實現載入等待介面我用了兩種方式，一種是用PopupWindow實現，另一種便是用Activity實現。用Activity實現方法請見我的另一篇部落格：

首先看效果：

用PopupWindow實現此功能還是比較簡單的，首先我們寫一個佈局，只有一個登入按鈕，用於觸發等待介面：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
 

    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop
 
="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.toprs.myapplication.MainActivity">

    <Button
        android:text="登入"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="loginClick"
        android:id
 
="@+id/button2"/>
</LinearLayout>

然後為登入按鈕新增監聽事件：

package com.wang.myapplication;

import ...

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void loginClick(View v){
        final PopupWindow popupWindow = new PopupWindow();
        popupWindow.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
        popupWindow.setWidth(ViewGroup.LayoutParams.WRAP_CONTENT);
        popupWindow.setFocusable(true);
        View view = LayoutInflater.from(this).inflate(R.layout.popup,null);
        popupWindow.setContentView(view);
        popupWindow.showAtLocation(getWindow().getDecorView(), Gravity.CENTER,0,0);

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(MainActivity.this, "登入成功", Toast.LENGTH_SHORT).show();
                popupWindow.dismiss();
            }
        },2000);
    }
}

其中彈出的PopupWindow需要一個佈局，也就是簡單放入一個ProgressBar：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="200dp"
                android:layout_height="200dp">

    <ProgressBar
        android:id="@+id/progressBar4"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"/>

</RelativeLayout>

大功告成，執行一下即可！！