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(Android实战)ProgressBar+AsyncTask实现界面数据异步加载(含效果图)

2011年07月27日 ⁄ 综合 ⁄ 共 6458字 ⁄ 字号 评论关闭

1 效果图

 

                             加载数据时

 

                        加载数据完成时

 

          加载数据异常时

 

 

2 实现说明

  加载前:界面显示异步加载控件,隐藏数据显示控件,加载异常控件

  加载成功:根据加载的数据,初始化数据显示控件

  加载失败:显示加载异常的控件,异常异步加载控件

 

 中间的加载过程,通过AsyncTask来实现,在AsyncTask中主要实现两个方法

 //后台运行,互联网后台数据加载接口

protected Integer doInBackground(String...
params)

 

//数据加载完成,结合数据,进行UI处理

protected void onPostExecute(Integer
result)

 

3 实现代码

 

  3.1界面部分


加载控件:

 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width
="fill_parent"
android:layout_height
="fill_parent"
android:background
="#ffffff"
android:orientation
="horizontal"
android:gravity
="center_horizontal"
android:id
="@+id/async_begin" >
<ProgressBar
android:layout_width="wrap_content"
android:layout_height
="wrap_content"
android:indeterminate
="true"
style
="@android:style/Widget.ProgressBar.Small.Inverse"
android:layout_marginRight
="5dp" />
<TextView android:text="加载信息中。。。。。"
android:id
="@+id/textView1"
android:layout_width
="wrap_content"
android:textColor
="#000000"
android:layout_height
="wrap_content"></TextView>
</LinearLayout>

加载失败控件:

 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width
="fill_parent"
android:layout_height
="fill_parent"
android:background
="#ffffff"
android:orientation
="horizontal"
android:id
="@+id/async_error"
android:visibility
="gone" >
<TextView android:text="网络异常,不能加载数据"
android:id
="@+id/textView1"
android:layout_width
="wrap_content"
android:textColor
="#000000"
android:layout_height
="wrap_content"></TextView>
<Button android:text=""
android:id
="@+id/but_reflesh"
android:background
="@drawable/but_reflesh"
android:layout_width
="wrap_content"
android:layout_height
="wrap_content"></Button>
</LinearLayout>

数据展示控件:

View Code

<LinearLayout 
android:layout_height="wrap_content"
android:layout_width
="fill_parent"
android:visibility
="gone"
android:id
="@+id/rl_content"
android:orientation
="vertical"
android:gravity
="center_horizontal"
>
<LinearLayout android:layout_height="wrap_content" android:id="@+id/linearLayout2" android:layout_width="300px">
<ImageView android:src="@drawable/ranklist_myrank" android:id="@+id/imageView2" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
</LinearLayout>

<RelativeLayout android:background="@drawable/ranklist_itembg" android:layout_height="wrap_content" android:id="@+id/relativeLayout1" android:layout_width="300px">
<LinearLayout android:gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/line_photo" android:background="@drawable/ranklist_photobg" >
<ImageView android:src="@drawable/ranklist_male" android:id="@+id/ranklist_male" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
</LinearLayout>
<LinearLayout android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/linearLayout4" android:layout_toRightOf="@id/line_photo" >
<TextView android:textColor="#000000" android:text="1. xuwenbing" android:id="@+id/txt_nicename" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
<TextView android:textColor="#000000" android:text="积分为:1234" android:id="@+id/txt_integral" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
</LinearLayout>

<LinearLayout android:gravity="center_vertical" android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/linearLayout4" android:layout_alignParentRight="true" >
<ImageView android:src="@drawable/ranklist_goto" android:id="@+id/imageView3" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>
</LinearLayout>
</RelativeLayout>

<LinearLayout android:layout_height="wrap_content" android:id="@+id/linearLayout3" android:layout_width="wrap_content">
<ImageView android:src="@drawable/ranklist_rank_other" android:id="@+id/imageView4" android:layout_height="wrap_content" android:layout_width="wrap_content"></ImageView>

</LinearLayout>
<LinearLayout android:layout_height="wrap_content" android:id="@+id/linearLayout5" android:layout_width="300px">
<ListView android:background="@drawable/ranklist_itembg" android:scrollbars="vertical" android:layout_height="300px" android:id="@+id/listView_ranklist" android:layout_width="wrap_content"></ListView>
</LinearLayout>
</LinearLayout>

3.2后台代码

AsyncTask
类的生成,和调用:

View Code

 //AsyncTask
class AsyncLoader_GuessInfo extends AsyncTask<String, Void, Integer>{
@Override
protected Integer doInBackground(String... params) {
int result=0;
try{
//加载数据
if(params[0].length()>0)
model
= IntegralDataServiceHelper.GetRank(params[0],ProjectConstant.AppID);
list
= IntegralDataServiceHelper.GetTopList(0, 10,ProjectConstant.AppID);
if(list!=null)
result
=2;
}
catch(Exception ex){
result
=-1;
}
return result;
}

@Override
//处理界面
protected void onPostExecute(Integer result) {
Log.i(
"ExerciseGuess", "onPostExecute(Result result) called");

if( result==2)
LoadAndBandingData();
else
{
LinearLayout async_begin
=(LinearLayout)findViewById(R.id.async_begin);
async_begin.setVisibility(View.GONE);

LinearLayout async_error
=(LinearLayout)findViewById(R.id.async_error);
async_error.setVisibility(View.VISIBLE);

}
}
}

调用:new AsyncLoader_GuessInfo().execute(account);


异步界面,重试部分实现

 

 //加载刷新按钮事件    
Button but_reflesh=(Button)findViewById(R.id.but_reflesh);
but_reflesh.setOnClickListener(
new Button.OnClickListener()
{
public void onClick(View v){
//显示加载的部分
LinearLayout async_begin=(LinearLayout)findViewById(R.id.async_begin);
async_begin.setVisibility(View.VISIBLE);

//隐藏异步加载失败部分
LinearLayout async_error=(LinearLayout)findViewById(R.id.async_error);
async_error.setVisibility(View.GONE);
//异步加载
new AsyncLoader_GuessInfo().execute(account);

}
});

界面初始化数据部分:

View Code

public void LoadAndBandingData()
{
LinearLayout async_begin
=(LinearLayout)findViewById(R.id.async_begin);
async_begin.setVisibility(View.GONE);
LinearLayout rl_content
=(LinearLayout)findViewById(R.id.rl_content);
rl_content.setVisibility(View.VISIBLE);


TextView txt_nicename
=(TextView)findViewById(R.id.txt_nicename);
TextView txt_integral
=(TextView)findViewById(R.id.txt_integral);

if(model!=null)
{
txt_nicename.setText(String.valueOf(model.RankNo)
+". "+model.UserNiceName);
txt_integral.setText(
"当前的积分:"+String.valueOf(model.IntegralSum));
}
else
{
txt_nicename.setText(
"当前还没有注册用户!");
txt_integral.setText(
"当前的积分:0");
}

ListView listview
=(ListView)findViewById(R.id.listView_ranklist);
listview.setAdapter(
new RankListAdapter(this, R.layout.sub_ranlist_item,list));
//增加选择事件
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
}
});


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