根据最终列表项错误修改列表视图中的按钮

Question

我正在制作一个具有三个选项卡的应用程序（类似于 WhatsApp 布局）。这三个选项卡是朋友、家人和联系人。每个选项卡中都有一个列表。每个列表项还具有以下视图：左侧的名称、名称下方的描述和右侧的具有可绘制背景的按钮，与名称在同一行。 （我之前已经发布过，但现在重新发布了，因为我已经能够找出主要错误并减少我需要放在这里的代码）

每个列表视图项都包含一个类（朋友、家人、联系人）。这三个类都有一个标志（canViewYouOnlineFlag）。如果此标志设置为 true，则相应的联系人、家人或朋友将知道您在线，反之亦然。如果 flag 设置为 true，则按钮的颜色必须为蓝色，如果 flag 设置为 false，则按钮的颜色必须为黑色。

我面临的问题是打开选项卡时按钮无法正确呈现。通常，必须根据 Listview 项中包含的 Object 的 CanViewYouOnlineFlag 设置按钮的颜色。但是，当在下一个列表视图项上调用 getView 函数时，当前列表视图项的按钮颜色会被下一个列表视图项的对象的 CanViewYouOnlineFlag 更改。例如：

listview 中的 3 个项目，每个项目都有一个对象，这三个项目的 CanViewYouOnlineflags 如下：Listview item 1：true，Listview item 2：false，Listview item 3：false。

列表视图项的按钮颜色在渲染时必须是蓝色、黑色、黑色。然而，事实证明，一切都是黑色的。

同样，如果 listview item 3 的对象的标志设置为“TRUE”，那么所有按钮都是蓝色的。基本上，按钮的颜色由最后一个 Listview 项目中存在的对象决定。列表视图项中包含的对象的实际标志不是问题，我也验证了这一点（即对象标志为真，但按钮仍呈现黑色，因为最后一个列表视图项的按钮为黑色）。请帮我解决这个问题。 以下是main_lp_view_item布局的xml文件：

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

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp"
    android:id="@+id/main_lp_text"
    android:textSize="18sp"
    android:textColor="@color/colorPrimaryDark"
    android:focusable="false" />

<TextView
    android:id="@+id/main_lp_subtitle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/main_lp_text"
    android:textSize="13sp"
    android:focusable="false" />

<Button
    android:id="@+id/can_view_you_online"
    android:layout_width="33sp"
    android:layout_height="29sp"
    android:layout_above="@+id/main_lp_subtitle"
    android:layout_marginTop="10dp"
    android:textStyle="bold"
    android:background="@drawable/lp_list_button"
    android:layout_alignParentEnd="true"
    android:focusable="false"
    />

</RelativeLayout>

下面是启动Listviews的LPListAdapter类的代码

public class LPListItemAdapter<T> extends BaseAdapter{  //Class for rendering each ListItem

Context context;
List<T> rowItems;

public LPListItemAdapter(Context context, List<T> rowItems)
{
    this.context=context;
    this.rowItems=rowItems;

}

@Override
public int getCount()
{
    return rowItems.size();
}

@Override
public Object getItem(int position)
{
    return rowItems.get(position);
}

@Override
public long getItemId(int position)
{
    return rowItems.indexOf(getItem(position));
}


private class ViewHolder{
    TextView main_text; //Display Name
    TextView subtitle;  //Display Description
    Button can_view_you_online;   //Button to set and display status of CanViewYouOnline flag of the class

}

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    ViewHolder holder=null;


    LayoutInflater mInflater= (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

    holder = new ViewHolder();



    if(convertView==null)
    {
        convertView=mInflater.inflate(R.layout.main_lp_view_item, null);

        holder.main_text= (TextView) convertView.findViewById(R.id.main_lp_text);
        holder.subtitle= (TextView) convertView.findViewById(R.id.main_lp_subtitle);
        holder.canViewYouOnline= (Button) convertView.findViewById(R.id.can_view_you_online);

        convertView.setTag(holder);

    }
    else{
        holder = (ViewHolder) convertView.getTag();
    }


    final T rowItem= rowItems.get(position);

    String main_text;
    String subtitle;

    if(rowItem instanceof Friends)    //If Row Item is a Friend class
    {
        main_text= ((Friends) rowItem).getName();
        subtitle=  ((Friends) rowItem).getDescription();
    }
    else if(rowItem instanceof Family)  //If Row Item is a Family class
    {
        main_text= ((Family) rowItem).getName();
        subtitle= ((Family) rowItem).getDescription();
    }
    else if(rowItem instanceof Contact) //If Row Item is a Contact class
    {
        main_text=((Contact) rowItem).getName();
        subtitle=((Contact) rowItem).getDescription();
    }
    else
    {
        main_text="NA";
        subtitle="";
    }

    holder.main_text.setText(main_text);
    holder.subtitle.setText(subtitle);

    if(getflagstatus(rowItem))              //If rowItem's canViewYouOnline flag is set true, then let color of button be default (i.e. blue)
        holder.canViewYouOnline.getBackground().clearColorFilter(); 
    else                                        //Else (if it false), make it black
        holder.canViewYouOnline.getBackground().setColorFilter(Color.argb(255, 0, 0, 0), PorterDuff.Mode.SRC_ATOP);     

//This part of the function is the problem because the color filter of the drawable of the button in the current list item gets overriden when
//this same code is executed for the next listview item.


    holder.canViewYouOnline.setOnClickListener(new View.OnClickListener() {
        boolean buttonClickFlag;



        @Override
        public void onClick(View v) {           //The Onclick function allows one to click the button on the list item and set/reset the canViewYouOnline flag. It is working fine. 
            buttonClickFlag=getflagstatus(rowItem);       //get buttonClickFlag from canViewYouOnline flag status
            if(buttonClickFlag==false)          //If buttonClickFlag is false
            {
                v.getBackground().clearColorFilter();   //set color of button drawable to default (which is blue)
                buttonClickFlag=true;           //set buttonClickflag to true

            }
            else    //if buttonClickFlag is true
            {

                v.getBackground().setColorFilter(Color.argb(255,0,0,0), PorterDuff.Mode.SRC_ATOP);  //set color of button drawable to black
                buttonClickFlag=false;          //set buttonClickflag to false

            }
    //update the canViewYouOnline flag in the rowItem by calling the onlineStatusUpdateButtonOnClickActivity function. 
    //Function is working perfectly so is not included in the stack overflow entry due to space constraints

            onlineStatusUpdateButtonOnClickActivity(rowItem, buttonClickFlag,v); 

        }
    });



return convertView;

}


public boolean getflagstatus(T rowItem)
{
    //Function to get the CanViewYouOnlineFlag() from the underlying class in the rowItem

    boolean flagStatus=false;
    if(rowItem instanceof Friends)      
        flagStatus=((Friends) rowItem).getCanViewYouOnlineFlag();   
    else if(rowItem instanceof  Family)
        flagStatus=((Family) rowItem).getCanViewYouOnlineFlag();
    else if(rowItem instanceof Contact)
        flagStatus= ((Contact) rowItem).getCanViewYouOnlineFlag();

    return flagStatus;
}
public void onlineStatusUpdateButtonOnClickActivity(T rowItem, boolean mLBflag, View convertView)   {//WORKS FINE SO NOT PUTTING IT HERE DUE TO SPACE CONSTRAINT}

}

Answer 1

我得到了答案。如果您使用单个可绘制资源并且仅在更改标志时更改颜色，则会出现此错误。相反，使用两个drawable，当CanViewYouOnline为true时，将按钮背景设置为drawable 1，当CanViewYouOnline为false时，将按钮背景设置为drawable 2。

Answer 2

你需要做这样的事情：

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ListView list = (ListView) findViewById(R.id.list);
        ArrayList<TopicDTO> data = new ArrayList<>();
        data.add(new TopicDTO("1", "Info 1", true));
        data.add(new TopicDTO("2", "Info 2", false));
        data.add(new TopicDTO("3", "Info 3", true));
        data.add(new TopicDTO("4", "Info 4", false));
        list.setAdapter(new ButtonListAdapter(getBaseContext(), data));


    }

}

ButtonListAdapter.java

public class ButtonListAdapter extends BaseAdapter {  //Class for rendering each ListItem

    Context context;
    List<TopicDTO> rowItems;

    public ButtonListAdapter(Context context, List<TopicDTO> rowItems) {
        this.context = context;
        this.rowItems = rowItems;

    }

    @Override
    public int getCount() {
        return rowItems.size();
    }

    @Override
    public Object getItem(int position) {
        return rowItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return rowItems.indexOf(getItem(position));
    }


    private class ViewHolder {
        TextView main_text; //Display Name
        TextView subtitle;  //Display Description
        Button can_view_you_online;   //Button to set and display status of CanViewYouOnline flag of the class

    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;


        LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

        holder = new ViewHolder();


        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.main_lp_view_item, null);

            holder.main_text = (TextView) convertView.findViewById(R.id.main_lp_text);
            holder.subtitle = (TextView) convertView.findViewById(R.id.main_lp_subtitle);
            holder.can_view_you_online = (Button) convertView.findViewById(R.id.can_view_you_online);

            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }


        final TopicDTO rowItem = rowItems.get(position);

        String main_text;
        String subtitle;


        holder.main_text.setText(rowItem.info);
        holder.subtitle.setText(rowItem.info);

        if (rowItem.canViewYouOnline) {
            holder.can_view_you_online.setBackgroundColor(context.getResources().getColor(R.color.colorPrimary));
        } else {
            holder.can_view_you_online.setBackgroundColor(context.getResources().getColor(R.color.colorAccent));
        }


        holder.can_view_you_online.setOnClickListener(new View.OnClickListener() {
            boolean buttonClickFlag;


            @Override
            public void onClick(View v) {           //The Onclick function allows one to click the button on the list item and set/reset the canViewYouOnline flag. It is working fine.

            }
        });


        return convertView;

    }
}