webview が URL の読み込みを開始したときに接続をチェックする、webview を含むアプリを作成しました。AVD では問題なく動作しますが、実機でテストすると大きなバグが発生します。表示されるのはすべて黒であるため、webviewがロードされなかったと思います。私が何をしても、すべて黒..それを機能させる方法を理解する3日前に、アプリでターゲットURLを開く前に、まずブラウザーアプリでターゲットURLを確認する必要があります。要するに、最初にブラウザーで開かない限り、webview にはターゲット URL が表示されません。私はこれについて調査しましたが、ブラウザーを開かない Web ビューでリンクを開く方法についての回答しか見つかりませんでした。
私の主な活動のコードは次のとおりです。
public class MainActivity extends Activity
{
private WebView wv;
private ProgressBar progress;
private static String mycaturl=" *target url* ";
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
if (reachable(this))
{
Toast.makeText(this, "Reachable", Toast.LENGTH_SHORT).show();
buildwv( savedInstanceState, WebSettings.LOAD_DEFAULT );
}
else if (!reachable(this))
{
Toast.makeText(this, "Unreachable", Toast.LENGTH_SHORT).show();
eolc( savedInstanceState );
}
else
{
Toast.makeText(this, "onCreate error.", Toast.LENGTH_SHORT).show();
finish();
}
}
@SuppressLint({ "SetJavaScriptEnabled" })
public void buildwv(Bundle sis, int load)
{
setContentView(R.layout.activity_main);
//assigning objects to variables
wv=(WebView) findViewById(R.id.wv);
wv.setWebViewClient( new wvc() );
progress=(ProgressBar) findViewById(R.id.progress);
//websettings
WebSettings ws = wv.getSettings();
ws.setAppCacheMaxSize( 100 * 1024 * 1024 ); // 100MB
ws.setAppCachePath( this.getCacheDir().getAbsolutePath() );
ws.setAllowFileAccess( true );
ws.setAppCacheEnabled( true );
ws.setJavaScriptEnabled( true );
ws.setCacheMode(load);
//if instance is saved, to catch orientation change
if(sis==null)
{ wv.loadUrl(mycaturl); }
}
public void eolc(final Bundle sis)
{
AlertDialog.Builder alertDialog = new AlertDialog.Builder( MainActivity.this );
alertDialog.setTitle("ERROR 1");
alertDialog.setMessage("Host is unreachable. Load from cache or exit.");
alertDialog.setIcon(R.drawable.tick);
alertDialog.setPositiveButton( "Load from Cache", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog,int which)
{
// Write your code here to execute after dialog
Toast.makeText(getApplicationContext(), "You chose to load cache.", Toast.LENGTH_SHORT).show();
buildwv( sis, WebSettings.LOAD_CACHE_ELSE_NETWORK );
}
});
alertDialog.setNeutralButton( "Help", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
Toast.makeText(getApplicationContext(), "You chose Help. EOLC", Toast.LENGTH_SHORT).show();
wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
}
});
alertDialog.setNegativeButton( "Exit", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
// Write your code here to execute after dialog
Toast.makeText(getApplicationContext(), "You chose to exit.", Toast.LENGTH_SHORT).show();
finish();
}
});
alertDialog.create();
alertDialog.show();
}
public void roe()
{
AlertDialog.Builder alertDialog = new AlertDialog.Builder( MainActivity.this );
alertDialog.setTitle("ERROR 2");
alertDialog.setMessage("Host is unreachable. Restart to load cache or exit.");
alertDialog.setIcon(R.drawable.tick);
alertDialog.setPositiveButton( "Restart", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog,int which)
{
Toast.makeText(getApplicationContext(), "You chose to restart and load cache.", Toast.LENGTH_SHORT).show();
Intent i = getBaseContext().getPackageManager()
.getLaunchIntentForPackage( getBaseContext().getPackageName() );
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK );
startActivity(i);
}
});
alertDialog.setNeutralButton( "Help", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
Toast.makeText(getApplicationContext(), "You chose Help. ROE", Toast.LENGTH_SHORT).show();
wv.stopLoading();
wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
}
});
alertDialog.setNegativeButton( "Exit", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
Toast.makeText(getApplicationContext(), "You chose to exit.", Toast.LENGTH_SHORT).show();
finish();
}
});
alertDialog.create();
alertDialog.show();
}
private class wvc extends WebViewClient
{
//when page started loading
public void onPageStarted(WebView view, String url, Bitmap favicon)
{
//circular progress bar open
progress.setVisibility(View.VISIBLE);
//if reachable and setting cache on every new page
//setcache(getApplicationContext());
WebSettings ws = wv.getSettings();
if ( !reachable(getApplicationContext()) )
{
if ( ws.getCacheMode() == WebSettings.LOAD_DEFAULT )
{
roe();
}
else if ( ws.getCacheMode() == WebSettings.LOAD_CACHE_ELSE_NETWORK )
{
Toast.makeText(getApplicationContext(), "loading cache coz not reachable", Toast.LENGTH_SHORT).show();
}
}
}
//when page finished
@Override
public void onPageFinished(WebView view, String url)
{
super.onPageFinished(view, mycaturl);
Toast.makeText(getApplicationContext(), "PAGE DONE LOADING!!", Toast.LENGTH_SHORT).show();
//circular progress bar close
progress.setVisibility(View.GONE);
}
//when received an error
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
{
wv.stopLoading();
//wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
WebSettings ws = wv.getSettings();
if ( ws.getCacheMode() == WebSettings.LOAD_DEFAULT )
{
Toast.makeText(getApplicationContext(), "Page unavailable", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(getApplicationContext(), "Page not cached", Toast.LENGTH_SHORT).show();
}
roe();
}
}
//checking connectivity by checking if site is reachable
public static boolean reachable(Context context)
{
final ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkInfo netInfo = connMgr.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnected())
{
try
{
URL url = new URL(mycaturl);
HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
urlc.setConnectTimeout(5000); // five seconds timeout in milliseconds
urlc.connect();
if (urlc.getResponseCode() == 200) // good response
{ return true; } else { return false; }
}
catch (IOException e)
{ return false; }
}
else
{ return false; }
}
//options menu inflation
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
//when back button is pressed
public void onBackPressed ()
{
if (wv.isFocused() && wv.canGoBack())
{ wv.goBack(); } else { finish(); }
}
//when options button is pressed
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
switch (item.getItemId())
{
case R.id.item1:
wv.loadUrl("file:///android_asset/otherpages/errorpage.htm");
break;
case R.id.item2:
String currurl=wv.getUrl();
wv.loadUrl(currurl);
break;
case R.id.item3:
Intent i = getBaseContext().getPackageManager()
.getLaunchIntentForPackage( getBaseContext().getPackageName() );
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
break;
case R.id.item4:
finish();
break;
default:
break;
}
return true;
}
//saving instance state
@Override
protected void onSaveInstanceState(Bundle outState )
{
super.onSaveInstanceState(outState);
wv.saveState(outState);
}
//restoring instance state
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
{
super.onSaveInstanceState(savedInstanceState);
wv.restoreState(savedInstanceState);
}
}
はい、これらも追加しました：
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />