下面是我的java代码和xml代码。我想在显示任何数据之前显示进度条。我怎样才能做到这一点？我使用asyntask来加载数据。如何在我的代码中显示进度条，以便在加载数据之前首先显示进度条。加载数据后，将删除进度条。
public class fifthscreen extends Activity {
String num = null;
TextView ingredient;
long Menu_ID;
String dish_name;
View row4;
View row3;
String status;
HorizontalListView listview;
CategoryListAdapter3 cla;
String DescriptionAPI;
TextView txt1, txt2, txt3;
ImageView img1;
String URL, URL2;
String SelectMenuAPI;
static ArrayList<Long> Category_ID = new ArrayList<Long>();
static ArrayList<String> Category_name = new ArrayList<String>();
static ArrayList<String> Category_image = new ArrayList<String>();
public static String allergen2;
private AQuery androidAQuery;
String name;
String description;
String url1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fifthscreen);
ingredient = (TextView) findViewById(R.id.ingredient);
img1 = (ImageView) findViewById(R.id.test_button_image);
txt1 = (TextView) findViewById(R.id.menuname);
txt3 = (TextView) findViewById(R.id.description);
Intent iGet = getIntent();
ImageView options = (ImageView) findViewById(R.id.options5);
androidAQuery = new AQuery(this);
options.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent iMenuList = new Intent(fifthscreen.this,
LinkButtons.class);
startActivity(iMenuList);
}
});
dish_name = iGet.getStringExtra("dish_name");
listview = (HorizontalListView) this.findViewById(R.id.listview2);
cla = new CategoryListAdapter3(fifthscreen.this);
new getDataTask().execute();
ImageView btnback = (ImageView) findViewById(R.id.btnback);
btnback.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
}
void clearData() {
Category_ID.clear();
Category_name.clear();
Category_image.clear();
}
public class getDataTask extends AsyncTask<Void, Void, Void> {
getDataTask() {
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
}
@Override
protected Void doInBackground(Void... arg0) {
// TODO Auto-generated method stub
parseJSONData();
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
txt1.setText(name);
txt3.setText(description);
androidAQuery.id(img1).image(url1, false, false);
listview.setAdapter(cla);
}
}
public void parseJSONData() {
SelectMenuAPI = Utils.dishdescription + dish_name;
clearData();
URL = SelectMenuAPI;
URL2 = URL.replace(" ", "%20");
try {
HttpClient client = new DefaultHttpClient();
HttpConnectionParams
.setConnectionTimeout(client.getParams(), 15000);
HttpConnectionParams.setSoTimeout(client.getParams(), 15000);
HttpUriRequest request = new HttpGet(URL2);
HttpResponse response = client.execute(request);
InputStream atomInputStream = response.getEntity().getContent();
BufferedReader in = new BufferedReader(new InputStreamReader(
atomInputStream),8192);
String line;
String str = "";
while ((line = in.readLine()) != null) {
str += line;
}
JSONObject json2 = new JSONObject(str);
status = json2.getString("status");
if (status.equals("1")) {
JSONArray school2 = json2.getJSONArray("data");
for (int i = 0; i < school2.length(); i++) {
name = school2.getJSONObject(0).getString("name");
description = school2.getJSONObject(0).getString(
"description");
url1 = school2.getJSONObject(0).getString("image");
}
JSONObject school3 = json2.getJSONObject("dish_nutrition");
final TableLayout table = (TableLayout) findViewById(R.id.table2);
for (int j = 0; j < school3.length(); j++) {
String s = String.valueOf(j + 1);
row3 = getLayoutInflater().inflate(R.layout.rows, null);
((TextView) row3.findViewById(R.id.localTime))
.setText(school3.getJSONObject(s).getString("qty"));
((TextView) row3.findViewById(R.id.apprentTemp))
.setText(school3.getJSONObject(s).getString("name"));
fifthscreen.this.runOnUiThread(new Runnable() {
public void run() {
table.addView(row3);
}
});
}
JSONArray school4 = json2.getJSONArray("dish_allergen");
//
for (int i = 0; i < school4.length(); i++) {
JSONObject object = school4.getJSONObject(i);
Category_ID.add((long) i);
Category_name.add(object.getString("name"));
Category_image.add(object.getString("image"));
}
final LinearLayout table3 = (LinearLayout)
findViewById(R.id.table3);
JSONArray school5 = json2.getJSONArray("dish_ingredient");
for (int i = 0; i < school5.length(); i++) {
row4 = getLayoutInflater().inflate(R.layout.row2, null);
((TextView) row4.findViewById(R.id.name)).setText(school5
.getJSONObject(i).getString("name"));
((TextView) row4.findViewById(R.id.subingredients))
.setText(school5.getJSONObject(i).getString(
"sub_ingredients"));
// table3.addView(row2);
fifthscreen.this.runOnUiThread(new Runnable() {
public void run() {
table3.addView(row4);
}
});
}
}
else {
JSONArray school2 = json2.getJSONArray("data");
for (int i = 0; i < school2.length(); i++) {
JSONObject object = school2.getJSONObject(i);
Category_ID.add((long) i);
Category_name.add(object.getString("name"));
}
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
// IOConnect = 1;
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#E5E5E5"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/layoutbordercolor" >
<ImageView
android:id="@+id/btnback"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:paddingLeft="3dp"
android:paddingTop="15dp"
android:src="@drawable/back"
android:visibility="gone" />
<ImageView
android:id="@+id/bitmap"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginLeft="60dp"
android:layout_weight="1.5"
android:src="@drawable/logostar" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="4"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="5dp"
android:paddingTop="12dp"
android:text="San Diego Unified"
android:textColor="#603311"
android:textSize="14sp"
android:textStyle="bold" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="8dp"
android:text="SCHOOL DISTRICT"
android:textColor="#603311"
android:textSize="10sp" />
</LinearLayout>
<ImageView
android:id="@+id/options"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:paddingBottom="5dp"
android:paddingTop="10dp"
android:src="@drawable/options1" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:id="@+id/lytContent"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:orientation="vertical" >
<RelativeLayout
android:id="@+id/relativeLayout1"
android:layout_width="match_parent"
android:background="@drawable/editbackground"
android:paddingBottom="5dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_height="wrap_content" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="8dp"
android:paddingBottom="2dp"
android:src="@drawable/search_btn" />
<EditText
android:id="@+id/editText2"
android:layout_width="fill_parent"
android:layout_height="36dp"
android:layout_toLeftOf="@+id/imageView1"
android:layout_marginTop="5dp"
android:paddingLeft="10dp"
android:layout_marginLeft="10dp"
android:paddingRight="5dp"
android:gravity="left"
android:background="#FFF"
android:hint=" Search School by name"
android:imeOptions="actionSearch"
android:paddingTop="10dp"
android:textSize="15dp" >
</EditText>
</RelativeLayout>
<LinearLayout
android:id="@+id/lytContent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/pleaseselect"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:paddingLeft="15dp"
android:text=" Select a school type"
android:textColor="#0A2A1B"
android:textSize="18sp"
android:textStyle="bold"
android:visibility="gone" />
<LinearLayout
android:id="@+id/lytContent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="10dp"
android:background="@drawable/layout_border"
android:orientation="vertical" >
<ListView
android:id="@+id/listMainMenuhome"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingTop="3dp"
android:paddingBottom="3dp"
android:paddingLeft="3dp"
android:paddingRight="3dp"
android:dividerHeight="1dip"
android:fadeScrollbars="true"
android:listSelector="@color/listview_selector"
android:visibility="gone" />
</LinearLayout>
<!-- android:listSelector="@drawable/listviewborder" -->
<ProgressBar
android:id="@+id/prgLoading"
style="?android:attr/progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
<TextView
android:id="@+id/txtAlert"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:paddingLeft="10dp"
android:text="@string/alert"
android:textColor="@color/text"
android:textSize="14sp"
android:visibility="gone" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
答案 0 :(得分：1)
你可以制作一个覆盖整个屏幕的相对布局，它的背景和中间的进度条，在你所有的活动内容之上，一旦你拥有了你需要的所有信息，你就可以忽略那个布局覆盖整个活动布局，这将成功。这不是一种干净的方法，但是常用。
为了做得更好，您可以创建一个完全独立的布局，只需将进度作为活动的一部分，直到您收集内容数据所需的所有信息，只需对其进行充气并显示，您的进度条应该可以重复使用，这样你就可以随时显示和消除进度......
希望这有助于。
问候！
答案 1 :(得分：0)
http://developer.android.com/reference/android/widget/ProgressBar.html
有一个例子。看起来完全像你需要做的
答案 2 :(得分：0)
试试这段代码。如果有效，请告诉我。
ProgressDialog mProgressDialog;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
// Create a progressdialog
mProgressDialog = new ProgressDialog(fifthscreen.this);
// Set progressdialog title
mProgressDialog.setTitle("Your Title");
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// TODO Auto-generated method stub
parseJSONData();
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
txt1.setText(name);
txt3.setText(description);
androidAQuery.id(img1).image(url1, false, false);
listview.setAdapter(cla);
mProgressDialog.dismiss();
}