Android中的IllegalArgumentException错误，Context不能为null

Question

I am trying to fetch image from an Url using 'Picasso' but I am getting a message in My Logcat like

Caused by: java.lang.IllegalArgumentException: Context must not be null.

Below is my code and Logcat.

09-10 02:53:14.420  29527-    29527/green.example.tejask.asynctasknetworking I/art﹕ Late-enabling -Xcheck:jni
09-10 02:53:14.764  29527-29562/green.example.tejask.asynctasknetworking D/OpenGLRenderer﹕ Render dirty regions requested: true
09-10 02:53:14.788  29527-29527/green.example.tejask.asynctasknetworking D/﹕ HostConnection::get() New Host Connection established 0xabc8c8b0, tid 29527
09-10 02:53:14.799  29527-29527/green.example.tejask.asynctasknetworking D/Atlas﹕ Validating map...
09-10 02:53:14.879  29527-29562/green.example.tejask.asynctasknetworking D/libEGL﹕ loaded /system/lib/egl/libEGL_emulation.so
09-10 02:53:14.881  29527-29562/green.example.tejask.asynctasknetworking D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_emulation.so
09-10 02:53:14.894  29527-29562/green.example.tejask.asynctasknetworking D/libEGL﹕ loaded /system/lib/egl/libGLESv2_emulation.so
09-10 02:53:14.914  29527-29562/green.example.tejask.asynctasknetworking D/﹕ HostConnection::get() New Host Connection established 0xa3116120, tid 29562
09-10 02:53:14.962  29527-29562/green.example.tejask.asynctasknetworking I/OpenGLRenderer﹕ Initialized EGL, version 1.4
09-10 02:53:15.132  29527-29562/green.example.tejask.asynctasknetworking D/OpenGLRenderer﹕ Enabling debug mode 0
09-10 02:53:15.166  29527-29562/green.example.tejask.asynctasknetworking W/EGL_emulation﹕ eglSurfaceAttrib not implemented
09-10 02:53:15.166  29527-29562/green.example.tejask.asynctasknetworking W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa3119220, error=EGL_SUCCESS
09-10 02:53:31.853  29527-29527/green.example.tejask.asynctasknetworking D/AndroidRuntime﹕ Shutting down VM
09-10 02:53:31.858  29527-29527/green.example.tejask.asynctasknetworking E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: green.example.tejask.asynctasknetworking, PID: 29527
    java.lang.RuntimeException: Unable to start activity ComponentInfo{green.example.tejask.asynctasknetworking/green.example.tejask.asynctasknetworking.SecondActivity}: java.lang.IllegalArgumentException: Context must not be null.
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.IllegalArgumentException: Context must not be null.
            at com.squareup.picasso.Picasso$Builder.<init>(Picasso.java:701)
            at com.squareup.picasso.Picasso.with(Picasso.java:662)
            at green.example.tejask.asynctasknetworking.SecondActivity.onCreate(SecondActivity.java:22)
            at android.app.Activity.performCreate(Activity.java:5933)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
09-10 02:53:39.188  29527-29527/green.example.tejask.asynctasknetworking I/Process﹕ Sending signal. PID: 29527 SIG: 9

This is my code:

    package green.example.tejask.asynctasknetworking;
    import android.content.Context;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.widget.ImageView;

    import com.squareup.picasso.Picasso;

/**
 * Created by tejas k on 10-09-2015.
 */
    public class SecondActivity extends AppCompatActivity {
    private ImageView img;
    Context context;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        String imgUri = "https://i.imgur.com/tGbaZCY.jpg";
        img= (ImageView) findViewById(R.id.img);
        Picasso.with(context).load(imgUri).into(img);

    }
}

Answer 1

You have not initialize Context in onCreate() method. please initialize it.

Try this.

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        context = SecondActivity.this;
        String imgUri = "https://i.imgur.com/tGbaZCY.jpg";
        img= (ImageView) findViewById(R.id.img);
        Picasso.with(context).load(imgUri).into(img);

    }

Answer 2

The exception says all

IllegalArgumentException error in Android,Context must not be null

in your case you declared a class member of type Context called context without initialising it. Its default value is null, hence the crash. Since Activity inherits from Context, you can use the keyword this .

Eg

Picasso.with(this).load(imgUri).into(img);

Answer 3

Always initialize a variable before using it

just put Context context=this;

Answer 4

Initialize you context as :

context=SecondActivity.this;

before :

Picasso.with(context).load(imgUri).into(img);

Answer 5

Either you should initialize your context. public class SecondActivity extends AppCompatActivity { private ImageView img; Context context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    String imgUri = "https://i.imgur.com/tGbaZCY.jpg";
    img= (ImageView) findViewById(R.id.img);
    context = SecondActivity.this;
    Picasso.with(context).load(imgUri).into(img);

}

}

or you dont need to declare the context.

Picasso.with(this).load(imgUri).into(img);