Android 文件斷點下載和通知欄的提示及apk更新安裝

第一步：創建一張表用來保存下載信息

public class DbHelper extends SQLiteOpenHelper {

    public static String TABLE = "file";//表名

    public DbHelper(Context context) {
        super(context, "download.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table file(fileName varchar,url varchar,length integer,finished integer)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

}

第二步：在DbHelper.class中來寫公用方法

/**
 * 插入一條下載信息
 */
public void insertData(SQLiteDatabase db, FileInfo info) {
    ContentValues values = new ContentValues();
    values.put("fileName", info.getFileName());
    values.put("url", info.getUrl());
    values.put("length", info.getLength());
    values.put("finished", info.getFinished());
    db.insert(TABLE, null, values);
    db.close();
}

/**
 * 更新一條下載信息
 */
public void updateData(SQLiteDatabase db, FileInfo info) {
    ContentValues values = new ContentValues();
    values.put("fileName", info.getFileName());
    values.put("length", info.getLength());
    values.put("finished", info.getFinished());
    db.update(TABLE, values, "url = ?", new String[]{info.getUrl()});
    db.close();
}

/**
 * 是否已經插入這條數據
 */
public boolean isExist(SQLiteDatabase db, FileInfo info) {
    Cursor cursor = db.query(TABLE, null, "url = ?", new String[]{info.getUrl()}, null, null, null, null);
    boolean exist = cursor.moveToNext();
    cursor.close();
    db.close();
    return exist;
}

/**
 * 查詢已經存在的一條信息
 */
public FileInfo queryData(SQLiteDatabase db, String url) {
    Cursor cursor = db.query(TABLE, null, "url = ?", new String[]{url}, null, null, null, null);
    FileInfo info = new FileInfo();
    if (cursor != null) {
        while (cursor.moveToNext()) {
            String fileName = cursor.getString(cursor.getColumnIndex("fileName"));
            int length = cursor.getInt(cursor.getColumnIndex("length"));
            int finished = cursor.getInt(cursor.getColumnIndex("finished"));
            info.setStop(false);
            info.setFileName(fileName);
            info.setUrl(url);
            info.setLength(length);
            info.setFinished(finished);
        }
        cursor.close();
        db.close();
    }
    return info;
}

第三步：創建FileInfo對象，一個下載任務實體類，set和get

private String fileName;//文件名
private String url;//下載地址
private int length;//文件大小
private int finished;//下載以已完成進度
private boolean isStop = false;//是否暫停下載
private boolean isDownLoading = false;//是否正在下載

第四步：創建DownLoaderManger來管理下載任務，包括添加下載任務、開始下載、暫停下載、重新下載

public class DownLoaderManger {

    public static String FILE_PATH = Environment.getExternalStorageDirectory() + "/cjy";
    private DbHelper helper;//數據庫幫助類
    private SQLiteDatabase db;
    private OnProgressListener listener;//進度回調監聽
    private Map<String, FileInfo> map = new HashMap<>();//保存正在下載的任務信息
    private static DownLoaderManger manger;

    private DownLoaderManger(DbHelper helper, OnProgressListener listener) {
        this.helper = helper;
        this.listener = listener;
        db = helper.getReadableDatabase();
    }

    /**
     * 單例模式
     *
     * @param helper   數據庫幫助類
     * @param listener 下載進度回調接口
     * @return
     */
    public static synchronized DownLoaderManger getInstance(DbHelper helper, OnProgressListener listener) {
        if (manger == null) {
            synchronized (DownLoaderManger.class) {
                if (manger == null) {
                    manger = new DownLoaderManger(helper, listener);
                }
            }
        }
        return manger;
    }

    /**
     * 開始下載任務
     */
    public void start(String url) {
        db = helper.getReadableDatabase();
        FileInfo info = helper.queryData(db, url);
        map.put(url, info);
        //開始任務下載
        new DownLoadTask(map.get(url), helper, listener).start();
    }

    /**
     * 停止下載任務
     */
    public void stop(String url) {
        map.get(url).setStop(true);
    }

    /**
     * 重新下載任務
     */
    public void restart(String url) {
        stop(url);
        try {
            File file = new File(FILE_PATH, map.get(url).getFileName());
            if (file.exists()) {
                file.delete();
            }
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        db = helper.getWritableDatabase();
        helper.resetData(db, url);
        start(url);
    }

    /**
     * 獲取當前任務狀態
     */
    public boolean getCurrentState(String url) {
        return map.get(url).isDownLoading();
    }

    /**
     * 添加下載任務
     *
     * @param info 下載文件信息
     */
    public void addTask(FileInfo info) {
        //判斷數據庫是否已經存在這條下載信息
        if (!helper.isExist(db, info)) {
            db = helper.getWritableDatabase();
            helper.insertData(db, info);
            map.put(info.getUrl(), info);
        } else {
            //從數據庫獲取最新的下載信息
            db = helper.getReadableDatabase();
            FileInfo o = helper.queryData(db, info.getUrl());
            if (!map.containsKey(info.getUrl())) {
                map.put(info.getUrl(), o);
            }
        }
    }
}

第五步：OnProgressListenter接口

public interface OnProgressListener {

    void updateProgress(int max, int progress, String path);

}

第六步：重點---下載線程

/**
 * 下載文件線程
 * 從服務器獲取需要下載的文件大小
 */
public class DownLoadTask extends Thread {
    private FileInfo info;
    private SQLiteDatabase db;
    private DbHelper helper;//數據庫幫助類
    private int finished = 0;//當前已下載完成的進度
    private OnProgressListener listener;//進度回調監聽

    public DownLoadTask(FileInfo info, DbHelper helper, OnProgressListener listener) {
        this.info = info;
        this.helper = helper;
        this.db = helper.getReadableDatabase();
        this.listener = listener;
        info.setDownLoading(true);
    }

    @Override
    public void run() {
        getLength();
        HttpURLConnection connection = null;
        RandomAccessFile rwd = null;
        try {
            URL url = new URL(info.getUrl());
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setConnectTimeout(3000);
            //從上次下載完成的地方下載
            int start = info.getFinished();
            //設置下載位置(從服務器上取要下載文件的某一段)
            connection.setRequestProperty("Range", "bytes=" + start + "-" + info.getLength());//設置下載範圍
            //設置文件寫入位置
            File file = new File(DownLoaderManger.FILE_PATH, info.getFileName());
            rwd = new RandomAccessFile(file, "rwd");
            //從文件的某一位置開始寫入
            rwd.seek(start);
            finished += info.getFinished();
            if (connection.getResponseCode() == 206) {//文件部分下載，返回碼爲206
                InputStream is = connection.getInputStream();
                byte[] buffer = new byte[1024 * 4];
                int len;
                while ((len = is.read(buffer)) != -1) {
                    //寫入文件
                    rwd.write(buffer, 0, len);
                    finished += len;
                    info.setFinished(finished);
                    //更新界面顯示
                    Message msg = new Message();
                    msg.what = 0x123;
                    msg.arg1 = info.getLength();
                    msg.arg2 = info.getFinished();
                    handler.sendMessage(msg);
                    //停止下載
                    if (info.isStop()) {
                        info.setDownLoading(false);
                        //保存此次下載的進度
                        helper.updateData(db, info);
                        db.close();
                        return;
                    }
                }
                //下載完成
                info.setDownLoading(false);
                helper.updateData(db, info);
                db.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
            try {
                if (rwd != null) {
                    rwd.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 首先開啓一個線程去獲取要下載文件的大小（長度）
     */
    private void getLength() {
        HttpURLConnection connection = null;
        try {
            //連接網絡
            URL url = new URL(info.getUrl());
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setConnectTimeout(3000);
            int length = -1;
            if (connection.getResponseCode() == 200) {//網絡連接成功
                //獲得文件長度
                length = connection.getContentLength();
            }
            if (length <= 0) {
                //連接失敗
                return;
            }
            //創建文件保存路徑
            File dir = new File(DownLoaderManger.FILE_PATH);
            if (!dir.exists()) {
                dir.mkdirs();
            }
            info.setLength(length);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //釋放資源
            try {
                if (connection != null) {
                    connection.disconnect();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 更新進度
     */
    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case 0x123:
                    if (listener != null) {
                        listener.updateProgress(msg.arg1, msg.arg2,DownLoaderManger.FILE_PATH);
                    }
                    break;
            }
        }
    };
}

第七步：使用，通知欄的提示及apk更新安裝

public class MainActivity extends AppCompatActivity implements OnProgressListener {

    private NotificationManager notificationManager;

    private NotificationCompat.Builder builder;

    private NumberProgressBar pb;//進度條
    private DownLoaderManger downLoader = null;
    private FileInfo info;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pb = (NumberProgressBar) findViewById(R.id.pb);
        final Button start = (Button) findViewById(R.id.start);//開始下載
        final Button restart = (Button) findViewById(R.id.restart);//重新下載
        final DbHelper helper = new DbHelper(this);
        downLoader = DownLoaderManger.getInstance(helper, this);
        info = new FileInfo("chuanglifeng.apk", "http://116.62.162.56:80/pjriver/chuanglifeng/app-release.apk");
        downLoader.addTask(info);
        start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (downLoader.getCurrentState(info.getUrl())) {
                    initNofication("暫停下載","創利豐");
                    downLoader.stop(info.getUrl());
                    start.setText("開始下載");
                } else {
                    initNofication("開始下載","創利豐");
                    downLoader.start(info.getUrl());
                    start.setText("暫停下載");
                }
            }
        });
        restart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                initNofication("重新下載","創利豐");
                downLoader.restart(info.getUrl());
                start.setText("暫停下載");
            }
        });
    }

    @Override
    public void updateProgress(final int max, final int progress, String path) {
        pb.setMax(max);
        pb.setProgress(progress);
        int percent = (int) (div(progress,max,2)*100);

        builder.setProgress(max,progress,false);

        notificationManager.notify(0x3,builder.build());
        //下載進度提示
        builder.setContentText("下載"+percent+"%");
        if(percent==100) {    //下載完成後點擊安裝
            Intent it = new Intent(Intent.ACTION_VIEW);
            it.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            it.setDataAndType(Uri.fromFile(new File(path,info.getFileName())), "application/vnd.android.package-archive");
            builder.setContentText("點擊安裝")
                    .setContentInfo("下載完成")
                    .setDefaults(Notification.DEFAULT_SOUND)
                    .setOngoing(false);
            startActivity(it);
            notificationManager.notify(0x3, builder.build());
        }

    }

    private void initNofication(String cticker, String title) {

        notificationManager = (NotificationManager) getSystemService(Activity.NOTIFICATION_SERVICE);
        builder = new NotificationCompat.Builder(this);
        builder.setSmallIcon(R.mipmap.logo)
                .setTicker(cticker)
                .setContentInfo("下載中...")
                .setContentTitle(title)
                .setOngoing(true);//設置爲不可清除模式
    }

    public static double div(double v1, double v2, int scale) {
        if (scale < 0) {
            throw new IllegalArgumentException(
                    "The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.divide(b2, scale, BigDecimal.ROUND_HALF_UP).doubleValue();
    }
}

Dome地址：http://download.csdn.net/download/qq_39735504/10271919