android 学习笔记3--静默安装功能的实现

静默安装的实现比较简单，但是有个前提：

你的应用必须有system权限。

所以分为两步：

1. 如何获取system权限。

    ①. 修改androidmanifest.xml ,       android:sharedUserId="android.uid.system"

    ②. 修改android.mk ,增加LOCAL_CERTIFICATE := platform

    ③. 编译即可，这样你的app就有了system权限。

2. 如何静默安装。

    在这里我选择的是用Runtime.getRuntime().exec("pm install -r -s " );的方法。

    具体实现如下，可以调用这个方法来安装/system/installapp/下以1.apk  2.apk 命名的apk，并选择是否安装到SD卡。

	private int installapk_internel(int apkid, boolean sd) {
		ByteArrayOutputStream byteary = new ByteArrayOutputStream();
		ByteArrayOutputStream errbyteary = new ByteArrayOutputStream();
		InputStream input = null;
		InputStream errin = null;
		Process proc = null;
		int read = -1;
		int readerr= -1;
		String errresult= null;
		String result = null;
		try {

			if (sd == true) {
				proc = Runtime.getRuntime().exec(
						"pm install -r -s " + APK_DIR + Integer.toString(apkid)
								+ ".apk");
			} else {
				proc = Runtime.getRuntime().exec(
						"pm install -r -f " + APK_DIR + Integer.toString(apkid)
								+ ".apk");
			}
			int exitVal = proc.waitFor();
			// wait for the proc to complete
			input = proc.getInputStream();
			errin = proc.getErrorStream();

			 while ((readerr = errin.read()) != -1) {
				 errbyteary.write(readerr);
			 }
		//	byteary.write('\n');
			while ((read = input.read()) != -1) {
				byteary.write(read);
			}
			byte data[] = byteary.toByteArray();
			byte dataerr[] = errbyteary.toByteArray();
			result = new String(data);
			errresult =new String(dataerr);

			Log.d(TAG, "INSTALL  done ! id= " + apkid + " result code = "
					+ exitVal);
            Log.d(TAG,"INSTALL DONE ,err = "+errresult);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			Log.d(TAG,"INSTALL  FAILD!");
			e.printStackTrace();
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();

		} finally {
			if (input != null) {
				try {
					input.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (errin != null) {
				try {
					errin.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (proc != null) {

				proc.destroy();
			}
			Log.d(TAG, " install  complete, result = " + result);
		}
		if (result != null&&errresult != null) {
			return handle_install_result(result,errresult);
		} else {
			return -3;
		}
	}

这里还增加了对 pm install 的结果的处理 

	private static final String APK_DIR = "/system/installapp/";
	private static final int INSTALL_APK_SUCESS = 0;
	private static final int INSTALL_APK_FAILED_SD_CARD_NOT_PRESENT = -1;
	private static final int INSTALL_APK_FAILED_INTENER_MEMORY_FULL = -2;
	private static final int INSTALL_APK_FAILED_OTHER = -3;
	private static final String INSTALL_RESULT_SUCCESS = "Success";
	private static final String INSTALL_RESULT_SD_NOT_PRESENT = "Failure [INSTALL_FAILED_MEDIA_UNAVAILABLE]";

	private int handle_install_result(String result,String errresult) {
		if (result.contains(INSTALL_RESULT_SUCCESS)) {
			return INSTALL_APK_SUCESS;
		} else if (errresult.contains(INSTALL_RESULT_SD_NOT_PRESENT)) {
			return INSTALL_APK_FAILED_SD_CARD_NOT_PRESENT;
		} else {
			return INSTALL_APK_FAILED_OTHER;
		}

	}

这样我们可以在安装到sd失败的情况下尝试安装到内存：

			int ret = installapk_internel(current_id, true);
			if (ret == INSTALL_APK_FAILED_SD_CARD_NOT_PRESENT) {
				// then we try to install apks to internel memory.
				Log.d(TAG,
						"sdcard not present, we try to install apk to internel flash .");
				ret = installapk_internel(current_id, false);
				Log.d(TAG,"ret= "+ret);
				if (ret != INSTALL_APK_SUCESS) {
					Log.d(TAG, "install faild again.");
					// WriteInstall_FAILD_FlagtoFile(current_id);
				}
			}

总的来说，静默安装还是比较简单的，与大家分享下，共同进步。