小编fre*_*ene的帖子

我有一个活动和几个片段。碎片之一包含具有锚定重力底端的FAB。看起来不错，但是当我开始另一个片段然后按返回按钮时，FAB出现在左上角。我使用协调器布局，但无济于事。这是我的布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:id="@+id/fragment_main_page">

<ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/main_page_listview"
    android:layout_marginTop="5dp">

</ListView>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="3dp">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="12dp"
        android:src="@drawable/info_main_page"
        android:layout_gravity="center_vertical"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_gravity="center_vertical"
        android:id="@+id/how_to_use"
        android:text="@string/how_to_use"
        android:textAllCaps="false"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textStyle="italic"
        android:background="@android:color/transparent"/>

</LinearLayout>

</LinearLayout>

<android.support.design.widget.FloatingActionButton
    android:id="@+id/floating_promos"
    android:layout_width="42dp"
    android:layout_height="42dp"
    android:layout_margin="16dp"
    android:clickable="true"
    android:src="@drawable/floating_promos"
    app:layout_anchor="@id/fragment_main_page"
    app:layout_anchorGravity="bottom|right|end"
    app:backgroundTint="#fb9f12"
    app:fabSize="mini"/>
   </android.support.design.widget.CoordinatorLayout>

我正在编写一个代码,它只为.txt文件创建一个文件选择器,然后在String中表示它的内容.问题是在选择文件后没有任何反应(日志表示结果代码为-1,请求代码为0).谁能帮我？这是我对.txt文件的选择:

 public void onUploadClicked(View view) {
    Intent intent = new Intent();
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    intent.setType("text/plain");
    intent.setAction(Intent.ACTION_GET_CONTENT);
    startActivityForResult(Intent.createChooser(intent, getText(R.string.select_file)), REQUEST_CODE);

}

这是我的OnActivityResult方法:

    @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (resultCode == Activity.RESULT_OK) {
        if (data == null) {
            return;
        } else {
            Uri uri = data.getData();
            uploadedFile = new File(uri.getPath());
            try {
                readFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    } else {
        return;
    }
}

这是我将.txt文件读入String的方法:

private void readFile() throws IOException {

    uploadedString = new StringBuilder();
    BufferedReader …

我无法解析这样的 json

[{"operation_id":"38911","external_id":null,"status":"SUCCESS","date":"2019-12-01T12:30:08.000Z","amount":200}]

问题在于具有动态名称的数组。这是我的 POJO：

class PaymentHistoryResponse {
final List<History> list;

PaymentHistoryResponse({this.list});
}

class History {
final String operationId;
final dynamic externalId;
final String status;
final DateTime date;
final int amount;

History({
@required this.operationId,
@required this.externalId,
@required this.status,
@required this.date,
@required this.amount
});

factory History.fromJson(String str) => History.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory History.fromMap(Map<String, dynamic> json) => History(
operationId: json["operation_id"],
externalId: json["external_id"],
status: json["status"],
date: DateTime.parse(json["date"]),
amount: json["amount"]
);

Map<String, dynamic> toMap() => {
"operation_id": operationId,
"external_id": externalId,
"status": status, …