Android 判断程序是否已安装 & 启动另一个程序

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

public boolean checkApkExist(Context context, String packageName) {
if (packageName == null || “”.equals(packageName))
return false;

try {
ApplicationInfo info = context.getPackageManager().getApplicationInfo(packageName,PackageManager.GET_UNINSTALLED_PACKAGES);
return true;
} catch (NameNotFoundException e) {
return false;
}
}

public static void RunActivity(String packetName, Context context)
{
try {
PackageInfo pi = context.getPackageManager().getPackageInfo(packetName, 0);
Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);
resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);
resolveIntent.setPackage(pi.packageName);

List<ResolveInfo> apps = context.getPackageManager().queryIntentActivities(resolveIntent,0);
ResolveInfo ri = apps.iterator().next();
if (ri != null ) {
String packageName1 = ri.activityInfo.packageName;
String className = ri.activityInfo.name;

Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_LAUNCHER);

ComponentName cn = new ComponentName(packageName1, className);

intent.setComponent(cn);
context.startActivity(intent);
}
} catch (NameNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}

}