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); 
} 
}