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我正在嘗試做一個PopupWindow
來解釋我的應用程序,但是對於看似簡單的事情我有很多困難。我嘗試過各種YouTube視頻,並在這裏查看幾乎所有類似的帖子,但我還沒有任何運氣。如果有人能指出我的缺陷,那會很棒。彈出式窗口繼續崩潰
我的最終目標是讓PopupWindow和on create方法一起出現,但是現在我包含了一個Button來啓動它,因爲所有的教程都包含了一個。
protected void onCreate(Bundle savedInstanceState) {
//BUILDING THE POP UP WINDOW ON CLICK OF HELP BUTTON
help=(Button)findViewById(R.id.help);
help.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
layoutInflater=(LayoutInflater)getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
View customView= layoutInflater.inflate(R.layout.activity_instructions, null);
popUpWindow=new PopupWindow(
customView,
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT
);
myButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
popUpWindow.dismiss();
}
});
}
});
任何幫助將不勝感激。如果我需要包含更多信息,請不要問。我是新來的機器人,這是我的第一個大應用程序,以保持我的希望。
07-30 23:32:07.062 9273-9273/my.myCompany.vinay.diversityformulaapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: my.myCompany.vinay.diversityformulaapplication, PID: 9273
java.lang.RuntimeException: Unable to start activity ComponentInfo{my.myCompany.vinay.diversityformulaapplication/my.myCompany.vinay.diversityformulaapplication.EntryScreen}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2947)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3008)
at android.app.ActivityThread.-wrap14(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1650)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6688)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at my.myCompany.vinay.diversityformulaapplication.EntryScreen.onCreate(EntryScreen.java:37)
at android.app.Activity.performCreate(Activity.java:6912)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1126)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2900)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3008)
at android.app.ActivityThread.-wrap14(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1650)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6688)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
你的日誌文件在哪裏? –
如何獲取日誌文件? – bobthebuilder
請參閱[本教程](https://www.javatpoint.com/android-popup-menu-example)。 – Abhi