java - Intent .CATEGORY_APP_CALCULATOR : ActivityNotFoundException

Question

我正在尝试在 Android 应用程序中打开默认计算器应用程序。设备中安装了两个计算器:默认安卓计算器和Google Calculator .

Intent calc = Intent.makeMainSelectorActivity(Intent.ACTION_MAIN, Intent.CATEGORY_APP_CALCULATOR);
startActivity(calc);

此代码抛出 ActivityNotFoundException 并在 logcat 中显示:

system_process W/IntentResolver: resolveIntent failed: found match, but none with CATEGORY_DEFAULT

此代码具有相同的行为:

Intent calc = new Intent(Intent.ACTION_MAIN);
calc.addCategory(Intent.CATEGORY_APP_CALCULATOR);
startActivity(calc);

这是一个 Android 错误？如何打开应用选择器，让用户选择默认应用？

堆栈跟踪:

android.content.ActivityNotFoundException: No Activity found to handle Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] sel=act=android.intent.action.MAIN cat=[android.intent.category.APP_CALCULATOR]} }
     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1805)
     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1514)
     at android.app.Activity.startActivityForResult(Activity.java:3930)
     at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:50)
     at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:79)
     at android.app.Activity.startActivityForResult(Activity.java:3890)
     at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859)
     at android.app.Activity.startActivity(Activity.java:4213)
     at android.app.Activity.startActivity(Activity.java:4181)
     at com.MyActivity.openCalc(MyActivity.java:202)
     at com.MyActivity.onOptionsItemSelected(MyActivity.java:191)
     at android.app.Activity.onMenuItemSelected(Activity.java:2914)
     at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:408)
     at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195)
     at android.app.ActivityThread.main(ActivityThread.java:5461)

Answer 1

文档指向的方式似乎不起作用。尽管如此，这段代码通常会打开默认的计算器应用程序。

Intent intent = new Intent();
intent.setClassName("com.android.calculator2", "com.android.calculator2.Calculator");
startActivity(intent);