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我正在尝试在其中一个应用程序页面上动态添加一个按钮。我收到以下错误：

01-04 13:14:28.733: E/AndroidRuntime(811): FATAL EXCEPTION: main
01-04 13:14:28.733: E/AndroidRuntime(811): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.wb/com.example.wb.MainActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.os.Looper.loop(Looper.java:137)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.ActivityThread.main(ActivityThread.java:5039)
01-04 13:14:28.733: E/AndroidRuntime(811):  at java.lang.reflect.Method.invokeNative(Native Method)
01-04 13:14:28.733: E/AndroidRuntime(811):  at java.lang.reflect.Method.invoke(Method.java:511)
01-04 13:14:28.733: E/AndroidRuntime(811):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-04 13:14:28.733: E/AndroidRuntime(811):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-04 13:14:28.733: E/AndroidRuntime(811):  at dalvik.system.NativeStart.main(Native Method)
01-04 13:14:28.733: E/AndroidRuntime(811): Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.view.ViewGroup.addViewInner(ViewGroup.java:3339)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.view.ViewGroup.addView(ViewGroup.java:3210)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.view.ViewGroup.addView(ViewGroup.java:3155)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.view.ViewGroup.addView(ViewGroup.java:3131)
01-04 13:14:28.733: E/AndroidRuntime(811):  at com.example.wb.MainActivity.onCreate(MainActivity.java:63)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.Activity.performCreate(Activity.java:5104)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-04 13:14:28.733: E/AndroidRuntime(811):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-04 13:14:28.733: E/AndroidRuntime(811):  ... 11 more

这是我要添加的活动

public class MainActivity extends Activity {

EditText text1;

@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    int MY_BUTTON = 9000;
    Bundle extras = getIntent().getExtras();
    String userid = extras.getString("userid");

    //LayoutInflater factory = getLayoutInflater();
    LinearLayout ll = (LinearLayout)findViewById(R.id.linear);

    Button b = new Button(this);
    b.setText("Button added dynamically!");
    b.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
    b.setId(MY_BUTTON);
    ll.addView(b);

    /*UserLoginTask mAuthTask = new UserLoginTask();
    String urlwithget="?userid="+userid+"&task=alltitles";

    mAuthTask.execute(urlwithget);

       LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);  //Can also be done in xml by android:orientation="vertical"
        LinearLayout row = new LinearLayout(this);
        row.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));

        Button btnTag = new Button(this);
        btnTag.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        btnTag.setText("Button 1");
        btnTag.setId(2);
        row.addView(btnTag);
*/        
}

以下是我对此活动的布局

<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"
tools:context=".MainActivity" >

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:onClick="onClick"
    android:text="@string/logout" />

<Button
    android:id="@+id/button2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_marginRight="19dp"
    android:layout_toLeftOf="@+id/button1"
    android:onClick="goOn"
    android:text="@string/forward" />

<EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/button1"
    android:layout_marginTop="36dp"
    android:ems="10"
    android:text="@string/vishal" />

<LinearLayout
    android:id="@+id/linear"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/editText1"
    android:layout_marginLeft="60dp"
    android:layout_marginTop="58dp"
    android:orientation="vertical" >

</LinearLayout>

</RelativeLayout>

问题是什么？

4

2 回答 2

3

您声明 LinearLayout 是错误的：

这个 ：

LinearLayout ll = (LinearLayout)findViewById(R.layout.activity_main);

必须是这样的：

LinearLayout ll = (LinearLayout)findViewById(R.id.linear);
于 2013-01-04T14:23:06.003 回答
2

LayoutParams这段代码指的是什么子类：

new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT))

有多种类型，LayoutParams您必须根据要添加子视图的 ViewGroup 类型使用正确的类型。

在这种情况下，请确保使用LinearLayout.LayoutParams（请参阅http://developer.android.com/reference/android/widget/LinearLayout.LayoutParams.html）

于 2013-01-04T15:16:31.790 回答