Android

Question

在 Whosebug 社区中搜索了很多解决方案，但 none 解决了我的问题：我在 Main.java activity 中有一个 button，当 button单击后，弹出菜单不显示，整个应用程序崩溃。

这是我的代码：

 Button _buyurtmaYaratish = (Button) findViewById(R.id.btn_buyurtma_berish);
    _buyurtmaYaratish.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
            View popupView = layoutInflater.inflate(R.layout.popup_menu, null);
            final PopupWindow popupWindow = new PopupWindow(popupView, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

Button btnPopup = (Button) findViewById(R.id.btn_popup);
                btnPopup.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        popupWindow.dismiss();
                    }
                });
                popupWindow.showAsDropDown(btnPopup, 50, -30);
            }
        });

我的Main.xml代码：

<RelativeLayout.......

<Button
        android:id="@+id/btn_buyurtma_berish"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:text="@string/buyurtma_berish"
        android:background="@drawable/button_kirish"
        android:textSize="18sp"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="20dp"
        android:textColor="@color/white"
        android:layout_below="@+id/edtx_summa_miqdori"/>

</RelativeLayout>

我的popup.xml代码：

 <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rl"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center">
    <TextView
        android:id="@+id/txt_kk_mas_popup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/aloqaga_chiqamiz"
        android:layout_centerHorizontal="true"
        android:textSize="18sp"
        android:layout_marginTop="30dp"
        android:textColor="@color/black"/>
    <Button
        android:layout_width="280dp"
        android:layout_height="wrap_content"
        android:background="@drawable/button_kirish"
        android:text="@string/tasdiqlash"
        android:textColor="@color/white"
        android:textSize="19sp"
        android:id="@+id/btn_popup"
        android:layout_below="@+id/txt_kk_mas_popup"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="25dp" />
   </RelativeLayout>

我做错了什么？

java.lang.NullPointerException
                                                                    at datasite.com.aroba.DelHome.onClick(DelHome.java:49)
                                                                    at android.view.View.performClick(View.java:4192)
                                                                    at android.view.View$PerformClick.run(View.java:17248)
                                                                    at android.os.Handler.handleCallback(Handler.java:615)
                                                                    at android.os.Handler.dispatchMessage(Handler.java:92)
                                                                    at android.os.Looper.loop(Looper.java:137)
                                                                    at android.app.ActivityThread.main(ActivityThread.java:4950)
                                                                    at java.lang.reflect.Method.invokeNative(Native Method)
                                                                    at java.lang.reflect.Method.invoke(Method.java:511)
                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:997)
                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:764)
                                                                    at dalvik.system.NativeStart.main(Native Method)

当我尝试单击 button

时，它在 Logcat 中突出显示为红色

Answer 1

改变这个 :-> Button btnPopup = (Button) findViewById(R.id.btn_popup);

用这个 :-> Button btnPopup = (Button) popupView.findViewById(R.id.btn_popup); 在你的代码中

喜欢下面的代码

     Button _buyurtmaYaratish = (Button) findViewById(R.id.btn_buyurtma_berish);
    _buyurtmaYaratish.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
            View popupView = layoutInflater.inflate(R.layout.popup_menu, null);
            final PopupWindow popupWindow = new PopupWindow(popupView, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

Button btnPopup = (Button) popupView.findViewById(R.id.btn_popup);
                btnPopup.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        popupWindow.dismiss();
                    }
                });
                popupWindow.showAsDropDown(btnPopup, 50, -30);
            }
        });

Answer 2

我认为你在这里犯了错误:

Button btnPopup = (Button) findViewById(R.id.btn_popup);

改成这样：

Button btnPopup = (Button) popupView.findViewById(R.id.btn_popup);

Answer 3

使用 Button btnPopup = (Button)popupView.findViewById(R.id.btn_popup) 而不是 Button btnPopup = (Button) findViewById(R.id.btn_popup) 作为

Answer 4

使用这个：

Button btnPopup = (Button) popupView.findViewById(R.id.btn_popup);

而不是这个：

Button btnPopup = (Button) findViewById(R.id.btn_popup);

Answer 5

不要使用Popup window，您最好使用AlertDialog，它不仅易于构建，而且可以同时获得类似的背景效果。更灵活 move/change 并且工作顺畅

Android - 弹出 window 崩溃

Android - Popup window crashing

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