根据url下载apk

首先我们开看一下效果图:

首先我来说一下，实现这个效果的整体思路：
自定义一个dialog，当有新版的时候，弹出这个dialog，当点击立即更新时，去下载apk。

一、我们首先需要自定义一个dialog

public class VersionDialog extends Dialog {    private int layoutRes;//布局文件    private Context mCtx;    private TextView versNameTv;    private TextView contentTv;    public Button positiveBtn;    public Button negativeBtn;    public VersionDialog(Context context) {        super(context);        // TODO Auto-generated constructor stub        this.mCtx = context;    }    public VersionDialog(Context context, int resLayout) {        super(context);        this.mCtx = context;        this.layoutRes = resLayout;    }    public VersionDialog(Context context, int theme,int resLayout) {        super(context, theme);        // TODO Auto-generated constructor stub        this.mCtx = context;        this.layoutRes = resLayout;    }    @Override    protected void onCreate(Bundle savedInstanceState) {        // TODO Auto-generated method stub        super.onCreate(savedInstanceState);        this.setContentView(layoutRes);        versNameTv = (TextView) findViewById(R.id.umeng_update_vers_name);        contentTv = (TextView) findViewById(R.id.umeng_update_content);        positiveBtn = (Button) findViewById(R.id.umeng_update_id_ok);        negativeBtn = (Button) findViewById(R.id.umeng_update_id_cancel);    }    public void setValue(String name,String content,int flag){        versNameTv.setText("最新版本："+name);        contentTv.setText(content);        if (flag == 1) {            negativeBtn.setVisibility(View.GONE);        }    }   }

二、在代码里引用布局，当点击更新时，就下载apk

private void versDialog(String name, String content) {        versDialg = new VersionDialog(mCtx, R.style.version_dialog, R.layout.umeng_update_dialog);        versDialg.setCancelable(false);        versDialg.show();        versDialg.setValue(name, content, updateFlag);        versDialg.positiveBtn.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                // TODO Auto-generated method stub                if (!"".equals(versUrl)) {                    Intent intent = new Intent(mCtx, DownloadService.class);                    intent.putExtra("apkUrl", versUrl);                    startService(intent);                    versDialg.dismiss();                } else {                    Tools.toast(mCtx, "下载地址有误，请重新登录");                    finish();                }            }        });        versDialg.negativeBtn.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                versDialg.dismiss();            }        });    }

R.style.version_dialog的样式

   <!-- 版本更新dialog -->    <style name="version_dialog" parent="@android:style/Theme.Dialog">        <item name="android:windowFrame">@null</item>        <item name="android:windowIsFloating">true</item>        <item name="android:windowIsTranslucent">false</item>        <item name="android:windowNoTitle">true</item>        <item name="android:background">@null</item>        <item name="android:backgroundDimEnabled">false</item>        <item name="android:windowBackground"> @android:color/transparent </item>    </style>

    <color name="transparent">#00000000</color>

三、我们来看一下DownloadService

public class DownloadService extends Service {    private DownloadManager dm;    private long enqueue;    private BroadcastReceiver receiver;    private String apkName = "";    private String apkUrl;    private File apkFile = null;    public DownloadService() {    }    @Override    public IBinder onBind(Intent intent) {        // TODO: Return the communication channel to the service.        throw new UnsupportedOperationException("Not yet implemented");    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        receiver = new BroadcastReceiver() {            @Override            public void onReceive(Context context, Intent intent) {                Intent intent1 = new Intent(Intent.ACTION_VIEW);                //判断是否是AndroidN以及更高的版本                if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.N){                    intent1.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);                    Uri contentUri = FileProvider.getUriForFile(context, "com.sanji.sjmallapp.fileprovider",new File(apkFile.getPath() + File.separator + apkName));                    intent1.setDataAndType(contentUri,"application/vnd.android.package-archive");                }else{                    intent1.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                    intent1.setDataAndType(Uri.fromFile(new File(apkFile.getPath() + File.separator + apkName)),                            "application/vnd.android.package-archive");                }                startActivity(intent1);                stopSelf();            }        };        apkUrl = intent.getStringExtra("apkUrl");        registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));        startDownload();        return Service.START_STICKY;    }    private void startDownload(){        dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(apkUrl));        request.setMimeType("application/vnd.android.package-archive");        apkName = "商城 " + Tools.getCurrentTime() + ".apk";        apkFile = new File(SDCardUtil.getApkPath());        if (apkFile != null && apkFile.exists() && apkFile.isDirectory()){            for (File item : apkFile.listFiles()){                item.delete();            }        }else{            apkFile.mkdirs();        }        if(SDCardUtil.checkSdCard()){            //下载到SD卡            request.setDestinationInExternalPublicDir(SDCardUtil.FILEAPK,apkName);        }else{            //下载到内置目录            request.setDestinationInExternalFilesDir(MallApplication.getApplication(),SDCardUtil.FILEAPK,apkName);        }        enqueue = dm.enqueue(request);    }    @Override    public void onDestroy() {        unregisterReceiver(receiver);        super.onDestroy();    }}

Tools.getApkPath(getApplicationContext()))方法是根据有没有SD卡，来确定存储路径

/**     * 检测Sdcard是否存在     *      * @return     */    public static boolean isExitsSdcard() {        if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))            return true;        else            return false;    }

/**     * 获取APK路径     *      * @param context     * @return     */    public static String getApkPath(Context context) {        String apkPath = "";        if (isExitsSdcard()) {            // SD卡            apkPath = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + Constants.apkPath;        } else {            // data            apkPath = context.getFilesDir().getAbsolutePath() + File.separator + Constants.apkPath;        }        return apkPath;    }

public static String rootPath = "ExampleOne";    // 存放apk    public static String apkPath = rootPath + File.separator + "apk";

这是调用安卓系统自带的DownLoadManager,下载速度一般自己封装的快。