Android Developer Interview

• Suppose you have a v-shape array, e.g [1, 12, 31, 44, 51, 54, 23, 22, 10]. How to find the maximum value in a v-shape array?
• 假如我们有一个v-shape数组，如[1, 12, 31, 44, 51, 54, 23, 22, 10]。怎样找出它的最大值？

• Describe three common use cases for using an Intent.
• 请说出 Intent 三个常用案例。

• Under what condition could the code sample below crash your application? How would you modify the code to avoid this potential problem? Explain your answer.
• 在什麽情况下以下代码会崩溃？你可以怎样避免？请解释。

Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_TEXT, textMessage);
sendIntent.setType(HTTP.PLAIN_TEXT_TYPE); // "text/plain" MIME type
startActivity(sendIntent);

• What is the relationship between the life cycle of an AsyncTask and an Activity? What problems can this result in? How can these problems be avoided?
• AsyncTask 和 Activity 的生命周期有什麽関系？这个関系有可能导致什麽问题？你可以如何避免？

• What is difference between Serializable and Parcelable ? Which is best approach in Android ?
• Serializable 和 Parcelable 有什麽分别？那一个在安卓使用比较好？

• Write down the log results at 4 different cases
  • Start MainActivity
  • Invoke onClick() at MainActivity
  • User press back button from ActivityTwo
  • Start ActivityThree

• 我们有以下三段代码，请分别写下以下四种执行后log的结果
  • 开始MainActivity
  • 触发onClick() at MainActivity
  • 用户在ActivityTwo按back button
  • 开始ActivityThree

public class MainActivity extends Activity implements OnClickListener {
  final String TAG = "States";
  Button btnActTwo;
 
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    btnActTwo = (Button) findViewById(R.id.btnActTwo);
    btnActTwo.setOnClickListener(this);
    Log.d(TAG, "MainActivity: onCreate()");
  }
 
  @Override
  protected void onRestart() {
    super.onRestart();
    Log.d(TAG, "MainActivity: onRestart()");
  }
 
  @Override
  protected void onStart() {
    super.onStart();
    Log.d(TAG, "MainActivity: onStart()");
  }
 
  @Override
  protected void onResume() {
    super.onResume();
    Log.d(TAG, "MainActivity: onResume()");
  }
 
  @Override
  protected void onPause() {
    super.onPause();
    Log.d(TAG, "MainActivity: onPause()");
  }
 
  @Override
  protected void onStop() {
    super.onStop();
    Log.d(TAG, "MainActivity: onStop()");
  }
 
  @Override
  protected void onDestroy() {
    super.onDestroy();
    Log.d(TAG, "MainActivity: onDestroy()");
  }
 
  @Override
  public void onClick(View v) {
    Intent intent = new Intent(this, ActivityTwo.class);
    startActivity(intent);
  }
}

public class ActivityTwo extends Activity {
  final String TAG = "States";
 
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.two);
    Log.d(TAG, "ActivityTwo: onCreate()");
  }
 
  @Override
  protected void onRestart() {
    super.onRestart();
    Log.d(TAG, "ActivityTwo: onRestart()");
  }
 
  @Override
  protected void onStart() {
    super.onStart();
    Log.d(TAG, "ActivityTwo: onStart()");
  }
 
  @Override
  protected void onResume() {
    super.onResume();
    Log.d(TAG, "ActivityTwo: onResume()");
  }
 
  @Override
  protected void onPause() {
    super.onPause();
    Log.d(TAG, "ActivityTwo: onPause()");
  }
 
  @Override
  protected void onStop() {
    super.onStop();
    Log.d(TAG, "ActivityTwo: onStop()");
  }
 
  @Override
  protected void onDestroy() {
    super.onDestroy();
    Log.d(TAG, "ActivityTwo: onDestroy()");
  }
}

public class ActivityThree extends Activity {
  final String TAG = "States";
 
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.three);
    Log.d(TAG, "ActivityThree: onCreate()");
    this.finish();
  }
 
  @Override
  protected void onRestart() {
    super.onRestart();
    Log.d(TAG, "ActivityThree: onRestart()");
  }
 
  @Override
  protected void onStart() {
    super.onStart();
    Log.d(TAG, "ActivityThree: onStart()");
  }
 
  @Override
  protected void onResume() {
    super.onResume();
    Log.d(TAG, "ActivityThree: onResume()");
  }
 
  @Override
  protected void onPause() {
    super.onPause();
    Log.d(TAG, "ActivityThree: onPause()");
  }
 
  @Override
  protected void onStop() {
    super.onStop();
    Log.d(TAG, "ActivityThree: onStop()");
  }
 
  @Override
  protected void onDestroy() {
    super.onDestroy();
    Log.d(TAG, "ActivityThree: onDestroy()");
  }
}