基于 仿小红书无限滚动 github改动。
新增 toDestination(Bitmap finallyBitmap)方法，可以设置循环结束，会在结尾出现传入的bitmap。
package com.baijiahulian.maodou.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.FrameLayout;
import androidx.annotation.ColorInt;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.baijiahulian.maodou.R;
import me.jessyan.autosize.utils.AutoSizeUtils;
public class SrcScrollFrameLayout extends FrameLayout {
/**
* 重绘间隔时间
*/
private final static long DEFAULT_DRAW_INTERVALS_TIME = 5L;
/**
* 间隔时间内平移距离
*/
private float mPanDistance = 0;
/**
* 间隔时间内平移增距
*/
private float mIntervalIncreaseDistance = AutoSizeUtils.dp2px(getContext(), 0.5f);
/**
* 填满当前view所需bitmap个数
*/
private int mBitmapCount = 0;
/**
* 是否开始滚动
*/
private boolean mIsScroll;
/****
* 是否要到终点了
*/
private boolean mIsToDestination;
/**
* 滚动方向：上移/左移，默认上移
*/
private int mScrollOrientation;
/**
* 遮罩层颜色
*/
@ColorInt
private int mMaskLayerColor;
private Drawable mDrawable;
private Bitmap mSrcBitmap;
private Bitmap mFinallyBitmap;
private Paint mPaint;
private Matrix mMatrix;
private float mLastNoShowDistance = 0F; //最后一张图展示出了多少
public SrcScrollFrameLayout(@NonNull Context context) {
this(context, null, 0);
}
public SrcScrollFrameLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
this(context, attrs, 0);
}
public SrcScrollFrameLayout(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
TypedArray array = context.getTheme().obtainStyledAttributes(attrs, R.styleable.SrcScrollFrameLayout, defStyleAttr, 0);
int speed = array.getInteger(R.styleable.SrcScrollFrameLayout_speed, 3);
mScrollOrientation = array.getInteger(R.styleable.SrcScrollFrameLayout_scrollOrientation, 0);
mIntervalIncreaseDistance = speed * mIntervalIncreaseDistance;
mDrawable = array.getDrawable(R.styleable.SrcScrollFrameLayout_src);
mIsScroll = array.getBoolean(R.styleable.SrcScrollFrameLayout_isScroll, true);
mMaskLayerColor = array.getColor(R.styleable.SrcScrollFrameLayout_maskLayerColor, Color.TRANSPARENT);
array.recycle();
setWillNotDraw(false);
mPaint = new Paint();
mMatrix = new Matrix();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
if (mDrawable == null || !(mDrawable instanceof BitmapDrawable)) {
return;
}
if (getVisibility() == GONE) {
return;
}
if (w == 0 || h == 0) {
return;
}
if (mSrcBitmap == null) {
Bitmap bitmap = ((BitmapDrawable) mDrawable).getBitmap();
//调整色彩模式进行质量压缩
Bitmap compressBitmap = bitmap.copy(Bitmap.Config.RGB_565, true);
//缩放 Bitmap
mSrcBitmap = scaleBitmap(compressBitmap);
//计算至少需要几个 bitmap 才能填满当前 view
mBitmapCount = scrollOrientationIsVertical() ?
getMeasuredHeight() / mSrcBitmap.getHeight() + 1
:
getMeasuredWidth() / mSrcBitmap.getWidth() + 1;
if (!compressBitmap.isRecycled()) {
compressBitmap.isRecycled();
System.gc();
}
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mSrcBitmap == null) {
return;
}
int length = scrollOrientationIsVertical() ? mSrcBitmap.getHeight() : mSrcBitmap.getWidth();
if (length + mPanDistance != 0) {
//第一张图片未完全滚出屏幕
mMatrix.reset();
if (scrollOrientationIsVertical()) {
mMatrix.postTranslate(0, mPanDistance);
} else {
mMatrix.postTranslate(mPanDistance, 0);
}
canvas.drawBitmap(mSrcBitmap, mMatrix, mPaint);
}
if (length + mPanDistance < (scrollOrientationIsVertical() ? getMeasuredHeight() : getMeasuredWidth())) {
//用于补充留白的图片出现在屏幕
drawOver(canvas);
}
//绘制遮罩层
if (mMaskLayerColor != Color.TRANSPARENT) {
canvas.drawColor(mMaskLayerColor);
}
//延时重绘实现滚动效果
if (mIsScroll) {
getHandler().postDelayed(mRedrawRunnable, DEFAULT_DRAW_INTERVALS_TIME);
}
}
private void drawOver(Canvas canvas) {
boolean needToLast = false;
if (mIsToDestination && mLastNoShowDistance <= 0) {
needToLast = true;
}
for (int i = 0; i < mBitmapCount; i++) {
mMatrix.reset();
//如果需要结尾，则显示区域为当前尾部未展示完的区域大小+结尾图大小
if (i == mBitmapCount - 1 && needToLast) {
if (scrollOrientationIsVertical()) {
mMatrix.postTranslate(0, getMeasuredHeight() + mLastNoShowDistance);
} else {
mMatrix.postTranslate(getMeasuredWidth() + mLastNoShowDistance, 0);
}
canvas.drawBitmap(mFinallyBitmap, mMatrix, mPaint);
} else {
int length = scrollOrientationIsVertical() ? mSrcBitmap.getHeight() : mSrcBitmap.getWidth();
if (scrollOrientationIsVertical()) {
mMatrix.postTranslate(0, (i + 1) * length + mPanDistance);
} else {
mMatrix.postTranslate((i + 1) * length + mPanDistance, 0);
}
canvas.drawBitmap(mSrcBitmap, mMatrix, mPaint);
}
}
}
/**
* + * 重绘
* +
*/
private Runnable mRedrawRunnable = new Runnable() {
@Override
public void run() {
int length = scrollOrientationIsVertical() ? mSrcBitmap.getHeight() : mSrcBitmap.getWidth();
if (length + mPanDistance <= 0) {
//第一张已完全滚出屏幕，重置平移距离
mPanDistance = 0;
}
mPanDistance = mPanDistance - mIntervalIncreaseDistance;
if (mIsToDestination) {
mLastNoShowDistance -= mIntervalIncreaseDistance;
int stopDistance = scrollOrientationIsVertical() ? -mFinallyBitmap.getHeight() : -mFinallyBitmap.getWidth();
float offset = mLastNoShowDistance - stopDistance;
//避免最后的位置停不到最后，会逐渐减速，直到为1
if (offset < mIntervalIncreaseDistance * 2 && offset > mIntervalIncreaseDistance && mIntervalIncreaseDistance > 1) {
mIntervalIncreaseDistance = 1;
}
if (mLastNoShowDistance <= stopDistance) {
stopScroll();
}
}
invalidate();
}
};
/**
* + * 开始滚动
* +
*/
public void startScroll() {
if (mIsScroll) {
return;
}
mIsScroll = true;
getHandler().postDelayed(mRedrawRunnable, DEFAULT_DRAW_INTERVALS_TIME);
}
/**
* + * 停止滚动
* +
*/
public void stopScroll() {
if (!mIsScroll) {
return;
}
mIsScroll = false;
if (mRedrawRunnable != null && getHandler() != null) {
getHandler().removeCallbacks(mRedrawRunnable);
}
}
//设置结尾图，并且结束滚动
public void toDestination(Bitmap finallyBitmap) {
mIsToDestination = true;
Bitmap compressFBitmap;
if (finallyBitmap.getConfig() != Bitmap.Config.RGB_565) {
if (finallyBitmap.isMutable()) {
finallyBitmap.setConfig(Bitmap.Config.RGB_565);
compressFBitmap = finallyBitmap;
} else {
compressFBitmap = finallyBitmap.copy(Bitmap.Config.RGB_565, true);
}
} else {
compressFBitmap = finallyBitmap;
}
mFinallyBitmap = scaleBitmap(compressFBitmap);
//计算当前还需要滚动多少距离
mLastNoShowDistance = mBitmapCount * mSrcBitmap.getWidth() - (scrollOrientationIsVertical() ? getMeasuredHeight() : getMeasuredWidth()) + mPanDistance;
}
/**
* 设置背景图 bitmap
* 通过该方法设置的背景图，当 屏幕翻转/暗黑模式切换 等涉及到 activity 重构的情况出现时，需要在 activity 重构后重新设置背景图
*/
public void setSrcBitmap(Bitmap srcBitmap) {
boolean oldScrollStatus = mIsScroll;
if (oldScrollStatus) {
stopScroll();
}
Bitmap compressBitmap;
if (srcBitmap.getConfig() != Bitmap.Config.RGB_565) {
if (srcBitmap.isMutable()) {
srcBitmap.setConfig(Bitmap.Config.RGB_565);
compressBitmap = srcBitmap;
} else {
compressBitmap = srcBitmap.copy(Bitmap.Config.RGB_565, true);
}
} else {
compressBitmap = srcBitmap;
}
//按当前View宽度比例缩放 Bitmap
mSrcBitmap = scaleBitmap(compressBitmap);
//计算至少需要几个 bitmap 才能填满当前 view
mBitmapCount = scrollOrientationIsVertical() ?
getMeasuredHeight() / mSrcBitmap.getHeight() + 1
:
getMeasuredWidth() / mSrcBitmap.getWidth() + 1;
if (!srcBitmap.isRecycled()) {
srcBitmap.isRecycled();
System.gc();
}
if (!compressBitmap.isRecycled()) {
compressBitmap.isRecycled();
System.gc();
}
if (oldScrollStatus) {
startScroll();
}
}
private boolean scrollOrientationIsVertical() {
return mScrollOrientation == 0;
}
public void changeScrollOrientation() {
mPanDistance = 0;
mScrollOrientation = scrollOrientationIsVertical() ? 1 : 0;
if (mSrcBitmap != null) {
if (mDrawable != null && (mDrawable instanceof BitmapDrawable)) {
Bitmap bitmap = ((BitmapDrawable) mDrawable).getBitmap();
if (!bitmap.isRecycled()) {
setSrcBitmap(bitmap);
return;
}
}
setSrcBitmap(mSrcBitmap);
}
}
/**
* 缩放Bitmap
*/
private Bitmap scaleBitmap(Bitmap originBitmap) {
int width = originBitmap.getWidth();
int height = originBitmap.getHeight();
int newHeight;
int newWidth;
if (scrollOrientationIsVertical()) {
newWidth = getMeasuredWidth();
newHeight = newWidth * height / width;
} else {
newHeight = getMeasuredHeight();
newWidth = newHeight * width / height;
}
return Bitmap.createScaledBitmap(originBitmap, newWidth, newHeight, true);
}
}
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