如何在relativelayout中以编程方式设置重力

Question

如何在relativelayout中以编程方式设置重力.我有一个名为chat_viewer_message.xml的XML布局,如下所示:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/background"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingRight="4dip"
    android:paddingBottom="4dip"
    android:gravity="left"
    android:background="@drawable/chat_bg_in">

    <ImageView
        android:id="@+id/avatar"
        android:layout_width="32dip"
        android:layout_height="32dip"
        android:layout_marginLeft="4dip"
        android:src="@drawable/avatar_1_1"
        />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/avatar"
        android:paddingLeft="4dip"
        />

</RelativeLayout>

编程中的代码视图如下:

@Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final int type = getItemViewType(position);
        final View view;
        if (convertView == null) {
            final int resource = R.layout.chat_viewer_message;
            view = activity.getLayoutInflater()
                    .inflate(resource, parent, false);
            if (type == TYPE_MESSAGE)
                ((TextView) view.findViewById(R.id.text)).setTextAppearance(
                        activity, appearanceStyle);
        } else
            view = convertView;



        final MessageItem messageItem = (MessageItem) getItem(position);
        String name;
        final String account = messageItem.getChat().getAccount();
        final String user = messageItem.getChat().getUser();
        final String resource = messageItem.getResource();
        final boolean incoming = messageItem.isIncoming();
        final String server_host = view.getResources().getString(
                R.string.server_host);
        if (isMUC) {
            name = resource;
        } 


        if (incoming) {
            view.setBackgroundResource(R.drawable.chat_bg_in);
        } else {
            // I WANT TO GRAVITY TO RIGHT. HOW TO CODE? THANKS
            view.setBackgroundResource(R.drawable.chat_bg_out);
        }

        return view;
}

在id = background的relativelayout上看重力,默认的重力是LEFT,所以我想if!在relativelayout输入值gravity是RIGHT而不是LEFT.

谢谢.

Answer 1

铸造view于容器布局,在这种情况下RelativeLayout,并使用setGravity(int)它:

if (incoming) {
    view.setBackgroundResource(R.drawable.chat_bg_in);
} else {
    // I WANT TO GRAVITY TO RIGHT. HOW TO CODE? THANKS
    view.setBackgroundResource(R.drawable.chat_bg_out);

    ((RelativeLayout) view).setGravity(Gravity.RIGHT);
}

提醒一下(来自文档):

请注意,由于RelativeLayout认为每个子项相对于彼此的定位很重要,因此设置重力会影响所有子项在父项中作为单个单元的定位.儿童相对定位后会发生这种情况.

Answer 2

有两种主要方法可以以编程方式设置重力RelativeLayout.您可以为所有子视图setGravity(int)设置重力()或单独设置重力(params.addRule(int)).注意:这些方法不适用于LinearLayouts.

为所有孩子设定重力:

RelativeLayout relativeLayout = findViewById(R.id.myRelativeLaout);
relativeLayout.setGravity(Gravity.CENTER);

要在以下内容中设置单个视图的重力RelativeLayout:

MyView myView = findViewById(R.id.myView);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
        LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
myView.setLayoutParams(params);

资料来源:

• RelativeLayout.setGravity(INT)
• RelativeLayout.LayoutParams.addRule(INT)
• RelativeLayout.LayoutParams.removeRule(INT)

Answer 3

它适合我的情况:

    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.WRAP_CONTENT,
                    RelativeLayout.LayoutParams.WRAP_CONTENT);

    layoutParams.topMargin = 700;//in my case
    layoutParams.addRule(RelativeLayout.CENTER_HORIZONTAL);//in my case
    varButton.setLayoutParams(layoutParams);