Java tutorial
/* * Copyright (C) 2014 Marten Gajda <marten@dmfs.org> * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * */ package ti.org.dmfs.android.colorpicker; import ti.org.dmfs.android.colorpicker.palettes.AbstractPalette; import ti.org.dmfs.android.colorpicker.utils.RHelper; import org.dmfs.android.retentionmagic.SupportFragment; import org.dmfs.android.retentionmagic.annotations.Retain; import android.annotation.SuppressLint; import android.os.Bundle; import android.support.v4.app.Fragment; import android.util.DisplayMetrics; import android.util.TypedValue; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewTreeObserver; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.GridView; import android.widget.LinearLayout; import android.widget.LinearLayout.LayoutParams; /** * A fragment that shows a color palette. * * @author Marten Gajda <marten@dmfs.org> */ public class PaletteFragment extends SupportFragment implements OnItemClickListener { public interface OnColorSelectedListener { public void onColorSelected(int color, String paletteId, String colorName, String paletteName); } /** * The palette to show. */ @Retain private AbstractPalette mPalette; /** * An adapter for the palette. */ private PaletteGridAdapter mAdapter; public void setPalette(AbstractPalette palette) { mPalette = palette; } @Override public View onCreateView(final LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { super.onCreateView(inflater, container, savedInstanceState); /* * TODO: build the layout programmatically to get rid of the resources, * so we can distribute this in a single jar */ final ViewGroup rootView = (ViewGroup) inflater .inflate(RHelper.getLayout("org_dmfs_colorpickerdialog_palette_grid"), container, false); final GridView gridview = (GridView) rootView.findViewById(android.R.id.content); mAdapter = new PaletteGridAdapter(getActivity(), mPalette); gridview.setAdapter(mAdapter); gridview.setOnItemClickListener(this); gridview.setNumColumns(mAdapter.getNumColumns()); /* * Adjust the layout of the gridview to a square. * * Inspired by Bill Lahti, see * http://blahti.wordpress.com/2012/07/23/three * -variations-of-image-squares/ */ gridview.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { @SuppressLint("NewApi") public void onGlobalLayout() { int parentHeight = rootView.getHeight() - rootView.getPaddingTop() - rootView.getPaddingBottom(); int parentWidth = rootView.getWidth() - rootView.getPaddingLeft() - rootView.getPaddingRight(); int gridWidth = Math.min(parentWidth, parentHeight); int columnSpacing; if (android.os.Build.VERSION.SDK_INT >= 16) { columnSpacing = gridview.getHorizontalSpacing() * (mAdapter.getNumColumns() - 1); } else { /* * TODO: getHorizontalSpacing() has been introduced * in SDK level 16. We need to find a way to get get * the actual spacing. Until then we use a hard * coded value of 8 dip. * * One way would be to use a dimension in the * layout. That would allow us to resolve the * dimension here. However, that would be one step * away from a library without resource * dependencies. Maybe there is an Android dimension * resource with a reasonable value? */ DisplayMetrics metrics = inflater.getContext().getResources().getDisplayMetrics(); if (android.os.Build.VERSION.SDK_INT > 10) { columnSpacing = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 8, metrics) * (mAdapter.getNumColumns() - 1); } else { // Android 2 seems to add spacing around the // entire gridview columnSpacing = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 8, metrics) * mAdapter.getNumColumns(); } } // width of a single column int columnWidth = (gridWidth - columnSpacing) / mAdapter.getNumColumns(); // estimated width of the grid int actualGridWidth = mAdapter.getNumColumns() * columnWidth + columnSpacing; // add padding to center the grid if we don't use the // entire space due to rounding errors if (actualGridWidth < gridWidth - 1) { int padding = (gridWidth - actualGridWidth) / 2; if (padding > 0) { gridview.setPadding(padding, padding, padding, padding); } } else { // no padding needed gridview.setPadding(0, 0, 0, 0); } // set the column width gridview.setColumnWidth(columnWidth); android.view.ViewGroup.LayoutParams params = gridview.getLayoutParams(); if (params == null || params.height != gridWidth) // avoid // unnecessary // updates { LayoutParams lparams = new LinearLayout.LayoutParams(gridWidth, gridWidth); gridview.setLayoutParams(lparams); } } }); return rootView; } @Override public void onItemClick(AdapterView<?> gridView, View View, int position, long id) { // pass the click event to the parent fragment Fragment parent = getParentFragment(); if (parent instanceof OnColorSelectedListener) { OnColorSelectedListener listener = (OnColorSelectedListener) parent; listener.onColorSelected(mPalette.getColor(position), mPalette.getId(), mPalette.getColorName(position), mPalette.getName()); } } }