layout _ height = " wrap _ content " android : layout _ gravity = " center _ horizontal " android : text = " 从缓存读取图片 " android : id = " @ + id / button " / > < / LinearLayout > 第四步 : 修改主核心程序 WebViewCacheDemo . java ，这里我只加载了 index . html 文件，按钮事件暂时没写 , 代码如下 : package com . ljq . activity ; import java . io . File ; import java . io . FileInputStream ; import android . app . Activity ; import android . app . Dialog ; import android . app . AlertDialog . Builder ; import android . content . DialogInterface ; import android . content . DialogInterface . OnClickListener ; import android . graphics . Bitmap ; import android . graphics . BitmapFactory ; import android . os . Bundle ; import android . view . View ; import android . webkit . WebView ; import android . widget . Button ; import android . widget . ImageView ; public class WebViewActivity extends Activity { private WebView webView ; private static final String url = " file : / / / android _ asset / index . html " ; @ Override public void onCreate ( Bundle savedInstanceState ) { super . onCreate ( savedInstanceState ) ; setContentView ( R . layout . main ) ; webView = ( WebView ) findViewById ( R . id . webView ) ; webView . loadUrl ( url ) ; } } package com . ljq . activity ; import java . io . File ; import java . io . FileInputStream ; import android . app . Activity ; import android . app . Dialog ; import android . app . AlertDialog . Builder ; import android . content . DialogInterface ; import android . content . DialogInterface . OnClickListener ; import android . graphics . Bitmap ; import android . graphics . BitmapFactory ; import android . os . Bundle ; import android . view . View ; import android . webkit . WebView ; import android . widget . Button ; import android . widget . ImageView ; public class WebViewActivity extends Activity { private WebView webView ; private static final String url = " file : / / / android _ asset / index . html " ; @ Override public void onCreate ( Bundle savedInstanceState ) { super . onCreate ( savedInstanceState ) ; setContentView ( R . layout . main ) ; webView = ( WebView ) findViewById ( R . id . webView ) ; webView . loadUrl ( url ) ; / / 点击按钮时弹出对话框 Button button = ( Button ) findViewById ( R . id . button ) ; button . setOnClickListener ( new View . OnClickListener ( ) { public void onClick ( View v ) { ImageView imageView = new ImageView ( WebViewActivity . this ) ; imageView . setImageBitmap ( getPictureFromCache ( ) ) ; Builder builder = new android . app . AlertDialog . Builder ( WebViewActivity . this ) ; / / 设置对话框的图标 builder . setTitle ( " 从缓存查看图片 " ) ; builder . setView ( imageView ) ; / / 退出按钮 builder . setPositiveButton ( " 退出 " , new OnClickListener ( ) { public void onClick ( DialogInterface dialog , int which ) { / / 关闭 alert 对话框架 dialog . cancel ( ) ; } } ) ; builder . create ( ) . show ( ) ; } } ) ; } / * * * 从缓存获取图片 * * @ return * / private Bitmap getPictureFromCache ( ) { Bitmap bitmap = null ; try { / / 这里写死，在实际开发项目中要灵活使用 File file = new File ( getCacheDir ( ) + " / webviewCache / 10d 8d 5 cd " ) ; FileInputStream inStream = new FileInputStream ( file ) ; bitmap = BitmapFactory . decodeStream ( inStream ) ; } catch ( Exception e ) { e . printStackTrace ( ) ; } return bitmap ; } }" />