Question

我正在设计自己的Android应用程序，我希望可以自定义启动画面。我希望用户能够打开和关闭启动画面（它可以工作！）并设置启动画面的持续时间（这里有轻微问题：D）。这是我的启动画面活动：

package info.androidhive.slidingmenu;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.Handler;
import android.preference.PreferenceManager;

public class SplashScreen2 extends Activity {

SharedPreferences pref=PreferenceManager.getDefaultSharedPreferences(getBaseContext());
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    boolean x = pref.getBoolean("checkbox", true);
    String time = pref.getString("list", "4000");
    // Splash screen timer
    int SPLASH_TIME_OUT = Integer.parseInt(time);
    if(x) {
        setContentView(R.layout.activity_splash2);

        new Handler().postDelayed(new Runnable() {

            /*
             * Showing splash screen with a timer. This will be useful when you
             * want to show case your app logo / company
             */

            @Override
            public void run() {
                // This method will be executed once the timer is over
                // Start your app main activity
                Intent i = new Intent(SplashScreen2.this, MainActivity.class);
                startActivity(i);

                // close this activity
                finish();
            }
        }, SPLASH_TIME_OUT);

    }
    else {
        Intent x1 = new Intent(SplashScreen2.this, MainActivity.class);
        startActivity(x1);
    }
        }

protected void onPause() {
    super.onPause();
    finish();
}

}

首选项xml文件：

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen 
xmlns:android="http://schemas.android.com/apk/res/android"
android:title="Splash Screen" >
<EditTextPreference 
    android:key="name" 
    android:title="EditText" 
    android:summary="Enter your name"/>

<CheckBoxPreference 
    android:summary="Check to enable splash screen" 
    android:title="Enable" 
    android:key="checkbox"/>

<ListPreference 
    android:entries="@array/list" 
    android:summary="Choose duration of splash screen" 
    android:key="list" 
    android:entryValues="@array/value" 
    android:title="Duration"/>



</PreferenceScreen>

数组文件：

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="list">

    <item>1 second</item>
    <item>2 second</item>
    <item>3 second</item>
    <item>4 second</item>

</string-array>

<string-array name="value">

    <item>1000</item>
    <item>2000</item>
    <item>3000</item>
    <item>4000</item>

</string-array>
</resources>

我的logcat：

12-18 17:12:47.139: E/AndroidRuntime(8302): FATAL EXCEPTION: main
12-18 17:12:47.139: E/AndroidRuntime(8302): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{info.androidhive.slidingmenu/info.androidhive.slidingmenu.SplashScreen2}: java.lang.NullPointerException
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1925)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2028)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.ActivityThread.access$600(ActivityThread.java:127)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1179)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.os.Looper.loop(Looper.java:137)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.ActivityThread.main(ActivityThread.java:4508)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at java.lang.reflect.Method.invokeNative(Native Method)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at java.lang.reflect.Method.invoke(Method.java:511)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at dalvik.system.NativeStart.main(Native Method)
12-18 17:12:47.139: E/AndroidRuntime(8302): Caused by: java.lang.NullPointerException
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.content.ContextWrapper.getPackageName(ContextWrapper.java:127)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:371)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:366)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at java.lang.Class.newInstanceImpl(Native Method)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at java.lang.Class.newInstance(Class.java:1319)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
12-18 17:12:47.139: E/AndroidRuntime(8302):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1916)
12-18 17:12:47.139: E/AndroidRuntime(8302):     ... 11 more

但是，只要应用程序启动，它就会在启动画面出现之前崩溃。这个应用程序在添加持续时间选项之前有效。帮助！

Answer 1

将此代码放在 onCreate（）中，而不是在其他任何地方之前。

SharedPreferences pref=PreferenceManager.getDefaultSharedPreferences(getBaseContext());

Answer 2

您可以尝试自己的偏好吗？

SharedPreferences mPreference = context.getSharedPreferences("your_app", Context.MODE_PRIVATE);

//Save user time
 mPreference.edit().putLong("DURATION", 3000).apply();

//Get duration
long duration = mPreference.getLong("DURATION", 3000);

Answer 3

由java.lang.NullPointerException

之外的SharedPreferences pref=PreferenceManager.getDefaultSharedPreferences(getBaseContext());引起的{p> onCreate()

是根本原因。

所以将代码更改为

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedPreferences pref=PreferenceManager.getDefaultSharedPreferences(getBaseContext());
boolean x = pref.getBoolean("checkbox", true);
String time = pref.getString("list", "4000");
// Splash screen timer
int SPLASH_TIME_OUT = Integer.parseInt(time);
if(x) {
    setContentView(R.layout.activity_splash2);

    new Handler().postDelayed(new Runnable() {

        /*
         * Showing splash screen with a timer. This will be useful when you
         * want to show case your app logo / company
         */

        @Override
        public void run() {
            // This method will be executed once the timer is over
            // Start your app main activity
            Intent i = new Intent(SplashScreen2.this, MainActivity.class);
            startActivity(i);

            // close this activity
            finish();
        }
    }, SPLASH_TIME_OUT);

}
else {
    Intent x1 = new Intent(SplashScreen2.this, MainActivity.class);
    startActivity(x1);
}
    }

Answer 4

检查此代码：

public class SplashScreen2 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        SharedPreferences pref=PreferenceManager.getDefaultSharedPreferences(SplashScreen2.this);
        boolean x = pref.getBoolean("checkbox", true);
        String time = pref.getString("list", "4000");

        // Splash screen timer
        ...

Android：启动画面持续时间取决于首选项

4 个答案: