Java tutorial
/* * Twittnuker - Twitter client for Android * * Copyright (C) 2013-2014 vanita5 <mail@vanita5.de> * * This program incorporates a modified version of Twidere. * Copyright (C) 2012-2014 Mariotaku Lee <mariotaku.lee@gmail.com> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package de.vanita5.twittnuker.view; import android.annotation.SuppressLint; import android.content.Context; import android.graphics.Canvas; import android.graphics.LinearGradient; import android.graphics.Paint; import android.graphics.PorterDuff; import android.graphics.PorterDuffXfermode; import android.graphics.Shader; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.MotionEvent; import de.vanita5.twittnuker.Constants; import de.vanita5.twittnuker.util.ThemeUtils; import de.vanita5.twittnuker.view.iface.IExtendedView; public class ProfileBannerImageView extends ForegroundImageView implements IExtendedView, Constants { private static final int[] COLORS = new int[] { 0xFFFFFFFF, 0x00FFFFFF }; private static final int[] COLORS_REVERSED = new int[] { 0x00FFFFFF, 0xFFFFFFFF }; private static final float[] POSITIONS = new float[] { 0.0f, 1.0f }; private static final PorterDuffXfermode DST_IN = new PorterDuffXfermode(PorterDuff.Mode.DST_IN); private OnSizeChangedListener mOnSizeChangedListener; private TouchInterceptor mTouchInterceptor; private final Paint mPaint = new Paint(); private LinearGradient mShader; public ProfileBannerImageView(final Context context) { this(context, null); } public ProfileBannerImageView(final Context context, final AttributeSet attrs) { this(context, attrs, 0); } public ProfileBannerImageView(final Context context, final AttributeSet attrs, final int defStyle) { super(context, attrs, defStyle); if (isInEditMode()) return; setScaleType(ScaleType.CENTER_CROP); ViewCompat.setLayerType(this, LAYER_TYPE_SOFTWARE, null); final boolean is_dark_theme = ThemeUtils.isDarkTheme(context); COLORS_REVERSED[1] = is_dark_theme ? 0xFF000000 : 0xFFFFFFFF; setForeground(ThemeUtils.getImageHighlightDrawable(context)); } @Override public final boolean dispatchTouchEvent(final MotionEvent event) { if (mTouchInterceptor != null) { final boolean ret = mTouchInterceptor.dispatchTouchEvent(this, event); if (ret) return true; } return super.dispatchTouchEvent(event); } @Override public final boolean onTouchEvent(final MotionEvent event) { if (mTouchInterceptor != null) { final boolean ret = mTouchInterceptor.onTouchEvent(this, event); if (ret) return true; } return super.onTouchEvent(event); } @Override public final void setOnSizeChangedListener(final OnSizeChangedListener listener) { mOnSizeChangedListener = listener; } @Override public final void setTouchInterceptor(final TouchInterceptor listener) { mTouchInterceptor = listener; } @Override protected void onDraw(final Canvas canvas) { if (isInEditMode()) return; final int width = getWidth(), height = getHeight(); if (mShader == null) return; super.onDraw(canvas); mPaint.setShader(mShader); mPaint.setXfermode(DST_IN); canvas.drawRect(0, 0, width, height, mPaint); } @SuppressLint("DrawAllocation") @Override protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) { final int width = MeasureSpec.getSize(widthMeasureSpec), height = width / 3; setMeasuredDimension(width, height); if (width > 0) { mShader = new LinearGradient(width / 2, 0, width / 2, height, COLORS, POSITIONS, Shader.TileMode.CLAMP); } super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY)); } @Override protected final void onSizeChanged(final int w, final int h, final int oldw, final int oldh) { super.onSizeChanged(w, h, oldw, oldh); if (mOnSizeChangedListener != null) { mOnSizeChangedListener.onSizeChanged(this, w, h, oldw, oldh); } } }