我试图弄清楚 Android 中的指令流程，我编写了以下代码
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "This is the ------------------- Start Line");
Intent intent = new Intent(MainActivity.this, TimeCheckService.class);
startService(intent);
for ( int i = 0; i < 10; i++ ) {
Log.d(TAG, "This line is to check the________________________ sequence of execeution in Android.");
}
Cursor cursor = getContentResolver().query(
ContactsContract.Contacts.CONTENT_URI, null, null, null, null);
cursor.close();
}
logcat 输出是
08-29 23:00:05.742: D/MainActivity(1462): This is the ------------------- Start Line
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:05.742: D/MainActivity(1462): This line is to check the________________________ sequence of execeution in Android.
08-29 23:00:07.502: D/IsContactEmpty(1462): Starting IsContactEmpty
08-29 23:00:09.162: D/IsContactEmpty(1462): End IsContactEmpty
08-29 23:00:09.162: D/TimeCheckService(1462): Contacts not Empty
现在 logcat 中的时间戳显示在MainActivity中 的所有代码IntentService执行后执行，根据 MainActivity 的顺序应该更早启动并并行执行？有人可以解释一下吗？23:00:07.502IntentService
代码为IsContactEmpty
public class IsContactEmpty {
public static final String TAG = "IsContactEmpty";
@SuppressWarnings("unused")
private void isContactsEmpty() {
}
public static boolean valueOf(Context context) {
Log.d(TAG, "Starting IsContactEmpty");
boolean isEmpty;
Cursor cursor = context.getContentResolver().query(
ContactsContract.Contacts.CONTENT_URI, null, null, null, null);
if (cursor.getCount() > 0) {
isEmpty = false;
} else {
isEmpty = true;
}
cursor.close();
cursor = null;
Log.d(TAG, "End IsContactEmpty");
return isEmpty;
}
}
我替换IntentService为Thread如下
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "This is the ------------------- Start Line");
new ChkServiceThread().start();
//Intent intent = new Intent(MainActivity.this, TimeCheckService.class);
//startService(intent);
for ( int i = 0; i < 10; i++ ) {
Log.d(TAG, "This line is to check the________________________ sequence of execeution in Android.");
}
Cursor cursor = getContentResolver().query(ContactsContract.Contacts.CONTENT_URI, null, null, null, null);
cursor.close();
}
private class ChkServiceThread extends Thread {
@Override
public void run() {
boolean isEmpty = IsContactEmpty.valueOf(MainActivity.this);
if ( isEmpty == true ) {
Log.d(TAG, "Contacts Empty");
} else {
Log.d(TAG, "Contacts not Empty");
// mHandler.post(new DisplayToast("Contacts Ok", this));
}
}
}
并运行应用程序 10 次，但结果与之前的 logcat 输出完全相同。