最近做的android專案中經常用到PopupWindow,今天就來總結一下如何實現透明懸浮的PopupWindow效果，廢話不多說，先上圖和程式碼。

下面是PopupWindow的佈局檔案XML：

<?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="match_parent"
android:orientation=
 
"vertical"
android:gravity="center_horizontal"
android:background="@drawable/bg_change_ip">
    <TextViewandroid:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/login_name2"
android:padding="5dp"
android:textSize="16sp"
android:layout_marginTop="10dp"
android:textColor=
 
"@color/bg_line"/>
    <TextViewandroid:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/login_name3"
android:textColor="@color/bg_line"/>
    <View
android:layout_width="match_parent"
android:layout_height="0.5dp"
android:background="@color/bg_line1"
android:layout_marginTop=
 
"15dp"/>
    <TextViewandroid:id="@+id/tv_change_ip_nei"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/login_name4"
android:padding="8dp"
android:textSize="16sp"
android:textColor="@color/colorPrimary"/>
    <View
android:layout_width="match_parent"
android:layout_height="0.5dp"
android:background="@color/bg_line1"
/>
    <TextViewandroid:id="@+id/tv_change_ip_wai"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/login_name5"
android:padding="5dp"
android:textSize="16sp"
android:textColor="@color/colorPrimary"/>
    <View
android:layout_width="match_parent"
android:layout_height="0.5dp"
android:background="@color/bg_line1"
/>
    <TextViewandroid:id="@+id/tv_change_ip_cancel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/login_name6"
android:paddingTop="5dp"
android:textSize="16sp"
android:textColor="@color/colorPrimaryDark"
android:paddingBottom="15dp"/>
</LinearLayout>

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
    <corners android:radius="10dp"/>//設定圓角角度
    <solid android:color="#EEFFFFFF"/>//設定背景為白色帶透明
</shape>

下面就自定義我們需要的PopupWindow了：

public class ChangeIPPopupWindow extends PopupWindow{

    private Context context;
//彈出的檢視物件
private View popView;
    private TextView tvNei;
    private TextView tvWai;
    private TextView tvCancel;
    public ChangeIPPopupWindow(Context context){
        this.context = context;
LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
popView = inflater.inflate(R.layout.popup_change_ip,null);
//設定引數
initSetting();
initView();
}

    private void initSetting() {
        //載入檢視
this.setContentView(popView);
//設定寬高
this.setWidth(400);
        this.setHeight(ActionBar.LayoutParams.WRAP_CONTENT);
//設定點選消失
this.setFocusable(true);
        this.setOutsideTouchable(true);
//設定背景
ColorDrawable cd = new ColorDrawable();
        this.setBackgroundDrawable(cd);
//this.getBackground().setAlpha(50);
        //this.setBackgroundDrawable(new ColorDrawable(android.graphics.Color.parseColor("#FFFFFF")));
}

    private void initView(){
        tvNei = (TextView) popView.findViewById(R.id.tv_change_ip_nei);
tvWai = (TextView) popView.findViewById(R.id.tv_change_ip_wai);
tvCancel = (TextView) popView.findViewById(R.id.tv_change_ip_cancel);
tvNei.setOnClickListener(new IpOnClickListener());
tvWai.setOnClickListener(new IpOnClickListener());
tvCancel.setOnClickListener(new IpOnClickListener());
}

    class IpOnClickListener implements View.OnClickListener {
        @Override
public void onClick(View v) {
            if(v == tvNei){//修改處內ip
}else if(v == tvWai){//修改處外ip
}else if(v == tvCancel){//取消
dismiss();
}
        }
    }

}

private void showChangeIPView(){
    //建立自定義的PopupWindow
ChangeIPPopupWindow ipView = new ChangeIPPopupWindow(this);
//背景變透明
MainUtils.setBackgroundAlpha(this,0.5f);
//居中顯示
ipView.showAtLocation(etName, Gravity.CENTER,0,0);
//設定PopupWindow消失監聽，消失時恢復背景透明
ipView.setOnDismissListener(new PopupWindow.OnDismissListener() {
        @Override
public void onDismiss() {
            MainUtils.setBackgroundAlpha(LoginActivity.this,1.0f);
}
    });
}

/**
 * 改變當前頁面的背景透明度
 * @param activity
* @param alpha 透明度值，0-1
 */
public static void setBackgroundAlpha(Activity activity,float alpha){
    WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
lp.alpha = alpha;
activity.getWindow().setAttributes(lp);
}