Android 在列表List中显示半透明小窗体效果的控件

想实现图中这样中间有半透明窗体的效果么？

Android 在列表List中显示半透明小窗体效果的控件，多的不多直接上代码，要说的都在注释里了：

import android.content.Context;  import android.graphics.PixelFormat;  import android.os.Handler;  import android.view.LayoutInflater;  import android.view.View;  import android.view.WindowManager;  import android.view.WindowManager.LayoutParams;  import android.widget.TextView;    /**  * 窗口中间显示半透明提示框的小组件  * 用法：1. new 2. showPrevLetter(String prevLetter)  * @author LL  *  */  public class PrevLetterDialog {      //窗体消失的延时时间      private static final int DELAYED_HIDEN = 500;        // 实现Runnable接口的类      private RemoveWindow mRemoveWindow = new RemoveWindow();      //在Handler里能实现对UI线程的修改      private Handler mHandler;      //窗体管理器      private WindowManager mWindowManager;      //显示在窗体中间半透明的字体框      private TextView mDialogText;      //是否正在显示中      private boolean mShowing;      //是否准备好显示了      private boolean mReady;      //显示在窗体中的字符      private char mPrevLetter = Character.MIN_VALUE;            /**      * 注明：context一定要在可见UI中通过getContext()获得，否则会抛异常。      * @param context      */      public PrevLetterDialog(Context context) {          //得到窗体管理器          mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);            //得到布部创建者          LayoutInflater inflate = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);          //得到TextView          mDialogText = (TextView) inflate.inflate(R.layout.list_position, null);          //设TextView为可见          mDialogText.setVisibility(View.INVISIBLE);                    //通过handler把mDialogText展示出来          mHandler = new Handler();          //要用post可实现在多线程里调用UI线程并改变          mHandler.post(new Runnable() {              public void run() {                  mReady = true;                  //窗体的布局参数                  WindowManager.LayoutParams lp = new WindowManager.LayoutParams(LayoutParams.WRAP_CONTENT,                          LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_APPLICATION,                          WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,                          PixelFormat.TRANSLUCENT);                  //把TextView添加到窗体中去                  mWindowManager.addView(mDialogText, lp);              }          });                }            //设置可见性      public void setmReady(boolean mReady) {          this.mReady = mReady;      }        /**      * 一般用在onScroll方法中,参数是字符串，不能为空，会取第一个字符显示      * @param prevLetter      */      public void showPrevLetter(String prevLetter) {          if (!mReady) {              return;          }          char firstLetter = prevLetter.charAt(0);            if (!mShowing && firstLetter != mPrevLetter) {                            mShowing = true;              mDialogText.setVisibility(View.VISIBLE);            }          //设TextView显示的字体          mDialogText.setText(((Character) firstLetter).toString());          //移除mRemoveWindow实现的Runnable接口类          mHandler.removeCallbacks(mRemoveWindow);          //添加mRemoveWindow实现的Runnable接口类，并设延时          mHandler.postDelayed(mRemoveWindow, DELAYED_HIDEN);          mPrevLetter = firstLetter;        }        /**      * 实现Runnable接口的类      */      private final class RemoveWindow implements Runnable {          public void run() {              removeWindow();          }      }        private void removeWindow() {          if (mShowing) {              mShowing = false;              mDialogText.setVisibility(View.INVISIBLE);          }      }    }

<?xml version="1.0" encoding="utf-8"?>  <TextView xmlns:android="http://schemas.android.com/apk/res/android"      android:textSize="50sp"      android:textColor="@color/band_common_content"      android:background="@drawable/common_list_title"      android:minWidth="70dip"      android:layout_height="wrap_content"      android:padding="5dip"      android:gravity="center"  />

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