java.lang.IndexOutOfBoundsException：索引2无效，大小为2错误

Question

我对Java很新。该应用程序运行，但当我点击＆＃34;隐私＆＃34;按钮它崩溃它给我在瓷砖中命名的错误。我怀疑它是setClickListener中的东西，但我没有看到它有什么问题。当我使用Arrays而不是ArrayLists时它工作得很好。任何建议表示赞赏，提前谢谢：）

我收到了这段代码：

public class accordion extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.accordion);

        ViewGroup ll = (ViewGroup)findViewById(R.id.root_layout);
        final int count = ll.getChildCount();

        final ArrayList<Button> buttons = new ArrayList <> (count);
        final ArrayList<LinearLayout> panels = new ArrayList <> (count);

        for(int i = 0; i < count; i++){
            View child = ll.getChildAt(i);
            if (child instanceof Button) {
                buttons.add((Button) child);
            } else if (child instanceof LinearLayout){
                panels.add((LinearLayout) child);
            }
        }

        for (int i = 0; i < panels.size(); i++){
            panels.get(i).setVisibility(View.GONE);
        }

        final Context context = getApplicationContext();

        for (int i = 0; i < buttons.size(); i++){
            final int x = i;

            buttons.get(i).setBackgroundColor(ContextCompat.getColor(context, R.color.button_not_pressed));
            buttons.get(i).setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    for (int y = 0; y < panels.size(); y++) {
                        panels.get(y).setVisibility(View.GONE);
                    }
                    panels.get(x).setVisibility(View.VISIBLE);


                    for (int y = 0; y < buttons.size(); y++) {
                        buttons.get(y).setBackgroundColor(ContextCompat.getColor(context, R.color.button_not_pressed));
                    }
                    buttons.get(x).setBackgroundColor(ContextCompat.getColor(context, R.color.button_pressed));
                }
            });
        }
    }
}

XML：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFFFF"
    android:orientation="vertical">

    <Button
        android:id="@+id/btnProfile"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Profile"
        android:textColor="#FFFFFFFF" />

    <LinearLayout
        android:id="@+id/panelProfile"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:background="#FFFFFFFF">

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

            <LinearLayout
                android:orientation="vertical"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="#FFFFFFFF">

                <LinearLayout
                    android:id="@+id/panelProfile1"
                    android:orientation="horizontal"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#FFFFFFFF">

                    <TextView
                        android:id="@+id/strName"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="Name" />

                    <EditText
                        android:id="@+id/txtName"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content" />

                </LinearLayout>


                <LinearLayout
                    android:id="@+id/panelProfile2"
                    android:orientation="horizontal"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#FFFFFFFF">

                    <TextView
                        android:id="@+id/strSurname"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="Surname" />

                    <EditText
                        android:id="@+id/txtSurname"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content" />

                </LinearLayout>

            </LinearLayout>

        </ScrollView>

    </LinearLayout>



    <Button
        android:id="@+id/btnSettings"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Settings"
        android:textColor="#FFFFFFFF" />

    <LinearLayout
        android:id="@+id/panelSettings"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:background="#FFFFFFFF">

        <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">

                <LinearLayout
                    android:id="@+id/panelSettings1"
                    android:orientation="horizontal"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#FFFFFFFF">

                    <TextView
                        android:id="@+id/strMail"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="e-mail" />

                    <EditText
                        android:id="@+id/txtMail"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content" />

                </LinearLayout>

                <LinearLayout
                    android:id="@+id/panelSettings2"
                    android:orientation="horizontal"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#FFFFFFFF">

                    <TextView
                        android:id="@+id/strPhone"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="Phone" />

                    <EditText
                        android:id="@+id/txtPhone"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content" />

                </LinearLayout>

            </LinearLayout>

        </ScrollView>

    </LinearLayout>



    <Button
        android:id="@+id/btnPrivacy"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Privacy"
        android:textColor="#FFFFFFFF" />

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

        <LinearLayout
            android:id="@+id/panelPrivacy"
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="#FFFFFFFF">

            <CheckBox
                android:id="@+id/checkFacebook"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Facebook"
                android:textColor="#ff355689">
            </CheckBox>
            <CheckBox
                android:id="@+id/checkLinkedIn"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="LinkedIn"
                android:textColor="#ff355689">
            </CheckBox>
            <CheckBox
                android:id="@+id/checkTwitter"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Twitter"
                android:textColor="#ff355689">
            </CheckBox>

        </LinearLayout>

    </ScrollView>

</LinearLayout>

堆栈跟踪（抱歉可怕的格式化）：

 FATAL EXCEPTION: main
 Process: mika.actual, PID: 19413
 java.lang.RuntimeException: Unable to start activity ComponentInfo{mika.actual/mika.actual.accordion}: java.lang.IndexOutOfBoundsException: Invalid index 2, size is 2
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2413)
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
 at android.app.ActivityThread.access$900(ActivityThread.java:175)
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
 at android.os.Handler.dispatchMessage(Handler.java:102)
 at android.os.Looper.loop(Looper.java:146)
 at android.app.ActivityThread.main(ActivityThread.java:5602)
 at java.lang.reflect.Method.invokeNative(Native Method)
 at java.lang.reflect.Method.invoke(Method.java:515)
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
 at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.IndexOutOfBoundsException: Invalid index 2, size is 2
 at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
 at java.util.ArrayList.get(ArrayList.java:308)
 at mika.actual.accordion.onCreate(accordion.java:37)
 at android.app.Activity.performCreate(Activity.java:5451)
 at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471) 
 at android.app.ActivityThread.access$900(ActivityThread.java:175) 
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308) 
 at android.os.Handler.dispatchMessage(Handler.java:102) 
 at android.os.Looper.loop(Looper.java:146) 
 at android.app.ActivityThread.main(ActivityThread.java:5602) 
 at java.lang.reflect.Method.invokeNative(Native Method) 
 at java.lang.reflect.Method.invoke(Method.java:515) 
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
 at dalvik.system.NativeStart.main(Native Method)

Answer 1

尝试替换

panels.get(x).setVisibility(View.VISIBLE);

与

panels.get(y).setVisibility(View.VISIBLE);

Answer 2

你的问题在这一行：

panels.get(x).setVisibility(View.VISIBLE);

您有三个按钮，但只有两个线性布局。当您单击第三个按钮时，您正在尝试访问第三个线性布局，而不是那里。