安卓系统已安装软件的判断及透过程序安装

1. 查看系统是否已经安装某个应用

private boolean appInstalledOrNot(String uri) {    PackageManager pm = getPackageManager();    boolean appInstalled;    try {        pm.getPackageInfo(uri, 0);        appInstalled = true;    }    catch (PackageManager.NameNotFoundException e) {        appInstalled = false;    }    return appInstalled;}

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?uri是指AndroidManifest.xml文件中的package，是安卓应用的标识符。

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2. 判断安装的版本号

private int getAPKVersion(String uri) {    Integer version = -1;    PackageManager packageManager=getPackageManager();    try {    	//0 means all the flags are turned off        PackageInfo Info=packageManager.getPackageInfo(uri, 0);        //like 5        version = Info.versionCode;        //like 1.0.5        versionName = Info.versionName;    } catch (PackageManager.NameNotFoundException e) {        Log.e("error", e.getMessage());    }    return version;}

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3. 安装

基本思路：apk放到assets目录下，安装时先写到sd，再调用intent安装

private void installScannerPlugin() {    AssetManager assetManager = getAssets();    InputStream in;    OutputStream out;    try {        in = assetManager.open("BarcodeScanner.apk");        out = new FileOutputStream(Environment.getExternalStorageDirectory()                + File.separator + "BarcodeScanner.apk");        byte[] buffer = new byte[1024];        int len;        while((len = in.read(buffer)) != -1) {            out.write(buffer, 0, len);        }        in.close();        out.flush();        out.close();        Intent intent = new Intent(Intent.ACTION_VIEW);        intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory()                        + File.separator + "BarcodeScanner.apk")),                "application/vnd.android.package-archive");        startActivity(intent);    } catch(Exception e) {        e.printStackTrace();    }}

?需要权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

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