主要的解决问题在adapter中加入方法,用来传入选择的item下标,根据下标设置背景selector。
{
musicList.requestFocus();
musicList.setSelection(selected);
//adapter的方法,传入选择的item下标,然后更新
simpleAdapter.setSelection(selected);
simpleAdapter.notifyDataSetInvalidated();
}
如 MainActivity.java中 button的点击事件
View.OnClickListener clicklistener = new View.OnClickListener() {
@Override
public void onClick(View v) {
switch(v.getId()){
case R.id.btn_next:
selected += 1;
if(selected == datalist.size()){
selected = 0;
}
mhandler.sendEmptyMessage(1001);
//Toast.makeText(mContext, "btn_next item:"+selected, Toast.LENGTH_SHORT).show();
break;
case R.id.btn_previous:
selected -= 1;
if(selected == 0){
selected = datalist.size();
}
mhandler.sendEmptyMessage(1001);
Toast.makeText(mContext, "btn_previous item:"+selected, Toast.LENGTH_SHORT).show();
break;
}
}
};
Handler mhandler = new Handler(){
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case 1001:
musicList.clearFocus();
musicList.post(new Runnable() {
@Override
public void run() {
musicList.requestFocus();
musicList.setSelection(selected);
simpleAdapter.setSelection(selected);
simpleAdapter.notifyDataSetInvalidated();
}
});
break;
default:
break;
}
};
};
}
adapter 文件
public class MusicListDataAdapter extends BaseAdapter {
private LayoutInflater mInflater;
private ViewHolder holder;
//FileData 自定义的集合类
private ArrayList<FileData> musicList;
private Context mContext;
private int defaultSelection = -1;
public MusicListDataAdapter(Context context,ArrayList<FileData> dataList) {
musicList = dataList;
mContext = context;
}
@Override
public int getCount() {
return musicList == null ? 0 : musicList.size();
}
@Override
public Object getItem(int position) {
return musicList == null ? 0 : musicList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
mInflater = LayoutInflater.from(parent.getContext());
//这样可以选中一整行
convertView = mInflater.inflate(R.layout.music_list_data_item,parent,false);
if((ViewHolder)convertView.getTag() == null){
holder = new ViewHolder();
}else{
holder = (ViewHolder)convertView.getTag();
}
holder.txtName = (TextView) convertView.findViewById(R.id.txt_musicName);
//holder.txtName = (MarqueTextView) convertView.findViewById(R.id.txt_musicName);
convertView.setTag(holder);
} else {
holder.txtName = (TextView) convertView.findViewById(R.id.txt_musicName);
}
//这里就是判断对应的item,然后设置背景selector
if(position == defaultSelection){
convertView.setBackground(mContext.getDrawable(R.drawable.button_bg_selector));
}else{
convertView.setBackground(null);
}
holder.txtName.setText(musicList.get(position).getTilte());
return convertView;
}
class ViewHolder {
TextView txtName;
//MarqueTextView txtName;
}
//这里在button的click方法中传入
public void setSelection(int position){
defaultSelection = position;
}
}
button_bg_selector.xml
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/button_bg" android:state_focused="true"/>
<item android:drawable="@drawable/button_bg" android:state_pressed="true"/>
<item android:drawable="@drawable/button_bg" android:state_selected="true"/>
<item android:drawable="@drawable/button_bg_unfocus"/>
</selector>
button_bg.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<solid android:color="#99000000" />
<gradient android:startColor="#2828FF" android:endColor="#000079" android:angle="180" android:type="radial"
android:centerX="0.5" android:centerY="-0.5"
android:gradientRadius="110"/>
<stroke
android:width="2dp"
android:color="@android:color/white" />
<corners android:radius="5dp" />
</shape>
</item>
</layer-list>
button_bg_unfocus.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<solid android:color="@android:color/transparent" />
<gradient android:startColor="#4f4f4f"
android:endColor="#272727"
android:angle="270"
android:type="linear"
/>
<stroke
android:width="2dp"
android:color="@android:color/black" />
<corners android:radius="5dp" />
</shape>
</item>
</layer-list>
主布局文件,一个listview 下方 两个按钮
<?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="vertical"
android:id="@+id/layout_list"
>
<LinearLayout
android:id="@+id/layout_music"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="3dip"
android:layout_marginTop="3dip" >
<ListView
android:id="@+id/music_list"
android:layout_width="wrap_content"
android:layout_height="200dp"
android:layout_marginTop="5dip"
android:layout_marginBottom="5dip"
android:layout_marginLeft="20dip"
android:layout_marginRight="20dip"
android:clickable="true"
android:focusableInTouchMode="true"
android:choiceMode="singleChoice"
android:listSelector="@drawable/button_bg"
android:scrollbars="none" />
</LinearLayout>
<LinearLayout
android:id="@+id/layout_bottom"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="3dip"
android:layout_marginTop="20dip"
android:orientation="horizontal"
android:gravity="center_horizontal"
>
<Button
android:id="@+id/btn_previous"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:gravity="center"
android:focusable="false"
android:text="@string/btn_musicPrevious"
/>
<Button
android:id="@+id/btn_next"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:gravity="center"
android:focusable="false"
android:layout_marginLeft="100dp"
android:text="@string/btn_musicNext"
/>
</LinearLayout>
</LinearLayout>
listview 的item布局文件 music_list_data_item.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="300dp"
android:layout_height="30dp"
android:gravity="center_vertical"
android:orientation="horizontal"
>
<ImageView
android:id="@+id/leftImageView"
android:layout_width="20dip"
android:layout_height="20dip"
android:layout_marginLeft="5dip"
android:src="@drawable/icon_file_song" />
<TextView
android:id="@+id/txt_musicName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dip"
android:singleLine="true"
android:textColor="@android:color/darker_gray"
android:textSize="15sp" />
</LinearLayout>