android异步任务载入数据界面实现

时间：2023-03-09 08:02:07
android异步任务载入数据界面实现

android 异步任务的一个后台方法本质是开启一个线程完毕耗时操作，其它onPostExecute方法和onPreExecute方法执行在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载入方式如今总结例如以下：

1、异步载入界面效果例如以下:

android异步任务载入数据界面实现

关键代码例如以下所看到的：

/**

	 * 异步任务给列表载入数据

	 */

	private void fillData(){

		new AsyncTask<Void,Void,Void>(){

			@Override

			protected void onPreExecute() {

				loading.setVisibility(View.VISIBLE);

				super.onPreExecute();

			}

			@Override

			protected 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);

			}

			@Override

			protected 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 block

					e.printStackTrace();

				}

				return null;

			}

		}.execute();

	}


loading相应的



loading=findViewById(R.id.ll_rublish_sms_info_loading);


布局文件例如以下：


activity_rubish_sms.xml




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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <FrameLayout

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_weight="100" >

        <LinearLayout

            android:layout_gravity="center"

            android:id="@+id/ll_rublish_sms_info_loading"

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:orientation="vertical"

            android:visibility="invisible" >

            <ProgressBar

                android:layout_width="match_parent"

                android:layout_height="wrap_content" />

            <TextView

                android:gravity="center"

                android:layout_width="match_parent"

                android:layout_height="wrap_content"

                android:text="数据载入中,请稍后..."

                android:textSize="13sp" />

        </LinearLayout>

    </FrameLayout>

    <ListView

        android:id="@+id/lv_rubish_sms_content"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

    </ListView>

</LinearLayout>


通过如上代码就可以实现上述效果。


2、利用对话框实现


实现效果图：


android异步任务载入数据界面实现


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<Void,Object, Void>() {

			List<VirusApp> apps=new ArrayList<VirusApp>();

			String desc=null;

			Dialog dialog=new Dialog(KillVirusActivity.this);

			View viewKilling=View.inflate(KillVirusActivity.this,R.layout.killing_dialog,null);

			@Override

			protected 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();

			}

			@Override

			protected void onPostExecute(Void result) {

				dialog.dismiss();

				if(apps.size()>0){

					mKillVirusResult.setTextColor(Color.RED);

					mKillVirusResult.setText("扫描完毕！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() {

							@Override

							public 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("扫描完毕！恭喜没有发现病毒。");

				}

				super.onPostExecute(result);

			}

			@Override

			protected Void doInBackground(Void... params) {

				int total=0;

				//获得数据库操作对象

				VirusDao virusDao=new VirusDao();

				//获得设备上全部应用的签名

				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写叙述

				 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 block

					e.printStackTrace();

				}

				return null;

			}

		}.execute();

	}
	


该逻辑处理相应的activity布局界面：


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

>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <TextView

        android:layout_width="match_parent"

        android:layout_height="35dp"

        android:background="@drawable/ll_title_bg"

        android:gravity="center"

        android:text="手机病毒查杀" />

    <TextView

        android:id="@+id/tv_kill_virus_result"

        android:layout_width="match_parent"

        android:layout_height="125dp"

        android:gravity="center"

        android:background="@drawable/ll_title_bg" />

    <ScrollView

        android:layout_width="match_parent"

        android:layout_height="wrap_content" >

        <LinearLayout

           <span style="color:#ff0000;"> android:id="@+id/ll_container"</span>

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:orientation="vertical" >

        </LinearLayout>

    </ScrollView>

</LinearLayout>


该界面有一个线性布局容器，能够实现动态载入数据的效果。


实现自己定义对话框的布局：




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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <ProgressBar

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_gravity="center" />

    <TextView

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:gravity="center"

        android:text="病毒扫描中..."

        android:textSize="15sp" />

</LinearLayout>


实现动态扫描并载入数据的整个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<span style="color:#ff0000;"> mContainer</span>;

private TextView mKillVirusResult;

private PackageManager pm;

private ProgressBar progressBar;

private List<PackageInfo> packageInfos;

	public KillVirusActivity() {

	}

	@Override

		protected void onCreate(Bundle savedInstanceState) {

			setContentView(R.layout.activity_kill_virus);

			<span style="color:#ff0000;">mContainer</span>=(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文件夹

			 scanVirus();

			super.onCreate(savedInstanceState);

		}

	/**

	 * 扫描病毒 并动态显示在界面

	 */

	private void scanVirus(){

		new AsyncTask<Void,Object, Void>() {

			List<VirusApp> apps=new ArrayList<VirusApp>();

			String desc=null;

			Dialog dialog=new Dialog(KillVirusActivity.this);

			View viewKilling=View.inflate(KillVirusActivity.this,R.layout.killing_dialog,null);

			@Override

			protected 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();

			}

			@Override

			protected void onPostExecute(Void result) {

				dialog.dismiss();

				if(apps.size()>0){

					mKillVirusResult.setTextColor(Color.RED);

					mKillVirusResult.setText("扫描完毕！

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() {

							@Override

							public 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());

						<span style="color:#ff0000;">mContainer.addView(view);</span>

					}

				}else if(apps.size()==0){

					mKillVirusResult.setText("扫描完毕！恭喜没有发现病毒！

");

				}

				super.onPostExecute(result);

			}

			@Override

			protected Void doInBackground(Void... params) {

				int total=0;

				//获得数据库操作对象

				VirusDao virusDao=new VirusDao();

				//获得设备上全部应用的签名

				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写叙述

				 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 block

					e.printStackTrace();

				}

				return null;

			}

		}.execute();

	}

	/**

	 * 拷贝本地病毒库数据库到app文件夹

	 */

	private void copyVirusDB(){

		new AsyncTask<Void,Void,Void>(){

			@Override

			protected Void doInBackground(Void... params) {

				//获得要复制到目的地的文件

				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 block

						e.printStackTrace();

					}

				}

				return null;

			}

		}.execute();

	}

}



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