本人剛入門安卓開發,在把item添加到listview之後,無法正常顯示,在手機上調試的結果是全空白,什麼都沒有。求大神指教,感激不盡代碼如下:
listview.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/LinearLayout01"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/listview1">
</ListView>
</LinearLayout>
testb.xml(放的是相關item)
<?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">
<ImageView
android:id="@+id/img"
android:layout_width="100dp"
android:layout_height="50dp"
/>
<LinearLayout
android:layout_width="160dp"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="@+id/textView_name"
android:layout_width="160dp"
android:layout_height="25dp"
android:gravity="center_vertical"
android:textColor="#ffffff00"
android:textSize="18dp" />
<TextView
android:id="@+id/textView_message"
android:layout_width="160dp"
android:layout_height="25dp"
android:gravity="center_vertical"
/>
</LinearLayout>
<Button
android:id="@+id/button_message"
android:layout_width="match_parent"
android:layout_height="50dp"
android:textColor="#ffffffff"
android:background="#ffff00ff"
android:text="@string/send_message" />
</LinearLayout>
TestB.java
package com.example.testb;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
public class TestB extends Activity {
Button button_message;
ImageView img;
TextView textView_name;
TextView textView_message;
private List<Map<String, Object>> mData;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
MyAdapter adapter = new MyAdapter(this);
setListAdapter(adapter);
}
private void setListAdapter(MyAdapter adapter) {
// TODO Auto-generated method stub
}
private List<Map<String, Object>> getData() {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
for(int i=0;i<50;i++)
{
Map<String, Object> map = new HashMap<String, Object>();
map.put("img", R.drawable.qq_btn_0);
map.put("textView_name", "聯繫人"+i);
map.put("text_message", "聊天信息 ");
list.add(map);
}
return list;
}
public final class ViewHolder{
public ImageView img;
public TextView textView_name;
public TextView textView_message;
public Button button_message;
}
public class MyAdapter extends BaseAdapter{
private LayoutInflater mInflater;
public MyAdapter(Context context){
this.mInflater = LayoutInflater.from(context);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return mData.size();
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
holder=new ViewHolder();
convertView = mInflater.inflate(R.layout.testb, null);
holder.img = (ImageView)convertView.findViewById(R.id.img);
holder.textView_name = (TextView)convertView.findViewById(R.id.textView_name);
holder.textView_message = (TextView)convertView.findViewById(R.id.textView_message);
holder.button_message = (Button)convertView.findViewById(R.id.button_message);
convertView.setTag(holder);
}else {
holder = (ViewHolder)convertView.getTag();
}
holder.img.setBackgroundResource((Integer)mData.get(position).get("img"));
holder.textView_name.setText((String)mData.get(position).get("textView_name"));
holder.textView_message.setText((String)mData.get(position).get("textView_message"));
return convertView;
}
}
}