安卓下载服务器文件到手机

这几天更新的文章都是与安卓程序更新有关的，昨天讲了使用ProgressDialog来呈现安卓程序更新时的UI交互，今天来实现下载的具体过程。

先说说本文实现的效果，将网络文件，例如：http://117.177.249.153/rpcs.myapp.com/myapp/rcps/d/1000017149/com.tencent.mtt_1000017149_170221201645a.apk这是腾讯的QQ浏览器文件，官方的。下载至本地文件夹daimadogdown中，并以下载地址中的com.tencent.mtt_1000017149_170221201645a.apk为文件名。再加上昨天的ProgressDialog对话框进行UI交互，子线程与主线程（UI线程）交互使用handler。

实现代码如下：

public class MainActivity extends AppCompatActivity {private Button bt1;    private Button qr;    Dialog dailog;    ProgressDialog pd;    Handler handler;    String path="http://117.177.249.153/rpcs.myapp.com/myapp/rcps/d/1000017149/com.tencent.mtt_1000017149_170221201645a.apk";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        bt1= (Button) findViewById(R.id.button);        handler=new Handler(){            @Override            public void handleMessage(Message msg) {                if (msg.what==1){pd.setProgress(msg.arg1);                }else if (msg.what==0){                    pd.dismiss();                }            }        };        bt1.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {showpress();                new Thread(){                    @Override                    public void run() {                       HttpURLConnection connt=null;                        FileOutputStream fos=null;                        InputStream in=null;                        File file=null;                        try {                            URL url = new URL(path);                            connt = (HttpURLConnection) url.openConnection();                            connt .setRequestProperty("Accept-Encoding", "identity");                            connt.setRequestMethod("GET");                            int wenjiancd=connt.getContentLength();                            int code = connt.getResponseCode();                            if (code == 200) {                                file = new File(Environment.getExternalStorageDirectory(), "/daimadogdown/"+getfilename());                                if (!file.exists()) {                                    if (!file.getParentFile().exists()) {                                        file.getParentFile().mkdirs();                                    }                                    file.createNewFile();                                }                                fos = new FileOutputStream(file);                                in = connt.getInputStream();                                int len = -1;                                int jdcd=0;                                System.out.println(wenjiancd);                                byte[] b = new byte[1024];                                while ((len = in.read(b)) != -1) {                                    jdcd+=len;                                    Message msg=Message.obtain();                                    System.out.println((int)((float)jdcd/wenjiancd*100));                                    msg.arg1=(int)((float)jdcd/wenjiancd*100);                                    msg.what=1;                                    handler.sendMessage(msg);                                    fos.write(b, 0, len);                                }                                fos.flush();                                handler.sendEmptyMessage(0);                            }                        }catch (IOException e){                            e.printStackTrace();                        }finally {                            try{                            if (fos!=null)fos.close();                                if (in!=null)in.close();                                if (connt!=null)connt.disconnect();                            } catch (IOException e) {                                e.printStackTrace();                            }                        }                    }                }.start();            }        });    }    //获取文件名private String getfilename(){int sata=path.lastIndexOf("/");    return path.substring(sata+1);}    //进度对话框    private  void showpress(){        pd=new ProgressDialog(MainActivity.this);        pd.setTitle("下载更新");        pd.setMessage("下载中，请稍后....");        pd.setCancelable(false);        pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);        pd.setMax(100);        pd.show();    }}

效果如下图所示：