Question

我试图在我的应用中进行设置，因此当用户选中一个框而不是应用程序全屏时，但每次我运行该活动时都会强制关闭：

CheckBox FullScreen;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.settings);

    if (FullScreen.isChecked()) {
        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                    WindowManager.LayoutParams.FLAG_FULLSCREEN);
    }
}

我如何实现理想的行为？
这是我的logcat错误：

08-20 23:09:23.328: E/AndroidRuntime(30491): FATAL EXCEPTION: main
08-20 23:09:23.328: E/AndroidRuntime(30491): Process: com.jason.payday, PID: 30491
08-20 23:09:23.328: E/AndroidRuntime(30491): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jason.payday/com.jason.payday.settings}: java.lang.NullPointerException
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2334)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2392)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.ActivityThread.access$900(ActivityThread.java:169)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1280)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.os.Handler.dispatchMessage(Handler.java:102)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.os.Looper.loop(Looper.java:146)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.ActivityThread.main(ActivityThread.java:5487)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at java.lang.reflect.Method.invokeNative(Native Method)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at java.lang.reflect.Method.invoke(Method.java:515)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at dalvik.system.NativeStart.main(Native Method)
08-20 23:09:23.328: E/AndroidRuntime(30491): Caused by: java.lang.NullPointerException
08-20 23:09:23.328: E/AndroidRuntime(30491):    at com.jason.payday.settings.onCreate(settings.java:42)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.Activity.performCreate(Activity.java:5451)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
08-20 23:09:23.328: E/AndroidRuntime(30491):    at           android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
08-20 23:09:23.328: E/AndroidRuntime(30491):    
... 11 more

Answer 1

你有两个问题：

如何制作全屏活动？
为什么我的应用程序会因为nullpointer而崩溃？

以下是

CheckBox FullScreen;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    setcontentview(R.layout.settings);
    // initialize the checkbox, else nullpointer in if-condition (q2)
    FullScreen = (CheckBox)findViewById(R.id.myFullscreenCheckbox);
    if (FullScreen.isChecked()) {
        // make app fullscreen (q1)
        this.getWindow().setFlags(
                    WindowManager.LayoutParams.FLAG_FULLSCREEN,
                    WindowManager.LayoutParams.FLAG_FULLSCREEN
        );
        setcontentview(R.layout.settings);
    }
}

但是再一次，这个代码有点无用，因为复选框总是初始化为true或false，具体取决于你的xml。您应该使用SharedPrefernces来保持设置并在应用启动后加载它们。快速教程。

获取全屏设置：

boolean fullscreen = 
    getSharedPreferences("settings", MODE_PRIVATE).getBoolean("fullscreen", false);

保存全屏设置：

boolean fullscreen = mycheckbox.isChecked();
getSharedPreferences("settings", MODE_PRIVATE).edit().putBoolean("fullscreen", fullscreen).commit();

Answer 2

致电setContentView(R.layout.settings);

之后

this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

Answer 3

您只需在

之后致电setcontentview(Your layout);

   this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

现在不会出现崩溃。如果您仍然发现任何问题，请与我们联系。另外，我建议您选择保存首选项中的复选框选项。

赞http://www.sanfoundry.com/java-android-program-demonstrate-preference-screen/

Answer 4

当您的复选框状态变为 true 时，请输入此代码

buttonFullscreen
            .setOnCheckedChangeListener(new OnCheckedChangeListener() {
                    @Override
                public void onCheckedChanged(CompoundButton arg0,
                        boolean b) {
                    // TODO Auto-generated method stub
                    if(b)
                    getWindow().setFlags(
                            WindowManager.LayoutParams.FLAG_FULLSCREEN,
                            WindowManager.LayoutParams.FLAG_FULLSCREEN);

                }

            });

Answer 5

请分享强制关闭日志。看看你的代码，我认为force close与Full Screen标志无关。我怀疑这是由于其他原因。如果您使用的是Ubuntu，则可以通过以下命令获取强制关闭日志，

adb logcat | grep "AndroidRuntime"

关于解决方案，请勿在OnCreate中设置FullScreen标志。如果要在按钮上单击，请设置onclicklistener。如果要在CheckBox状态更改列表器上执行此操作，请设置checkstate change listener。在事件中添加以下代码

if (fullScreen == true) {
                    getWindow().addFlags(
                            WindowManager.LayoutParams.FLAG_FULLSCREEN);
                } else {
                    getWindow().clearFlags(
                            WindowManager.LayoutParams.FLAG_FULLSCREEN);
                }

如何在选中框时进行全屏活动

5 个答案: