Android简单PopWindow的实现方法。

直接上代码。
首先是布局：
activity_main.xml中：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
 >

<Button
 android:id="@+id/start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="点击弹出" />

</RelativeLayout>

然后popwindowlayout.xml中代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/layout_shape"
android:orientation="vertical" >

<Button
 android:id="@+id/first"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="5dp"
android:background="@drawable/btn_shape"
android:text="一" />

<Button
 android:id="@+id/second"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_marginLeft="10dp"
android:background="@drawable/btn_shape"
android:layout_marginRight="10dp"
android:text="二" />

<Button
 android:id="@+id/third"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_marginLeft="10dp"
android:background="@drawable/btn_shape"
android:layout_marginRight="10dp"
android:text="三" />

</LinearLayout>

然后，两个动画:
popshow_anim.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate
 android:duration="1000"
android:fromYDelta="100%p"
android:toYDelta="0" />

<alpha
 android:duration="1000"
android:fromAlpha="0.0"
android:toAlpha="1.0" />
</set>

pophidden_anim.xml:

<set xmlns:android="http://schemas.android.com/apk/res/android">

<translate
 android:duration="1000"
android:fromYDelta="0"
android:toYDelta="50%p" />

<alpha
 android:duration="1000"
android:fromAlpha="1.0"
android:toAlpha="0.0" />
</set>

再次。两个shape文件：
btn_shape.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android">    
<corners android:topLeftRadius="8dp" 
android:topRightRadius="8dp" 
android:bottomRightRadius="8dp" 
android:bottomLeftRadius="8dp"/>    
</shape>  

layout_shape.xml：

<shape xmlns:android="http://schemas.android.com/apk/res/android">    
<solid android:color="#f4f4f4" />    
<corners android:topLeftRadius="8dp" 
android:topRightRadius="8dp" 
 />    
</shape>  

最后，MainActivity代码：

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button start = (Button) findViewById(R.id.start);
        start.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
                showPopwindow();
            }

        });

    }
private void showPopwindow() {
        LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.popwindowlayout, null);
        PopupWindow window = new PopupWindow(view,
                WindowManager.LayoutParams.MATCH_PARENT,
                WindowManager.LayoutParams.WRAP_CONTENT);
        window.setFocusable(true);

        ColorDrawable dw = new ColorDrawable(0xffffffff);
        window.setBackgroundDrawable(dw);

        window.setAnimationStyle(R.style.PopupAnimation);
        window.showAtLocation(MainActivity.this.findViewById(R.id.start),
                Gravity.BOTTOM, 0, 0);
        Button first = (Button) view.findViewById(R.id.first);
        first.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {


            }
        });

        window.setOnDismissListener(new OnDismissListener() {

@Override
public void onDismiss() {

            }
        });

    }
}

当然，还需要在style.xml文件中定义动画样式。

<style name="PopupAnimation">          
        <item name="android:windowEnterAnimation">@anim/popshow_anim</item>     
        <item name="android:windowExitAnimation">@anim/pophidden_anim</item>     
    </style> 

完。效果如下