在了解了 Material Design 中的新方法后,我尝试在应用中实现一个 float 操作按钮。但是,我在预览(预览 Android 版本 21)中遇到此错误:
The following classes could not be instantiated:
- android.support.design.widget.FloatingActionButton
(First paragraph of error)
java.lang.NullPointerException
at android.support.v4.graphics.drawable.DrawableCompatLollipop.setTintList(DrawableCompatLollipop.java:56)
at android.support.v4.graphics.drawable.DrawableCompat$LollipopDrawableImpl.setTintList(DrawableCompat.java:145)
at android.support.v4.graphics.drawable.DrawableCompat.setTintList(DrawableCompat.java:270)
etc...
有人知道吗?这是我的 build.gradle:
android {
compileSdkVersion 22
buildToolsVersion "22.0.1"
classpath 'com.android.tools.build:gradle:1.2.3'
defaultConfig {
applicationId "owensetiawan.tutorials.fab"
minSdkVersion 15
targetSdkVersion 22
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:22.2.0'
compile 'com.android.support:design:22.2.0'
}
如果有人能帮助我阐明我的问题,那就太好了。
最佳答案
嘿,我在实例化设计库时遇到了同样的问题,并通过这个解决了
第 1 步 > fab 代码
<android.support.design.widget.FloatingActionButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:clickable="true"
android:src="@drawable/search"
app:backgroundTint="@color/color_fav"
app:borderWidth="0dp"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
/>
第二步>依赖
compile 'com.android.support:appcompat-v7:22.2.1'
compile 'com.android.support:recyclerview-v7:22.2.1'
compile 'com.android.support:design:22.2.1'
compile "com.android.support:support-v4:22.2.1"
步骤3>解决上述问题的主要步骤
简单的:- 转到您的 xml 并单击预览,然后在预览栏中选择 AP1 21
关于android - FloatingActionButton 类无法实例化,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31319127/