自定义ArrayAdapter初始化时不能显示，加新数据时重复显示所有

zzytn 2014-04-14 07:57:52

HI，各位安卓研发高级工程师，请教问题如下

仿网上自定义写了一个ArrayAdapter，如下：



mport java.util.List;



import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.FrameLayout;

import android.widget.ImageView;

import android.widget.LinearLayout;

import android.widget.TextView;

import cn.com.ccxe.bean.Article;

import cn.com.ccxe.bean.ComplexMessage;

import cn.com.ccxe.message.R;

import cn.com.ccxe.util.AsyncImageLoaderTask;



public class MessageArrayAdapter extends ArrayAdapter<ComplexMessage> {

	

	private int resourceId;  

	Context mContext;  

	LayoutInflater mLayoutInflater;  

	



	public MessageArrayAdapter(Context context, int textViewResourceId,List<ComplexMessage> cms) {

		super(context, textViewResourceId,cms);

		this.resourceId = textViewResourceId;

		mContext = context;

		mLayoutInflater = LayoutInflater.from(context); 

	}



	@Override  

    public View getView(int position, View convertView, ViewGroup parent){  

		ComplexMessage cm = getItem(position);  

		

		View view;

		if (convertView == null) {

            view = mLayoutInflater.inflate(resourceId, parent, false);

        } else {

            view = convertView;

        }

		

		LinearLayout linearLayout = (LinearLayout) view.findViewById(R.id.messageArrayAdapterLinerlayout); 

		Article[] arts = cm.getNews().getArticles();

		if(arts != null && arts.length == 1){

			//如果只有一条消息

		}else{

			//如果有多条消息

			for(int i=0;i<arts.length;i++){

				if(i ==0){

					Article art = arts[i];

					FrameLayout frameLayout = new FrameLayout(mContext);

					FrameLayout.LayoutParams frameLayoutParams = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.FILL_PARENT,FrameLayout.LayoutParams.WRAP_CONTENT);

					frameLayoutParams.leftMargin=20;

					frameLayoutParams.rightMargin = 20;

					frameLayout.setLayoutParams(frameLayoutParams);

					ImageView iv = new ImageView(mContext);

					android.view.ViewGroup.LayoutParams ivLayoutParams = new android.view.ViewGroup.LayoutParams(linearLayout.getWidth(),linearLayout.getWidth()/2);

					iv.setLayoutParams(ivLayoutParams);

					iv.setTag(art.getPicurl());

					new AsyncImageLoaderTask().execute(art.getPicurl(),iv);

					TextView  tv = new TextView (mContext);

					android.view.ViewGroup.LayoutParams tvLayoutParams = new android.view.ViewGroup.LayoutParams(linearLayout.getWidth(),linearLayout.getWidth()/4);

					tv.setLayoutParams(tvLayoutParams);

					tv.setText(art.getTitle());

					frameLayout.addView(iv);

					frameLayout.addView(tv);

					linearLayout.addView(frameLayout);

				}else{

				}

			}

		}

        return view;  

    }  

	

}

那么，在Activity中调用如下：





	DatabaseHelper dbHelper = DBUtil.getDatabaseHelper(MainActivity.this);

	Cursor c =null;

	try{

		SQLiteDatabase sqliteDatabase = dbHelper.getReadableDatabase();

		c = sqliteDatabase.rawQuery("SELECT * FROM message ORDER BY _id DESC limit 0,10 ", new String[]{});

		 while (c.moveToNext()) {  

	        int _id = c.getInt(c.getColumnIndex("_id"));

	        idMax=idMax>_id?idMax:_id;

	        idMin=idMin>_id?_id:idMin;

	        String message = c.getString(c.getColumnIndex("message")); 

	        Gson g=new Gson();

	        ComplexMessage cm=g.fromJson(message,new TypeToken<ComplexMessage>(){}.getType());

	        mListItems.add(cm);

	    }

		

		 

	}catch(Exception e){

		Log.e(MainActivity.class.toString(), e.toString());

	}finally{

		if(c != null){

			c.close();

		}

	}

	

	 mAdapter = new MessageArrayAdapter(this, R.layout.list_view1_item, mListItems);

		// You can also just use setListAdapter(mAdapter)

	 actualListView.setAdapter(mAdapter);

	 mAdapter.notifyDataSetChanged();

	 mPullRefreshListView.getRefreshableView().setSelection(mAdapter.getCount()-1);

发现打开应用时，即使有数据都不显示。
该MainActivity实现了OnScrollListener,做了一个异步线程，当手指划动时加载数据却可以显示出来，但每加载一次却是显示所有的数据，并不是仅显示新增加的内容



private class GetDataTask extends AsyncTask<Void, Void, String[]> {



	@Override

	protected String[] doInBackground(Void... params) {

		

		return null;

	}



	@Override

	protected void onPostExecute(String[] result) {

		DatabaseHelper dbHelper = DBUtil.getDatabaseHelper(MainActivity.this);

	   	SQLiteDatabase sqliteDatabase = dbHelper.getReadableDatabase();

	   	Cursor c = sqliteDatabase.rawQuery("select * from message where _id < ? order by _id desc  limit 0,10 ", new String[]{idMin+""});

	   	int count = c.getCount();

	   	try{

	   		if(c.getCount() > 0){

	   			while (c.moveToNext()) {  

		   			int _id = c.getInt(c.getColumnIndex("_id"));

	        		idMax=idMax>_id?idMax:_id;

	     	        idMin=idMin>_id?_id:idMin;

					String message = c.getString(c.getColumnIndex("message"));  

					Gson g=new Gson();

					ComplexMessage cm=g.fromJson(message,new TypeToken<ComplexMessage>(){}.getType());

		        	mListItems.addFirst(cm);

			    }

	   			

	   		}

	   	}catch(Exception e){

	   		Log.e(MainActivity.class.toString(), e.toString());

	   	}finally{

	   		c.close();

	   	}

	   	mAdapter.notifyDataSetChanged();

//			// Call onRefreshComplete when the list has been refreshed.

			mPullRefreshListView.onRefreshComplete();

			mPullRefreshListView.getRefreshableView().setSelection(count-1);

	   	super.onPostExecute(result);

	}

}