如何为Android Studio中PopupWindow弹窗内的按钮设置setOnClickListener？

问题根因 #

onCreate执行阶段，弹窗布局confirm_number_popup尚未被加载，直接调用Activity自带的findViewById()查找弹窗内的控件会返回null，后续调用setOnClickListener()触发空指针异常，就是你遇到的应用停止响应问题。

修复代码 #

你需要在弹窗布局完成inflate后，通过inflate返回的popupView对象查找弹窗内的按钮，再绑定点击事件，修改后的代码如下：

public void onButtonShowPopupWindowClick(View view) {
    // inflate the layout of the popup window
    LayoutInflater inflater = (LayoutInflater)
            getSystemService(LAYOUT_INFLATER_SERVICE);
    View popupView = inflater.inflate(R.layout.confirm_number_popup, null);

    hideSoftKeyboard(Register.this);

    // 在这里绑定弹窗内按钮的点击事件
    Button btnEdit = popupView.findViewById(R.id.btn_edit);
    Button btnOk = popupView.findViewById(R.id.btn_Ok);
    btnEdit.setOnClickListener(v -> {
        // 编写edit按钮的逻辑
        popupWindow.dismiss(); // 可选：点击后关闭弹窗
    });
    btnOk.setOnClickListener(v -> {
        // 编写ok按钮的逻辑
        popupWindow.dismiss(); // 可选：点击后关闭弹窗
    });

    // create the popup window
    int width = LinearLayout.LayoutParams.WRAP_CONTENT;
    int height = LinearLayout.LayoutParams.WRAP_CONTENT;
    boolean focusable = true; // lets taps outside the popup also dismiss it
    final PopupWindow popupWindow = new PopupWindow(popupView, width, height, false);

    // show the popup window
    // which view you pass in doesn't matter, it is only used for the window token
    popupWindow.showAtLocation(view, Gravity.CENTER, 0, 0);

    // dismiss the popup window when touched
    popupView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            popupWindow.dismiss();
            return true;
        }
    });
}

注意点 #

• 查找弹窗内控件必须调用弹窗根布局的findViewById()方法，不能用Activity的findViewById()
• 点击事件绑定逻辑要放在inflate布局之后，showAtLocation之前或之后都可以，只要保证是在布局加载完成后执行即可。

内容的提问来源于stack exchange，提问作者Shaurya Goyal