Download。interface
package lbstest.example.com.lbs.ServiceBestPractice;
/**
* 功能：对下载过程中的各种状态进行监听
* Created by bummer on 2017/7/26.
*/
public interface DownloadListener {
void onProgress(int progress); //用于通知当前的下载进度
void onSuccess(); //用于通知下载成功事件
void onFailed(); //用于通知下载失败事件
void onPaused(); //用于通知下载暂停事件
void onCanceled(); //用于通知下载取消事件
}
DownloadTask.java
package lbstest.example.com.lbs.ServiceBestPractice;
import android.os.AsyncTask;
import android.os.Environment;
import android.util.Log;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
/**
* Created by bummer on 2017/7/26.
*/
/**
* params AsyncTask 中的三个泛型参数
* String 需要传入一个字符串给给后台任务
* Integer 整型数据表示进度显示的单位
* Integer 整型数据反馈执行的结果
*/
public class DownloadTask extends AsyncTask <String,Integer,Integer>{
public final static int TYPE_SUCCESS = 0; //表示下载成功
public final static int TYPE_FAILED = 1; //表示下载失败
public final static int TYPE_PAUSED = 2; //表示下载暂停
public final static int TYPE_CANCELED = 3;//表示下载取消
private DownloadListener listener;
private boolean isCanceled = false;
private boolean isPaused = false;
private int lastProgress;
//在DownloadTask的构造函数中传入一个刚定义的DownloadListener参数,我们待会会将下载的状态通过这个状态进行回调
public DownloadTask(DownloadListener listener) {
this.listener = listener;
}
/**
* 功能:后台执行的具体的下载逻辑
*
* @param params
* @return
*/
@Override
protected Integer doInBackground(String... params) {
InputStream is = null;
RandomAccessFile savedFile = null;
File file = null;
try {
long downloadLength = 0; //记录下载文件长度
// 从参数中获得了下载的URL地址
String downloadUrl = params[0];
// 并根据URL地址解析出了下载的文件名
String fileName = downloadUrl.substring(downloadUrl.lastIndexOf("/"));
// 将指定的文件下载到Environment.DIRECTORY_DOWNLOADS目录,也就是SD卡的Download目录
String directory = Environment.getExternalStoragePublicDirectory
(Environment.DIRECTORY_DOWNLOADS).getPath();
file = new File(directory + fileName);
Log.d("File","file is"+file+" "+"directory is "+directory+" "+"fileName is"+fileName);
//判断Download中是否已经存在要下载的文件了
if (file.exists()){
//如果存在则读取已下载的字节数 这样后面就能实现断点续传的功能
downloadLength = file.length();
}
//调用getContentLength()方法获得文件的总长度
long contentLength = getContentLength(downloadUrl);
if (contentLength == 0){
//如果文件长度为0,说明文件有问题
return TYPE_FAILED;
}else if (contentLength == downloadLength){
//已下载字节和文件总字节相等，说明已经下载完成了
return TYPE_SUCCESS;
}
//使用OKhttp发送网络请求
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
//断点下载，指定从哪个字节开始下载
.addHeader("RANGE","bytes="+downloadLength + "-")
.url(downloadUrl)
.build();
Response response = client.newCall(request).execute();
//读取服务器响应的数据,并使用java的IO流的方式,不断从网络上读取数据,不断写入到本地
if(response != null){
is = response.body().byteStream();
savedFile = new RandomAccessFile(file,"rw");
savedFile.seek(downloadLength); //跳过已下载的字节
byte[] b = new byte[1024];
int total = 0;
int len;
while ((len = is.read(b))!= -1){
if(isCanceled){ //判断用户有没有触发取消按钮
return TYPE_CANCELED;
}else if (isPaused){ //判断你用户有没有触发暂停按钮
return TYPE_PAUSED;
}else {
total += len;
savedFile.write(b,0,len);
//计算已下载的百分比
int progress = (int)((total + downloadLength)*100/contentLength);
//调用publicProgress方法进行通知
publishProgress(progress);
}
}
response.body().close();
return TYPE_SUCCESS;
}
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if (is != null) {
is.close();
}
if(savedFile != null){
savedFile.close();
}
if(isCanceled && file != null){
file.delete();
}
} catch (Exception e) {
e.printStackTrace();
}
}
return TYPE_FAILED;
}
/**
* 功能:界面上更新当前的下载逻辑
* @param values
*/
@Override
protected void onProgressUpdate(Integer... values) {
//从参数中获得当前下载进度
int progress = values[0];
if(progress > lastProgress){
//和上一次进度进行对比,如果有变化
//调用listener.onProgress通知下载进度进行更新
listener.onProgress(progress);
lastProgress = progress;
}
}
/**
* 功能:用于通知最后的下载结果
* @param status
*/
@Override
protected void onPostExecute(Integer status) {
//将参数中传入的下载状态进行回调,下载成功就调用DownloadListener.onSuccess()方法,
// 取消下载就调用onCanceled()方法
switch (status){
case TYPE_SUCCESS:
listener.onSuccess();
break;
case TYPE_FAILED:
listener.onFailed();
break;
case TYPE_PAUSED:
listener.onPaused();
break;
case TYPE_CANCELED:
listener.onCanceled();
break;
default:
break;
}
}
public void pauseDownload(){
isPaused = true;
}
public void cancelDownload(){
isCanceled = true;
}
private long getContentLength(String downloadUrl) throws IOException{
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(downloadUrl)
.build();
Response response = client.newCall(request).execute();
if(response != null && response.isSuccessful()){
long contentLength = response.body().contentLength();
response.close();
return contentLength;
}
return 0;
}
}
DownloadService.java
package lbstest.example.com.lbs.ServiceBestPractice;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.os.Binder;
import android.os.Environment;
import android.os.IBinder;
import android.support.v4.app.NotificationCompat;
import android.widget.Toast;
import java.io.File;
import lbstest.example.com.lbs.R;
public class DownloadService extends Service {
DownloadTask downloadTask;
private String downloadUrl;
private DownloadListener listener = new DownloadListener() {
@Override
public void onProgress(int progress) {
getNotificationManager().notify(1,getNotification("Downloading...",
progress));
}
@Override
public void onSuccess() {
downloadTask = null;
//下载成功将前台服务通知关闭,并创建一个下载成功的通知
stopForeground(true);
getNotificationManager().notify(1,getNotification("Download Success",
-1));
Toast.makeText(DownloadService.this,"Download Success",
Toast.LENGTH_SHORT).show();
}
@Override
public void onFailed() {
downloadTask = null;
//下载失败时将前台服务关闭,并创建一个下载失败的通知
stopForeground(true);
//触发通知，这样就可以在下拉状态栏中实时看到下载进度
getNotificationManager().notify(1,getNotification("Download Failed",-1));
Toast.makeText(DownloadService.this,"Download Failed",Toast.LENGTH_SHORT).show();
}
@Override
public void onPaused() {
downloadTask = null;
Toast.makeText(DownloadService.this,"Download Pause",Toast.LENGTH_SHORT).show();
}
@Override
public void onCanceled() {
downloadTask = null;
stopForeground(true);
Toast.makeText(DownloadService.this,"Download Canceled",Toast.LENGTH_SHORT).show();
}
};
/**
* 让DownloadService 可以和活动进行通信
*/
private DownloadBinder mBinder = new DownloadBinder();
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public class DownloadBinder extends Binder{
//用于开始下载
public void startDownload(String Url){
//创建一个downloadTask实例，
if(downloadTask == null){
downloadUrl = Url;
downloadTask = new DownloadTask(listener); //把刚才的DownloadListener作为参数传入
downloadTask.execute(downloadUrl);
//让服务成为前台服务 ，在状态栏创建一个持续运行的通知
startForeground(1,getNotification("Downloading......",0));
Toast.makeText(DownloadService.this,"Downloading......",Toast.LENGTH_SHORT).show();
}
}
//用于暂停下载
public void pauseDownload(){
if (downloadTask != null) {
downloadTask.pauseDownload();
}
}
//用于取消下载
public void cancelDownload(){
if (downloadTask != null) {
downloadTask.cancelDownload();
}else {
//取消下载将正在下载的文件删除掉
if (downloadUrl != null) {
//取消下载时需将文件删除，并将通知进行关闭
String fileName = downloadUrl.substring(downloadUrl.lastIndexOf("/"));
String directory = Environment.getExternalStoragePublicDirectory
(Environment.DIRECTORY_DOWNLOADS).getPath();
File file = new File(directory + fileName);
if(file.exists()){
file.delete();
}
getNotificationManager().cancel(1);
stopForeground(true);
Toast.makeText(DownloadService.this,"Canceled",Toast.LENGTH_SHORT).show();
}
}
}
}
private Notification getNotification(String title, int progress){
Intent intent = new Intent(this,Main4Activity.class);
PendingIntent pi = PendingIntent.getActivity(this,0,intent,0);
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
builder.setSmallIcon(R.mipmap.ic_launcher);
builder.setLargeIcon(BitmapFactory.decodeResource(getResources(),
R.mipmap.ic_launcher));
builder.setContentIntent(pi);
builder.setContentTitle(title);
if(progress > 0){
//当progress 大于或等于0时才需要显示下载进度
builder.setContentText(progress + "%");
builder.setProgress(100,progress,false);
}
return builder.build();
}
private NotificationManager getNotificationManager() {
return (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
};
}
Main4Activity.java
package lbstest.example.com.lbs.ServiceBestPractice;
import android.Manifest;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.IBinder;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import lbstest.example.com.lbs.R;
/**
* 功能：完整版的下载实例
*/
public class Main4Activity extends AppCompatActivity implements View.OnClickListener {
private static boolean Justice = false;
EditText urlWeb = null;
private DownloadService.DownloadBinder downloadBinder;
//先创建一个SerViceConnection 的匿名类，
private ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
// onServiceConnection()方法中获得DownloadBinder的实例
//有了这个实例，可以在活动中调用服务提供的各种方法
downloadBinder = (DownloadService.DownloadBinder) service;
}
@Override
public void onServiceDisconnected(ComponentName name) {
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main4);
Button startDownload = (Button) findViewById(R.id.start_download);
Button pauseDownload = (Button) findViewById(R.id.pause_download);
Button cancelDownload = (Button) findViewById(R.id.cancel_download);
urlWeb = (EditText) findViewById(R.id.webUrl);
startDownload.setOnClickListener(this);
pauseDownload.setOnClickListener(this);
cancelDownload.setOnClickListener(this);
Intent intent = new Intent(this,DownloadService.class);
//启动和绑定服务
startService(intent); //启动服务可以保证DownloadService一直在后台运行
bindService(intent,connection,BIND_AUTO_CREATE); //绑定服务 让Main4Activity和DownloadService进行通信
if(ContextCompat.checkSelfPermission(Main4Activity.this, Manifest
.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(Main4Activity.this,new
String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
}
}
@Override
public void onClick(View v) {
if(downloadBinder == null){
return;
}
switch (v.getId()){
case R.id.start_download:
String url = null;
if(!urlWeb.getText().toString().equals("")){
Log.d("XXX","urlWeb.get is"+urlWeb.getText().toString());
url = urlWeb.getText().toString();
downloadBinder.startDownload(url);
Justice = true;
}else {
Justice = false;
Toast.makeText(Main4Activity.this,"请先填写要下载的网址!",Toast.LENGTH_SHORT).show();
}
break;
case R.id.pause_download:
if(Justice){
downloadBinder.pauseDownload();
}else {
Toast.makeText(Main4Activity.this,"请先填写要下载的网址!",Toast.LENGTH_SHORT).show();
}
break;
case R.id.cancel_download:
if(Justice){
downloadBinder.cancelDownload();
}else {
Toast.makeText(Main4Activity.this,"请先填写要下载的网址!",Toast.LENGTH_SHORT).show();
}
break;
default:
break;
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode){
case 1:
if(grantResults.length > 0 && grantResults[0] != PackageManager.PERMISSION_GRANTED){
Toast.makeText(this,"拒绝权限将无法使用程序",Toast.LENGTH_SHORT).show();
finish();
}
break;
default:
}
}
@Override
protected void onDestroy() {
super.onDestroy();
unbindService(connection);
}
}
activity_main.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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="输入要下载的网址"
android:textSize="20sp"
/>
<EditText
android:textSize="18sp"
android:textColor="#000"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="例:http://www.baidu.com"
android:id="@+id/webUrl"
/>
</LinearLayout>
<Button
android:id="@+id/start_download"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="开始下载" />
<Button
android:id="@+id/pause_download"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="暂停下载" />
<Button
android:id="@+id/cancel_download"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="取消下载" />
</LinearLayout>