addView() 的 IllegalStateException答案

【问题标题】：IllegalStateException for addView()addView() 的 IllegalStateException
【发布时间】：2016-07-10 13:06:35
【问题描述】：

XML：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.utente.test_dimensions.MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/main"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <EditText
                android:layout_width="160dp"
                android:layout_height="wrap_content"
                android:digits="123456789"
                android:hint="ID promemoria"/>
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="rimuovi prom." />
        </LinearLayout>
    </LinearLayout>
</RelativeLayout>

Java：

package com.example.utente.test_dimensions;

import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    LinearLayout main = (LinearLayout)findViewById(R.id.main);
    LinearLayout ll_eti = new LinearLayout(this);
    ll_eti.setOrientation(LinearLayout.VERTICAL);
    ll_eti.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    main.addView(ll_eti);

    TextView eti_txtv = new TextView(this);
    eti_txtv.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    eti_txtv.setText("Etichetta:");
    ll_eti.addView(eti_txtv);

    TextView val_eti_txtv = new TextView(this);
    val_eti_txtv.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    HorizontalScrollView eti_hsv = new HorizontalScrollView(this);
    eti_hsv.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    eti_hsv.addView(val_eti_txtv);
    ll_eti.addView(eti_hsv);

    LinearLayout ll_info = new LinearLayout(this);
    ll_info.setOrientation(LinearLayout.VERTICAL);
    LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    params.setMargins(0, 3, 0, 0);
    ll_info.setLayoutParams(params);
    main.addView(ll_info);

    LinearLayout ll_date = new LinearLayout(this);
    ll_date.setOrientation(LinearLayout.HORIZONTAL);
    ll_date.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    ll_info.addView(ll_date);

    TextView date = new TextView(this);
    date.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    date.setText("01/01/2000");
    ll_date.addView(date);

    TextView perm_not_y_or_n = new TextView(this);
    LinearLayout.LayoutParams params1 = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    params1.setMargins(10, 0, 0, 0);
    perm_not_y_or_n.setText("without permanent notificationW");
    ll_date.addView(perm_not_y_or_n);

    LinearLayout ll_details = new LinearLayout(this);
    LinearLayout.LayoutParams params2 = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    params2.setMargins(0, 3, 0, 0);
    ll_details.setOrientation(LinearLayout.HORIZONTAL);
    ll_details.setLayoutParams(params2);
    ll_info.addView(ll_details);

    TextView perm_val = new TextView(this);
    perm_val.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    perm_val.setText("Repetitive notification:");
    ll_details.addView(ll_info);

    TextView var_val = new TextView(this);
    LinearLayout.LayoutParams params3 = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    params3.setMargins(5, 0 , 0 , 0);
    var_val.setLayoutParams(params3);
    var_val.setText("every 100 minutes");
    ll_details.addView(var_val);

    LinearLayout ll_id = new LinearLayout(this);
    ll_id.setOrientation(LinearLayout.VERTICAL);
    ll_id.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    main.addView(ll_id);

    TextView ID_txtv = new TextView(this);
    LinearLayout.LayoutParams params4 = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    params4.setMargins(0, 5, 0, 0);
    ID_txtv.setLayoutParams(params4);
    ID_txtv.setText("ID:");
    ll_id.addView(ID_txtv);

    HorizontalScrollView horizontalScrollView = new HorizontalScrollView(this);
    horizontalScrollView.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    ll_id.addView(horizontalScrollView);

    TextView id_txtv = new TextView(this);
    id_txtv.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
    id_txtv.setText("p");
    horizontalScrollView.addView(id_txtv);


}

}

这是日志：

07-10 14:50:13.023 27776-27776/com.example.utente.test_dimensions E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                Process: com.example.utente.test_dimensions, PID: 27776
                                                                                java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.utente.test_dimensions/com.example.utente.test_dimensions.MainActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
                                                                                    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2352)
                                                                                    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2414)
                                                                                    at android.app.ActivityThread.access$900(ActivityThread.java:151)
                                                                                    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1318)
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                    at android.os.Looper.loop(Looper.java:135)
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5282)
                                                                                    at java.lang.reflect.Method.invoke(Native Method)
                                                                                    at java.lang.reflect.Method.invoke(Method.java:375)
                                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)
                                                                                 Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
                                                                                    at android.view.ViewGroup.addViewInner(ViewGroup.java:3937)
                                                                                    at android.view.ViewGroup.addView(ViewGroup.java:3787)
                                                                                    at android.view.ViewGroup.addView(ViewGroup.java:3728)
                                                                                    at android.view.ViewGroup.addView(ViewGroup.java:3701)
                                                                                    at com.example.utente.test_dimensions.MainActivity.onCreate(MainActivity.java:67)
                                                                                    at android.app.Activity.performCreate(Activity.java:6865)
                                                                                    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                                                                                    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
                                                                                    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2414) 
                                                                                    at android.app.ActivityThread.access$900(ActivityThread.java:151) 
                                                                                    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1318) 
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                                    at android.os.Looper.loop(Looper.java:135) 
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5282) 
                                                                                    at java.lang.reflect.Method.invoke(Native Method) 
                                                                                    at java.lang.reflect.Method.invoke(Method.java:375) 
                                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904) 
                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

我正在测试将视图添加到 xml 文件（对于我的应用程序）；我不明白为什么这不起作用，你有什么建议吗？我看到每个人都使用 addView() 将视图添加到布局中，但是为什么这对我不起作用？

【问题讨论】：

标签： java android xml view illegalstateexception

【解决方案1】：

您不能将同一个视图添加到两个不同的父级或将一个视图添加到一个父级两次。

您似乎正在尝试将ll_info 视图添加到main 视图和ll_details。

【讨论】：

非常感谢；事实上，应该是ll_details.addView(ll_info);，但是我看不到那个错误

【解决方案2】：

您的问题是您试图将视图添加到另一个视图，但该视图已添加到另一个视图。

在第 67 行你正在做：

ll_details.addView(ll_info);

尝试将 ll_info 添加到 ll_details。但是在第 39 行，您已经将 ll_info 添加到主视图中：

main.addView(ll_info);

您不能将同一个视图对象添加到两个不同的父级。

【讨论】：