- 环境
- 项目结构
- 演示下载
- 参考资料
本文是 github 上 Trinea-Android-common 和 Trinea-Android-Demo 项目的一部分，将下载部分分离出来，看看如何实现。（不知道此人学了多久，Android 水平不低~ 貌似年龄跟我差不多~
）
假设，现在有个下载 apk 包的需求，你大概能想到什么？
- 下载本身；
- 下载进度；
- 期间还能取消；
- 由于网络不好或中断，下载失败，还要能重试；
- 因为下载的是 apk，下载完还要能提示安装更好，而且，很多手机管理 app，还能静默安装；
- 还能在手机通知栏看到下载提示；
- 这些就涉及到 android.app.DownloadManager、android.content.BroadcastReceiver 和 android.os.Handler。
自己下载 Demo 调试一下~
下载 Demo
更多 Demo
环境
- Windows 2008 R2 64 位
- Eclipse ADT V22.6.2，Android 4.4.2（API 19）
- SAMSUNG GT-8618，Android OS 4.1.2
项目结构
图 1 项目结构
图 2 主程序
图 3 下载
（注意：顶部通知栏，是有下载图标的~）
package com.example.download.ui;
import java.io.File;
import java.text.DecimalFormat;
import com.example.download.R;
import com.example.download.utils.DownloadManagerPro;
import com.example.download.utils.PreferencesUtils;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.DownloadManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
/**
* DownloadManagerDemo
*
*/
public class DownloadManagerDemo extends Activity {
public static final String DOWNLOAD_FOLDER_NAME = "Trinea";
public static final String DOWNLOAD_FILE_NAME = "MeiLiShuo.apk";
public static final String APK_URL = "http://img.meilishuo.net/css/images/AndroidShare/Meilishuo_3.6.1_10006.apk";
public static final String KEY_NAME_DOWNLOAD_ID = "downloadId";
private Button downloadButton;
private ProgressBar downloadProgress;
private TextView downloadTip;
private TextView downloadSize;
private TextView downloadPrecent;
private Button downloadCancel;
private DownloadManager downloadManager;
private DownloadManagerPro downloadManagerPro;
private long downloadId = 0;
private MyHandler handler;
private DownloadChangeObserver downloadObserver;
private CompleteReceiver completeReceiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.download_manager_demo);
handler = new MyHandler();
downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
downloadManagerPro = new DownloadManagerPro(downloadManager);
// see android mainfest.xml,
// accept minetype of cn.trinea.download.file
Intent intent = getIntent();
if (intent != null) {
/**
* below android 4.2, intent.getDataString() is
* file:///storage/sdcard1/Trinea/MeLiShuo.apk<br/>
* equal or above 4.2 intent.getDataString() is
* content://media/external/file/29669
*/
Uri data = intent.getData();
if (data != null) {
Toast.makeText(getApplicationContext(), data.toString(), Toast.LENGTH_LONG)
.show();
}
}
initView();
initData();
downloadObserver = new DownloadChangeObserver();
completeReceiver = new CompleteReceiver();
/** register download success broadcast **/
registerReceiver(completeReceiver, new IntentFilter(
DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
@Override
protected void onResume() {
super.onResume();
/** observer download change **/
getContentResolver().registerContentObserver(
DownloadManagerPro.CONTENT_URI, true, downloadObserver);
updateView();
}
@Override
protected void onPause() {
super.onPause();
getContentResolver().unregisterContentObserver(downloadObserver);
}
@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(completeReceiver);
}
private void initView() {
downloadButton = (Button) findViewById(R.id.download_button);
downloadCancel = (Button) findViewById(R.id.download_cancel);
downloadProgress = (ProgressBar) findViewById(R.id.download_progress);
downloadTip = (TextView) findViewById(R.id.download_tip);
downloadTip
.setText(getString(R.string.tip_download_file)
+ Environment
.getExternalStoragePublicDirectory(DOWNLOAD_FOLDER_NAME));
downloadSize = (TextView) findViewById(R.id.download_size);
downloadPrecent = (TextView) findViewById(R.id.download_precent);
}
private void initData() {
/**
* get download id from preferences.<br/>
* if download id bigger than 0, means it has been downloaded, then
* query status and show right text;
*/
downloadId = PreferencesUtils.getLong(getApplicationContext(), KEY_NAME_DOWNLOAD_ID);
updateView();
downloadButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
File folder = new File(DOWNLOAD_FOLDER_NAME);
if (!folder.exists() || !folder.isDirectory()) {
folder.mkdirs();
}
DownloadManager.Request request = new DownloadManager.Request(
Uri.parse(APK_URL));
request.setDestinationInExternalPublicDir(DOWNLOAD_FOLDER_NAME,
DOWNLOAD_FILE_NAME);
request.setTitle(getString(R.string.download_notification_title));
request.setDescription("meilishuo desc");
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setVisibleInDownloadsUi(false);
// request.allowScanningByMediaScanner();
// request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);
// request.setShowRunningNotification(false);
// request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_HIDDEN);
request.setMimeType("application/cn.trinea.download.file");
downloadId = downloadManager.enqueue(request);
/** save download id to preferences **/
PreferencesUtils.putLong(getApplicationContext(), KEY_NAME_DOWNLOAD_ID,
downloadId);
updateView();
}
});
downloadCancel.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
downloadManager.remove(downloadId);
updateView();
}
});
}
/**
* install app
*
* @param context
* @param filePath
* @return whether apk exist
*/
public static boolean install(Context context, String filePath) {
Intent i = new Intent(Intent.ACTION_VIEW);
File file = new File(filePath);
if (file != null && file.length() > 0 && file.exists() && file.isFile()) {
i.setDataAndType(Uri.parse("file://" + filePath),
"application/vnd.android.package-archive");
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
return true;
}
return false;
}
class DownloadChangeObserver extends ContentObserver {
public DownloadChangeObserver() {
super(handler);
}
@Override
public void onChange(boolean selfChange) {
updateView();
}
}
class CompleteReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
/**
* get the id of download which have download success, if the id is
* my id and it's status is successful, then install it
**/
long completeDownloadId = intent.getLongExtra(
DownloadManager.EXTRA_DOWNLOAD_ID, -1);
if (completeDownloadId == downloadId) {
initData();
updateView();
// if download successful, install apk
if (downloadManagerPro.getStatusById(downloadId) == DownloadManager.STATUS_SUCCESSFUL) {
String apkFilePath = new StringBuilder(Environment
.getExternalStorageDirectory().getAbsolutePath())
.append(File.separator)
.append(DOWNLOAD_FOLDER_NAME)
.append(File.separator).append(DOWNLOAD_FILE_NAME)
.toString();
install(context, apkFilePath);
}
}
}
};
public void updateView() {
int[] bytesAndStatus = downloadManagerPro.getBytesAndStatus(downloadId);
handler.sendMessage(handler.obtainMessage(0, bytesAndStatus[0],
bytesAndStatus[1], bytesAndStatus[2]));
}
@SuppressLint("HandlerLeak")
private class MyHandler extends Handler {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case 0:
int status = (Integer) msg.obj;
if (isDownloading(status)) {
downloadProgress.setVisibility(View.VISIBLE);
downloadProgress.setMax(0);
downloadProgress.setProgress(0);
downloadButton.setVisibility(View.GONE);
downloadSize.setVisibility(View.VISIBLE);
downloadPrecent.setVisibility(View.VISIBLE);
downloadCancel.setVisibility(View.VISIBLE);
if (msg.arg2 < 0) {
downloadProgress.setIndeterminate(true);
downloadPrecent.setText("0%");
downloadSize.setText("0M/0M");
} else {
downloadProgress.setIndeterminate(false);
downloadProgress.setMax(msg.arg2);
downloadProgress.setProgress(msg.arg1);
downloadPrecent.setText(getNotiPercent(msg.arg1,
msg.arg2));
downloadSize.setText(getAppSize(msg.arg1) + "/"
+ getAppSize(msg.arg2));
}
} else {
downloadProgress.setVisibility(View.GONE);
downloadProgress.setMax(0);
downloadProgress.setProgress(0);
downloadButton.setVisibility(View.VISIBLE);
downloadSize.setVisibility(View.GONE);
downloadPrecent.setVisibility(View.GONE);
downloadCancel.setVisibility(View.GONE);
if (status == DownloadManager.STATUS_FAILED) {
downloadButton
.setText(getString(R.string.app_status_download_fail));
} else if (status == DownloadManager.STATUS_SUCCESSFUL) {
downloadButton
.setText(getString(R.string.app_status_downloaded));
} else {
downloadButton
.setText(getString(R.string.app_status_download));
}
}
break;
}
}
}
static final DecimalFormat DOUBLE_DECIMAL_FORMAT = new DecimalFormat("0.##");
public static final int MB_2_BYTE = 1024 * 1024;
public static final int KB_2_BYTE = 1024;
/**
* @param size
* @return
*/
public static CharSequence getAppSize(long size) {
if (size <= 0) {
return "0M";
}
if (size >= MB_2_BYTE) {
return new StringBuilder(16).append(
DOUBLE_DECIMAL_FORMAT.format((double) size / MB_2_BYTE))
.append("M");
} else if (size >= KB_2_BYTE) {
return new StringBuilder(16).append(
DOUBLE_DECIMAL_FORMAT.format((double) size / KB_2_BYTE))
.append("K");
} else {
return size + "B";
}
}
public static String getNotiPercent(long progress, long max) {
int rate = 0;
if (progress <= 0 || max <= 0) {
rate = 0;
} else if (progress > max) {
rate = 100;
} else {
rate = (int) ((double) progress / max * 100);
}
return new StringBuilder(16).append(rate).append("%").toString();
}
public static boolean isDownloading(int downloadManagerStatus) {
return downloadManagerStatus == DownloadManager.STATUS_RUNNING
|| downloadManagerStatus == DownloadManager.STATUS_PAUSED
|| downloadManagerStatus == DownloadManager.STATUS_PENDING;
}
}