1

Android でチャット アプリケーション用の ListView を作成したいのですが、ユーザーがテキストを入力した場合はテキスト レイアウトを表示し、ユーザーが画像を送信した場合は画像レイアウトを表示したいリストビューで、sms_row.xml と sms_chat_row.xml として 2 つのレイアウトを設計しました。 Text と Just Image のみを使用し、条件を手動で true と false にすることで、アプリは正常に動作しますが、動的に getItemViewType(int position) を実行しようとすると、エラーと Image crashed が表示されます。これが Adapter クラスのコードです。 -->

DevAdapter.java

    package com.example.imageinsertdynamic;

import java.util.ArrayList;
import android.content.Context;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.LinearLayout.LayoutParams;

public class DevAdapter extends BaseAdapter {

    private ArrayList<Message> list;
    private Context mCont;
    LayoutParams lp;
    public Message ob;
    int type;

    public DevAdapter(Context context, ArrayList<Message> msg) {
        super();
        this.mCont = context;
        this.list = msg;
    }

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

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

 @Override
     public int getViewTypeCount() {
         return 2;
     }

 @Override
 public int getItemViewType(int position) {
     if(true)//if ob.issetStatus() true if user types and image if user selects an image from the directory. but getting nullPointerException here.
     {
     return 0; 
     }
     else
     {
   return 1;
     } 
 }



    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ob=(Message) this.getItem(position);
        ViewHolder holder;
        type=getItemViewType(position);//1 for case one and 2 for case 2 , need getItemViewtype() to bring this 1 and 2 but app crashes doing so need help in this function only

        /*
         * 
         * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         * 
         * HHHHHHHHEEEEEEEEEEEELLLLLLLLLLLPPPPPPPPPPP HERE !!
         * 
         * 
         * \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
         */

        if(convertView == null)
        {
            holder = new ViewHolder();
            switch (type) {
            case 0:
            convertView = LayoutInflater.from(mCont).inflate(R.layout.sms_row_chat, parent, false);
            holder.text = (TextView) convertView.findViewById(R.id.message_text);
            convertView.setTag(holder);
            break;
            case 1:
            convertView = LayoutInflater.from(mCont).inflate(R.layout.sms_row, parent, false);
            holder.message = (ImageView) convertView.findViewById(R.id.message);
            convertView.setTag(holder); 
        break;

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

        switch(type){
        case 0:
        holder.text.setText(ob.getmsg());
        System.out.println("value of isStatus image or text-->");
        lp = (LayoutParams) holder.text.getLayoutParams();
        break;
        case 1:
            holder.message.setImageBitmap(ob.getMessage());
            System.out.println("value of isStatus image or text-->");
            lp = (LayoutParams) holder.message.getLayoutParams();
            break;

        }
        //Check whether message is mine to show green background and align to right
            if(ob.isMine())
            {  switch(type){
            case 0:
                holder.text.setBackgroundResource(R.drawable.speech_bubble_orange);
                lp.gravity = Gravity.LEFT;
            break;
            case 1:
                holder.message.setBackgroundResource(R.drawable.speech_bubble_orange);
                lp.gravity = Gravity.LEFT;
                break;
            }
            }
            //If not mine then it is from sender to show orange background and align to left
            else
            {
                 switch(type){
                    case 0:
                holder.text.setBackgroundResource(R.drawable.speech_bubble_green);
                lp.gravity = Gravity.RIGHT;
                break;
                    case 1:
                        holder.message.setBackgroundResource(R.drawable.speech_bubble_green);
                        lp.gravity = Gravity.RIGHT;
                       break;
                 }
                 }
             switch(type){
                case 0:
            holder.text.setLayoutParams(lp);
            break;
                case 1:
                    holder.message.setLayoutParams(lp);
                    break;
             }
            //holder.message.setTextColor(R.color.textColor);   

        return convertView;
    }

    private static class ViewHolder
    {

        ImageView message;
        TextView text;
    }




    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }
}

return を 0 と 1 に変更しましたが、getItemViewType(int position) の if ステートメントで、ob オブジェクトが getView で定義されているため、getItemView(int position) で使用できない?

 public int getItemViewType(int position) {
         if(ob.isStatusMessage)//if ob.issetStatus() true if user types and image if user selects an image from the directory. but getting nullPointerException here.
         {
         return 0; 
         }
         else
         {
       return 1;
         } 
     }

isStatusMessage は --> Message.javaからのものです

package com.example.imageinsertdynamic;

import android.graphics.Bitmap;

public class Message {
    /**
     * The content of the message
     */
    Bitmap message;
    String msg;
    /**
     * boolean to determine, who is sender of this message
     */
    boolean isMine;
    /**
     * boolean to determine, whether the message is a status message or not.
     * it reflects the changes/updates about the sender is writing, have entered text etc
     */
    boolean isStatusMessage;

    /**
     * Constructor to make a Message object
     */
    public Message(Bitmap message, boolean isMine,boolean status) {
        super();
        this.message = message;
        this.isMine = isMine;
        this.isStatusMessage = status;
    }
    /**
     * Constructor to make a status Message object
     * consider the parameters are swaped from default Message constructor,
     *  not a good approach but have to go with it.
     */
    public Message(boolean status, String message,boolean isMine) {
        super();
        this.msg = message;
        this.isMine = isMine;
        this.isStatusMessage = status;
    }
    public Bitmap getMessage() {
        return message;
    }
    public void setMessage(Bitmap message) {
        this.message = message;
    }
    public String getmsg() {
        return msg;
    }
    public void setMessage(String text) {
        this.msg = text;
    }


    public boolean isMine() {
        return isMine;
    }
    public void setMine(boolean isMine) {
        this.isMine = isMine;
    }
    public boolean isStatusMessage() {
        return isStatusMessage;
    }
    public void setStatusMessage(boolean isStatusMessage) {
        this.isStatusMessage = isStatusMessage;
    }


}
4

1 に答える 1