以编程方式为 RecyclerView 中的项目设置引力 Android

Question

我正在使用 RecyclerView Android 与 left/right 消息框进行聊天。我想将重力设置为 RecyclerView 的项目。通常，我将 itemView 转换为 LinearLayout，然后为其设置 ParamLayout 引力。但是如果是RecyclerView，投给LinearLayout好像不太对。它将 return RecyclerView.LayoutParams。因为：

LayoutParams subclass for children of RecyclerView. Custom layout managers are encouraged to create their own subclass of this LayoutParams class to store any additional required per-child view metadata about the layout.

而且我找不到用 RecyclerView.LayoutParams 设置重力的方法:| 不管怎样，有人能在 RecyclerView 中找到引力项的方法吗？请推荐我。

------------POST 解决方案-----------------
//1。 RecyclerView 的子级

      <LinearLayout
android:id="@+id/id_grandparent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:color/transparent"
android:divider="@android:color/transparent"
android:gravity="left"
android:orientation="vertical">
<LinearLayout
    android:id="@+id/id_llparent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/bg_customer_feedback_left"
    android:gravity="left"
    android:orientation="vertical">
</LinearLayout>

//2。 OnBindView()

 LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        params = setLayoutParamsForParent(params, item.isPosition());
        holder.llParentLayout.setLayoutParams(params); //corresponding to id_llparent ID

//3。

     private LinearLayout.LayoutParams setLayoutParamsForParent(LinearLayout.LayoutParams params, boolean position) {
        params.gravity = position ? Gravity.RIGHT : Gravity.LEFT;
         return params;
    }

Answer 1

问题已解决。简单地说，我使用

 LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

而不是

RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) holder.llGrandParent.getLayoutParams();

然后正常设置LinearLayout Params的gravity。

Answer 2

我通过在项目布局内的视图上设置重力来做到这一点。

LinearLayout.LayoutParams paramsMsg = new LinearLayout.
            LayoutParams(android.view.ViewGroup.LayoutParams.WRAP_CONTENT,
            android.view.ViewGroup.LayoutParams.WRAP_CONTENT);
    if (position%2 == 0){
        holder.bodyView.setBackgroundResource(R.drawable.outgoing_messages);
        paramsMsg.gravity = Gravity.END;
    } else {
        holder.bodyView.setBackgroundResource(R.drawable.incoming_messages);
        holder.bodyView.setTextColor(0xf08888);
        paramsMsg.gravity = Gravity.START;
    }
    holder.bodyView.setLayoutParams(paramsMsg);

bodyView 是项目布局中的 TextView，项目宽度为 "match_parent"。

以编程方式为 RecyclerView 中的项目设置引力 Android

Set gravity programmatically for item in RecycerView Android

android

gravity

android-recyclerview