Question

我想给那个包含ImageView和TextView的相对布局选项，当它尝试打开它时，它会在模拟器上提供FC，即使我只将onClick提供给ImageView，即使我做了对于孩子来说可点击为假

<RelativeLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:weightSum="1"
    android:background="@android:color/holo_red_light"
    android:onClick="OpenHBDapp">

    <ImageView
        android:layout_width="88dp"
        android:layout_height="110dp"
        android:id="@+id/imageView2"
        android:layout_weight="0.18"
        android:src="@drawable/happy_birthday_cake"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:paddingLeft="16dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/happy_birthday_apk"
        android:id="@+id/textView5"
        android:textSize="20sp"
        android:textStyle="bold"
        android:layout_centerVertical="true"
        android:layout_toRightOf="@+id/imageView2"
        android:layout_toEndOf="@+id/imageView2"
        android:paddingLeft="16dp" />
</RelativeLayout>

它是班级

package courses.omy.dasser.androidcousres;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;

public class C1Lesson1 extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.c1_lesson1);
    }

public void OpenHBDapp(View view) {
    Intent intent = new Intent(this, HappyBirthday_app.class);
    startActivity(intent);
    }

}

清单

<activity
     android:name=".HappyBirthday_app"
     android:label="Happy Birthday">
</activity>

logcat的

02-02 13:02:50.418 23653-23653/courses.omy.dasser.androidcousres E/AndroidRuntime: FATAL EXCEPTION: main
   Process: courses.omy.dasser.androidcousres, PID: 23653
   java.lang.RuntimeException: Unable to start activity ComponentInfo{courses.omy.dasser.androidcousres/courses.omy.dasser.androidcousres.HappyBirthday_app}: java.lang.NullPointerException
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
       at android.app.ActivityThread.access$800(ActivityThread.java:135)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:136)
       at android.app.ActivityThread.main(ActivityThread.java:5001)
       at java.lang.reflect.Method.invokeNative(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:515)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
       at dalvik.system.NativeStart.main(Native Method)
    Caused by: java.lang.NullPointerException
       at courses.omy.dasser.androidcousres.HappyBirthday_app.onCreate(HappyBirthday_app.java:17)
       at android.app.Activity.performCreate(Activity.java:5231)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233) 
       at android.app.ActivityThread.access$800(ActivityThread.java:135) 
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 
       at android.os.Handler.dispatchMessage(Handler.java:102) 
       at android.os.Looper.loop(Looper.java:136) 
       at android.app.ActivityThread.main(ActivityThread.java:5001) 
       at java.lang.reflect.Method.invokeNative(Native Method) 
       at java.lang.reflect.Method.invoke(Method.java:515) 
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 
       at dalvik.system.NativeStart.main(Native Method)

生日快乐课

package courses.omy.dasser.androidcousres;

import android.app.ActionBar;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
public class HappyBirthday_app extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.happy_birthday_app);
        ActionBar actionBar = null;
        actionBar.setTitle("Happy Birthday");
    }
}

Answer 1

更改

ActionBar actionBar = null;

到

ActionBar actionBar = getSupportActionBar();

可以更改为

android.support.v7.app.ActionBar actionBar = getSupportActionBar();

将解决FC感谢

Answer 2

您正在将null初始化为操作栏实例并在空对象上调用setTitle。这是应用程序崩溃的主要原因。我不知道你为什么这样做，但为了避免崩溃只是评论 ActionBar actionBar = null; actionBar.setTitle("Happy Birthday");行，它会起作用。

或按照@ankitagrawal

的建议更新您的代码

希望这会对你有帮助!!!

onClick with Relativelayout FC

2 个答案: