java - 类似旅行顾问的对话框，并在 Android 中显示自定义背景或启动画面

Question

我是 android 开发的初学者。下面我给出了我的主要 activity.java 代码。我的要求，如果互联网连接或 wifi 不能在移动设备上工作，那么执行以下操作

1. 如果互联网连接无法正常工作，则在应用程序启动时显示我的初始屏幕背景，并提供对话框或警报，如 trip advisor Check this image and screenshot 的屏幕截图.如果按下取消按钮，则对话框消失，仅显示启动画面，如果再次按下尝试，则尝试连接到互联网。

在我的代码中，我使用代码购买对话框，我不想要购买功能，这不是我的要求。我想要完全一样的旅行顾问。对我来说很容易，如果有人编辑我的代码并显示在哪里进行更改，非常感谢提前

package com.example.edarabia;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.Bundle;
import android.view.KeyEvent;
import android.webkit.WebView;
import android.webkit.WebViewClient;


@SuppressLint("SetJavaScriptEnabled")

public class MainActivity extends Activity{
WebView mywebview;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
     mywebview = (WebView) findViewById(R.id.webview);
    if(isNetworkConnected() == true){
    mywebview.getSettings().setJavaScriptEnabled(true);
    mywebview.setWebViewClient(new myWebClient());
        mywebview.loadUrl("http://www.grafdom.com/operations/projects/ma/edarabiaapp/");        
    mywebview.getSettings().setBuiltInZoomControls(true);
    mywebview.getSettings().setLoadWithOverviewMode(false);
    mywebview.getSettings().setUseWideViewPort(false);
    }else{
    showBuyDialog();
    }
}






//  @Override
//    public boolean onKeyDown(int keyCode, KeyEvent event) {
    // Check if the key event was the Back button and if there's history
//        if ((keyCode == KeyEvent.KEYCODE_BACK) && mywebview.canGoBack()) {
//          mywebview.goBack();
//            return true;
 //       }

 //       return super.onKeyDown(keyCode, event);

//  }

 // To handle "Back" key press event for WebView to go back to previous screen.
@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    if ((keyCode == KeyEvent.KEYCODE_BACK) && mywebview.canGoBack()) {
        mywebview.goBack();
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

@Override
public void onBackPressed() {
    finish();
}


public class myWebClient extends WebViewClient
{
    @Override
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
        super.onPageStarted(view, url, favicon);
    }

    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) { 
        view.loadUrl(url);
        return true;
    }
}

//// This method will retun boolean value if net conect then value will be true otherwise false
private boolean isNetworkConnected() {
    ConnectivityManager connectivity = (ConnectivityManager)     getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity != null) {
        NetworkInfo[] info = connectivity.getAllNetworkInfo();
        if (info != null)
            for (int i = 0; i < info.length; i++)
                if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                    return true;
                }
    }
    return false;
}

public void showBuyDialog() {
    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
    builder.setTitle("just for testing");

    builder.setMessage("Check you net conectivity....");
    builder.setCancelable(false);
    builder.setPositiveButton("Buy", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            Intent browserIntent = new Intent(
                    Intent.ACTION_VIEW,
                    Uri.parse("https://www.google.com"));
            startActivity(browserIntent);
        }
    });
    builder.show();
}




}

Answer 1

这可能会有帮助: Detect whether there is an Internet connection available on Android

或尝试深入研究 BroadcastReceivers。 示例代码:

public class InternetConnectionStateReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        _v("Network connectivity change");
        if (intent.getExtras() != null) {
            NetworkInfo ni = (NetworkInfo) intent.getExtras().get(ConnectivityManager.EXTRA_NETWORK_INFO);
            if (ni != null && ni.getState() == NetworkInfo.State.CONNECTED) {
                _v("Network " + ni.getTypeName() + " connected");
                onNetworkConnection(context, true);
            }
        }
        if (intent.getExtras().getBoolean(ConnectivityManager.EXTRA_NO_CONNECTIVITY, Boolean.FALSE)) {
            _v("There's no network connectivity");
            onNetworkConnection(context, false);
        }
    }

    private void onNetworkConnection(Context context, boolean isConnected) {
          //show dialog
    }

}