当有人按下手机上的默认后退按钮时，我想播放间隙广告

Question

我想在有人在我的Webview中打开帖子时显示间隙广告，然后在手机上按下默认后退按钮后显示间隙广告。请帮助我编写代码。我不懂编码。我是一名学生。帮助在我的应用程序上实现此功能。告诉我需要做什么。我放了MainActivity.java文件。

package com.sinhalagossip.Blogger.Tharu;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.DownloadListener;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import com.google.android.gms.ads.AdListener;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.ads.InterstitialAd;
public class MainActivity extends AppCompatActivity {
InterstitialAd mInterstitialAd;
private InterstitialAd interstitial;
private WebView myWebView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myWebView = (WebView)findViewById(R.id.webView);
WebSettings webSettings = myWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
myWebView.loadUrl("http://paththaramalli.info/");
myWebView.setWebViewClient(new WebViewClient());
AdView mAdView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
mAdView.loadAd(adRequest);
myWebView.setDownloadListener(new DownloadListener()
{
public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength)
{
//download file using web browser
Intent i = new Intent(Intent.ACTION_VIEW);
i.setData(Uri.parse(url));
startActivity(i);
}
});
}
}

Answer 1

要处理按下后退按钮的情况，您需要覆盖活动中的onBackPressed

public class MainActivity extends AppCompatActivity {
// other Activity stuff, like onCreate
@Override
public void onBackPressed() {
// do stuff, like show the ad
// call this if you want to let them go back
super.onBackPressed();
}
}

也就是说，如果一个应用程序在我尝试返回时向我显示了一个广告，我的下一站将是卸载它的Android设置…