小编use*_*755的帖子

我的应用背景为720x1280像素,1080x1920像素和1440x2560像素.

我应该在哪个文件夹(mdpi,hdpi,xhdpi和xxhdpi)中放置每个背景？

我有这样的JSON:

{"posts":
    [
    {
    "id":"1","title":"title 1"
    },
    {
    "id":"2","title":"title 2"
    },
    {
    "id":"3","title":"title 3"
    },
    {
    "id":"4","title":"title 4"
    },
    {
    "id":"5","title":"title 5"
    }
    ],
    "text":"Some text",
    "result":1
}

如何使用Swift 3解析JSON？

我有这个:

let url = URL(string: "http://domain.com/file.php")!
let request = URLRequest(url: url)

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    guard let data = data else {
        print("request failed \(error)")
            return
    }

    do {
        if let json = try JSONSerialization.jsonObject(with: data) as? [String: String], let result = json["result"] { …

如何删除字符串中的多个空格和换行符,但为每组空行保留至少一个空行.

例如,更改:

"This      is



a        string.




Something."

至

"This is

a string.

Something."

我正在使用.trim()从字符串的开头和结尾去除空格,但我找不到任何用于删除字符串中的多个空格和换行符的内容.

我想只保留一个空格和一个换行符.

如何在ImageView中水平居中TextView？目前位于ImageView的右下角.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageView"
        android:background="@drawable/img" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView"
        android:layout_alignBottom="@+id/imageView"
        android:layout_alignRight="@+id/imageView"
        android:layout_alignEnd="@+id/imageView" />
</RelativeLayout>