android 调用系统其他已经安装的应用的方法

ComponentName comp = new ComponentName("com.antroid.Test","com.antroid.Test.TestActivity");
/*
"com.antroid.Test"//被调用应用的包名，与AndroidManifest.xml中一致
"com.antroid.Test.TestActivity"//被调用应用的activity
*/
 Intent intent = new Intent();
 intent.setComponent(comp);
 intent.setAction("android.intent.action.VIEW");         
 startActivity(intent);