实现自动检测更新功能

public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

new UpdateManager(this).checkUpdate();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}

public class UpdateManager {//更新处理类实现方法

private ProgressBar mProgressBar;
private Dialog mDownloadDialog;

private String mSavePath;
private int mProgress;

private boolean mIsCancel = false;

private static final int DOWNLOADING = 1;
private static final int DOWNLOAD_FINISH = 2;

private static final String PATH = "http://172.31.27.82/autoupdate/version.html";

private String mVersion_code;
private String mVersion_name;
private String mVersion_desc;
private String mVersion_path;

private Context mContext;

public UpdateManager(Context context) {
mContext = context;
}

private Handler mGetVersionHandler = new Handler(){
public void handleMessage(Message msg) {
JSONObject jsonObject = (JSONObject) msg.obj;
System.out.println(jsonObject.toString());
try {
mVersion_code = jsonObject.getString("version_code");
mVersion_name = jsonObject.getString("version_name");
mVersion_desc = jsonObject.getString("version_desc");
mVersion_path = jsonObject.getString("version_path");

if (isUpdate()){
Toast.makeText(mContext, "需要更新", Toast.LENGTH_SHORT).show();
// 显示提示更新对话框
showNoticeDialog();
} else{
Toast.makeText(mContext, "已是最新版本", Toast.LENGTH_SHORT).show();
}

} catch (Exception e){
e.printStackTrace();
}
};
};

private Handler mUpdateProgressHandler = new Handler(){
public void handleMessage(Message msg) {
switch (msg.what){
case DOWNLOADING:
// 设置进度条
mProgressBar.setProgress(mProgress);
break;
case DOWNLOAD_FINISH:
// 隐藏当前下载对话框
mDownloadDialog.dismiss();
// 安装 APK 文件
installAPK();
}
};
};

/*
* 检测软件是否需要更新
*/
public void checkUpdate() {//Volley可以访问小型的json数据
RequestQueue requestQueue = Volley.newRequestQueue(mContext);
JsonObjectRequest request = new JsonObjectRequest(PATH, null, new Listener<JSONObject>() {
@Override
public void onResponse(JSONObject jsonObject) {
Message msg = Message.obtain();
msg.obj = jsonObject;
mGetVersionHandler.sendMessage(msg);
}

}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError arg0) {
System.out.println(arg0.toString());
}
});
requestQueue.add(request);
}

/*
* 与本地版本比较判断是否需要更新
*/
protected boolean isUpdate() {
int serverVersion = Integer.parseInt(mVersion_code);
//int serverVersion = 2;
int localVersion = 1;

try {
localVersion = mContext.getPackageManager().getPackageInfo("com.jikexueyuan.autoupdate", 0).versionCode;
} catch (NameNotFoundException e) {
e.printStackTrace();
}

if (serverVersion > localVersion)
return true;
else
return false;
}

/*
* 有更新时显示提示对话框
*/
protected void showNoticeDialog() {
AlertDialog.Builder builder = new Builder(mContext);
builder.setTitle("提示");
String message = "软件有更新，要下载安装吗？\n" + mVersion_desc;
builder.setMessage(message);

builder.setPositiveButton("更新", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// 隐藏当前对话框
dialog.dismiss();
// 显示下载对话框
showDownloadDialog();
}
});

builder.setNegativeButton("下次再说", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// 隐藏当前对话框
dialog.dismiss();
}
});

builder.create().show();
}

/*
* 显示正在下载对话框
*/
protected void showDownloadDialog() {
AlertDialog.Builder builder = new Builder(mContext);
builder.setTitle("下载中");
View view = LayoutInflater.from(mContext).inflate(R.layout.dialog_progress, null);
mProgressBar = (ProgressBar) view.findViewById(R.id.id_progress);
builder.setView(view);

builder.setNegativeButton("取消", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// 隐藏当前对话框
dialog.dismiss();
// 设置下载状态为取消
mIsCancel = true;
}
});

mDownloadDialog = builder.create();
mDownloadDialog.show();

// 下载文件
downloadAPK();
}

/*
* 开启新线程下载文件
*/
private void downloadAPK() {
new Thread(new Runnable() {
@Override
public void run() {
try{
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
String sdPath = Environment.getExternalStorageDirectory() + "/";
mSavePath = sdPath + "jikedownload";

File dir = new File(mSavePath);
if (!dir.exists())
dir.mkdir();

// 下载文件
HttpURLConnection conn = (HttpURLConnection) new URL(mVersion_path).openConnection();
conn.connect();
InputStream is = conn.getInputStream();
int length = conn.getContentLength();

File apkFile = new File(mSavePath, mVersion_name);
FileOutputStream fos = new FileOutputStream(apkFile);

int count = 0;
byte[] buffer = new byte[1024];
while (!mIsCancel){
int numread = is.read(buffer);
count += numread;
// 计算进度条的当前位置
mProgress = (int) (((float)count/length) * 100);
// 更新进度条
mUpdateProgressHandler.sendEmptyMessage(DOWNLOADING);

// 下载完成
if (numread < 0){
mUpdateProgressHandler.sendEmptyMessage(DOWNLOAD_FINISH);
break;
}
fos.write(buffer, 0, numread);
}
fos.close();
is.close();
}
}catch(Exception e){
e.printStackTrace();
}
}
}).start();
}

/*
* 下载到本地后执行安装
*/
protected void installAPK() {
File apkFile = new File(mSavePath, mVersion_name);
if (!apkFile.exists())
return;

Intent intent = new Intent(Intent.ACTION_VIEW);
Uri uri = Uri.parse("file://" + apkFile.toString());
intent.setDataAndType(uri, "application/vnd.android.package-archive");
mContext.startActivity(intent);

}

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:orientation="vertical"

    tools:context=".MainActivity" >

    <ProgressBar

        android:id="@+id/id_progress"

        style="?android:attr/progressBarStyleHorizontal"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

</LinearLayout>