Android控件使用—Listview加载网络数据、图片并跳转传值

1、自定义Adapter，里面有一个Imageview跟三个Textview，其中只有两个Textview是显示出来的，另一个是不显示，用来存值，将这个值传递到跳转的界面的：

public class LvImageAdapter extends BaseAdapter {

private ArrayList<String> mArrayList,mArrayList1,mArrayList2,mArrayList3;
private Context mContext;
private static Handler mHandler;
private static LruCache<String, Bitmap> mCache;
private ListView mListView;

public LvImageAdapter(ArrayList<String> arrayList , ArrayList<String> arrayList1,
ArrayList<String> arrayList2,ArrayList<String> arrayList3,Context context, ListView listView) {
this.mArrayList = arrayList;
this.mArrayList1 = arrayList1;
this.mArrayList2 = arrayList2;
this.mArrayList3 = arrayList3;
mContext = context;
mHandler = new Handler();
int maxSize = (int) (Runtime.getRuntime().maxMemory() / 1024);
mCache = new LruCache<String, Bitmap>(maxSize / 2);
mListView = listView;
}

@Override
public int getCount() {
return mArrayList.size();
}

@Override
public String getItem(int arg0) {
return mArrayList.get(arg0);
}

@Override
public long getItemId(int arg0) {
return arg0;
}

public int getCount1() {
return mArrayList1.size();
}

public String getItem1(int arg1) {
return mArrayList1.get(arg1);
}

public long getItemId1(int arg1) {
return arg1;
}
public int getCount2() {
return mArrayList2.size();
}

public String getItem2(int arg2) {
return mArrayList2.get(arg2);
}

public long getItemId2(int arg2) {
return arg2;
}

public int getCount3() {
return mArrayList3.size();
}

public String getItem3(int arg1) {
return mArrayList3.get(arg1);
}

@Override
public View getView(int position, View convertView, ViewGroup arg2) {
ViewHolder holder;

convertView = View.inflate(mContext, R.layout.image_item, null);
holder = new ViewHolder();
holder.imageView = (ImageView) convertView.findViewById(R.id.imageView);
holder.textView1 = (TextView) convertView.findViewById(R.id.textView1);
holder.textView2 = (TextView) convertView.findViewById(R.id.textView2);
holder.textview00 = (TextView) convertView.findViewById(R.id.textview00);
convertView.setTag(holder);

if (convertView == null) {
convertView = View.inflate(mContext, R.layout.image_item, null);
holder = new ViewHolder();
holder.imageView = (ImageView) convertView.findViewById(R.id.imageView);
holder.textView1 = (TextView) convertView.findViewById(R.id.textView1);
holder.textView2 = (TextView) convertView.findViewById(R.id.textView2);
holder.textview00 = (TextView) convertView.findViewById(R.id.textview00);
convertView.setTag(holder);
}else{
holder = (ViewHolder) convertView.getTag();
}

//download image
holder.imageView.setImageResource(R.mipmap.download);
holder.imageView.setScaleType(ScaleType.FIT_XY);
holder.textView1.setText(mArrayList1.get(position));
holder.textView2.setText(mArrayList2.get(position));
holder.textview00.setText(mArrayList3.get(position));
holder.textview00.setVisibility(View.GONE);
Utils.loadImageFromUrl(mArrayList.get(position),
mHandler, holder.imageView, mCache, mListView, position);
Log.i("LvImageAdapter", position+"");
return convertView;
}
static class ViewHolder{
private ImageView imageView;
private TextView textView1,textView2,textview00;
}

}

2、下载图片的类：

public class Utils {

public static void loadImageFromUrl(final String url, final Handler handler, final ImageView imageView, final LruCache<String, Bitmap> lruCache, final ListView listView, final int position){

if (lruCache.get(url) == null) {
new Thread(new Runnable() {

@Override
public void run() {
final DefaultHttpClient client = new DefaultHttpClient();
final HttpGet getRequest = new HttpGet(url);

HttpResponse response = null;
try {
response = client.execute(getRequest);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK)  {
Log.e("PicShow", "Request URL failed, error code =" + statusCode);
}

HttpEntity entity = response.getEntity();
if (entity == null) {
Log.e("PicShow", "HttpEntity is null");
}
InputStream is = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
is = entity.getContent();
byte[] buf = new byte[1024];
int readBytes = -1;
while ((readBytes = is.read(buf)) != -1) {
baos.write(buf, 0, readBytes);
}
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (baos != null) {
try {
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
byte[] imageArray = baos.toByteArray();
final Bitmap bitmap = BitmapFactory.decodeByteArray(
imageArray, 0, imageArray.length);
handler.post(new Runnable() {

@Override
public void run() {
imageView.setImageBitmap(bitmap);
lruCache.put(url, bitmap);
}
});
}
}).start();
}else{
handler.post(new Runnable() {

@Override
public void run() {
imageView.setImageBitmap(lruCache.get(url));
//listView.smoothScrollToPosition(position + 1);
}
});
}

}

public static void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
return;
}
int totalHeight = 0;
for (int i = 0; i < listAdapter.getCount(); i++) {
View listItem = listAdapter.getView(i, null, listView);
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight
+ (listView.getDividerHeight() * (listAdapter.getCount() - 1));
listView.setLayoutParams(params);
}

}

3、请求服务器，解析Json，得到数组，将数据加载到Listview中，传入的值包括三个显示的，还有一个不显示的：

Handlerhandler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
mArrayList = new ArrayList<String>();
mArrayList1 = new ArrayList<String>();
mArrayList2 = new ArrayList<String>();
mArrayList3 = new ArrayList<String>();
try {
final String status = jsonObject.getString("status");
if ("true".equals(status)) {
jsonArray = jsonObject.getJSONArray("results");
for (int i = 0; i < jsonArray.length(); i++) {
item1 = jsonArray.getJSONObject(i);
title = item1.getString("title");
info = item1.getString("info");
imageurl = item1.getString("img");
myid = item1.getInt("id");
mArrayList.add(imageurl);
mArrayList1.add(title);
mArrayList2.add(info);
mArrayList3.add(myid+"");
}
LvImageAdapter lvImageAdapter = new
LvImageAdapter(mArrayList, mArrayList1, mArrayList2,mArrayList3, OperateActivity.this, main_operate_listview);
main_operate_listview.setAdapter(lvImageAdapter);
main_operate_listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String str = mArrayList3.get(position);
Intent intent = new Intent();
intent.putExtra("ArticleNum", str);                                         intent.setClass(OperateActivity.this, Article.class);
startActivity(intent);
}
});
} else {
}
} catch (JSONException e) {
e.printStackTrace();
}
break;
default:
break;
}
}
};

private class OperateThread implements Runnable {
@Override
public void run() {
path = path_url + 1 + "/aa/" + count;
responseMsg = JsonUtil.loginServer(path);
Message msg = handler.obtainMessage();
try {
jsonObject = new JSONObject(responseMsg);

} catch (JSONException e) {
e.printStackTrace();
}
msg.what = 0;
handler.sendMessage(msg);
}
}