android异步任务加载数据界面实现

android 异步任务的一个后台方法本质是开启一个线程完成耗时操作，其他onPostExecute方法和onPreExecute方法运行在UI主线程用于更新UI界面。为了提高用户体验常见的异步任务加载方式现在总结如下：

1、异步加载界面效果如下:

android异步任务加载数据界面实现_第1张图片

关键代码如下所示：

/** * 异步任务给列表加载数据 */private void fillData(){new AsyncTask(){@Overrideprotected void onPreExecute() {loading.setVisibility(View.VISIBLE);super.onPreExecute();}@Overrideprotected void onPostExecute(Void result) {loading.setVisibility(View.INVISIBLE);//刷新界面列表数据if(mAdapter==null){mAdapter=new RubishSmsInfosAdapter();mRubishSms.setAdapter(mAdapter);}else{mAdapter.notifyDataSetChanged();}super.onPostExecute(result);}@Overrideprotected Void doInBackground(Void... params) {if(mInfos==null){mInfos=mRubishSmsInfoDao.findInfosbyPage(maxNum, offset);}else{mInfos.addAll(mRubishSmsInfoDao.findInfosbyPage(maxNum, offset));}try {Thread.sleep(2000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}}.execute();}

loading对应的

loading=findViewById(R.id.ll_rublish_sms_info_loading);

布局文件如下：

activity_rubish_sms.xml

<?xml version="1.0" encoding="utf-8"?>

通过如上代码即可实现上述效果。

2、利用对话框实现

实现效果图：

android异步任务加载数据界面实现_第2张图片

异步任务实现逻辑代码：

/** * 扫描病毒 并动态显示在界面 */private void scanVirus(){new AsyncTask() {List apps=new ArrayList();String desc=null;Dialog dialog=new Dialog(KillVirusActivity.this);View viewKilling=View.inflate(KillVirusActivity.this,R.layout.killing_dialog,null);@Overrideprotected void onPreExecute() {mKillVirusResult.setText("正在扫描中，请稍等...");dialog.setCancelable(false);dialog.setContentView(viewKilling);dialog.show();pm=getPackageManager(); packageInfos=pm.getInstalledPackages(PackageManager.GET_UNINSTALLED_PACKAGES|PackageManager.GET_SIGNATURES);// progressBar.setMax(packageInfos.size());super.onPreExecute();}@Overrideprotected void onPostExecute(Void result) {dialog.dismiss();if(apps.size()>0){mKillVirusResult.setTextColor(Color.RED);mKillVirusResult.setText("扫描完成！发现病毒"+apps.size()+"个"+","+"请及时清理");for(final VirusApp app:apps){//有病毒View view=View.inflate(KillVirusActivity.this,R.layout.app_virus_info_item,null);view.setClickable(true);view.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {//卸载程序Intent intent = new Intent();intent.setAction("android.intent.action.DELETE");intent.addCategory(Intent.CATEGORY_DEFAULT);intent.setData(Uri.parse("package:"+ app.getmAppVirusName()));startActivity(intent);}});ImageView appIcon=(ImageView) view.findViewById(R.id.iv_app_icon);TextView appName=(TextView) view.findViewById(R.id.tv_app_name);TextView appDesc=(TextView)view.findViewById(R.id.tv_app_virus_desc);appIcon.setBackground(app.getmAppVirusIcon());appName.setText(app.getmAppVirusName());appDesc.setText(app.getmAPPVirusDesc());mContainer.addView(view);}}else if(apps.size()==0){mKillVirusResult.setText("扫描完成！恭喜没有发现病毒！");}super.onPostExecute(result);}@Overrideprotected Void doInBackground(Void... params) {int total=0;//获得数据库操作对象VirusDao virusDao=new VirusDao();//获得设备上所有应用的签名for(PackageInfo info:packageInfos){ total++;Signature[] signature=info.signatures;try {String md5=Md5Util.encode(signature[0].toString()); desc=virusDao.findVirus(md5);Log.i("杀毒MD5<<<", md5); desc=virusDao.findVirus(md5);} catch (Exception e) {// TODO: handle exception}//Log.i("杀毒<<<", (signature[0]).toString());//签名用MD5编码获得MD5加密后的应用的签名信息//Log.i("杀毒MD5<<<", md5);//查询本地病毒签名数据库// desc=virusDao.findVirus(md5); if(desc!=null){//查询到病毒 VirusApp app=new VirusApp(); //获得应用的图标Drawable drawable=pm.getApplicationIcon(info.applicationInfo);app.setmAppVirusIcon(drawable); //获得应用名String appName=(String) pm.getApplicationLabel(info.applicationInfo);app.setmAppVirusName(appName); //获得该应用的病毒描述 app.setmAPPVirusDesc(desc); apps.add(app); app=null; //publishProgress(total,app); }else{ Log.i("杀毒MD5<<<","不是病毒"+total); }}//progressBar.setProgress(total);try {Thread.sleep(200);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}}.execute();}

该逻辑处理对应的activity布局界面：

<?xml version="1.0" encoding="utf-8"?>                     android:id="@+id/ll_container"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:orientation="vertical" >

该界面有一个线性布局容器，可以实现动态加载数据的效果。

实现自定义对话框的布局：

<?xml version="1.0" encoding="utf-8"?>

实现动态扫描并加载数据的整个Activity代码:

package com.example.yqqmobilesafe;import java.io.File;import java.io.IOException;import java.io.InputStream;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.app.Dialog;import android.content.Intent;import android.content.pm.PackageInfo;import android.content.pm.PackageManager;import android.content.pm.Signature;import android.graphics.Color;import android.graphics.drawable.Drawable;import android.net.Uri;import android.os.AsyncTask;import android.os.Bundle;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.ProgressBar;import android.widget.TextView;import com.example.yqqmobilesafe.db.dao.VirusDao;import com.example.yqqmobilesafe.domain.VirusApp;import com.example.yqqmobilesafe.utils.CopyFileToSystem;import com.example.yqqmobilesafe.utils.Md5Util;//本地病毒查杀public class KillVirusActivity extends Activity {private LinearLayout mContainer;private TextView mKillVirusResult;private PackageManager pm;private ProgressBar progressBar;private List packageInfos;public KillVirusActivity() {}@Overrideprotected void onCreate(Bundle savedInstanceState) {setContentView(R.layout.activity_kill_virus);mContainer=(LinearLayout) this.findViewById(R.id.ll_container);mKillVirusResult=(TextView) this.findViewById(R.id.tv_kill_virus_result);//progressBar=(ProgressBar) this.findViewById(R.id.pb_scanning_virus);copyVirusDB();//拷贝本地病毒签名到系统目录 scanVirus();super.onCreate(savedInstanceState);}/** * 扫描病毒 并动态显示在界面 */private void scanVirus(){new AsyncTask() {List apps=new ArrayList();String desc=null;Dialog dialog=new Dialog(KillVirusActivity.this);View viewKilling=View.inflate(KillVirusActivity.this,R.layout.killing_dialog,null);@Overrideprotected void onPreExecute() {mKillVirusResult.setText("正在扫描中，请稍等...");dialog.setCancelable(false);dialog.setContentView(viewKilling);dialog.show();pm=getPackageManager(); packageInfos=pm.getInstalledPackages(PackageManager.GET_UNINSTALLED_PACKAGES|PackageManager.GET_SIGNATURES);// progressBar.setMax(packageInfos.size());super.onPreExecute();}@Overrideprotected void onPostExecute(Void result) {dialog.dismiss();if(apps.size()>0){mKillVirusResult.setTextColor(Color.RED);mKillVirusResult.setText("扫描完成！发现病毒"+apps.size()+"个"+","+"请及时清理");for(final VirusApp app:apps){//有病毒View view=View.inflate(KillVirusActivity.this,R.layout.app_virus_info_item,null);view.setClickable(true);view.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {//卸载程序Intent intent = new Intent();intent.setAction("android.intent.action.DELETE");intent.addCategory(Intent.CATEGORY_DEFAULT);intent.setData(Uri.parse("package:"+ app.getmAppVirusName()));startActivity(intent);}});ImageView appIcon=(ImageView) view.findViewById(R.id.iv_app_icon);TextView appName=(TextView) view.findViewById(R.id.tv_app_name);TextView appDesc=(TextView)view.findViewById(R.id.tv_app_virus_desc);appIcon.setBackground(app.getmAppVirusIcon());appName.setText(app.getmAppVirusName());appDesc.setText(app.getmAPPVirusDesc());mContainer.addView(view);}}else if(apps.size()==0){mKillVirusResult.setText("扫描完成！恭喜没有发现病毒！");}super.onPostExecute(result);}@Overrideprotected Void doInBackground(Void... params) {int total=0;//获得数据库操作对象VirusDao virusDao=new VirusDao();//获得设备上所有应用的签名for(PackageInfo info:packageInfos){ total++;Signature[] signature=info.signatures;try {String md5=Md5Util.encode(signature[0].toString()); desc=virusDao.findVirus(md5);Log.i("杀毒MD5<<<", md5); desc=virusDao.findVirus(md5);} catch (Exception e) {// TODO: handle exception}//Log.i("杀毒<<<", (signature[0]).toString());//签名用MD5编码获得MD5加密后的应用的签名信息//Log.i("杀毒MD5<<<", md5);//查询本地病毒签名数据库// desc=virusDao.findVirus(md5); if(desc!=null){//查询到病毒 VirusApp app=new VirusApp(); //获得应用的图标Drawable drawable=pm.getApplicationIcon(info.applicationInfo);app.setmAppVirusIcon(drawable); //获得应用名String appName=(String) pm.getApplicationLabel(info.applicationInfo);app.setmAppVirusName(appName); //获得该应用的病毒描述 app.setmAPPVirusDesc(desc); apps.add(app); app=null; //publishProgress(total,app); }else{ Log.i("杀毒MD5<<<","不是病毒"+total); }}//progressBar.setProgress(total);try {Thread.sleep(200);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}}.execute();}/** * 拷贝本地病毒库数据库到app目录 */private void copyVirusDB(){new AsyncTask(){@Overrideprotected Void doInBackground(Void... params) {//获得要拷贝到目的地的文件File file=new File(getFilesDir(),"antivirus.db");if(file.exists()&&file.length()>0){}else{//获得文件输入流InputStream is=null;try {is=getResources().getAssets().open("antivirus.db");CopyFileToSystem.copyFile(is, file.getAbsolutePath());} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}return null;}}.execute();}}

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