Android：我的应用在离线时总是崩溃

Question

我今天刚刚在我的应用程序中实现了横幅插页式广告，我的应用程序是一款游戏，它应该是在线游戏，但我注意到如果用户离线，游戏会打开，我对此没有问题，但问题是每当任何 activity 或有插页式广告的地方，如果没有互联网连接，应用程序就会崩溃那么如何解决这个问题？

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_anagram);

    questionCounter = findViewById(R.id.questionCounter);


    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);

    tv_info = findViewById(R.id.tv_info);
    tv_word = findViewById(R.id.tv_word);
    et_guess = findViewById(R.id.et_guess);
    b_check = findViewById(R.id.b_check);
    guessItTimer = findViewById(R.id.guessItTimer);
    scaling = AnimationUtils.loadAnimation(this,R.anim.scale);


    //ads
    MobileAds.initialize(this, new OnInitializationCompleteListener() {
        @Override
        public void onInitializationComplete(@NonNull InitializationStatus initializationStatus) {

        }
    });

    AdRequest adRequest1 = new AdRequest.Builder().build();
    // Attempt loading ad for interstitial
    InterstitialAd.load(this,"MyAd--ID", adRequest1,
            new InterstitialAdLoadCallback() {
                @Override
                public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
                    // The mInterstitialAd reference will be null until
                    // an ad is loaded.
                    mInterstitialAd = interstitialAd;
                    Log.i("TAG", "onAdLoaded");
                }

                @Override
                public void onAdFailedToLoad(@NonNull LoadAdError loadAdError) {
                    // Handle the error
                    Log.i("TAG", loadAdError.getMessage());
                    mInterstitialAd = null;
                }
            });

    r = new Random();

    newGame();
    checkAnswer();

}

private String shuffleWord(String word){
    List<String> letters = Arrays.asList(word.split(""));
    Collections.shuffle(letters);
    String shuffled = "";
    for(String letter: letters){
        shuffled += letter;
    }
    return shuffled;
}

private void newGame(){
    //get random word from dictionary
    currentWord = dictionary[r.nextInt(dictionary.length)];

    // show the shuffled word
    tv_word.setText(shuffleWord(currentWord));
    et_guess.setText("");
    b_check.setEnabled(true);
    //so tv_info color change and not to cancel the other request
    if (tv_info.getText().toString() == "Fantastic!"){
        tv_info.setVisibility(View.VISIBLE);
    } else{
        tv_info.setVisibility(View.INVISIBLE);
    }
}

//CountdownTimer
public void resetTimer() {
    timer = new CountDownTimer(35150, 1000) {
        @Override
        public void onTick(long l) {
            int timerColor = Integer.parseInt(guessItTimer.getText().toString());
            guessItTimer.setText(String.valueOf(l / 1000));
            //Animation for timer and color
            if (timerColor < 11 && timerColor >= 1) {
                guessItTimer.setTextColor(Color.parseColor("#E10F0F"));
                guessItTimer.startAnimation(scaling);//----------------->
            }

        }

        @Override
        public void onFinish() {
            Toast.makeText(AnagramActivity.this, "Time is over", Toast.LENGTH_SHORT).show();
            startActivity(new Intent(AnagramActivity.this, anagramAgainActivity.class));
            finish();
        }
    }.start();
}

public void onBackPressed() {
    super.onBackPressed();
    timer.cancel();
    mInterstitialAd.show(AnagramActivity.this);
    this.finish();
}

public void checkAnswer() {
    b_check.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if(et_guess.getText().toString().equalsIgnoreCase(currentWord)){
                tv_info.setVisibility(View.VISIBLE);
                tv_info.setTextColor(Color.GREEN);
                tv_info.setText("Fantastic!");
                b_check.setEnabled(false);

                // set count of numb of question answered
                index = index +1;
                String ar = String.valueOf(index);
                questionCounter.setText(ar);

                newGame();

            } else {
                tv_info.setVisibility(View.VISIBLE);
                tv_info.setTextColor(Color.RED);
                tv_info.setText("Try Again!");
            }
        }
    });
    resetTimer();
}

}

Answer 1

您正在 onBackPressed() 方法中调用 mInterstitialAd.show(AnagramActivity.this);。 App离线时，mInterstitialAd为null，导致崩溃。添加条件以仅在加载时显示广告（mInterstitialAd 不为空）。

public void onBackPressed() {
    super.onBackPressed();
    timer.cancel();
    if(mInterstitialAd !=null)
    mInterstitialAd.show(AnagramActivity.this);
    this.finish();
}

Android：我的应用在离线时总是崩溃

Android: My App keep crashing when offline

android

ads

interstitial

android-studio