Get Drawable from image view

Question

When I do the clip drawable example described in this document ImageView.getDrawable always return null. Can anyone pls help me?

In MainActivity.java onCreate

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

        ImageView imageview = (ImageView) findViewById(R.id.image);
        ClipDrawable drawable = (ClipDrawable) imageview.getDrawable();
        drawable.setLevel(drawable.getLevel() + 1000); //Line number 21
    }

Logcat

 02-04 12:16:31.156: E/AndroidRuntime(4611): FATAL EXCEPTION: main02-04 12:16:31.156: E/AndroidRuntime(4611): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test/com.example.test.MainActivity}: java.lang.NullPointerException

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.ActivityThread.access$1500(ActivityThread.java:117)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.os.Handler.dispatchMessage(Handler.java:99)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.os.Looper.loop(Looper.java:123)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.ActivityThread.main(ActivityThread.java:3683)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at java.lang.reflect.Method.invokeNative(Native Method)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at java.lang.reflect.Method.invoke(Method.java:507)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at dalvik.system.NativeStart.main(Native Method)

02-04 12:16:31.156: E/AndroidRuntime(4611): Caused by: java.lang.NullPointerException

02-04 12:16:31.156: E/AndroidRuntime(4611):      at com.example.test.MainActivity.onCreate(MainActivity.java:21)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

02-04 12:16:31.156: E/AndroidRuntime(4611):      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)

02-04 12:16:31.156: E/AndroidRuntime(4611):      ... 11 more

Solution 1

You have to override onWindowsFocusChanged()

 @Override
 public void onWindowFocusChanged(boolean hasWindowFocus) {
    super.onWindowFocusChanged(hasWindowFocus);
   ClipDrawable drawable = (ClipDrawable) imageview.getBackground();
    drawable.setLevel(drawable.getLevel() + 1000); //Line number 21
 }

the imageView was not yet displayed properly when you tried to get its value(drawable image). onWindowsFocusChanged() will inform the user that the view has been loaded already that's the time you can get its data.

Solution 2

May be you will get null drawable so this error will occure.

First set any image to ImageView so you will get Drawable.

protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ImageView imageview = (ImageView) findViewById(R.id.image);
        imageview.setBackgroundResource(R.drawable.icon);
        ClipDrawable drawable = (ClipDrawable) imageview.getDrawable();
        if(drawable != null){
        drawable.setLevel(drawable.getLevel() + 1000); //Line number 21
        }
    }

Solution 3

None of the answers till now is correct

The issue here is that in the image view the drawable is attached using android:background="@drawable/clip" and it is retrieved using ClipDrawable drawable = (ClipDrawable) imageview.getDrawable();

Fixes:

Change the imageview xml

android:background="@drawable/clip" -> android:src="@drawable/clip"

OR

Change the button callback code

ClipDrawable drawable = (ClipDrawable) imageview.getDrawable(); -> ClipDrawable drawable = (ClipDrawable) imageview.getBackground();

Don't change both, otherwise the problem will get created again. Change any one.

Solution 4

This is an easy approach if you can use the view's id member variable: just store the R.drawable id using v.setId(). Then get it back with v.getId().

View more solutions

Comments

[Dinesh T A]

developer.android.com/guide/topics/resources/… look this link for clip drawable example i do the same in image i didn't give the src instead of i gave the background clip drawable

[Parag Chauhan]

android:background="@drawable/clip" have you set this?

[She Smile GM]

I updated my code above, instead of imageview.getDrawable changed to image.getBackground().

[Dinesh T A]

thanks @SheSmile It's works fine i have add a button in button onclick i have do the drawable.setLevel