android {
 defaultConfig {
  ...
  multiDexEnabled true
 }
 ...
}

android {
 defaultConfig {
  ...
  multiDexEnabled true
 }
 ...
}
dependencies {
 compile 'com.android.support:multidex:1.0.1'
}

@Override
protected void attachBaseContext(Context base) {
 super.attachBaseContext(context);
 Multidex.install(this);
}

@Override
protected void attachBaseContext(Context context) {
 super.attachBaseContext(context);
 if (MultiDexUtils.isMainProcess(context)) { // 判断是否是主进程，避免重复执行
  MultiDexUtils.setMainActivityStarted(this, false); // 保存本地数据，标记主页面是否已经开启
  MultiDexUtils.setLoadDexActivityClosed(this, false); // 保存本地数据，标记加载Dex进程是否已经关闭
  MultiDexUtils.startLoadDexActivity(context); // 打开加载 Dex 的进程页面，这样我们的APP就变成后台进程了
 }
}

public class LoadDexActivity extends Activity {
 private static final int MULTIDEX_ERROR = 0;
 private static final int MULTIDEX_ACTIVITY_STARTED = 1;
 Handler handler = new Handler() {
  @Override
  public void handleMessage(Message msg) {
   switch (msg.what) {
    case MULTIDEX_ERROR:
    case MULTIDEX_ACTIVITY_STARTED: // 退出当前进程
     MultiDexUtils.setLoadDexActivityClosed(getApplication());
     finish();
     System.exit(0);
     break;
    default:
     break;
   }
  }
 };
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_loaddex);
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
   getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
  }
  new Thread() {
   @Override
   public void run() {
    Message message = handler.obtainMessage();
    long startTime = System.currentTimeMillis();
    long timeout = 10 * 1000; // 加载超时时间
    try {
     MultiDex.install(getApplication());
     Thread.sleep(500);
     // 等待主界面启动
     while (!MultiDexUtils.isMainActivityStarted(getApplication()) &&
       (System.currentTimeMillis() - startTime) < timeout) {
      Thread.sleep(200);
     }
     message.what = MULTIDEX_ACTIVITY_STARTED;
     handler.sendMessage(message);
    } catch (Exception e) {
     message.what = MULTIDEX_ERROR;
     handler.sendMessage(message);
    }
   }
  }.start();
 }
 @Override
 public void onBackPressed() {
  //cannot backpress
 }
}

<activity
 android:name=".LoadDexActivity"
 android:alwaysRetainTaskState="false"
 android:excludeFromRecents="true"
 android:launchMode="singleTask"
 android:process=":loadDex"
 android:screenOrientation="portrait">
</activity>

@Override
public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 ...
 MultiDexUtils.setMainActivityStarted(getApplication()); // 告诉loadDex进程，主界面已启动
 ...
}

public class MultiDexUtils {
 public static final String KEY_ACTIVITY_STARTED = "activity-started-";
 public static final String KEY_LOADDEX_CLOSED = "loaddex-closed-";
 /**
  * 当前进程是否是主进程
  */
 public static boolean isMainProcess(Context context) {
  return "com.***.***(进程名一般是包名)".equals(getCurProcessName(context));
 }
 /**
  * 设置-主界面已经打开
  */
 public static void setMainActivityStarted(Context context) {
  setMainActivityStarted(context, true);
 }
 /**
  * 设置-主界面是否已经打开
  */
 public static void setMainActivityStarted(Context context, boolean b) {
  SharedPreferences sp = context.getSharedPreferences("multidex", Context.MODE_MULTI_PROCESS);
  sp.edit().putBoolean(KEY_ACTIVITY_STARTED + getPackageInfo(context).versionCode, b).commit();
 }
 /**
  * 是否需要等待主界面
  */
 public static boolean isMainActivityStarted(Context context) {
  SharedPreferences sp = context.getSharedPreferences("multidex", Context.MODE_MULTI_PROCESS);
  return sp.getBoolean(KEY_ACTIVITY_STARTED + getPackageInfo(context).versionCode, false);
 }
 /**
  * 判断加载页面是否关闭
  */
 public static boolean isLoadDexActivityClosed(Context context) {
  SharedPreferences sp = context.getSharedPreferences("multidex", Context.MODE_MULTI_PROCESS);
  return sp.getBoolean(KEY_LOADDEX_CLOSED + getPackageInfo(context).versionCode, false);
 }
 /**
  * 设置加载页面已经关闭
  */
 public static void setLoadDexActivityClosed(Context context) {
  setLoadDexActivityClosed(context, true);
 }
 /**
  * 设置-加载页面是否已经关闭
  */
 public static void setLoadDexActivityClosed(Context context, boolean b) {
  SharedPreferences sp = context.getSharedPreferences("multidex", Context.MODE_MULTI_PROCESS);
  sp.edit().putBoolean(KEY_LOADDEX_CLOSED + getPackageInfo(context).versionCode, b).commit();
 }
 /**
  * 开启等待页面，新的进程
  */
 public static void startLoadDexActivity(Context context) {
  Intent intent = new Intent();
  ComponentName componentName = new ComponentName("com.***.***(包名)", LoadDexActivity.class.getName());
  intent.setComponent(componentName);
  intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  context.startActivity(intent);
 }
 /**
  * 获取进程名
  */
 public static String getCurProcessName(Context context) {
  try {
   int pid = android.os.Process.myPid();
   ActivityManager mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
   for (ActivityManager.RunningAppProcessInfo appProcess : mActivityManager.getRunningAppProcesses()) {
    if (appProcess.pid == pid) {
     return appProcess.processName;
    }
   }
  } catch (Exception e) {
   // ignore
  }
  return null;
 }
 /**
  * 获取包信息
  */
 private static PackageInfo getPackageInfo(Context context) {
  PackageManager pm = context.getPackageManager();
  try {
   return pm.getPackageInfo(context.getPackageName(), 0);
  } catch (PackageManager.NameNotFoundException e) {
//   Log.i(TAG, e.getLocalizedMessage());
  }
  return new PackageInfo();
 }
}

android:theme="@style/SplashTheme"

<style name="SplashTheme" parent="@android:style/Theme.NoTitleBar">
 <item name="android:background">@drawable/logo_splash</item>
</style>

<style name="SplashTheme" parent="@android:style/Theme.NoTitleBar.Fullscreen">
 <item name="android:windowBackground">@drawable/logo_splash</item>
</style>

@Override
public void setTheme(int resid) {
 super.setTheme(R.style.CustomTransparent);
}

<style name="CustomTransparent" parent="@android:style/Theme.Translucent">
 <item name="android:background">@null</item>
 <item name="android:windowBackground">@color/curve_floater_frameColor</item>
</style>