我想使用此库进行更改颜色：Color Picker。我在PrefrenceSreen中使用此库，我希望使用此组件更改文本颜色！但是在开始申请时会显示错误
LogCat错误：
02-29 15:24:09.541 19631-19631/com.tellfa.mytestpreference E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.tellfa.mytestpreference, PID: 19631
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tellfa.mytestpreference/com.tellfa.mytestpreference.MainPage}: java.lang.NullPointerException: Attempt to invoke virtual method 'int com.tellfa.mytestpreference.AppPreference.getContentTextColor()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2331)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2391)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1309)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5349)
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:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int com.tellfa.mytestpreference.AppPreference.getContentTextColor()' on a null object reference
at com.tellfa.mytestpreference.MainPage.ContentTextColor(MainPage.java:66)
at com.tellfa.mytestpreference.MainPage.onCreate(MainPage.java:46)
at android.app.Activity.performCreate(Activity.java:6020)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2284)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2391)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1309)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5349)
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:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
AppPreference代码：
public class AppPreference {
private SharedPreferences sharedPreferences;
private SharedPreferences.Editor editor;
private Context context;
private static final String KeyContentTextColor = "textColor_pref";
public AppPreference(Context context){
this.sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
this.editor = sharedPreferences.edit();
this.context = context;
}
public int getContentTextColor(){
return sharedPreferences.getInt(KeyContentTextColor, context.getResources().getColor(R.color.textDark));
}
public void setContentTextColor(Integer res){
editor.putInt(KeyContentTextColor, res);
editor.commit();
}
}
设置网页代码：
public class SettingPage extends PreferenceActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
private AppCompatDelegate mDelegate;
private AppPreference myAppPreference;
private Context context;
private Toolbar toolbar;
private AmbilWarnaPreference ContentTextColor_pref;
private Preference defaultColor;
@Override
protected void onCreate(Bundle savedInstanceState) {
getmDelegate().installViewFactory();
getmDelegate().onCreate(savedInstanceState);
super.onCreate(savedInstanceState);
setContentView(R.layout.toolbar_setting);
toolbar = (Toolbar) findViewById(R.id.setting_toolbar);
setSupportActionBar(toolbar);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onBackPressed();
}
});
addPreferencesFromResource(R.xml.pref_setting);
//getFragmentManager().beginTransaction().replace(android.R.id.content, new myPreferenceFragment()).commit();
this.context = this;
this.myAppPreference = TestPreference.getAppPreference();
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
pref.registerOnSharedPreferenceChangeListener(this);
ContentTextColor_pref = (AmbilWarnaPreference) findPreference("textColor_pref");
defaultColor = findPreference("prefDefaultValues");
defaultColor.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
@Override
public boolean onPreferenceClick(Preference preference) {
myAppPreference.setContentTextColor(getResources().getColor(R.color.textDark));
return true;
}
});
}
主页代码：
public class MainPage extends AppCompatActivity {
private Toolbar toolbar;
private WebView webView;
private TextView textView;
private AppPreference appPreference;
private Context context;
private Activity activity;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_page);
this.appPreference = TestPreference.getAppPreference();
this.activity = this;
this.context = this;
toolbar = (Toolbar) findViewById(R.id.main_toolbar);
setSupportActionBar(toolbar);
if (getSupportActionBar() != null) {
getSupportActionBar().setTitle("Main Page");
}
//toolbar.setLogo(R.drawable.ic_menu_toolbar);
toolbar.setLogoDescription("Logo");
toolbar.setTitle("Main Page");
toolbar.setSubtitle("Home Page");
toolbar.inflateMenu(R.menu.main_manu);
textView = (TextView) findViewById(R.id.main_textView);
textView.setTextColor(appPreference.getContentTextColor());
}
TestPreference代码：
public class TestPreference extends Application {
private static AppPreference appPreference;
@Override
public void onCreate() {
appPreference = new AppPreference(this);
super.onCreate();
}
public static AppPreference getAppPreference(){
return appPreference;
}
}
如何解决这个问题？我真的需要帮助！谢谢所有＆lt; 3
答案 0 :(得分：1)
只需将Application类TestPreference添加到清单中即可。必须注册此类才能正常工作：
<application
android:icon="@drawable/yourAppIcon"
android:label="@string/yourAppName"
android:name="yourPackage.TestPreference">
<!-- your other classes/services etc between application tag -->
</application>