Getting IllegalStateException when trying to take snapshot of the graph for https://github.com/appsthatmatter/GraphView

问题

I'm trying to take snapshot of the GraphView but it gives an error "GraphView must be used in hardware accelerated mode." I'm using the following code to take snapshot

Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888); 
Canvas canvas = new Canvas(bitmap); 
view.draw(canvas);

Also, i've already set android:hardwareAccelerated="true" at application level.

回答1:

i used this:

dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  testCompile 'junit:junit:4.12'
 compile 'com.android.support:appcompat-v7:23.1.1'
 compile files('libs/GraphView-4.0.1.jar')
  compile 'com.jjoe64:graphview:4.1.0'
}

especially

compile 'com.jjoe64:graphview:4.1.0'

this helped me.

回答2:

The problem is that GraphView in recent version include additional conditions - if canvas in hardware accelerated mode or not:

GraphView.java (https://github.com/appsthatmatter/GraphView/commit/0740de3e0a93633f7f168115b96edfdce156b19e)

public class GraphView extends View {

    ...

    protected void drawGraphElements(Canvas canvas) {
        // must be in hardware accelerated mode
        if (android.os.Build.VERSION.SDK_INT >= 11 && !canvas.isHardwareAccelerated()) {
            throw new IllegalStateException("GraphView must be used in hardware accelerated mode." +
                "You can use android:hardwareAccelerated=\"true\" on your activity. Read this for more info:" +
                "https://developer.android.com/guide/topics/graphics/hardware-accel.html");
        }
        ...
    }

    ...
}

When you create off-screen canvas it doesn't have hardware accelerated mode. But you can just override isHardwareAccelerated for your Canvas instance. Use this workaround:

Bitmap bitmap = Bitmap.createBitmap(graphView.getWidth(), graphView.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap) {
    @Override
    public boolean isHardwareAccelerated() {
        return true;
    }
};

// not it's work
graphView.draw(canvas);

// save somewhere
bitmap.compress(Bitmap.CompressFormat.JPEG, 100,  new FileOutputStream(imagePath));

回答3:

In the recent release 4.2.2 the snapshot feature is function properly. You can check out the documentation and the example project:

http://www.android-graphview.org/take-snapshots/

This are basically the API calls:

// directly share it
graph.takeSnapshotAndShare(mActivity, "exampleGraph", "GraphViewSnapshot");

// get the bitmap
Bitmap bitmap = graph.takeSnapshot();

来源：https://stackoverflow.com/questions/41920458/getting-illegalstateexception-when-trying-to-take-snapshot-of-the-graph-for-http

标签

android

android-graphview