错误"The specified child already has a parent"之后 LinearLayout.addView() 然后是 Linearlayout.removeView()

Question

我正在处理一个项目，在该项目中，我在activity_main.xml上创建了一个id为linear_parent的父LinearLayout。在该父布局中，n个LinearLayouts是基于用户在EditText(id为no_of_views_input(处的输入以编程方式创建的。在每个LinearLayout中，都有更多以编程方式创建的子视图(imageView、edit、button(。

假设用户输入4no_of_views_input，则视图层次结构将类似于

====================

1. linear_parent
   • linear布局//位置1
     • imageView
     • 编辑
     • 按钮
   • linearLayout //位置2
     • imageView
     • 编辑
     • 按钮
   • linearLayout //位置3
     • imageView
     • 编辑
     • 按钮
   • linearLayout //位置4
     • imageView
     • 编辑
     • 按钮

=======

创建这些布局和视图后，我想根据子id＝编辑的用户输入重新排列LinearLayouts。假设用户在LinearLayout位置3的edit上输入1，我想要的是，必须将位置3的当前LinearLayouts及其子项添加到位置1，并最终删除位置3的旧LinearLayoutout。(如果指数向下移动，当前将处于4位(。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical">

<LinearLayout
android:id="@+id/linear_parent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:gravity="center"
android:orientation="vertical">
<!-- Views are added here programmatically -->
</LinearLayout>

<EditText
android:id="@+id/no_of_views_input"
android:layout_width="100dp"
android:layout_height="40dp"
android:hint="Number of view to add"/>
<Button
android:id="@+id/add_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add"/>
</LinearLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
LinearLayout linear_parent;
Button add_button;
EditText no_of_views_input;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
linear_parent = findViewById(R.id.linear_parent);
add_button= findViewById(R.id.add_button);
no_of_views_input= findViewById(R.id.no_of_views_input);
no_of_views_input.setInputType(InputType.TYPE_CLASS_NUMBER);
add_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (!no_of_views_input.getText().toString().isEmpty()) {
String no_of_views_temp = no_of_views_input.getText().toString();
int no_of_views = Integer.parseInt(no_of_views_temp);
for (int i = 0; i < no_of_views; i++) {
LinearLayout linearLayout = new LinearLayout(MainActivity.this);
LinearLayout.LayoutParams lp_ll = new LinearLayout.LayoutParams(600, 1500);
lp_ll.setMargins(0, 50, 0, 0);
linearLayout.setOrientation(LinearLayout.VERTICAL);
linearLayout.setId(View.generateViewId()); // id = 1, 2, 3, 4, ...
int linearLayoutID = linearLayout.getId();
linearLayout.setLayoutParams(lp_ll);
ImageView imageView = new ImageView(MainActivity.this);
LinearLayout.LayoutParams lp_image = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 800);
imageView.setBackgroundColor(Color.Yellow);
imageView.setLayoutParams(lp_image);
EditText edit = new EditText(MainActivity.this);
LinearLayout.LayoutParams lp_edit = new LinearLayout.LayoutParams(300, ViewGroup.LayoutParams.WRAP_CONTENT);
edit.setBackgroundColor(Color.WHITE);
edit.setInputType(InputType.TYPE_CLASS_NUMBER);
edit.setHint("move to index");
edit.setLayoutParams(lp_edit);
Button button = new Button(MainActivity.this);
LinearLayout.LayoutParams lp_button= new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
button.setBackgroundColor(Color.BLUE);
button.setText("Move");
button.setLayoutParams(lp_button);
linear_parent.addView(linearLayout);
linearLayout.addView(imageView);
linearLayout.addView(edit);
linearLayout.addView(button);

button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String indexTarget_temp = edit.getText().toString();
int indexTarget = Integer.parseInt(indexTarget_temp );
int childCount = linear_parent.getChildCount();
int currentLinearLayoutPos = linear_parent.indexOfChild(linearLayout);

try {
linear_parent.addView(linearLayout, indexTarget - 1); //adding current linearLayout to indexTarget  
//error occurs this line

linear_parent.removeView(linear_parent.getChildAt(currentLinearLayoutPos + 1)); //removing linearLayout at old index
}
catch(IllegalStateException e) {
e.printStackTrace();
}

}
});

}
}else {
Toast.makeText(MainActivity.this, "Enter index no", Toast.LENGTH_SHORT).show();
}
}
});
}
}

我得到的错误是
java.lang.IollegalStateException：指定的子级已经有一个父级。必须首先对子级的父级调用removeView((
如有任何帮助，我们将不胜感激。

Answer 1

在将子视图添加为子视图之前，尝试将其从父视图中删除：

try {
if (linearLayout.getParent() != null) {
// Remove child from parent
((ViewGroup) linearLayout.getParent()).removeView(linearLayout)
}
linear_parent.addView(linearLayout, indexTarget - 1); 
}
catch(IllegalStateException e) {
e.printStackTrace();
}

但是，请考虑切换到RecyclerView
这将简化您的代码结构。