如何在网格视图底部添加进度条页脚?
如何在我的网格视图的底部添加一个进度条页脚,当我加载更多的网格视图项目时可见,并在请求的数据加载完成时隐藏进度栏?我需要知道如何在我的xml文件上实现它的UI,它可以应用于所有屏幕尺寸。下面,是我对我的网格视图代码:如何在网格视图底部添加进度条页脚?
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/grid_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:numColumns="auto_fit"
android:gravity="center"
android:stretchMode="columnWidth"
android:background="#ffb4d9">
</GridView>
GridViewActivity
public class GridViewActivity extends Activity implements AbsListView.OnScrollListener, AbsListView.OnItemClickListener{
private GridView gridView;
private GridViewImageAdapter adapter;
private Utils utils;
private GenerateData generateData;
private ArrayList<HashMap<String, String>> galleryAttributes;
private int columnWidth;
private int urlPageIndex = 1;
private boolean hasRequestedMore;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_grid_view);
setTitle("Gallery");
gridView = (GridView) findViewById(R.id.grid_view);
utils = new Utils(this);
InitializeGridLayout();
galleryAttributes = new ArrayList<HashMap<String, String>>();
generateData = utils.new GenerateData(urlPageIndex);
try {
galleryAttributes.addAll(generateData.execute().get());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
adapter = new GridViewImageAdapter(GridViewActivity.this, galleryAttributes , columnWidth);
gridView.setAdapter(adapter);
gridView.setOnScrollListener(this);
gridView.setOnItemClickListener(this);
}
public void InitializeGridLayout() {
Resources r = getResources();
float padding = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,AppConstant.GRID_PADDING, r.getDisplayMetrics());
columnWidth = (int) ((utils.getScreenWidth() - ((AppConstant.NUM_OF_COLUMNS + 1) * padding))/AppConstant.NUM_OF_COLUMNS);
gridView.setNumColumns(AppConstant.NUM_OF_COLUMNS);
gridView.setColumnWidth(columnWidth);
gridView.setStretchMode(GridView.NO_STRETCH);
gridView.setPadding((int) padding, (int) padding, (int) padding,(int) padding);
gridView.setHorizontalSpacing((int) padding);
gridView.setVerticalSpacing((int) padding);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// TODO Auto-generated method stub
Intent intent = new Intent(GridViewActivity.this, CarouselViewActivity.class);
intent.putExtra("position", position);
intent.putExtra("galleryAttributes", galleryAttributes);
startActivity(intent);
Log.e("onItemClick: ", ""+position);
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// TODO Auto-generated method stub
Log.e("onScrollStateChanged: ", ""+scrollState);
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// TODO Auto-generated method stub
Log.e("onScroll: ","firstVisibleItem:"+firstVisibleItem+" visibleItemCount:"+visibleItemCount+" totalItemCount:"+totalItemCount);
if(!hasRequestedMore){
int lastInScreen = firstVisibleItem+visibleItemCount;
if(lastInScreen>=totalItemCount){
hasRequestedMore = true;
onLoadMoreItems();
}
}
}
public void onLoadMoreItems(){
if(urlPageIndex<3){
urlPageIndex++;
generateData = utils.new GenerateData(urlPageIndex);
try {
galleryAttributes.addAll(generateData.execute().get());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
adapter.notifyDataSetChanged();
hasRequestedMore = false;
}
}
}
这是我的utils的课,这就是被请求的数据:
public class Utils {
private Context context;
private Activity activity;
private ProgressDialog progress;
public Utils(){}
public Utils(Context context){
this.context = context;
}
public class GenerateData extends AsyncTask<Void, Void, ArrayList<HashMap<String, String>>>{
private JSONArray dataJsonArr;
private JsonParser jParser;
private JSONObject json;
private JSONObject c;
private HashMap<String, String> map;
private ArrayList<HashMap<String,String>> galleryAttributes;
private int urlPageIndex;
public GenerateData(int urlPageIndex){
this.urlPageIndex = urlPageIndex;
new InitializeJsonArray().execute();
}
@Override
protected ArrayList<HashMap<String, String>> doInBackground(
Void... params) {
// TODO Auto-generated method stub
try{
for(int i = 0; i< dataJsonArr.length(); i++)
{
c = dataJsonArr.getJSONObject(i);
map = new HashMap<String, String>();
map.put("Link", c.getString("Link"));
galleryAttributes.add(map);
}
}
catch (JSONException e) {
e.printStackTrace();
}
return galleryAttributes;
}
public class InitializeJsonArray extends AsyncTask<Void, Void, Void>{
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
dataJsonArr = null;
jParser = new JsonParser();
json = jParser.getJSONFromUrl(AppConstant.JSON_URL+urlPageIndex);
try {
dataJsonArr = json.getJSONArray(AppConstant.JSON_ARRAY_NAME);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
galleryAttributes = new ArrayList<HashMap<String, String>>();
galleryAttributes.ensureCapacity(dataJsonArr.length());
return null;
}
}
}
@SuppressLint("NewApi") public int getScreenWidth() {
int columnWidth;
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
final Point point = new Point();
try {
display.getSize(point);
} catch (java.lang.NoSuchMethodError ignore) {
point.x = display.getWidth();
point.y = display.getHeight();
}
columnWidth = point.x;
return columnWidth;
}
}
最后,我的适配器类:
public class GridViewImageAdapter extends BaseAdapter{
private Context context;
private int imageWidth;
private ArrayList<HashMap<String, String>> galleryAttributes;
ImageView imageView;
public GridViewImageAdapter(Context context, ArrayList<HashMap<String, String>> galleryAttributes, int imageWidth){
this.galleryAttributes = galleryAttributes;
this.context = context;
this.imageWidth = imageWidth;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return galleryAttributes.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return galleryAttributes.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
imageView = new ImageView(context);
} else {
imageView = (ImageView) convertView;
}
Picasso.with(context).load(galleryAttributes.get(position).get("Link")).placeholder(R.drawable.loadingimage).into(imageView);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setLayoutParams(new GridView.LayoutParams(imageWidth,imageWidth));
return imageView;
}
}
尝试在底部定位ProgressDialog
这样的:
//In your asynctask
ProgressDialog progressDialog;
//In onPreExecute
progressDialog = new ProgressDialog(context);
progressDialog.setMessage("Fetching images");
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.setIndeterminate(true);
progressDialog.setCancelable(false);
progressDialog.getWindow().setGravity(Gravity.BOTTOM);
progressDialog.show();
//In onPostExecute
progressDialog.dismiss();
希望它能帮助。
m_ctx里面,是否正确?对不起,因为我是Android编程新手 – 2014-10-22 06:16:37
是的。它的上下文@KirbyAsterAbadilla – 2014-10-22 06:17:05
谢谢,我会试试这个。 – 2014-10-22 06:19:13
试试这种方式,希望这会帮助你解决你的问题。
而不是采取只在您的布局采取垂直的LinearLayout作为父和GridView后放进度,GridView控件默认进度定的重量1到GridView.now走了,所以当你需要显示进度条就在你的代码和GONE可见当不再需要时。
activity_grid_view.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center">
<GridView
android:id="@+id/grid_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:numColumns="auto_fit"
android:gravity="center"
android:stretchMode="columnWidth"
android:background="#ffb4d9">
</GridView>
<ProgressBar
android:id="@+id/progress_bar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone" />
</LinearLayout>
这里是代码如何为您的服务器响应,并更新数据,以您的活动实现接口。
WebServicesCallListener.java
public interface WebServicesCallListener {
public void onResponse(ArrayList<HashMap<String,String>> response);
}
这里使用上述界面修改的Utils类
Utils.java
public class Utils {
private Context context;
public Utils(){}
public Utils(Context context){
this.context = context;
}
public void getDataFromServer(final int urlPageIndex,final WebServicesCallListener listener){
new AsyncTask<Void,Void,ArrayList<HashMap<String,String>>>(){
@Override
protected ArrayList<HashMap<String, String>> doInBackground(Void... params) {
JsonParser jParser = new JsonParser();
JSONObject json = jParser.getJSONFromUrl(AppConstant.JSON_URL + urlPageIndex);
JSONArray dataJsonArr;
try {
dataJsonArr = json.getJSONArray(AppConstant.JSON_ARRAY_NAME);
} catch (JSONException e) {
e.printStackTrace();
}
ArrayList<HashMap<String, String>> galleryAttributes = new ArrayList<HashMap<String, String>>();
galleryAttributes.ensureCapacity(dataJsonArr.length());
for (int i = 0; i < dataJsonArr.length(); i++) {
JSONObject c = dataJsonArr.getJSONObject(i);
HashMap<String, String>() map = new HashMap<String, String>();
map.put("Link", c.getString("Link"));
galleryAttributes.add(map);
}
return galleryAttributes;
}
@Override
protected void onPostExecute(ArrayList<HashMap<String, String>> data) {
super.onPostExecute(data);
listener.onResponse(data);
}
}.execute();
}
@SuppressLint("NewApi")
public int getScreenWidth() {
int columnWidth;
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
final Point point = new Point();
try {
display.getSize(point);
} catch (java.lang.NoSuchMethodError ignore) {
point.x = display.getWidth();
point.y = display.getHeight();
}
columnWidth = point.x;
return columnWidth;
}
}
这里改变的Utils实施
GridViewActivity.java
public class GridViewActivity extends Activity implements AbsListView.OnScrollListener, AbsListView.OnItemClickListener{
private GridView gridView;
private GridViewImageAdapter adapter;
private Utils utils;
private GenerateData generateData;
private ArrayList<HashMap<String, String>> galleryAttributes;
private int columnWidth;
private int urlPageIndex = 1;
private boolean hasRequestedMore;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_grid_view);
setTitle("Gallery");
gridView = (GridView) findViewById(R.id.grid_view);
utils = new Utils(this);
InitializeGridLayout();
galleryAttributes = new ArrayList<HashMap<String, String>>();
utils.getDataFromServer(new WebServicesCallListener() {
@Override
public void onResponse(ArrayList<HashMap<String, String>> response) {
galleryAttributes.addAll(response);
adapter = new GridViewImageAdapter(GridViewActivity.this, galleryAttributes , columnWidth);
gridView.setAdapter(adapter);
}
});
gridView.setOnScrollListener(this);
gridView.setOnItemClickListener(this);
}
public void InitializeGridLayout() {
Resources r = getResources();
float padding = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,AppConstant.GRID_PADDING, r.getDisplayMetrics());
columnWidth = (int) ((utils.getScreenWidth() - ((AppConstant.NUM_OF_COLUMNS + 1) * padding))/AppConstant.NUM_OF_COLUMNS);
gridView.setNumColumns(AppConstant.NUM_OF_COLUMNS);
gridView.setColumnWidth(columnWidth);
gridView.setStretchMode(GridView.NO_STRETCH);
gridView.setPadding((int) padding, (int) padding, (int) padding,(int) padding);
gridView.setHorizontalSpacing((int) padding);
gridView.setVerticalSpacing((int) padding);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
Intent intent = new Intent(GridViewActivity.this, CarouselViewActivity.class);
intent.putExtra("position", position);
intent.putExtra("galleryAttributes", galleryAttributes);
startActivity(intent);
Log.e("onItemClick: ", ""+position);
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
Log.e("onScrollStateChanged: ", "" + scrollState);
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {
Log.e("onScroll: ", "firstVisibleItem:" + firstVisibleItem + " visibleItemCount:" + visibleItemCount + " totalItemCount:" + totalItemCount);
if(!hasRequestedMore){
int lastInScreen = firstVisibleItem+visibleItemCount;
if(lastInScreen>=totalItemCount){
hasRequestedMore = true;
onLoadMoreItems();
}
}
}
public void onLoadMoreItems(){
if(urlPageIndex<3){
urlPageIndex++;
utils.getDataFromServer(urlPageIndex,new WebServicesCallListener() {
@Override
public void onResponse(ArrayList<HashMap<String, String>> response) {
galleryAttributes.addAll(response);
adapter.notifyDataSetChanged();
hasRequestedMore = false;
}
});
}
}
}
感谢这个!我现在唯一需要做的是将进度条显示为可见并隐藏它的逻辑。 – 2014-10-22 06:39:55
@ KirbyAsterAbadilla,是的非常好赶上我认为这你很容易做到。 – 2014-10-22 06:42:35
是的,但我认为我需要改进我的工作,因为我认为从Web服务请求数据是导致onLoadMoreItems()触发时我的活动滞后的原因,但它不是。 – 2014-10-22 07:05:03
你能请张贴GridView的XML? (): – 2014-10-22 06:11:50
@HareshChhelana我张贴它上面,这是我的网格视图xml – 2014-10-22 06:13:01
我刚刚注意到这部分里面onLoadMoreItems(): -galleryAttributes.addAll(generateData.execute()。get()); 我建议用: -generateData替换此部分。执行() 然后重写GenerateData的onPostExecute。把galleryAttributes.addAll(args)放在 – 2014-10-24 10:49:47