在查看材料设计中的新方法后,我尝试在应用程序中实现浮动操作按钮.但是,我在预览中收到此错误(预览
Android版本21)：
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...
任何人都有想法？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'
}
如果有人可以帮助我解释我的问题,这绝对是太棒了.
解决方法
嘿,我遇到了与实例化的设计库相同的问题,并解决了这一点
步骤1>晶圆代码
<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"
/>
步骤2>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>上述问题的主要步骤
容易的一个： – 去你的xml并点击预览,并在预览中的栏选择AP1 21
