private boolean isAvilible(Context context, String packageName){
     final PackageManager packageManager = context.getPackageManager();//获取packagemanager
     List< packageInfo> pinfo = packageManager.getInstalledPackages(0);//获取所有已安装程序的包信息
     List<String> pName = new ArrayList<String>();//用于存储所有已安装程序的包名
     //从pinfo中将包名字逐一取出，压入pName list中
       if(pinfo != null){
       for(int i = 0; i < pinfo.size(); i++){
         String pn = pinfo.get(i).packageName;
         pName.add(pn);
       }
     }
     return pName.contains(packageName);//判断pName中是否有目标程序的包名，有TRUE，没有FALSE
}

//已安装，打开程序，需传入参数包名："com.skype.android.verizon"
if(isAvilible(this, "com.skype.android.verizon")){
    Intent i = new Intent();
    ComponentName cn = new ComponentName("com.skype.android.verizon",
        "com.skype.android.verizon.SkypeActivity");
    i.setComponent(cn);
    startActivityForResult(i, RESULT_OK);
}
//未安装，跳转至market下载该程序
else {
    Uri uri = Uri.parse("market://details?id=com.skype.android.verizon");//id为包名
    Intent it = new Intent(Intent.ACTION_VIEW, uri);
    startActivity(it);
}

public static boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List<ResolveInfo> list =
        packageManager.queryIntentActivities(intent,
            PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}

public boolean isIntentAvailable(Intent intent) {
    final PackageManager packageManager = this.getPackageManager();
    List<ResolveInfo> list = packageManager.queryIntentActivities(intent,
        PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}

private boolean isAvilible(Context context, String packageName){
 final PackageManager packageManager = context.getPackageManager();//获取packagemanager
 List< packageInfo> pinfo = packageManager.getInstalledPackages(0);//获取所有已安装程序的包信息
 List<String> pName = new ArrayList<String>();//用于存储所有已安装程序的包名
 //从pinfo中将包名字逐一取出，压入pName list中
   if(pinfo != null){
   for(int i = 0; i < pinfo.size(); i++){
     String pn = pinfo.get(i).packageName;
     pName.add(pn);
   }
 }
 return pName.contains(packageName);//判断pName中是否有目标程序的包名，有TRUE，没有FALSE
}

//已安装，打开程序，需传入参数包名："com.skype.android.verizon"
if(isAvilible(this, "com.skype.android.verizon")){
    Intent i = new Intent();
    ComponentName cn = new ComponentName("com.skype.android.verizon",
        "com.skype.android.verizon.SkypeActivity");
    i.setComponent(cn);
    startActivityForResult(i, RESULT_OK);
}
//未安装，跳转至market下载该程序
else {
    Uri uri = Uri.parse("market://details?id=com.skype.android.verizon");//id为包名
    Intent it = new Intent(Intent.ACTION_VIEW, uri);
    startActivity(it);
}

public static boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List<ResolveInfo> list =
        packageManager.queryIntentActivities(intent,
            PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}

public boolean isIntentAvailable(Intent intent) {
    final PackageManager packageManager = this.getPackageManager();
    List<ResolveInfo> list = packageManager.queryIntentActivities(intent,
        PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}