用於實現彈窗，可以任意自定義佈局，android中彈窗可以分為AlertDialog和popupWindow，AlertDialog只能顯示固定在中間位置，popupWindow可以在任意位置，相對更加靈活。

1.主佈局設定

<Button
        android:id="@+id/button_submit"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="提交"
        android:textSize="20sp"
 

        android:onClick="submitClick"/>

2.自定義彈窗佈局

<Button
        android:id="@+id/button_update"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="更新"
        android:textSize="20sp"
        android:layout_weight="1"/>
    <Button
        android:id
 
="@+id/button_delete"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="刪除"
        android:textSize="20sp"
        android:layout_weight="1"/>

3.程式碼實現
//為彈窗提供自定義的佈局
//建立彈窗PopupWindow
//設定相關的屬性
//顯示彈窗

private View button_update;
    private
 
 View button_delete;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    //點選button事件
    public void submitClick(View view){
        showSubmitClick(view);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private void showSubmitClick(View view) {  View v=getLayoutInflater().inflate(R.layout.popup_window,null);  //載入的佈局
        button_update = v.findViewById(R.id.button_update);
        button_delete = v.findViewById(R.id.button_delete);

//建立彈窗popupwindow
        PopupWindow popupWindow =new PopupWindow(v, ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,true);

 //設定背景      popupWindow.setBackgroundDrawable(getDrawable(R.mipmap.index_intro_bg));
        BitmapDrawable bitmapDrawable =new BitmapDrawable(getResources(),
                BitmapFactory.decodeResource(getResources(),R.mipmap.index_intro_bg));
        //設定透明度
        popupWindow.getBackground().setAlpha(80);
        //設定動畫效果      popupWindow.setAnimationStyle(android.R.anim.fade_in);
        //設定點選彈窗外面消失
        popupWindow.setOutsideTouchable(true);
        //設定防止軟鍵盤遮擋popupWindow.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_MODE_CHANGED);
        //顯示彈窗
        popupWindow.showAsDropDown(view);
        //設定點選事件
        button_delete.setOnClickListener(this);
        button_update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "更新成功", Toast.LENGTH_SHORT).show();
            }
        });
    }

    @Override
    public void onClick(View v) {
        Toast.makeText(MainActivity.this, "刪除成功", Toast.LENGTH_SHORT).show();
    }