ClassCastException：String到ArrayList cast抛出异常

Question

我在MainActivity中有以下功能：

private void exportToMail(String[] tos)
{
    Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND_MULTIPLE);
    emailIntent.setType("text/plain");
    emailIntent.putExtra(Intent.EXTRA_EMAIL, tos);
    emailIntent.putExtra(Intent.EXTRA_SUBJECT, "gradius data ver: " + getAppVersion());
    emailIntent.putExtra(Intent.EXTRA_TEXT, getFormattedData());

    ArrayList<Uri> uris = new ArrayList<>();
    for (File fileIn : new File(getExportFolder(this)).listFiles())
    {
        uris.add(FileProvider.getUriForFile(MainActivity.this, getString(R.string.file_provider_authority),fileIn));
    }

    if(!uris.isEmpty())
        emailIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, uris);

    //This is where the error occurs according to the Logcat.
    startActivity(Intent.createChooser(emailIntent, "Pick an Email provider")); 
}

当我尝试运行此代码时，我在Logcat中有附加的消息。

2019-04-02 14:05:58.566 10783-10783/com.crowdx.gradius.testapp W/Bundle: Key android.intent.extra.TEXT expected ArrayList<CharSequence> but value was a java.lang.String.  The default value <null> was returned.
2019-04-02 14:05:58.567 10783-10783/com.crowdx.gradius.testapp W/Bundle: Attempt to cast generated internal exception:
    java.lang.ClassCastException: java.lang.String cannot be cast to java.util.ArrayList
        at android.os.BaseBundle.getCharSequenceArrayList(BaseBundle.java:1302)
        at android.os.Bundle.getCharSequenceArrayList(Bundle.java:1076)
        at android.content.Intent.getCharSequenceArrayListExtra(Intent.java:8227)
        at android.content.Intent.migrateExtraStreamToClipData(Intent.java:11093)
        at android.content.Intent.migrateExtraStreamToClipData(Intent.java:11056)
        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1666)
        at android.app.Activity.startActivityForResult(Activity.java:4688)
        at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:767)
        at android.app.Activity.startActivityForResult(Activity.java:4646)
        at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:754)
        at android.app.Activity.startActivity(Activity.java:5007)
        at android.app.Activity.startActivity(Activity.java:4975)
        at com.crowdx.gradius_sdk.testApp.ui.activities.MainActivity.exportToMail(MainActivity.java:523)
        at com.crowdx.gradius_sdk.testApp.ui.activities.MainActivity.selectedStrings(MainActivity.java:485)
        at com.crowdx.gradius_sdk.testApp.ui.components.MultiSelectionSpinner$1.onClick(MultiSelectionSpinner.java:74)
        at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:184)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:6981)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1445)

我不明白这段代码有什么问题，因为putExtra()可以将String数组作为参数，所以这里有什么问题？

编辑：

//这是根据Logcat发生错误的地方。

 startActivity(Intent.createChooser(emailIntent, "Pick an Email provider")); 

Answer 1

如果你想使用字符串到ArrayList使用GSON类并将其转换为字符串，然后将其放在意图中它将起作用。