以编程方式将垂直和水平滚动添加到Android中的LinearLayout

Question

I'm trying to create a layout of a activity as follows:

the game_board.xml code is is follows:

<LinearLayout 
        android:id="@+id/layoutFilterContent"
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:weightSum="4"
        android:background="#837E7C" >

        <LinearLayout 
            android:id="@+id/layoutTopicGrade"
            android:orientation="vertical"
            android:layout_width="0dp"
            android:layout_height="fill_parent"
            android:layout_weight="1"
            android:padding="0dp"
            android:background="#BCC6CC" >

        </LinearLayout>

        <LinearLayout 
            android:id="@+id/layoutGames"
            android:orientation="vertical"
            android:layout_width="0dp"
            android:layout_height="fill_parent"
            android:layout_weight="3"
            android:padding="0dp"
            android:background="#E5E4E2" >

        </LinearLayout>

    </LinearLayout>

The java code in GameBoardActivity.java is as follows:

import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.view.Menu;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.ScrollView;

public class GameBoardActivity extends Activity {

    LinearLayout topicGrade;
    LinearLayout gameContent;
    ScrollView scroll;
    ImageButton[] imgBtn;

    @SuppressWarnings("deprecation")
    @SuppressLint({ "NewApi", "InlinedApi", "ResourceAsColor" })
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.game_board);

        topicGrade = (LinearLayout)findViewById(R.id.layoutTopicGrade);

        scroll = new ScrollView(this);
        scroll.setBackgroundColor(android.R.color.transparent);
        scroll.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
        scroll.addView(topicGrade);

        imgBtn = new ImageButton[15];

        for(int i=0;i<15;i++){
            imgBtn[i] = new ImageButton(this);
            imgBtn[i].setId(i);
            imgBtn[i].setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
            topicGrade.addView(imgBtn[i]);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.game_board, menu);
        return true;
    }

}

I'm getting error as: The specified child already has a parent. You must call removeView() on the child's parent first. The specified child already has a parent. You must call removeView() on the child's parent first.

I first tried adding buttons to LinearLayout1 without ScrollView , and I'm able to add the buttons as I want, but when I implement ScrollView I'm getting the error as mentioned above. So I got stuck and didn't try anything on LinearLayout2

Please anyone help me to design the activity shown above,

Answer 1

what do you want do achiev? this is what you actually doing:

setContentView(R.layout.game_board);

->game_board is inflatet with both childs layoutTopicGrade and layoutGames

topicGrade = (LinearLayout)findViewById(R.id.layoutTopicGrade);

->this is a instance of layoutTopicGrade

scroll = new ScrollView(this);

->you create a scroll view

scroll.addView(topicGrade);

->you add topicGrade to the scroll view

This failed, because topicGrade already has a parent (layoutFilterContent)

this.setContentView(scroll);

->you set the croll view as content.
(why did you set R.layout.game_board as content before?)

if you only want topicGrade in a ScrollView as ContentView , why didn't you create a xml with this structure?

if it is recommended to do it like you do, the solution is:

topicGrade = (LinearLayout)findViewById(R.id.layoutTopicGrade);
((LinearLayout)topicGrade.getParent()).removeView(topicGrade)

but i can't see why you should do it in this way ^^

--edit: now i've got it, here is the you need:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:weightSum="4" >

<ScrollView
    android:id="@+id/scrollView1"
    android:layout_width="wrap_content"
    android:layout_height="match_parent" 
    android:layout_weight="1">
    <LinearLayout
        android:id="@+id/vertical_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >
    </LinearLayout>
</ScrollView>

<HorizontalScrollView
    android:id="@+id/horizontalScrollView1"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_weight="3">

    <LinearLayout
        android:id="@+id/horizontal_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal" >
    </LinearLayout>
</HorizontalScrollView>
</LinearLayout>

Answer 2

Each element can have exactly one parent, that's an XML file structure.

In your layout xml file you defined layoutTopicGrade as the child of layoutFilterContent . Then, in the code, you set layoutTopicGrade as the child of the newly created ScrollView .

You should wrap your layoutTopicGrade the ScrollView . Also, since you're not doing any dynamic configuration to the ScrollView , there's no reason adding it in the code, you should do it straight in the layout xml file:

<ScrollView android:id="@+id/scrollViewTopicGrade"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:background="@android:color/transparent" >
    <LinearLayout 
        android:id="@+id/layoutTopicGrade"
        android:orientation="vertical"
        android:layout_width="0dp"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:padding="0dp"
        android:background="#BCC6CC" >
    </LinearLayout>
</ScrollView>

---

EDIT

In order to have layoutTopicGrade take 25% of parent's width and layoutGames take 75%, do the following:

1. Move the layout_weight and layout_width from layoutTopicGrade to the ScrollView .
2. Set ScrollView 's layout_weight to .25 .
3. Set layoutGames 's layout_weight to .75 .
4. layoutTopicGrade 's children should have layout_width set to fill_parent .

See this answer .

---

ADDITION

BTW, looks like the line this.setContentView(scroll); should be deleted. Activity.setContentView is used to set a view for the whole activity = whole screen. But your ScrolView is apparently only for the topic layout. Rather the whole game board is the activity's content view, as you use it a few lines of code earlier: setContentView(R.layout.game_board); (so keep that one).