java - 我在抽屉导航的 fragment 标记内放置了一个按钮。单击按钮时应用程序崩溃

Question

当我将 setText 添加到 onclickListener 中时，应用程序崩溃。

buttonlar = container.findViewById(R.id.buttonlar);
        text = container.findViewById(R.id.text);

        View view = inflater.inflate(R.layout.fragment_first, container, false);
        buttonlar = view.findViewById(R.id.buttonlar);
        buttonlar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                text.setText("test");


            }
        });
        return view;



    }

日志猫

2019-07-14 23:49:09.953 16842-16842/com.medicalsix.doctorsix E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.medicalsix.doctorsix, PID: 16842
    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
        at com.medicalsix.doctorsix.First$1.onClick(First.java:50)
        at android.view.View.performClick(View.java:7251)
        at android.view.View.performClickInternal(View.java:7228)
        at android.view.View.access$3500(View.java:802)
        at android.view.View$PerformClick.run(View.java:27843)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7116)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:925)

而不是

text.setText("test");

如果我使用它，就会发生这种情况。

Log.i("Test", "Test.");

您可以通过 github 链接访问我的项目的详细信息。

https://github.com/prensmiskin/DoctorSix/blob/master/app/src/main/java/com/medicalsix/doctorsix/First.java

fragment.xml代码

如果你知道的话，可以帮忙吗？

 <?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        tools:context=".First"
        android:orientation="vertical"
        android:id="@+id/bir">


            <ScrollView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                >

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                    <Button
                        android:id="@+id/buttonlar"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Dentofasiyal deformite"
                        android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <TextView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="ssss"
                    android:id="@+id/text"
                    android:textSize="20sp"/>
                    <Button
                        android:id="@+id/legcdurlyvideo"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Dumbbell Fly "
                        android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <Button
                    android:id="@+id/legcurlydvideo"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dumbbell Fly "
                    android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <Button
                    android:id="@+id/legcurlyvidedo"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dumbbell Fly "
                    android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <Button
                    android:id="@+id/legcurlyvidseo"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dumbbell Fly "
                    android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <Button
                    android:id="@+id/legcurlyvideso"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dumbbell Fly "
                    android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <Button
                    android:id="@+id/legcurlyvaideos"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dumbbell Fly "
                    android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>
                    <Button
                    android:id="@+id/legcurlsyvideos"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dumbbell Fly "
                    android:textSize="20sp"
                        android:background="@color/colorPrimary"
                        android:textColor="@android:color/black"/>

                    <ImageView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:src="@drawable/cene"
                        android:adjustViewBounds="true"/>




                    <WebView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        tools:ignore="WebViewLayout"
                        android:id="@+id/webview"/>


    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/cene"
        android:textSize="20sp"/>


                </LinearLayout>




            </ScrollView>










    </FrameLayout>

Answer 1

我相信您应该从膨胀 View 中获取 TextView 而不是 container (无论是什么)。尝试以下操作，

        //buttonlar = container.findViewById(R.id.buttonlar);
        //text = container.findViewById(R.id.text);

        View view = inflater.inflate(R.layout.fragment_first, container, false);
        buttonlar = view.findViewById(R.id.buttonlar);
        //Use the inflated view to get the text (just like you did for buttonlar)
        text = view.findViewById(R.id.text);
        buttonlar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                text.setText("test");
            }
        });
        return view;
    }