java.lang.NullPointerException：尝试在空对象引用上调用虚方法，而它不为空

Question

I am trying to use a variable from 1 class into another class so i do not have to make a URL call and a parser all over again but i get the error in the title and i do not understand why. The name variable i have as testing is not empty, it has a value that it has taken from a different class.

CoatJacket Code :

package com.example.ma18uus.myapplication;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class CoatsJackets extends AppCompatActivity {

    TextView text;

    Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_coats_jackets);
        btn=(Button)findViewById(R.id.AddCoatsJackets);
        btn.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                Intent i=new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
                startActivity(i);
            }
        });

        WeatherConditions recievingInfo = new WeatherConditions();
        recievingInfo.info();
    }

    public void getInfo(String recievedInfo){

        text = (TextView)findViewById(R.id.grabber);
        text.setText(recievedInfo);

    }


}

WeatherCondition Code :

package com.example.ma18uus.myapplication;

public class WeatherConditions {

    public String name, wind_mph, wind_kph, celsius, feelsCelsius, fahrenheit, feelsFahrenheit, humidity, condition_text;

    public void info(){

        CoatsJackets sendInfo = new CoatsJackets();
        sendInfo.getInfo(name);
    }
}

Error Output :

01/27 07:47:00: Launching 'app' on Pixel 2 API 29.
$ adb shell am start -n "com.example.ma18uus.myapplication/com.example.ma18uus.myapplication.ClothesApp" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Waiting for process to come online...
Connected to process 26822 on device 'emulator-5554'.
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
I/s.myapplicatio: Not late-enabling -Xcheck:jni (already on)
W/main: type=1400 audit(0.0:332): avc: granted { read } for name="u:object_r:net_dns_prop:s0" dev="tmpfs" ino=8398 scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:object_r:net_dns_prop:s0 tclass=file
E/s.myapplicatio: Unknown bits set in runtime_flags: 0x8000
W/s.myapplicatio: Unexpected CPU variant for X86 using defaults: x86
I/s.myapplicatio: The ClassLoaderContext is a special shared library.
D/libEGL: Emulator has host GPU support, qemu.gles is set to 1.
W/libc: Unable to set property "qemu.gles" to "1": connection failed; errno=13 (Permission denied)
W/RenderThread: type=1400 audit(0.0:333): avc: denied { write } for name="property_service" dev="tmpfs" ino=8445 scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:object_r:property_socket:s0 tclass=sock_file permissive=0
D/libEGL: loaded /vendor/lib/egl/libEGL_emulation.so
D/libEGL: loaded /vendor/lib/egl/libGLESv1_CM_emulation.so
D/libEGL: loaded /vendor/lib/egl/libGLESv2_emulation.so
W/s.myapplicatio: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
W/s.myapplicatio: Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
D/HostConnection: HostConnection::get() New Host Connection established 0xdff5e190, tid 26856
D/HostConnection: HostComposition ext ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_native_sync_v2 ANDROID_EMU_native_sync_v3 ANDROID_EMU_native_sync_v4 ANDROID_EMU_dma_v1 ANDROID_EMU_direct_mem ANDROID_EMU_host_composition_v1 ANDROID_EMU_host_composition_v2 ANDROID_EMU_vulkan ANDROID_EMU_deferred_vulkan_commands ANDROID_EMU_vulkan_null_optional_strings ANDROID_EMU_vulkan_create_resources_with_requirements ANDROID_EMU_YUV420_888_to_NV21 ANDROID_EMU_YUV_Cache ANDROID_EMU_async_unmap_buffer GL_OES_EGL_image_external_essl3 GL_OES_vertex_array_object GL_KHR_texture_compression_astc_ldr ANDROID_EMU_gles_max_version_3_0 
W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
D/eglCodecCommon: setVertexArrayObject: set vao to 0 (0) 0 0
D/EGL_emulation: eglCreateContext: 0xdff1a240: maj 3 min 0 rcv 3
D/EGL_emulation: eglMakeCurrent: 0xdff1a240: ver 3 0 (tinfo 0xdff0f7c0)
W/Gralloc3: mapper 3.x is not supported
D/HostConnection: createUnique: call
D/HostConnection: HostConnection::get() New Host Connection established 0xdff5e460, tid 26856
D/HostConnection: HostComposition ext ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_native_sync_v2 ANDROID_EMU_native_sync_v3 ANDROID_EMU_native_sync_v4 ANDROID_EMU_dma_v1 ANDROID_EMU_direct_mem ANDROID_EMU_host_composition_v1 ANDROID_EMU_host_composition_v2 ANDROID_EMU_vulkan ANDROID_EMU_deferred_vulkan_commands ANDROID_EMU_vulkan_null_optional_strings ANDROID_EMU_vulkan_create_resources_with_requirements ANDROID_EMU_YUV420_888_to_NV21 ANDROID_EMU_YUV_Cache ANDROID_EMU_async_unmap_buffer GL_OES_EGL_image_external_essl3 GL_OES_vertex_array_object GL_KHR_texture_compression_astc_ldr ANDROID_EMU_gles_max_version_3_0 
D/eglCodecCommon: allocate: Ask for block of size 0x1000
D/eglCodecCommon: allocate: ioctl allocate returned offset 0x3ff805000 size 0x2000
D/EGL_emulation: eglMakeCurrent: 0xdff1a240: ver 3 0 (tinfo 0xdff0f7c0)
D/eglCodecCommon: setVertexArrayObject: set vao to 0 (0) 1 0
W/ActivityThread: handleWindowVisibility: no activity for token android.os.BinderProxy@dffd53e
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.ma18uus.myapplication, PID: 26822
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ma18uus.myapplication/com.example.ma18uus.myapplication.CoatsJackets}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
        at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:120)
        at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:155)
        at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:31)
        at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:55)
        at android.support.v7.app.AppCompatDelegateImplV23.<init>(AppCompatDelegateImplV23.java:33)
        at android.support.v7.app.AppCompatDelegateImplN.<init>(AppCompatDelegateImplN.java:33)
        at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:201)
        at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:185)
        at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:519)
        at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:190)
        at com.example.ma18uus.myapplication.CoatsJackets.getInfo(CoatsJackets.java:39)
        at com.example.ma18uus.myapplication.WeatherConditions.info(WeatherConditions.java:10)
        at com.example.ma18uus.myapplication.CoatsJackets.onCreate(CoatsJackets.java:34)
        at android.app.Activity.performCreate(Activity.java:7802)
        at android.app.Activity.performCreate(Activity.java:7791)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
Process 26822 terminated.

Answer 1

You can't do this

public void info(){

    CoatsJackets sendInfo = new CoatsJackets();
    sendInfo.getInfo(name);
}

You must do someting like this

 public void info(CoatsJackets sendInfo){
    sendInfo.getInfo(name);
}

And in your activity do something like this

WeatherConditions recievingInfo = new WeatherConditions();
recievingInfo.info(CoatsJackets.this);

But you maybe will have a crash if the name of weather conditions is null at this line

text.setText(recievedInfo);