android converting XML View to Bitmap without showing it

android, bitmap, xml

Solution

Your `cluster.getLayoutParams()` is probably `null`. First, you need to measure the width/height of your inflated view and then assign to it. Do it as below:

private Bitmap createClusterBitmap(int clusterSize) {
    View cluster = LayoutInflater.from(context).inflate(R.layout.map_cluster,
            null);

    TextView clusterSizeText = (TextView) cluster.findViewById(R.id.map_cluster_text);
    clusterSizeText.setText(String.valueOf(clusterSize));

    cluster.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    cluster.layout(0, 0, cluster.getMeasuredWidth(),cluster.getMeasuredHeight());

    final Bitmap clusterBitmap = Bitmap.createBitmap(cluster.getMeasuredWidth(),
            cluster.getMeasuredHeight(), Bitmap.Config.ARGB_8888);

    Canvas canvas = new Canvas(clusterBitmap);
    cluster.draw(canvas);

    return clusterBitmap;
}

Problem

i'm trying to set a view to my map cluster. i'm inflating a view from an XML and setting the Text according to cluster size and i want to show that view. in the following code i get a null bitmap in return: ``` private Bitmap createClusterBitmap(int clusterSize) { View cluster = LayoutInflater.from(context).inflate(R.layout.map_cluster, null); cluster.setText(String.valueOf(clusterSize)); cluster.setDrawingCacheEnabled(true); cluster.buildDrawingCache(true); Bitmap bm = cluster.getDrawingCache(); return bm; } ``` in the following code i get null pointer on the fourth line (the layout params): ``` private Bitmap createClusterBitmap(int clusterSize) { View cluster = LayoutInflater.from(context).inflate(R.layout.map_cluster, null); TextView clusterSizeText = (TextView) cluster.findViewById(R.map.cluster); clusterSizeText.setText(String.valueOf(clusterSize)); Bitmap clusterBitmap = Bitmap.createBitmap( cluster.getLayoutParams().width, cluster.getLayoutParams().height, Bitmap.Config.ARGB_8888); Canvas clusterCanvas = new Canvas(clusterBitmap); cluster.layout(cluster.getLeft(), cluster.getTop(), cluster.getRight(), cluster.getBottom()); cluster.draw(clusterCanvas); return clusterBitmap; } ``` and when changing it to the following code i get not error but nothing is drawed: ``` private Bitmap createClusterBitmap(int clusterSize) { View cluster = LayoutInflater.from(context).inflate(R.layout.map_cluster, null); TextView clusterSizeText = (TextView) cluster.findViewById(R.map.cluster); clusterSizeText.setText(String.valueOf(clusterSize)); Bitmap clusterBitmap = Bitmap.createBitmap( 50,50 , Bitmap.Config.ARGB_8888); Canvas clusterCanvas = new Canvas(clusterBitmap); cluster.layout(50, 50, 50, 50; cluster.draw(clusterCanvas); return clusterBitmap; } ``` this is my XML: ``` <?xml version="1.0" encoding="utf-8"?> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+map/cluster" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/map_pointer_cluster" android:gravity="center" android:orientation="vertical" android:textColor="@android:color/black" android:textSize="35dp" android:textStyle="bold" /> ```

Original source

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