小编Kev*_*jan的帖子

我想以编程方式更改我的应用程序的背景颜色,而不是IB.是否有可能获得Swift和Obj-C答案.

我是一位探索Android世界的新开发者.我目前正在通过Udacity教程创建Sunshine应用程序.在片段活动类中,为了从openweathermap获取数据,我必须将从我的帐户获得的API密钥添加到生成的URL的末尾.在Fragment活动中调用BuildConfig.java (单击以查看对作为String apiKey的一部分在第6行的BuildConfig.java的调用).

build.gradle文件如下:

apply plugin: 'com.android.application'
android {
    compileSdkVersion 23
    buildToolsVersion "23.0.1"
    defaultConfig {
        applicationId "com.example.android.sunshine.app"
        minSdkVersion 10
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }

    }
    buildTypes.each {
        it.buildConfigField 'String', 'OPEN_WEATHER_MAP_API_KEY', 'c882c94be45fff9d16a1cf845fc16ec5'
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:23.1.0'
}

在buildTypes.each it.buildConfigField中使用'String','OPEN_WEATHER_MAP_API_KEY','c882c94be45fff9d16a1cf845fc16ec5'调用

public static final String OPEN_WEATHER_MAP_API_KEY = c882c94be45fff9d16a1cf845fc16ec5;

在BuildConfig.java中生成,但我不断收到此错误: 无法解析符号(单击以查看错误消息和BuildConfig.java文件)我不明白为什么字符串OPEN_WEATHER_MAP_API_KEY自动创建为一组字母和数字而没有引用它们,但如果我编辑代码阅读:

public static final String OPEN_WEATHER_MAP_API_KEY = "c882c94be45fff9d16a1cf845fc16ec5";

要么

public static final …

我目前正在开发一个欢迎页面,我遇到了这个有趣的设计:

我正试图在底部制作一个按钮,文本通过后面的半透明视图.我尝试了以下代码,但它似乎没有工作:

let transparent = UIColor(red: 0, green: 0, blue: 0, alpha: 0)
let semiwhite = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 0.15)        
bottomView.backgroundColor = semiwhite
loginButton.backgroundColor = semiwhite
loginButton.setTitleColor(transparent, forState: .Normal)
loginButton.layer.cornerRadius = 10
loginButton.layer.masksToBounds = true
loginButton.layer.borderWidth = 2.5
loginButton.layer.borderColor = transparent.CGColor

有谁知道如何做到这一点？

我想制作一个5频段音频均衡器(60Hz,230Hz,910Hz,4kHz,14kHz)AVAudioEngine.我希望通过垂直滑块获得每个频段的用户输入增益,并相应地调整正在播放的音频.我尝试过AVAudioUnitEQ这样做,但是在播放音频时听不到任何区别.我试图在值中硬编码以指定每个频率的增益,但它仍然不起作用.这是我的代码:

var audioEngine: AVAudioEngine = AVAudioEngine()
var equalizer: AVAudioUnitEQ!
var audioPlayerNode: AVAudioPlayerNode = AVAudioPlayerNode()
var audioFile: AVAudioFile!

// in viewDidLoad():
equalizer = AVAudioUnitEQ(numberOfBands: 5)
audioEngine.attach(audioPlayerNode)
audioEngine.attach(equalizer)
let bands = equalizer.bands
let freqs = [60, 230, 910, 4000, 14000]
audioEngine.connect(audioPlayerNode, to: equalizer, format: nil)
audioEngine.connect(equalizer, to: audioEngine.outputNode, format: nil)
for i in 0...(bands.count - 1) {
    bands[i].frequency = Float(freqs[i])
}

bands[0].gain = -10.0
bands[0].filterType = .lowShelf
bands[1].gain = -10.0
bands[1].filterType = .lowShelf
bands[2].gain = -10.0
bands[2].filterType = …