我想從v7支持庫中使用PreferenceFragmentCompat。當我嘗試添加它時,它始終返回以下例外PreferenceFragmentCompat不會加載在AppCompatPreferenceActivity - 試圖實例化一個類不是片段
Process: com.sample.preferencetest, PID: 14444
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sample.preferencetest/com.sample.preferencetest.SettingsActivity}: android.app.Fragment$InstantiationException: Trying to instantiate a class com.sample.preferencetest.SettingsActivity$EmptyFragment that is not a Fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3155)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3263)
at android.app.ActivityThread.access$1000(ActivityThread.java:197)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1687)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6897)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
當我嘗試使用此PreferenceFragment時,一切正常。只有當我嘗試使用PreferenceFragmentCompat時,它會失敗
我想使用它的原因是因爲onAttach(Activity)方法現在已被棄用,並且較早的設備未附加我的接口。
這是類
package com.sample.preferencetest;
import android.os.Bundle;
//import android.preference.PreferenceFragment; I toggle this to try regular preference fragments.
import android.support.v7.preference.PreferenceFragmentCompat;
import java.util.List;
public class SettingsActivity extends AppCompatPreferenceActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onBuildHeaders(List<Header> target) {
loadHeadersFromResource(R.xml.pref_headers, target);
}
protected boolean isValidFragment(String fragmentName) {
return true;
}
public static class EmptyFragment extends PreferenceFragmentCompat {
public EmptyFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onCreatePreferences(Bundle bundle, String s) {
}
}
}
頁眉XML
<preference-headers xmlns:android="http://schemas.android.com/apk/res/android">
<header
android:fragment="com.sample.preferencetest.SettingsActivity$EmptyFragment"
android:icon="@drawable/ic_info_black_24dp"
android:title="@string/pref_header_general" />
</preference-headers>
搖籃
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.2"
defaultConfig {
applicationId "com.sample.preferencetest"
minSdkVersion 16
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.2.1'
compile 'com.android.support:design:23.2.1'
compile 'com.android.support:support-v4:23.2.1'
compile 'com.android.support:preference-v7:23.3.0'
}
我怎麼使用PreferenceFragmentCompat,如果不是這樣?
'onAttach(Activity activity)'已棄用。使用onAttach(上下文上下文)'。在這兩種情況下工作 – piotrek1543