Android使用webView长按保存下载网络图片

package demo.sam.webview_demo; 

import android.app.Activity; 
import android.app.Dialog; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.net.Uri; 
import android.os.Handler; 
import android.os.Message; 
import android.provider.MediaStore; 
import android.support.v7.app.AlertDialog; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.text.Editable; 
import android.util.Log; 
import android.view.KeyEvent; 
import android.view.View; 
import android.webkit.WebChromeClient; 
import android.webkit.WebResourceRequest; 
import android.webkit.WebSettings; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.ProgressBar; 
import android.widget.Toast; 

import java.io.FileNotFoundException; 

public class MainActivity extends Activity { 

 private ProgressBar progress; 
 private WebView webView; 
 private EditText editText; 
 private Button click; 
 private Context context; 


 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_main); 
  context= this; 
  initView(); 
  initData(); 
  initListener(); 



 } 

 private void initData() { 
  WebSettings settings = webView.getSettings(); 
  settings.setJavaScriptEnabled(true); 
  settings.setUseWideViewPort(true);//设置此属性，可任意比例缩放 
  settings.setLoadWithOverviewMode(true); 
  // 使页面支持缩放 
  settings.setBuiltInZoomControls(true); 
  settings.setSupportZoom(true); 
  //支持自动加载图片 
  settings.setLoadsImagesAutomatically(true); 
  settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NORMAL);// 排版适应屏幕 
  // 缩放按钮 
  settings.setDisplayZoomControls(false); 

  webView.setWebViewClient(new WebViewClient(){ 

   // 页面在当前页面跳转 
   @Override 
   public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) { 
    return super.shouldOverrideUrlLoading(view, request); 
   } 

   // 页面加载结束 
   @Override 
   public void onPageFinished(WebView view, String url) { 
    super.onPageFinished(view, url); 
    if(progress!=null){ 
     progress.setVisibility(View.GONE); 
    } 
   } 
  }); 

 } 

 private void initView() { 
  progress = (ProgressBar) findViewById(R.id.progress); 
  webView = (WebView) findViewById(R.id.webView); 
  editText = (EditText) findViewById(R.id.url); 
  click = (Button) findViewById(R.id.click); 
 } 

 private void initListener() { 
  // 网页加载进度显示 
  webView.setWebChromeClient(new WebChromeClient(){ 
   @Override 
   public void onProgressChanged(WebView view, int newProgress) { 
    super.onProgressChanged(view, newProgress); 
    progress.setVisibility(View.VISIBLE); 
    progress.setProgress(newProgress); 
   } 
  }); 

  click.setOnClickListener(new View.OnClickListener() { 
   @Override 
   public void onClick(View view) { 
    Log.e("输入的网站",editText.getText().toString().trim()); 
    webView.loadUrl(editText.getText().toString().trim()); 
   } 
  }); 

  // 长按点击事件 
  webView.setOnLongClickListener(new View.OnLongClickListener() { 
   @Override 
   public boolean onLongClick(View view) { 
    final WebView.HitTestResult hitTestResult = webView.getHitTestResult(); 
    // 如果是图片类型或者是带有图片链接的类型 
    if(hitTestResult.getType()== WebView.HitTestResult.IMAGE_TYPE|| 
      hitTestResult.getType()== WebView.HitTestResult.SRC_IMAGE_ANCHOR_TYPE){ 
     // 弹出保存图片的对话框 
     AlertDialog.Builder builder = new AlertDialog.Builder(context); 
     builder.setTitle("提示"); 
     builder.setMessage("保存图片到本地"); 
     builder.setPositiveButton("确认", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialogInterface, int i) { 
       String url = hitTestResult.getExtra(); 
       // 下载图片到本地 
       DownPicUtil.downPic(url, new DownPicUtil.DownFinishListener(){ 

        @Override 
        public void getDownPath(String s) { 
         Toast.makeText(context,"下载完成",Toast.LENGTH_LONG).show(); 
         Message msg = Message.obtain(); 
         msg.obj=s; 
         handler.sendMessage(msg); 
        } 
       }); 

      } 
     }); 
     builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { 
      // 自动dismiss 
      @Override 
      public void onClick(DialogInterface dialogInterface, int i) { 
      } 
     }); 
     AlertDialog dialog = builder.create(); 
     dialog.show(); 
    } 
    return true; 
   } 
  }); 

  webView.loadUrl("http://www.baidu.com"); 
 } 

 Handler handler =new Handler(){ 
  @Override 
  public void handleMessage(Message msg) { 
   super.handleMessage(msg); 
   String picFile = (String) msg.obj; 
   String[] split = picFile.split("/"); 
   String fileName = split[split.length-1]; 
   try { 
    MediaStore.Images.Media.insertImage(getApplicationContext().getContentResolver(), picFile, fileName, null); 
   } catch (FileNotFoundException e) { 
    e.printStackTrace(); 
   } 
   // 最后通知图库更新 
   getApplicationContext().sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + picFile))); 
   Toast.makeText(context,"图片保存图库成功",Toast.LENGTH_LONG).show(); 
  } 
 }; 


 // 监听返回键返回网页的上一层 
 @Override 
 public boolean onKeyDown(int keyCode, KeyEvent event) { 
  if(keyCode == KeyEvent.KEYCODE_BACK && webView.canGoBack()){ 
   if(webView != null){ 
    webView.goBack(); 
    return true; 
   } 
  } 
  return super.onKeyDown(keyCode, event); 
 } 

} 

import android.os.AsyncTask; 
import android.os.Environment; 
import android.util.Log; 

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.net.URL; 
import java.util.Random; 

/** 
 * 图片下载的工具类 
 */ 
public class DownPicUtil { 

 /** 
  *下载图片，返回图片的地址 
  * @param url 
  */ 
 public static void downPic(String url,DownFinishListener downFinishListener){ 
  // 获取存储卡的目录 
  String filePath = Environment.getExternalStorageDirectory().getPath(); 
  File file = new File(filePath+File.separator+"webViewCache"); 
  if(!file.exists()){ 
   file.mkdir(); 
  } 

  loadPic(file.getPath(),url,downFinishListener); 

 } 

 private static void loadPic(final String filePath, final String url, final DownFinishListener downFinishListener) { 
  Log.e("下载图片的url",url); 
  new AsyncTask<Void,Void,String>(){ 
   String fileName; 
   InputStream is; 
   OutputStream out; 

   @Override 
   protected String doInBackground(Void... voids) { 

    // 下载文件的名称 
    String[] split = url.split("/"); 
    String newString = split[split.length - 1]; 
    fileName =newString.substring(newString.length()-20,newString.length()-1) ; 
    // 创建目标文件,不是文件夹 
    File picFile = new File(filePath + File.separator + fileName); 
    if(picFile.exists()){ 
     return picFile.getPath(); 
    } 

    try { 
     URL picUrl = new URL(url); 
     //通过图片的链接打开输入流 
     is = picUrl.openStream(); 
     if(is==null){ 
      return null; 
     } 
     out = new FileOutputStream(picFile); 
     byte[] b=new byte[1024]; 
     int end ; 
     while ((end=is.read(b))!=-1){ 
      out.write(b,0,end); 
     } 

     Log.e("OK??","----------"); 
     if(is!=null){ 
      is.close(); 
     } 

     if(out!=null){ 
      out.close(); 
     } 

    } catch (FileNotFoundException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 



    return picFile.getPath(); 
   } 

   @Override 
   protected void onPostExecute(String s) { 
    super.onPostExecute(s); 
    if(s!=null){ 
     downFinishListener.getDownPath(s); 
    } 
   } 
  }.execute(); 
 } 
 //下载完成回调的接口 
 public interface DownFinishListener{ 

  void getDownPath(String s); 
 } 
}