java - 如何获取设备用户的电子邮件地址？

Question

你能帮我解决这个代码吗？它应该从当前 Android 设备获取电子邮件地址，但每次都返回 null。 我已经尝试过 this但每次仍然为空

 public String getUsername() {
    Pattern emailPattern = Patterns.EMAIL_ADDRESS; // API level 8+
    Account[] accounts = AccountManager.get(getApplicationContext()).getAccounts();
    for (Account account : accounts) {
        if (emailPattern.matcher(account.name).matches()) {
            String possibleEmail = account.name;
            return possibleEmail;
        }
    }
    return null;
}

这是我的 list 文件:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="Upload FTP"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

Answer 1

下面的代码对我来说非常有用。您所要做的就是

在您的 OnCreate() 中包含以下代码并根据您的要求进行调整

if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.GET_ACCOUNTS) != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, Manifest.permission.GET_ACCOUNTS)) {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.GET_ACCOUNTS}, 1);
        } else {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.GET_ACCOUNTS}, 1);
        }
    }
        else {
        List<String> accountList = new ArrayList<String>();
        Pattern gmailPattern = Patterns.EMAIL_ADDRESS;
        Account[] accounts = AccountManager.get(this).getAccounts();
        for (Account account : accounts) {
            if (gmailPattern.matcher(account.name).matches()) {
                accountsList.add(account.name);
                Toast.makeText(getApplicationContext(), account.name, Toast.LENGTH_SHORT).show();
            }
        }

然后你必须在AndroidManifest.xml文件中添加GET_ACCOUNTS的权限

 <uses-permission android:name="android.permission.GET_ACCOUNTS" />