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in Technique[技术] by (71.8m points)

android - How to refresh a GridView?

I have a GridView which is pretty similar to the Google tutorial, except that I want to add the ImageViews on runtime (via a subactivity). The results are okay, but the layout of the View is messed up: The GridView doesn't fill the content of its parent, what do I have to do to design it properly?

Here the code of adding the children:

public void initializeWorkbench(GridView gv, Vector<String> items) {
        Prototype.workbench.setDimension(screenWidth, divider.height()+workbenchArea.height());
        Prototype.workbench.activateWorkbench();
        // this measures the workbench correctly
        Log.d(Prototype.TAG, "workbench width: "+Prototype.workbench.getMeasuredWidth());
        // 320
        Log.d(Prototype.TAG, "workbench height: "+Prototype.workbench.getMeasuredHeight());
        // 30
        ImageAdapter imgAdapter = new ImageAdapter(this.getContext(), items);
        gv.setAdapter(imgAdapter);
        gv.measure(screenWidth, screenHeight);
        gv.requestLayout();
        gv.forceLayout();
        Log.d(Prototype.TAG, "gv width: "+gv.getMeasuredWidth());
        // 22
        Log.d(Prototype.TAG, "gv height: "+gv.getMeasuredHeight());
        // 119
        Prototype.workbench.setDimension(screenWidth, divider.height()+workbenchArea.height());
    }
}

activateWorkbench, setDimension and measure in the workbench (LinearLayout above the GridView):

public void activateWorkbench() {
    if(this.equals(Prototype.workbench)) {
        this.setOrientation(VERTICAL);
        show = true;
        measure();
    }
}

public void setDimension(int w, int h) {
    width = w;
    height = h;
    this.setLayoutParams(new LinearLayout.LayoutParams(width, height));
    this.invalidate();
}

private void measure() {
    if (this.getOrientation() == LinearLayout.VERTICAL) {
        int h = 0;
        int w = 0;
        this.measureChildren(0, 0);
        for (int i = 0; i < this.getChildCount(); i++) {
            View v = this.getChildAt(i);
            h += v.getMeasuredHeight();
            w = (w < v.getMeasuredWidth()) ? v.getMeasuredWidth() : w;
        }
        if (this.equals(Prototype.tagarea))
            height = (h < height) ? height : h;
        if (this.equals(Prototype.tagarea))
            width = (w < width) ? width : w;
    }
    this.setMeasuredDimension(width, height);
}

The ImageAdapter constructor:

public ImageAdapter(Context c, Vector<String> items) {
    mContext = c;

    boolean mExternalStorageAvailable = false;
    boolean mExternalStorageWriteable = false;
    String state = Environment.getExternalStorageState();

    if (Environment.MEDIA_MOUNTED.equals(state)) {
        // We can read and write the media
        mExternalStorageAvailable = mExternalStorageWriteable = true;
    } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
        // We can only read the media
        mExternalStorageAvailable = true;
        mExternalStorageWriteable = false;
    } else {
        // Something else is wrong. It may be one of many other states, but
        // all we need
        // to know is we can neither read nor write
        mExternalStorageAvailable = mExternalStorageWriteable = false;
    }

    if (mExternalStorageAvailable && mExternalStorageWriteable) {
        for (String item : items) {
            File f = new File(item);
            if (f.exists()) {
                try {
                    FileInputStream fis = new FileInputStream(f);
                    Bitmap b = BitmapFactory.decodeStream(fis);
                    bitmaps.add(b);
                    files.add(f);
                } catch (FileNotFoundException e) {
                    Log.e(Prototype.TAG, "", e);
                }
            }
        }
    }
}

And the xml layout:

<LinearLayout   xmlns:android="http://schemas.android.com/apk/res/android" 
            android:layout_width="fill_parent" 
            android:layout_height="fill_parent"
                android:orientation="vertical"
                android:gravity="bottom"

                android:paddingLeft="0px"
                android:paddingTop="0px"
                android:paddingRight="0px">

    <com.unimelb.pt3.ui.TransparentPanel
            android:id="@+id/workbench" 
            android:layout_width="fill_parent"
            android:layout_height="10px"
            android:paddingTop="0px"
            android:paddingLeft="0px"
            android:paddingBottom="0px"
            android:paddingRight="0px">

        <GridView xmlns:android="http://schemas.android.com/apk/res/android" 
            android:id="@+id/gridview"
            android:layout_width="fill_parent" 
            android:layout_height="fill_parent"
            android:columnWidth="90dp"
            android:numColumns="auto_fit"
            android:verticalSpacing="10dp"
            android:horizontalSpacing="10dp"
            android:stretchMode="columnWidth"
            android:gravity="center" />

    </com.unimelb.pt3.ui.TransparentPanel>

</LinearLayout>
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1 Reply

0 votes
by (71.8m points)

the GridView has an invalidateViews() method.

when you call this method: "all the views to be rebuilt and redrawn." http://developer.android.com/reference/android/widget/GridView.html

i think this is what you need:)


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