entity类:Data.java: /** * Created by Jay on 2015/9/21 0021. */ public class Data { private int imgId; private String content; public Data() {} public Data(int imgId, String content) { this.imgId = imgId; this.content = content; } public int getImgId() { return imgId; } public String getContent() { return content; } public void setImgId(int imgId) { this.imgId = imgId; } public void setContent(String content) { this.content = content; } } Activity布局以及列表项布局: activity_main.xml: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".MainActivity"> <ListView android:id="@+id/list_one" android:layout_width="match_parent" android:layout_height="match_parent" /> </LinearLayout> item_list.xml: <?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"> <ImageView android:id="@+id/img_icon" android:layout_width="56dp" android:layout_height="56dp"/> <TextView android:id="@+id/txt_content" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="20dp" android:layout_marginLeft="10dp" android:textSize="18sp" /> </LinearLayout> 自定义BaseAdapter的实现:MyAdapter.java: /** * Created by Jay on 2015/9/21 0021. */ public class MyAdapter extends BaseAdapter { private Context mContext; private LinkedList<Data> mData; public MyAdapter() {} public MyAdapter(LinkedList<Data> mData, Context mContext) { this.mData = mData; this.mContext = mContext; } @Override public int getCount() { return mData.size(); } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; if(convertView == null){ convertView = LayoutInflater.from(mContext).inflate(R.layout.item_list,parent,false); holder = new ViewHolder(); holder.img_icon = (ImageView) convertView.findViewById(R.id.img_icon); holder.txt_content = (TextView) convertView.findViewById(R.id.txt_content); convertView.setTag(holder); }else{ holder = (ViewHolder) convertView.getTag(); } holder.img_icon.setImageResource(mData.get(position).getImgId()); holder.txt_content.setText(mData.get(position).getContent()); return convertView; } private class ViewHolder{ ImageView img_icon; TextView txt_content; } } MainActivity.java的编写: public class MainActivity extends AppCompatActivity { private ListView list_one; private MyAdapter mAdapter = null; private List<Data> mData = null; private Context mContext = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mContext = MainActivity.this; bindViews(); mData = new LinkedList<Data>(); mAdapter = new MyAdapter((LinkedList<Data>) mData,mContext); list_one.setAdapter(mAdapter); } private void bindViews(){ list_one = (ListView) findViewById(R.id.list_one); } }
<TextView android:id="@+id/txt_empty" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:textSize="15pt" android:textColor="#000000"/> txt_empty = (TextView) findViewById(R.id.txt_empty); txt_empty.setText("暂无数据~"); list_one.setEmptyView(txt_empty); 当然除了这种方法外我们还可以定义一个与ListView一样大小位置的布局,然后设置, android:visibility="gone",在Java代码中对mData集合的size进行判断,如果==0, 说明没数据,让这个布局显示出来,当有数据的时候让这个布局隐藏
代码实现 在我们自定义的BaseAdapter中定义一个方法,方法内容如下: public void add(Data data) { if (mData == null) { mData = new LinkedList<>(); } mData.add(data); notifyDataSetChanged(); } 然后布局自己加个按钮,然后设置下事件,代码如下: private Button btn_add; btn_add = (Button) findViewById(R.id.btn_add); btn_add.setOnClickListener(this); @Override public void onClick(View v) { switch (v.getId()){ case R.id.btn_add: mAdapter.add(new Data(R.mipmap.ic_icon_qitao,"给猪哥跪了~~~ x " + flag)); flag++; break; } }
如果你想插入到特定位置,也行,我们Adapter类里,再另外 写一个方法: //往特定位置,添加一个元素 public void add(int position,Data data){ if (mData == null) { mData = new LinkedList<>(); } mData.add(position,data); notifyDataSetChanged(); } 然后加个按钮,写个事件: private Button btn_add2; btn_add2 = (Button) findViewById(R.id.btn_add2); btn_add2.setOnClickListener(this); case R.id.btn_add2: //position从0开始算的 mAdapter.add(4,new Data(R.mipmap.ic_icon_qitao,"给猪哥跪了~~~ x " + flag)); break;
3.删除某一项 同样的,我们写两个方法,一个直接删对象,一个根据游标来删: public void remove(Data data) { if(mData != null) { mData.remove(data); } notifyDataSetChanged(); } public void remove(int position) { if(mData != null) { mData.remove(position); } notifyDataSetChanged(); } 然后加两个Button,调用下这两个方法: case R.id.btn_remove: mAdapter.remove(mData_5); break; case R.id.btn_remove2: mAdapter.remove(2); break;
从图中我们可以看到,第五项被移除了,然后点击游标删除数据,一直删的是第三项! 4.移除所有的记录: 这个更加简单,直接调用clear方法即可!方法代码如下: public void clear() { if(mData != null) { mData.clear(); } notifyDataSetChanged(); }