Android判斷應用是否存在

經過包名判斷

    public boolean checkBrowser(String packageName) {
        if (packageName == null || "".equals(packageName))
            return false;
        try {
            ApplicationInfo info = getPackageManager().getApplicationInfo(
                    packageName, PackageManager.GET_UNINSTALLED_PACKAGES);
            return true;
        } catch (NameNotFoundException e) {
            return false;
        }
    }


判斷包中的Activity


        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setClassName("com.android.settings", //$NON-NLS-1$

                "com.android.settings.InstalledAppDetails"); //$NON-NLS-1$

        intent.putExtra("com.android.settings.ApplicationPkgName", //$NON-NLS-1$

                mCurrentPkgName);
        List<ResolveInfo> acts = getPackageManager().queryIntentActivities(
                intent, 0);
        if (acts.size() > 0) {
            startActivity(intent);
        } else {
            Toast.makeText(this,
                    getString(R.string.failed_to_resolve_activity),
                    Toast.LENGTH_SHORT).show();
        }