Question

BaseActivity.java

    public class BaseActivity extends Activity{
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            DMCApplication.getInstance().addActivity(this);
        }

        @Override
        protected void onDestroy() {
            DMCApplication.getInstance().removeActivity(this);
            super.onDestroy();
        }
    }

SplashScreenActivity.java

    public class SplashScreenActivity extends BaseActivity {

        private Handler handler = new Handler();

        private static final int sDelayTime = 2000;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_splash_screen);

            startService();
            handler.postDelayed(new Runnable() {

                @Override
                public void run() {
                    startMainActivity();
                }
            }, sDelayTime);
        }

        private void startMainActivity() {
            Intent intent = new Intent(getApplicationContext(), MainActivity.class);
            startActivity(intent);
            finish();
        }

        private void startService() {

        }
}

DMCApplication.java

public class DMCApplication extends Application {

    private static DMCApplication mDmcApplication;

    private List<Activity> activities;

    public ControlPoint mControlPoint;

    @Override
    public void onCreate() {
        super.onCreate();
        if (activities != null) {
            activities = null;
        }
        activities = new ArrayList<Activity>();
        mDmcApplication = this;
    }


    public void addActivity(Activity activity) {
        if (activities != null) {
            if (activities.contains(activity)) {
                activities.remove(activity);
            }
            activities.add(activity);
        }
    }


    public void removeActivity(Activity activity) {
        if (activities != null && activities.contains(activity)) {
            activities.remove(activity);
        }
    }


    public static DMCApplication getInstance() {
        return mDmcApplication;
    }


    public void quit() {
        if (activities != null) {
            for (Activity activity : activities) {
                activity.finish();
            }
            activities = null;
        }
    }


    public void setControlPoint(ControlPoint controlPoint) {
        mControlPoint = controlPoint;
    }


    public ControlPoint getControlPoint() {
        return mControlPoint;
    }
}

logcat的

java.lang.RuntimeException：无法启动活动ComponentInfo { com.abc.xyx / com.abc.xyx.actvities.SplashScreenActivity}：

java.lang.NullPointerException：尝试在空对象引用上调用虚方法'void com.abc.xyx.DMCApplication.addActivity（android.app.Activity）' 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2946）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3046）在android.app.ActivityThread.-wrap11（未知来源：0）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1688）在android.os.Handler.dispatchMessage（Handler.java:105）在android.os.Looper.loop（Looper.java:164）在android.app.ActivityThread.main（ActivityThread.java:6809） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.Zygote $ MethodAndArgsCaller.run（Zygote.java:240）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:767）引发者：java.lang.NullPointerException：尝试在空对象引用上调用虚方法'void com.agileapps.dlnaupnp.DMCApplication.addActivity（android.app.Activity）' 在com.abc.xyx.actvities.BaseActivity.onCreate（BaseActivity.java:14）在com.abc.xyx.actvities.SplashScreenActivity.onCreate（SplashScreenActivity.java:22）在android.app.Activity.performCreate（Activity.java:6998）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1230）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2899）

Answer 1

您尚未在DMCApplication中注册Manifest。你必须做这样的事情

 <application
    android:name=".DMCApplication"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"

P.S。名称应完全合格。

扩展BaseActivity，在super.oncreate

1 个答案: