判断android系统中是否有指定apk存在，并打开

在android系统中有方法获取package info来判断apk是否存在且安装：

所在类：

// Compiled from PackageManager.java (version 1.5 : 49.0, super bit)

public abstract class android.content.pm.PackageManager {

方法：

// Method descriptor #180 (Ljava/lang/String;I)Landroid/content/pm/PackageInfo;

public abstract android.content.pm.PackageInfo getPackageInfo(java.lang.String arg0, int arg1) throws android.content.pm.PackageManager$NameNotFoundException;

使用：

如果获取package info 不为null，则使用intent打开该apk：

PackageInfo isPackageExit = null;
try {
isPackageExit = this.getPackageManager().getPackageInfo("com.ckt.mobileinfo", 0);
} catch (NameNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(null != isPackageExit){
ComponentName comp = new ComponentName("com.ckt.mobileinfo", "com.ckt.mobileinfo.Mobileinfo");//1.package name 2.class name
Intent intent = new Intent("android.intent.action.MAIN");
intent.setComponent(comp);
startActivity(intent);
}