是的，我在这个网站上尝试了很多答案，但所有答案都不起作用 我有一个webview应用程序，我希望将图像保存在网站中。 我已执行长按以在应用程序中复制文本。 但长按则无法保存图像。 这些关于上下文的答案不起作用
这是我的主要活动代码，任何人都可以编辑并回答我 并请记住，我只用Java编写了一些基本代码，而我使用不同来源的代码制作了该应用的大部分内容
我的主要活动：
package com.example.ragulsundaram.typicaltamilan;
import android.Manifest;
import android.annotation.TargetApi;
import android.app.DownloadManager;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Environment;
import android.os.Handler;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.ContextMenu;
import android.view.KeyEvent;
import android.view.MenuItem;
import android.view.View;
import android.webkit.DownloadListener;
import android.webkit.URLUtil;
import android.webkit.ValueCallback;
import android.webkit.WebResourceRequest;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.CookieManager;
import java.net.HttpURLConnection;
import java.net.URL;
public class MainActivity extends AppCompatActivity {
WebView mWebView;
SwipeRefreshLayout swipe;
private long backPressedTime;
private static final String TAG = "MainActivity";
public static int TIME_OUT=4000;
@Override
public void onBackPressed() {
if(backPressedTime + 2000 > System.currentTimeMillis()){
super.onBackPressed();
return;
}else{
Toast.makeText(getBaseContext(),"Press back again to exit,",Toast.LENGTH_SHORT).show();
}
backPressedTime = System.currentTimeMillis();
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction()== KeyEvent.ACTION_DOWN){
switch (keyCode){
case KeyEvent.KEYCODE_BACK:
if (mWebView.canGoBack()){
mWebView.goBack();
}
else {
if(backPressedTime + 2000 > System.currentTimeMillis()){
super.onBackPressed();
}else{
Toast.makeText(getBaseContext(),"Press back again to exit",Toast.LENGTH_SHORT).show();
}
backPressedTime = System.currentTimeMillis();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}
@Override
protected void onStop() {
Toast.makeText(getApplicationContext(),"Pogatheeey",Toast.LENGTH_SHORT).show();
super.onStop();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toast.makeText(getApplicationContext(),"Vankakkam",Toast.LENGTH_LONG).show();
swipe = (SwipeRefreshLayout) findViewById(R.id.swipe);
swipe.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener()
{
public void onRefresh(){
LoadWeb();
}
});
LoadWeb();
if (Build.VERSION.SDK_INT >=Build.VERSION_CODES.M){
if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE)==PackageManager.PERMISSION_DENIED){
String[] permissions = new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE};
requestPermissions(permissions,1);
}
}
swipe.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
mWebView.reload();
}
});
}
public void LoadWeb()
{
mWebView = (WebView) findViewById(R.id.webView);
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.getSettings().setAppCacheEnabled(true);
mWebView.loadUrl("https://typicaltamila.blogspot.com/ ");
swipe.setRefreshing(true);
mWebView.evaluateJavascript("(function(){return window.getSelection().toString()})()",
new ValueCallback<String>()
{
@Override
public void onReceiveValue(String value)
{
Log.v(TAG, "SELECTION:" + value);
}
});
mWebView.setWebViewClient(new WebViewClient() {
public void onReveivedError(WebView view, int errorCode, String description, String failingUrl){
mWebView.loadUrl("file://android_asset/error.html");
}
public void onPageFinished(WebView view, String url)
{
//hide the swipe refreshlayout
swipe.setRefreshing(false);
}
@SuppressWarnings("deprecation")
@Override
public boolean shouldOverrideUrlLoading(WebView webView, String url) {
if (url.startsWith("magnet")) {
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
try {
startActivity(i);
} catch (ActivityNotFoundException e) {
Toast.makeText(getBaseContext(), "Team localpeers: No bittorent client installed in system.", Toast.LENGTH_SHORT).show();
}
return true;
}
return false;
}
//torrent
@TargetApi(Build.VERSION_CODES.N)
@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
String url=request.getUrl().toString();
if (url.startsWith("magnet")) { Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
try {
startActivity(i);
} catch (ActivityNotFoundException e) {
Toast.makeText(getBaseContext(), "Team localpeers: No bittorent client installed in Android.", Toast.LENGTH_SHORT).show();
}
return true;
}
return false;
}
});
//downloading files
mWebView.setDownloadListener(new DownloadListener() {
@Override
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
DownloadManager.Request request= new DownloadManager.Request(Uri.parse(url));
request.setMimeType(mimetype);
String cookies = android.webkit.CookieManager.getInstance().getCookie(url);
request.addRequestHeader("cookie",cookies);
request.addRequestHeader("User-Agent",userAgent);
request.setDescription(("Downloading"));
request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,URLUtil.guessFileName(url,contentDisposition,mimetype));
DownloadManager dm=(DownloadManager)getSystemService(DOWNLOAD_SERVICE);
dm.enqueue(request);
Toast.makeText(MainActivity.this,"Your file is downloading",Toast.LENGTH_SHORT).show();
}
});
}
}