android ListView与EditText共存错位

在一个ListView中,如果里面有EditText会很麻烦,因为修改EditText里面的数据会发生错位现象.

这时候,需要在适配器BaseAdapter的getView中设置setTag(),将position缓存起来.

下面来解决这个问题.

1.打开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="com.example.listviewdemo1.MainActivity" >

    <Button 

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:id="@+id/btn_addRow"

        android:text="增加一行"

        />

    <ListView 

        android:layout_width="fill_parent"

        android:layout_height="fill_parent"

        android:id="@+id/lv"

        android:cacheColorHint="@android:color/transparent"

        ></ListView>

</LinearLayout>

在这个布局中,只有一个简单的Button和一个ListView,Button是用来动态添加  一行记录的.

2.新建一个item.xml,作为listView的子布局.

<?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:descendantFocusability="beforeDescendants"

    android:orientation="horizontal" >

    

    <TextView 

        android:layout_width="10dp"

        android:layout_height="wrap_content"

        android:id="@+id/tv_position"

        />

    <Spinner 

        android:layout_width="100dp"

        android:layout_height="wrap_content"

        android:id="@+id/sp_type"

        />

    <EditText 

        android:layout_width="100dp"

        android:layout_height="wrap_content"

        android:id="@+id/et_number"

        />

    <Button 

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:id="@+id/btn_delete"

        android:text="删除"

        />

</LinearLayout>

子布局元素也只有四个, 一个TextView用来放索引位置,  Spinner用来显示一个下拉窗口  , 还有一个EditText和一个Button.

3.新建一个NumberInfo.java,用来存储数据的javaBean.

public class NumberInfo {

    private String type;

    private String number;

    public String getType() {

        return type;

    }

    public void setType(String type) {

        this.type = type;

    }

    public String getNumber() {

        return number;

    }

    public void setNumber(String number) {

        this.number = number;

    }   

}

只有简单的两个属性  

4.新建一个MyAdapter.java 适配器, 用来展示ListView的数据, 解决混乱的重点.

public class MyAdapter extends BaseAdapter {

    private List<NumberInfo> list=new ArrayList<NumberInfo>();

    

    private Context context;

    private OnListRemovedListener mListener;

    

    //下拉列表的适配器

    private ArrayAdapter<String> arrayAdapter;

    //下拉列表的选项

    private static final String[] SPINNER_TIME = {"手机","住宅","其他"};

    

    public void setOnListRemovedListener(OnListRemovedListener listener){

        this.mListener=listener;

    }

    

    public MyAdapter(List<NumberInfo> list,Context context) {

        this.context=context;

        this.list=list;

        arrayAdapter=new ArrayAdapter<String>(context, android.R.layout.simple_spinner_item, SPINNER_TIME);

        arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    }

    

    @Override

    public int getCount() {

        return list.size();

    }

    @Override

    public Object getItem(int arg0) {

        return null;

    }

    @Override

    public long getItemId(int arg0) {

        return 0;

    }

    @Override

    public View getView(int position, View convertView, ViewGroup arg2) {

        ViewHolder holder=null;

        if(convertView==null){

            convertView=LayoutInflater.from(context).inflate(R.layout.item, null);

            holder=new ViewHolder();

            holder.tv_position=(TextView) convertView.findViewById(R.id.tv_position);

            holder.sp_type=(Spinner) convertView.findViewById(R.id.sp_type);

            holder.sp_type.setOnItemSelectedListener(new MySpinnerListener(holder) {

                @Override

                public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,

                        long arg3, ViewHolder holder) {

                    TextView tv=(TextView) arg1;

                    int position=(Integer) holder.et_number.getTag();

                    NumberInfo n=list.get(position);

                    n.setType(tv.getText().toString());

                    list.set(position, n);

                }

            });

            holder.et_number=(EditText) convertView.findViewById(R.id.et_number);

            holder.et_number.setTag(position);

            holder.et_number.addTextChangedListener(new MyTextWatcher(holder) {

                @Override

                public void afterTextChanged(Editable s, ViewHolder holder) {

                    int position=(Integer) holder.et_number.getTag();

                    NumberInfo n=list.get(position);

                    n.setNumber(s.toString());

                    list.set(position, n);

                }

            });

            holder.btn_delete=(Button) convertView.findViewById(R.id.btn_delete);

            holder.btn_delete.setOnClickListener(new MyOnClickListener(holder) {

                @Override

                public void onClick(View v, ViewHolder holder) {

                    if(mListener!=null){

                        int position=(Integer) holder.et_number.getTag();

                        list.remove(position);

                        mListener.onRemoved();  //通知主线程更新Adapter

                    }

                }

            });

            convertView.setTag(holder);

        }

        else{

            holder=(ViewHolder) convertView.getTag();

            holder.et_number.setTag(position);

        }

        NumberInfo n=list.get(position);

        holder.tv_position.setText(position+1+"");

        holder.sp_type.setAdapter(arrayAdapter);

        holder.et_number.setText(n.getNumber());

        

        int p=getPositionForAdapter(position);

        holder.sp_type.setSelection(p,true);

        

        return convertView;

    }

    

    private int getPositionForAdapter(int po){

        

        NumberInfo  t = list.get(po);

        int p = 0;

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

            if(t.getType().equals(SPINNER_TIME[i])){

                p = i;

            }

        }

        return p;

    }

    

    //动态添加List里面数据

    public void addItem(NumberInfo n){

        list.add(n);

    }

    

    private abstract class MySpinnerListener implements OnItemSelectedListener{

        private ViewHolder holder;

        

        public MySpinnerListener(ViewHolder holder) {

            this.holder=holder;

        }

        @Override

        public void onNothingSelected(AdapterView<?> arg0) {

        }

        @Override

        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,

                long arg3) {

            onItemSelected(arg0, arg1, arg2, arg3, holder);

        }

        

        public abstract void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,long arg3,ViewHolder holder);

    }

    

    private abstract class MyTextWatcher implements TextWatcher{

        private ViewHolder mHolder;

        

        public MyTextWatcher(ViewHolder holder) {

            this.mHolder=holder;

        }

        

        @Override

        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,

                int arg3) {

        }

        @Override

        public void onTextChanged(CharSequence arg0, int arg1, int arg2,

                int arg3) {

        }

        @Override

        public void afterTextChanged(Editable s) {

            afterTextChanged(s, mHolder);

        }

        public abstract void afterTextChanged(Editable s,ViewHolder holder);

    }

    

    private abstract class MyOnClickListener implements OnClickListener{

        

        private ViewHolder mHolder;

        

        public MyOnClickListener(ViewHolder holder) {

            this.mHolder=holder;

        }

        

        @Override

        public void onClick(View v) {

            onClick(v, mHolder);

        }

        public abstract void onClick(View v,ViewHolder holder);

        

    }

    private class ViewHolder{

        TextView tv_position;

        Spinner sp_type;

        EditText et_number;

        Button btn_delete;

    }

    

    //删除操作回调

    public interface OnListRemovedListener{

        public void onRemoved();

    }

    

}

仔细看,其实只是对每一个可点击的事件重写了一遍,与原来不同的是,这里多了一个ViewHolder,为什么需要这个,因为这里面存储了每一个Item的Position信息.这样,就可以对item进行准确操作.从而不会发生错乱.

5.打开MainActivity.java

public class MainActivity extends ActionBarActivity implements OnClickListener,OnItemSelectedListener,OnListRemovedListener {

    private List<NumberInfo> list=new ArrayList<NumberInfo>();

    

    ListView lv;

    Button btn_addRow;

    MyAdapter mAdapter;

    

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        btn_addRow=(Button) findViewById(R.id.btn_addRow);

        btn_addRow.setOnClickListener(this);

        

        lv=(ListView) findViewById(R.id.lv);

        NumberInfo n=new NumberInfo();

        n.setNumber("1");

        n.setType("其他");

        list.add(n);

        

        

        mAdapter=new MyAdapter(list, this);

        lv.setAdapter(mAdapter);

        mAdapter.setOnListRemovedListener(this);

    }

    @Override

    public void onClick(View v) {

        if(v.getId()==R.id.btn_addRow){

            NumberInfo n=new NumberInfo();

            n.setNumber("");

            n.setType("手机");

            mAdapter.addItem(n);

            mAdapter.notifyDataSetChanged();

        }

    }

    @Override

    public void onRemoved() {

        mAdapter.notifyDataSetChanged();

    }

    @Override

    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,

            long arg3) {

        

    }

    @Override

    public void onNothingSelected(AdapterView<?> arg0) {

        

    }

}

运行结果:

从此ListView再也不会错乱.

 

来自为知笔记(Wiz)