android.os.Parcelable#writeToParcel ( )源码实例Demo

/**
 * Test all parcels within package to see if they properly implement {@link Parcelable}
 *
 * @throws Exception
 */
public void testParcel() throws Exception {
    Class[] classesToCheck = getClassesToCheck();
    for (Class classToCheck : classesToCheck) {
        if (ObjectHelper.isParcelable(classToCheck) && !Modifier.isAbstract(classToCheck.getModifiers())) {
            /**
             * Helps us to not get into infinite loops if we have a structure in our models where something
             * like a Person model can have a Person field
             */
            ObjectStack objectStack = new ObjectStack();
            Parcelable parcelable = (Parcelable) ObjectHelper.getTestObject(objectStack, classToCheck);
            Parcel parcel = Parcel.obtain();
            parcelable.writeToParcel(parcel, 0);
            parcel.setDataPosition(0);
            Field creatorField = classToCheck.getField("CREATOR");
            Parcelable.Creator creator = (Parcelable.Creator) creatorField.get(null);
            Parcelable read = (Parcelable) creator.createFromParcel(parcel);
            if (checkingForSuccess()) {
                assertTrue(classToCheck.getSimpleName() + " did not equal after parceling", ObjectHelper.checkFieldsEqual(classToCheck.getSimpleName(), parcelable, read, checkingForSuccess()));
            } else {
                boolean success = ObjectHelper.checkFieldsEqual(classToCheck.getSimpleName(), parcelable, read, checkingForSuccess());
                assertFalse("Looks like " + classToCheck.getSimpleName() + " was supposed to have failed, but didn't", success);
            }
        }
    }
}
 

public static byte[] serialize(Parcelable parceable) {
  Parcel parcel = Parcel.obtain();
  parceable.writeToParcel(parcel, 0);
  byte[] bytes = parcel.marshall();
  parcel.recycle();
  return bytes;
}
 

/**
 * Convert a {@link Parcelable} into its {@link ByteString} representation.
 *
 * @param parcelable to convert into a {@link ByteString}
 */
@Override
public ByteString convert(@NonNull Parcelable parcelable) {
  Parcel parcel = null;
  try {
    parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    return copyFrom(parcel.marshall());
  } finally {
    if (parcel != null) {
      parcel.recycle();
    }
  }
}
 

private void writeNullParcelable(Parcelable p, Parcel dest, int flags) {
    if (p != null) {
        dest.writeInt(1);
        p.writeToParcel(dest, flags);
    } else {
        dest.writeInt(0);
    }
}
 

@NonNull
public static byte[] marshall(@NonNull final Parcelable parcelable) {
    final Parcel parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    final byte[] bytes = parcel.marshall();
    parcel.recycle();
    return bytes;
}
 

public static byte[] marshall(Parcelable parceable) {

    Parcel parcel = Parcel.obtain();
    parceable.writeToParcel(parcel, 0);
    byte[] bytes = parcel.marshall();
    parcel.recycle();
    return bytes;
  }
 

private static byte[] parcelable2Bytes(Parcelable parcelable) {
    if (parcelable == null) return null;
    Parcel parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    byte[] bytes = parcel.marshall();
    parcel.recycle();
    return bytes;
}
 

public static byte[] marshall(Parcelable parcelable) {
    Parcel parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    byte[] bytes = parcel.marshall();
    parcel.recycle();
    return bytes;
}
 

public static void putParcelable(Context context, String key, Parcelable parcelable) {
    Parcel parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    getSharedPreferences(context).edit()
            .putString(key, Base64.encodeToString(parcel.marshall(), 0))
            .apply();
}
 

public static byte[] marshall(Parcelable parceable) {
    Parcel parcel = Parcel.obtain();
    parceable.writeToParcel(parcel, 0);
    byte[] bytes = parcel.marshall();
    parcel.recycle();
    return bytes;
}
 

public static byte[] marshall(Parcelable parceable) {
    Parcel parcel = Parcel.obtain();
    parceable.writeToParcel(parcel, 0);
    byte[] bytes = parcel.marshall();
    parcel.recycle(); // not sure if needed or a good idea
    return bytes;
}
 

public static byte[] serialize(Parcelable parceable) {
  Parcel parcel = Parcel.obtain();
  parceable.writeToParcel(parcel, 0);
  byte[] bytes = parcel.marshall();
  parcel.recycle();
  return bytes;
}
 

private static void writeParcelable(LinkedList<Object> parcelData, Parcelable parcelable, Parcel parcel1) {
    if (parcelable == null) {
        parcelData.add(null);
    } else {
        parcelable.describeContents();
        parcelData.add(parcelable.getClass());
        parcelable.writeToParcel(parcel1, 0);
    }
}
 

/**
 * Converts the Parcelable object to a byte[]
 *
 * @param parcelable
 * @return
 */
public static byte[] parcelToByte(@NonNull Parcelable parcelable) {
    Parcel parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    byte[] bytes = parcel.marshall();
    parcel.recycle();
    return bytes;
}
 

private void testSerialization(ParcelableDescriptor descriptor) throws Exception {
    generator.generateParcelable(targetType, descriptor);

    ClassLoader classLoader = codeGenerationUtil.build();
    Class<Parcelable> parcelableClass = (Class<Parcelable>) classLoader.loadClass(ClassNamer.className(targetType).append(Parcels.IMPL_EXT).build().toString());

    Parcelable outputParcelable = parcelableClass.getConstructor(Target.class).newInstance(target);

    outputParcelable.writeToParcel(parcel, 0);

    parcel.setDataPosition(0);

    Parcelable inputParcelable = ((Parcelable.Creator<Parcelable>)parcelableClass.getField("CREATOR").get(null)).createFromParcel(parcel);

    Target wrapped = Parcels.unwrap(inputParcelable);

    assertEquals(target.getValue(), wrapped.getValue());
}
 

private static List<String> getText(Notification notification) {
    RemoteViews contentView = notification.contentView;
    /*if (Build.VERSION.SDK_INT >= 16) {
        contentView = notification.bigContentView;
    }*/

    // Use reflection to examine the m_actions member of the given RemoteViews object.
    // It's not pretty, but it works.
    List<String> text = new ArrayList<>();
    try
    {
        Field field = contentView.getClass().getDeclaredField("mActions");
        field.setAccessible(true);

        @SuppressWarnings("unchecked")
        ArrayList<Parcelable> actions = (ArrayList<Parcelable>) field.get(contentView);

        // Find the setText() and setTime() reflection actions
        for (Parcelable p : actions)
        {
            Parcel parcel = Parcel.obtain();
            p.writeToParcel(parcel, 0);
            parcel.setDataPosition(0);

            // The tag tells which type of action it is (2 is ReflectionAction, from the source)
            int tag = parcel.readInt();
            if (tag != 2) continue;

            // View ID
            parcel.readInt();

            String methodName = parcel.readString();
            //noinspection ConstantConditions
            if (methodName == null) continue;

                // Save strings
            else if (methodName.equals("setText"))
            {
                // Parameter type (10 = Character Sequence)
                parcel.readInt();

                // Store the actual string
                String t = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(parcel).toString().trim();
                if (!text.contains(t)) {
                    text.add(t);
                }
            }

            // Save times. Comment this section out if the notification time isn't important
            /*else if (methodName.equals("setTime"))
            {
                // Parameter type (5 = Long)
                parcel.readInt();

                String t = new SimpleDateFormat("h:mm a").format(new Date(parcel.readLong()));
                text.add(t);
            }*/

            parcel.recycle();
        }
    }

    // It's not usually good style to do this, but then again, neither is the use of reflection...
    catch (Exception e)
    {
        Mlog.e("NotificationClassifier", e.toString());
        return null;
    }
    return text;
}
 

private ProgressInfo getProgressInfo(String id, Notification n) {
    if (id == null || n == null) return null;

    ProgressInfo pInfo = new ProgressInfo(id, false, 0, 0);

    // We have to extract the information from the content view
    RemoteViews views = n.bigContentView;
    if (views == null) views = n.contentView;
    if (views == null) return pInfo;

    try {
        @SuppressWarnings("unchecked")
        List<Parcelable> actions = (List<Parcelable>) 
            XposedHelpers.getObjectField(views, "mActions");
        if (actions == null) return pInfo;

        for (Parcelable p : actions) {
            Parcel parcel = Parcel.obtain();
            p.writeToParcel(parcel, 0);
            parcel.setDataPosition(0);

            // The tag tells which type of action it is (2 is ReflectionAction)
            int tag = parcel.readInt();
            if (tag != 2)  {
                parcel.recycle();
                continue;
            }

            parcel.readInt(); // skip View ID
            String methodName = parcel.readString();
            if ("setMax".equals(methodName)) {
                parcel.readInt(); // skip type value
                pInfo.max = parcel.readInt();
                if (DEBUG) log("getProgressInfo: total=" + pInfo.max);
            } else if ("setProgress".equals(methodName)) {
                parcel.readInt(); // skip type value
                pInfo.progress = parcel.readInt();
                pInfo.hasProgressBar = true;
                if (DEBUG) log("getProgressInfo: current=" + pInfo.progress);
            }

            parcel.recycle();
        }
    } catch (Throwable  t) {
        XposedBridge.log(t);
    }

    return pInfo;
}
 

@Test
public void testGeneratedParcelable() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException, InstantiationException, NoSuchFieldException {

    ParcelTarget parcelTarget = new ParcelTarget();
    ParcelSecondTarget parcelSecondTarget = new ParcelSecondTarget();

    parcelTarget.setDoubleValue(Math.PI);
    parcelTarget.setStringValue(TEST_VALUE);
    parcelTarget.setSecondTarget(parcelSecondTarget);

    parcelSecondTarget.setValue(TEST_VALUE);

    Parcelable outputParcelable = parcelableClass.getConstructor(ParcelTarget.class).newInstance(parcelTarget);

    outputParcelable.writeToParcel(parcel, 0);
    parcel.setDataPosition(0);

    Parcelable inputParcelable = ((Parcelable.Creator<Parcelable>)parcelableClass.getField("CREATOR").get(null)).createFromParcel(parcel);

    ParcelTarget wrapped = Parcels.unwrap(inputParcelable);

    assertEquals(parcelTarget, wrapped);
}
 

public static Parcel writeToParcel(Parcelable parcelable) {
    Parcel parcel = Parcel.obtain();
    parcelable.writeToParcel(parcel, 0);
    parcel.setDataPosition(0);
    return parcel;
}
 

/**
 * 根据Parcelable对象，构造出适合在任何地方使用的Parcel对象
 * 该方法可杜绝ClassCastException异常
 * <p>
 * 注意：
 * 用完必须调用p.recycle方法
 * <p>
 * Before:
 * <pre class="prettyprint">\
 * // ERROR: Might be "ClassCastException" Error
 * XXX x = intent.getParcelableExtra("XXX");
 * </pre>
 * <p>
 * After:
 * <pre class="prettyprint">
 * Parcelable pa = intent.getParcelableExtra("XXX");
 * Parcel p = ParcelUtils.createFromParcelable(pa);
 * <p>
 * // Create a new XXX object to avoid "ClassCastException"
 * XXX x = new XXX(p);
 * </pre>
 * <p>
 * 原因：
 * 即使包名、类名完全相同，若ClassLoader对象不同，则仍会抛出类型转换异常
 * 因此需要将其“重新”生成一份，等于用不同的ClassLoader生成两个对象，自然避免该问题
 * <p>
 * 常见于BroadcastReceiver中的Bundle，系统在判断源进程和目标进程一致时，会“透传”Bundle过来，
 * 故就算设置了setClassLoader，也不会做unparcel，自然也就会导致ClassCastException了
 *
 * @param pa 要构造的Parcelable对象
 * @return 可被构造函数使用的Parcel对象
 */
public static Parcel createFromParcelable(Parcelable pa) {
    if (pa == null) {
        return null;
    }

    Parcel p = Parcel.obtain();
    pa.writeToParcel(p, 0);
    p.setDataPosition(0);

    return p;
}