源码如下：

import java.io.DataOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;

public class InstallApkUtils {

public static void installAndStartApk(final Context context, final String apkPath) {
if ((apkPath==null) || (context==null)) {
return;
}

File file = new File(apkPath);
if (file.exists() == false) {
return;
}

new Thread() {
public void run() {
String packageName = getUninstallApkPackageName(context, apkPath);
if (silentInstall(apkPath)) {
List matches = findActivitiesForPackage(context, packageName);
if ((matches!=null) && (matches.size()>0)) {
ResolveInfo resolveInfo = matches.get(0);
ActivityInfo activityInfo = resolveInfo.activityInfo;
startApk(activityInfo.packageName, activityInfo.name);
}
}
};
}.start();

}

public static String getUninstallApkPackageName(Context context, String apkPath) {
String packageName = null;
if (apkPath == null) {
return packageName;
}

PackageManager pm = context.getPackageManager();
PackageInfo info = pm.getPackageArchiveInfo(apkPath,
PackageManager.GET_ACTIVITIES);
if (info == null) {
return packageName;
}

packageName = info.packageName;
return packageName;
}

public static List findActivitiesForPackage(Context context, String packageName) {
final PackageManager pm = context.getPackageManager();

final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
mainIntent.setPackage(packageName);

final List apps = pm.queryIntentActivities(mainIntent, 0);
return apps != null apps : new ArrayList();
}

public static boolean silentInstall(String apkPath) {
String cmd1 = "chmod 777 " + apkPath + " \n";
String cmd2 = "LD_LIBRARY_PATH=/vendor/lib:/system/lib pm install -r " + apkPath + " \n";
return execWithSID(cmd1, cmd2);
}

private static boolean execWithSID(String... args) {
boolean isSuccess = false;
Process process = null;
OutputStream out = null;
try {
process = Runtime.getRuntime().exec("su");
out = process.getOutputStream();
DataOutputStream dataOutputStream = new DataOutputStream(out);

for (String tmp : args) {
dataOutputStream.writeBytes(tmp);
}

dataOutputStream.flush(); // 提交命令
dataOutputStream.close(); // 关闭流操作
out.close();

isSuccess = waitForProcess(process);
} catch (IOException e) {
e.printStackTrace();
}